Cleaner compilation

- Check for errors immediately after loading shaders
   - Done through FileResolution
   - Add class SourceChecks to
 - Throw away GatherContextEvent, do everything on client init
 - Unify FileResolution and Resolver, PartialModel style
 - Pass around error reporter to detect errors during load

src/main/java/com/jozufozu/flywheel/Flywheel.java

@@ -76,15 +76,16 @@ public class Flywheel {
 		forgeEventBus.<ReloadRenderersEvent>addListener(ProgramCompiler::invalidateAll);
 		forgeEventBus.addListener(Models::onReload);
 
-		modEventBus.addListener(LayoutShaders::flwInit);
-		modEventBus.addListener(InstanceShaders::flwInit);
-		modEventBus.addListener(MaterialShaders::flwInit);
-		modEventBus.addListener(Contexts::flwInit);
 		modEventBus.addListener(PartialModel::onModelRegistry);
 		modEventBus.addListener(PartialModel::onModelBake);
 		modEventBus.addListener(StitchedSprite::onTextureStitchPre);
 		modEventBus.addListener(StitchedSprite::onTextureStitchPost);
 
+		LayoutShaders.init();
+		InstanceShaders.init();
+		Contexts.init();
+		MaterialShaders.init();
+
 		VanillaInstances.init();
 
 		// https://github.com/Jozufozu/Flywheel/issues/69

src/main/java/com/jozufozu/flywheel/backend/Loader.java

@@ -1,18 +1,17 @@
 package com.jozufozu.flywheel.backend;
 
 import com.jozufozu.flywheel.backend.instancing.InstancedRenderDispatcher;
-import com.jozufozu.flywheel.core.GameStateRegistry;
 import com.jozufozu.flywheel.core.crumbling.CrumblingRenderer;
-import com.jozufozu.flywheel.core.source.Resolver;
+import com.jozufozu.flywheel.core.source.FileResolution;
+import com.jozufozu.flywheel.core.source.ShaderLoadingException;
 import com.jozufozu.flywheel.core.source.ShaderSources;
-import com.jozufozu.flywheel.event.GatherContextEvent;
+import com.jozufozu.flywheel.core.source.error.ErrorReporter;
 
 import net.minecraft.client.Minecraft;
 import net.minecraft.client.multiplayer.ClientLevel;
 import net.minecraft.server.packs.resources.ReloadableResourceManager;
 import net.minecraft.server.packs.resources.ResourceManager;
 import net.minecraft.server.packs.resources.ResourceManagerReloadListener;
-import net.minecraftforge.fml.ModLoader;
 
 /**
  * The main entity for loading shaders.
@@ -22,7 +21,6 @@ import net.minecraftforge.fml.ModLoader;
  * </p>
  */
 public class Loader implements ResourceManagerReloadListener {
-	private boolean firstLoad = true;
 
 	Loader() {
 		// Can be null when running datagenerators due to the unfortunate time we call this
@@ -39,15 +37,15 @@ public class Loader implements ResourceManagerReloadListener {
 	public void onResourceManagerReload(ResourceManager manager) {
 		Backend.refresh();
 
-		GameStateRegistry._clear();
+		var errorReporter = new ErrorReporter();
+		ShaderSources sources = new ShaderSources(errorReporter, manager);
 
-		Resolver.INSTANCE.invalidate();
-		ModLoader.get()
-				.postEvent(new GatherContextEvent(firstLoad));
+		FileResolution.run(errorReporter, sources);
 
-		ShaderSources sources = new ShaderSources(manager);
-
-		Resolver.INSTANCE.run(sources);
+		if (errorReporter.hasErrored()) {
+			errorReporter.dump();
+			throw new ShaderLoadingException("Failed to resolve all source files, see log for details");
+		}
 
 		Backend.LOGGER.info("Loaded all shader sources.");
 
@@ -58,6 +56,5 @@ public class Loader implements ResourceManagerReloadListener {
 			CrumblingRenderer.reset();
 		}
 
-		firstLoad = false;
 	}
 }

src/main/java/com/jozufozu/flywheel/backend/gl/GLSLVersion.java

@@ -1,8 +1,16 @@
 package com.jozufozu.flywheel.backend.gl;
 
 public enum GLSLVersion {
+	V110(110),
+	V120(120),
+	V130(130),
+	V140(140),
 	V150(150),
 	V330(330),
+	V400(400),
+	V410(410),
+	V420(420),
+	V430(430),
 	;
 
 	public final int version;

src/main/java/com/jozufozu/flywheel/backend/gl/shader/GlShader.java

@@ -1,34 +1,37 @@
 package com.jozufozu.flywheel.backend.gl.shader;
 
+import java.io.File;
+import java.io.FileWriter;
+import java.util.List;
+import java.util.Objects;
+import java.util.stream.Collectors;
+
 import org.lwjgl.opengl.GL20;
 
 import com.jozufozu.flywheel.backend.gl.GlObject;
 import com.jozufozu.flywheel.backend.gl.versioned.GlCompat;
+import com.jozufozu.flywheel.core.shader.ShaderConstants;
 import com.jozufozu.flywheel.core.source.ShaderLoadingException;
 
+import net.minecraft.client.Minecraft;
 import net.minecraft.resources.ResourceLocation;
 
 public class GlShader extends GlObject {
 
-	public final ResourceLocation name;
 	public final ShaderType type;
+	private final List<ResourceLocation> parts;
+	private final ShaderConstants constants;
 
-	public GlShader(ResourceLocation name, ShaderType type, String source) {
-		this.name = name;
+	public GlShader(String source, ShaderType type, List<ResourceLocation> parts, ShaderConstants constants) {
+		this.parts = parts;
 		this.type = type;
+		this.constants = constants;
 		int handle = GL20.glCreateShader(type.glEnum);
 
 		GlCompat.safeShaderSource(handle, source);
 		GL20.glCompileShader(handle);
 
-//		File dir = new File(Minecraft.getInstance().gameDirectory, "flywheel_sources");
-//		dir.mkdirs();
-//		File file = new File(dir, name.toString().replaceAll("[:/]", "_"));
-//		try (FileWriter writer = new FileWriter(file)) {
-//			writer.write(source);
-//		} catch (Exception e) {
-//			e.printStackTrace();
-//		}
+		dumpSource(source, type);
 
 //		String log = GL20.glGetShaderInfoLog(handle);
 //
@@ -38,7 +41,7 @@ public class GlShader extends GlObject {
 //		}
 
 		if (GL20.glGetShaderi(handle, GL20.GL_COMPILE_STATUS) != GL20.GL_TRUE) {
-			throw new ShaderLoadingException("Could not compile " + name + ". See log for details.");
+			throw new ShaderLoadingException("Could not compile " + getName() + ". See log for details.");
 		}
 
 		setHandle(handle);
@@ -49,4 +52,22 @@ public class GlShader extends GlObject {
 		GL20.glDeleteShader(handle);
 	}
 
+	public String getName() {
+		return parts.stream()
+				.map(ResourceLocation::toString)
+				.map(s -> s.replaceAll("/", "_")
+						.replaceAll(":", "\\$"))
+				.collect(Collectors.joining(";")) + ';' + Integer.toHexString(constants.hashCode());
+	}
+
+	private void dumpSource(String source, ShaderType type) {
+		File dir = new File(Minecraft.getInstance().gameDirectory, "flywheel_sources");
+		dir.mkdirs();
+		File file = new File(dir, type.getFileName(getName()));
+		try (FileWriter writer = new FileWriter(file)) {
+			writer.write(source);
+		} catch (Exception e) {
+			e.printStackTrace();
+		}
+	}
 }

src/main/java/com/jozufozu/flywheel/backend/gl/shader/ShaderType.java

@@ -3,21 +3,27 @@ package com.jozufozu.flywheel.backend.gl.shader;
 import org.lwjgl.opengl.GL20;
 
 public enum ShaderType {
-	VERTEX("vertex", "VERTEX_SHADER", GL20.GL_VERTEX_SHADER),
-	FRAGMENT("fragment", "FRAGMENT_SHADER", GL20.GL_FRAGMENT_SHADER),
+	VERTEX("vertex", "VERTEX_SHADER", "vert", GL20.GL_VERTEX_SHADER),
+	FRAGMENT("fragment", "FRAGMENT_SHADER", "frag", GL20.GL_FRAGMENT_SHADER),
 	;
 
 	public final String name;
 	public final String define;
+	public final String extension;
 	public final int glEnum;
 
-	ShaderType(String name, String define, int glEnum) {
+	ShaderType(String name, String define, String extension, int glEnum) {
 		this.name = name;
 		this.define = define;
+		this.extension = extension;
 		this.glEnum = glEnum;
 	}
 
 	public String getDefineStatement() {
 		return "#define " + define + "\n";
 	}
+
+	public String getFileName(String baseName) {
+		return baseName + "." + extension;
+	}
 }

src/main/java/com/jozufozu/flywheel/backend/instancing/instancing/InstancingEngine.java

@@ -20,7 +20,6 @@ import com.jozufozu.flywheel.core.CoreShaderInfoMap.CoreShaderInfo;
 import com.jozufozu.flywheel.core.GameStateRegistry;
 import com.jozufozu.flywheel.core.RenderContext;
 import com.jozufozu.flywheel.core.compile.ProgramCompiler;
-import com.jozufozu.flywheel.core.compile.ProgramContext;
 import com.jozufozu.flywheel.core.shader.WorldProgram;
 import com.jozufozu.flywheel.core.vertex.Formats;
 import com.jozufozu.flywheel.util.Textures;
@@ -155,7 +154,7 @@ public class InstancingEngine<P extends WorldProgram> implements Engine {
 			alphaDiscard = 0;
 		}
 
-		P program = context.getProgram(new ProgramContext(Formats.POS_TEX_NORMAL, instanceType.getInstanceShader(), material.getVertexShader(), material.getFragmentShader(), alphaDiscard, coreShaderInfo.fogType(), GameStateRegistry.takeSnapshot()));
+		P program = context.getProgram(new ProgramCompiler.Context(Formats.POS_TEX_NORMAL, instanceType.getInstanceShader(), material.getVertexShader(), material.getFragmentShader(), alphaDiscard, coreShaderInfo.fogType(), GameStateRegistry.takeSnapshot()));
 
 		program.bind();
 		program.uploadUniforms(camX, camY, camZ, viewProjection, level);

src/main/java/com/jozufozu/flywheel/core/Contexts.java

@@ -1,13 +1,13 @@
 package com.jozufozu.flywheel.core;
 
 import com.jozufozu.flywheel.Flywheel;
+import com.jozufozu.flywheel.backend.gl.GLSLVersion;
 import com.jozufozu.flywheel.core.compile.ProgramCompiler;
 import com.jozufozu.flywheel.core.crumbling.CrumblingProgram;
 import com.jozufozu.flywheel.core.shader.NormalDebugStateProvider;
 import com.jozufozu.flywheel.core.shader.WorldProgram;
 import com.jozufozu.flywheel.core.source.FileResolution;
-import com.jozufozu.flywheel.core.source.Resolver;
-import com.jozufozu.flywheel.event.GatherContextEvent;
+import com.jozufozu.flywheel.core.source.SourceChecks;
 import com.jozufozu.flywheel.util.ResourceUtil;
 
 import net.minecraft.resources.ResourceLocation;
@@ -17,16 +17,23 @@ public class Contexts {
 	public static ProgramCompiler<WorldProgram> WORLD;
 	public static ProgramCompiler<CrumblingProgram> CRUMBLING;
 
-	public static void flwInit(GatherContextEvent event) {
+	public static void init() {
 		GameStateRegistry.register(NormalDebugStateProvider.INSTANCE);
 
-		FileResolution worldVertex = Resolver.INSTANCE.get(ResourceUtil.subPath(Names.WORLD, ".vert"));
-		FileResolution worldFragment = Resolver.INSTANCE.get(ResourceUtil.subPath(Names.WORLD, ".frag"));
-		FileResolution crumblingVertex = Resolver.INSTANCE.get(ResourceUtil.subPath(Names.CRUMBLING, ".vert"));
-		FileResolution crumblingFragment = Resolver.INSTANCE.get(ResourceUtil.subPath(Names.CRUMBLING, ".frag"));
+		var checkFrag = SourceChecks.checkFunctionArity("flw_contextFragment", 0);
+		var checkVert = SourceChecks.checkFunctionArity("flw_contextVertex", 0);
 
-		WORLD = ProgramCompiler.create(WorldProgram::new, worldVertex, worldFragment);
-		CRUMBLING = ProgramCompiler.create(CrumblingProgram::new, crumblingVertex, crumblingFragment);
+		var worldVertex = FileResolution.get(ResourceUtil.subPath(Names.WORLD, ".vert"))
+				.validateWith(checkVert);
+		var worldFragment = FileResolution.get(ResourceUtil.subPath(Names.WORLD, ".frag"))
+				.validateWith(checkFrag);
+		var crumblingVertex = FileResolution.get(ResourceUtil.subPath(Names.CRUMBLING, ".vert"))
+				.validateWith(checkVert);
+		var crumblingFragment = FileResolution.get(ResourceUtil.subPath(Names.CRUMBLING, ".frag"))
+				.validateWith(checkFrag);
+
+		WORLD = ProgramCompiler.create(WorldProgram::new, worldVertex, worldFragment, GLSLVersion.V330);
+		CRUMBLING = ProgramCompiler.create(CrumblingProgram::new, crumblingVertex, crumblingFragment, GLSLVersion.V330);
 	}
 
 	public static class Names {

src/main/java/com/jozufozu/flywheel/core/GameStateRegistry.java

@@ -51,8 +51,4 @@ public class GameStateRegistry {
 		}
 		return shaderConstants;
 	}
-
-	public static void _clear() {
-		PROVIDERS.clear();
-	}
 }

src/main/java/com/jozufozu/flywheel/core/compile/CompileUtil.java

@@ -2,9 +2,14 @@ package com.jozufozu.flywheel.core.compile;
 
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+import org.jetbrains.annotations.NotNull;
 
 import com.jozufozu.flywheel.backend.gl.GLSLVersion;
 import com.jozufozu.flywheel.backend.gl.shader.ShaderType;
+import com.jozufozu.flywheel.core.source.SourceFile;
 
 public class CompileUtil {
 
@@ -45,4 +50,11 @@ public class CompileUtil {
 
 		return 1;
 	}
+
+    @NotNull
+    public static String generateDebugName(SourceFile... stages) {
+        return Stream.of(stages)
+                .map(SourceFile::toString)
+                .collect(Collectors.joining(" -> "));
+    }
 }

src/main/java/com/jozufozu/flywheel/core/compile/FragmentCompiler.java

@@ -1,7 +1,6 @@
 package com.jozufozu.flywheel.core.compile;
 
 import java.util.Objects;
-import java.util.Optional;
 
 import com.google.common.collect.ImmutableList;
 import com.jozufozu.flywheel.backend.gl.GLSLVersion;
@@ -12,92 +11,57 @@ import com.jozufozu.flywheel.core.shader.ShaderConstants;
 import com.jozufozu.flywheel.core.shader.StateSnapshot;
 import com.jozufozu.flywheel.core.source.FileIndexImpl;
 import com.jozufozu.flywheel.core.source.FileResolution;
-import com.jozufozu.flywheel.core.source.ShaderLoadingException;
 import com.jozufozu.flywheel.core.source.SourceFile;
-import com.jozufozu.flywheel.core.source.error.ErrorReporter;
-import com.jozufozu.flywheel.core.source.parse.ShaderFunction;
-import com.jozufozu.flywheel.core.source.parse.Variable;
 
+/**
+ * Handles compilation and deletion of fragment shaders.
+ */
 public class FragmentCompiler extends Memoizer<FragmentCompiler.Context, GlShader> {
 	private final FileResolution contextShader;
+	private final GLSLVersion glslVersion;
 
-	public FragmentCompiler(FileResolution contextShader) {
+	public FragmentCompiler(FileResolution contextShader, GLSLVersion glslVersion) {
 		this.contextShader = contextShader;
+		this.glslVersion = glslVersion;
 	}
 
 	@Override
 	protected GlShader _create(Context key) {
 		StringBuilder finalSource = new StringBuilder();
 
-		finalSource.append(CompileUtil.generateHeader(GLSLVersion.V150, ShaderType.FRAGMENT));
+		finalSource.append(CompileUtil.generateHeader(glslVersion, ShaderType.FRAGMENT));
 
-		key.getShaderConstants().writeInto(finalSource);
+		ShaderConstants shaderConstants = key.getShaderConstants();
+		shaderConstants.writeInto(finalSource);
 		finalSource.append('\n');
 
 		FileIndexImpl index = new FileIndexImpl();
 
-		//
+		// MATERIAL
 
 		SourceFile materialShader = key.materialShader;
-
-		Optional<ShaderFunction> maybeMaterialFragment = materialShader.findFunction("flw_materialFragment");
-
-		if (maybeMaterialFragment.isEmpty()) {
-			ErrorReporter.generateMissingFunction(materialShader, "flw_materialFragment", "\"flw_materialFragment\" function not defined");
-			throw new ShaderLoadingException();
-		}
-
-		ShaderFunction materialFragment = maybeMaterialFragment.get();
-		ImmutableList<Variable> params = materialFragment.getParameters();
-
-		if (params.size() != 0) {
-			ErrorReporter.generateSpanError(materialFragment.getArgs(), "\"flw_materialFragment\" function must not have any arguments");
-			throw new ShaderLoadingException();
-		}
-
 		materialShader.generateFinalSource(index, finalSource);
 
-		//
+		// CONTEXT
 
 		SourceFile contextShaderSource = contextShader.getFile();
-
-		Optional<ShaderFunction> maybeContextFragment = contextShaderSource.findFunction("flw_contextFragment");
-
-		if (maybeContextFragment.isEmpty()) {
-			ErrorReporter.generateMissingFunction(contextShaderSource, "flw_contextFragment", "\"flw_contextFragment\" function not defined");
-			throw new ShaderLoadingException();
-		}
-
-		ShaderFunction contextFragment = maybeContextFragment.get();
-		params = contextFragment.getParameters();
-
-		if (params.size() != 0) {
-			ErrorReporter.generateSpanError(contextFragment.getArgs(), "\"flw_contextFragment\" function must not have any arguments");
-			throw new ShaderLoadingException();
-		}
-
 		contextShaderSource.generateFinalSource(index, finalSource);
 
-		//
+		// MAIN
 
 		finalSource.append(generateFooter());
 
-		return new GlShader(contextShader.getFile().name, ShaderType.FRAGMENT, finalSource.toString());
+		return new GlShader(finalSource.toString(), ShaderType.FRAGMENT, ImmutableList.of(materialShader.name, contextShaderSource.name), shaderConstants);
 	}
 
 	protected String generateFooter() {
-		StringBuilder footer = new StringBuilder();
-
-		footer.append("""
+		return """
 				void main() {
 					flw_materialFragment();
 
 				    flw_contextFragment();
 				}
-				"""
-		);
-
-		return footer.toString();
+				""";
 	}
 
 	@Override
@@ -107,34 +71,12 @@ public class FragmentCompiler extends Memoizer<FragmentCompiler.Context, GlShade
 
 	/**
 	 * Represents the conditions under which a shader is compiled.
+	 * @param materialShader The fragment material shader source.
+	 * @param alphaDiscard Alpha threshold below which fragments are discarded.
+	 * @param fogType Which type of fog should be applied.
+	 * @param ctx The shader constants to apply.
 	 */
-	public static final class Context {
-		/**
-		 * The fragment material shader source.
-		 */
-		private final SourceFile materialShader;
-
-		/**
-		 * Alpha threshold below which fragments are discarded.
-		 */
-		private final float alphaDiscard;
-
-		/**
-		 * Which type of fog should be applied.
-		 */
-		private final FogType fogType;
-
-		/**
-		 * The shader constants to apply.
-		 */
-		private final StateSnapshot ctx;
-
-		public Context(SourceFile materialShader, float alphaDiscard, FogType fogType, StateSnapshot ctx) {
-			this.materialShader = materialShader;
-			this.alphaDiscard = alphaDiscard;
-			this.fogType = fogType;
-			this.ctx = ctx;
-		}
+	public record Context(SourceFile materialShader, float alphaDiscard, FogType fogType, StateSnapshot ctx) {
 
 		public ShaderConstants getShaderConstants() {
 			ShaderConstants shaderConstants = ctx.getShaderConstants();
@@ -146,23 +88,5 @@ public class FragmentCompiler extends Memoizer<FragmentCompiler.Context, GlShade
 
 			return shaderConstants;
 		}
-
-		@Override
-		public boolean equals(Object obj) {
-			if (obj == this) return true;
-			if (obj == null || obj.getClass() != this.getClass()) return false;
-			var that = (Context) obj;
-			return materialShader == that.materialShader && Objects.equals(this.ctx, that.ctx) && Float.floatToIntBits(this.alphaDiscard) == Float.floatToIntBits(that.alphaDiscard) && fogType == that.fogType;
-		}
-
-		@Override
-		public int hashCode() {
-			return Objects.hash(materialShader, alphaDiscard, fogType, ctx);
-		}
-
-		@Override
-		public String toString() {
-			return "Context[" + "materialShader=" + materialShader + ", " + "alphaDiscard=" + alphaDiscard + ", " + "fogType=" + fogType + ", " + "ctx=" + ctx + ']';
-		}
 	}
 }

src/main/java/com/jozufozu/flywheel/core/compile/ProgramAssembler.java

@@ -21,8 +21,6 @@ public class ProgramAssembler {
 	public final int program;
 	private final ResourceLocation name;
 
-	private final List<GlShader> shaders = new ObjectArrayList<>();
-
 	public ProgramAssembler(ResourceLocation name) {
 		this.name = name;
 		this.program = glCreateProgram();
@@ -49,13 +47,7 @@ public class ProgramAssembler {
 		return this;
 	}
 
-	public ProgramAssembler deleteLinkedShaders() {
-		shaders.forEach(GlShader::delete);
-		return this;
-	}
-
 	public ProgramAssembler attachShader(GlShader glShader) {
-		shaders.add(glShader);
 		glAttachShader(this.program, glShader.handle());
 		return this;
 	}

src/main/java/com/jozufozu/flywheel/core/compile/ProgramCompiler.java

@@ -3,7 +3,11 @@ package com.jozufozu.flywheel.core.compile;
 import java.util.ArrayList;
 import java.util.List;
 
+import com.jozufozu.flywheel.api.vertex.VertexType;
+import com.jozufozu.flywheel.backend.gl.GLSLVersion;
 import com.jozufozu.flywheel.backend.gl.shader.GlProgram;
+import com.jozufozu.flywheel.core.CoreShaderInfoMap;
+import com.jozufozu.flywheel.core.shader.StateSnapshot;
 import com.jozufozu.flywheel.core.source.FileResolution;
 import com.jozufozu.flywheel.event.ReloadRenderersEvent;
 
@@ -14,8 +18,11 @@ import com.jozufozu.flywheel.event.ReloadRenderersEvent;
  *     This class is responsible for compiling programs on the fly. An instance of this class will keep a cache of
  *     compiled programs, and will only compile a program if it is not already in the cache.
  * </p>
+ * <p>
+ *     A ProgramCompiler is also responsible for deleting programs and shaders on renderer reload.
+ * </p>
  */
-public class ProgramCompiler<P extends GlProgram> extends Memoizer<ProgramContext, P> {
+public class ProgramCompiler<P extends GlProgram> extends Memoizer<ProgramCompiler.Context, P> {
 
 	private static final List<ProgramCompiler<?>> ALL_COMPILERS = new ArrayList<>();
 
@@ -39,8 +46,8 @@ public class ProgramCompiler<P extends GlProgram> extends Memoizer<ProgramContex
 	 * @param <P> The type of program to compile.
 	 * @return A program compiler.
 	 */
-	public static <P extends GlProgram> ProgramCompiler<P> create(GlProgram.Factory<P> factory, FileResolution vertexContextShader, FileResolution fragmentContextShader) {
-		return new ProgramCompiler<>(factory, new VertexCompiler(vertexContextShader), new FragmentCompiler(fragmentContextShader));
+	public static <P extends GlProgram> ProgramCompiler<P> create(GlProgram.Factory<P> factory, FileResolution vertexContextShader, FileResolution fragmentContextShader, GLSLVersion glslVersion) {
+		return new ProgramCompiler<>(factory, new VertexCompiler(vertexContextShader, glslVersion), new FragmentCompiler(fragmentContextShader, glslVersion));
 	}
 
 	/**
@@ -49,7 +56,7 @@ public class ProgramCompiler<P extends GlProgram> extends Memoizer<ProgramContex
 	 * @param ctx The context of compilation.
 	 * @return A compiled GlProgram.
 	 */
-	public P getProgram(ProgramContext ctx) {
+	public P getProgram(Context ctx) {
 		return super.get(ctx);
 	}
 
@@ -61,10 +68,10 @@ public class ProgramCompiler<P extends GlProgram> extends Memoizer<ProgramContex
 	}
 
 	@Override
-	protected P _create(ProgramContext ctx) {
-		return new ProgramAssembler(ctx.instanceShader.getFileLoc())
-				.attachShader(vertexCompiler.get(new VertexCompiler.Context(ctx.vertexType, ctx.instanceShader.getFile(), ctx.vertexMaterialShader.getFile(), ctx.ctx)))
-				.attachShader(fragmentCompiler.get(new FragmentCompiler.Context(ctx.fragmentMaterialShader.getFile(), ctx.alphaDiscard, ctx.fogType, ctx.ctx)))
+	protected P _create(Context ctx) {
+		return new ProgramAssembler(ctx.instanceShader().getFileLoc())
+				.attachShader(vertexCompiler.get(new VertexCompiler.Context(ctx.vertexType(), ctx.instanceShader().getFile(), ctx.vertexMaterialShader().getFile(), ctx.ctx())))
+				.attachShader(fragmentCompiler.get(new FragmentCompiler.Context(ctx.fragmentMaterialShader().getFile(), ctx.alphaDiscard(), ctx.fogType(), ctx.ctx())))
 				.link()
 				.build(this.factory);
 	}
@@ -77,4 +84,19 @@ public class ProgramCompiler<P extends GlProgram> extends Memoizer<ProgramContex
 	public static void invalidateAll(ReloadRenderersEvent ignored) {
 		ALL_COMPILERS.forEach(ProgramCompiler::invalidate);
 	}
+
+	/**
+	 * Represents the entire context of a program's usage.
+	 *
+	 * @param vertexType             The vertexType the program should be adapted for.
+	 * @param instanceShader         The instance shader to use.
+	 * @param vertexMaterialShader   The vertex material shader to use.
+	 * @param fragmentMaterialShader The fragment material shader to use.
+	 * @param alphaDiscard           Alpha threshold below which pixels are discarded.
+	 * @param fogType                Which type of fog should be applied.
+	 * @param ctx                    A snapshot of the game state.
+	 */
+	public record Context(VertexType vertexType, FileResolution instanceShader, FileResolution vertexMaterialShader,
+						  FileResolution fragmentMaterialShader, float alphaDiscard, CoreShaderInfoMap.CoreShaderInfo.FogType fogType, StateSnapshot ctx) {
+	}
 }

src/main/java/com/jozufozu/flywheel/core/compile/ProgramContext.java

@@ -1,59 +0,0 @@
-package com.jozufozu.flywheel.core.compile;
-
-import java.util.Objects;
-
-import com.jozufozu.flywheel.api.vertex.VertexType;
-import com.jozufozu.flywheel.core.CoreShaderInfoMap.CoreShaderInfo.FogType;
-import com.jozufozu.flywheel.core.shader.StateSnapshot;
-import com.jozufozu.flywheel.core.source.FileResolution;
-
-/**
- * Represents the entire context of a program's usage.
- */
-public final class ProgramContext {
-
-	public final VertexType vertexType;
-	public final FileResolution instanceShader;
-	public final FileResolution vertexMaterialShader;
-	public final FileResolution fragmentMaterialShader;
-	public final float alphaDiscard;
-	public final FogType fogType;
-	public final StateSnapshot ctx;
-
-	/**
-	 * @param vertexType              The vertexType the program should be adapted for.
-	 * @param instanceShader          The instance shader to use.
-	 * @param vertexMaterialShader    The vertex material shader to use.
-	 * @param fragmentMaterialShader  The fragment material shader to use.
-	 * @param alphaDiscard            Alpha threshold below which pixels are discarded.
-	 * @param fogType                 Which type of fog should be applied.
-	 * @param ctx                     A snapshot of the game state.
-	 */
-	public ProgramContext(VertexType vertexType, FileResolution instanceShader, FileResolution vertexMaterialShader, FileResolution fragmentMaterialShader, float alphaDiscard, FogType fogType, StateSnapshot ctx) {
-		this.vertexType = vertexType;
-		this.instanceShader = instanceShader;
-		this.vertexMaterialShader = vertexMaterialShader;
-		this.fragmentMaterialShader = fragmentMaterialShader;
-		this.alphaDiscard = alphaDiscard;
-		this.fogType = fogType;
-		this.ctx = ctx;
-	}
-
-	@Override
-	public boolean equals(Object o) {
-		if (this == o) return true;
-		if (o == null || getClass() != o.getClass()) return false;
-		var that = (ProgramContext) o;
-		return vertexType == that.vertexType && instanceShader == that.instanceShader && vertexMaterialShader == that.vertexMaterialShader && fragmentMaterialShader == that.fragmentMaterialShader && ctx.equals(that.ctx) && Float.floatToIntBits(alphaDiscard) == Float.floatToIntBits(that.alphaDiscard) && fogType == that.fogType;
-	}
-
-	@Override
-	public int hashCode() {
-		return Objects.hash(vertexType, instanceShader, vertexMaterialShader, fragmentMaterialShader, alphaDiscard, fogType, ctx);
-	}
-
-	@Override
-	public String toString() {
-		return "ProgramContext{" + "vertexType=" + vertexType + ", instanceShader=" + instanceShader + ", vertexMaterialShader=" + vertexMaterialShader + ", fragmentMaterialShader=" + fragmentMaterialShader + ", alphaDiscard=" + alphaDiscard + ", fogType=" + fogType + ", ctx=" + ctx + '}';
-	}
-}

src/main/java/com/jozufozu/flywheel/core/compile/VertexCompiler.java

@@ -1,8 +1,5 @@
 package com.jozufozu.flywheel.core.compile;
 
-import java.util.Objects;
-import java.util.Optional;
-
 import com.google.common.collect.ImmutableList;
 import com.jozufozu.flywheel.api.vertex.VertexType;
 import com.jozufozu.flywheel.backend.gl.GLSLVersion;
@@ -11,132 +8,63 @@ import com.jozufozu.flywheel.backend.gl.shader.ShaderType;
 import com.jozufozu.flywheel.core.shader.StateSnapshot;
 import com.jozufozu.flywheel.core.source.FileIndexImpl;
 import com.jozufozu.flywheel.core.source.FileResolution;
-import com.jozufozu.flywheel.core.source.ShaderLoadingException;
 import com.jozufozu.flywheel.core.source.SourceFile;
-import com.jozufozu.flywheel.core.source.error.ErrorReporter;
-import com.jozufozu.flywheel.core.source.parse.ShaderFunction;
 import com.jozufozu.flywheel.core.source.parse.ShaderStruct;
 import com.jozufozu.flywheel.core.source.parse.StructField;
-import com.jozufozu.flywheel.core.source.parse.Variable;
-import com.jozufozu.flywheel.core.source.span.Span;
 
+/**
+ * Handles compilation and deletion of vertex shaders.
+ */
 public class VertexCompiler extends Memoizer<VertexCompiler.Context, GlShader> {
 	private final FileResolution contextShader;
+	private final GLSLVersion glslVersion;
 
-	public VertexCompiler(FileResolution contextShader) {
+	public VertexCompiler(FileResolution contextShader, GLSLVersion glslVersion) {
 		this.contextShader = contextShader;
+		this.glslVersion = glslVersion;
 	}
 
 	@Override
 	protected GlShader _create(Context key) {
 		StringBuilder finalSource = new StringBuilder();
 
-		finalSource.append(CompileUtil.generateHeader(GLSLVersion.V330, ShaderType.VERTEX));
+		finalSource.append(CompileUtil.generateHeader(glslVersion, ShaderType.VERTEX));
 
-		key.ctx.getShaderConstants().writeInto(finalSource);
+		var shaderConstants = key.ctx.getShaderConstants();
+		shaderConstants.writeInto(finalSource);
 		finalSource.append('\n');
 
-		FileIndexImpl index = new FileIndexImpl();
+		var index = new FileIndexImpl();
 
-		//
-
-		SourceFile layoutShader = key.vertexType.getLayoutShader().getFile();
-
-		Optional<ShaderFunction> maybeLayoutVertex = layoutShader.findFunction("flw_layoutVertex");
-
-		if (maybeLayoutVertex.isEmpty()) {
-			ErrorReporter.generateMissingFunction(layoutShader, "flw_layoutVertex", "\"flw_layoutVertex\" function not defined");
-			throw new ShaderLoadingException();
-		}
-
-		ShaderFunction layoutVertex = maybeLayoutVertex.get();
-		ImmutableList<Variable> params = layoutVertex.getParameters();
-
-		if (params.size() != 0) {
-			ErrorReporter.generateSpanError(layoutVertex.getArgs(), "\"flw_layoutVertex\" function must not have any arguments");
-			throw new ShaderLoadingException();
-		}
+		// LAYOUT
 
+		var layoutShader = key.vertexType.getLayoutShader().getFile();
 		layoutShader.generateFinalSource(index, finalSource);
 
-		//
-
-		SourceFile instanceShader = key.instanceShader;
-
-		Optional<ShaderFunction> maybeInstanceVertex = instanceShader.findFunction("flw_instanceVertex");
-
-		if (maybeInstanceVertex.isEmpty()) {
-			ErrorReporter.generateMissingFunction(instanceShader, "flw_instanceVertex", "\"flw_instanceVertex\" function not defined");
-			throw new ShaderLoadingException();
-		}
-
-		ShaderFunction instanceVertex = maybeInstanceVertex.get();
-		params = instanceVertex.getParameters();
-
-		if (params.size() != 1) {
-			ErrorReporter.generateSpanError(instanceVertex.getArgs(), "\"flw_instanceVertex\" function must have exactly 1 argument");
-			throw new ShaderLoadingException();
-		}
-
-		Span instanceName = params.get(0).type;
-		Optional<ShaderStruct> maybeInstance = instanceShader.findStruct(instanceName);
-
-		if (maybeInstance.isEmpty()) {
-			ErrorReporter.generateMissingStruct(instanceShader, instanceName, "instance struct not defined");
-			throw new ShaderLoadingException();
-		}
-
-		ShaderStruct instance = maybeInstance.get();
+		// INSTANCE
 
+		var instanceShader = key.instanceShader;
 		instanceShader.generateFinalSource(index, finalSource);
 
-		//
-
-		SourceFile materialShader = key.materialShader;
-
-		Optional<ShaderFunction> maybeMaterialVertex = materialShader.findFunction("flw_materialVertex");
-
-		if (maybeMaterialVertex.isEmpty()) {
-			ErrorReporter.generateMissingFunction(materialShader, "flw_materialVertex", "\"flw_materialVertex\" function not defined");
-			throw new ShaderLoadingException();
-		}
-
-		ShaderFunction materialVertex = maybeMaterialVertex.get();
-		params = materialVertex.getParameters();
-
-		if (params.size() != 0) {
-			ErrorReporter.generateSpanError(materialVertex.getArgs(), "\"flw_materialVertex\" function must not have any arguments");
-			throw new ShaderLoadingException();
-		}
+		// MATERIAL
 
+		var materialShader = key.materialShader;
 		materialShader.generateFinalSource(index, finalSource);
 
-		//
-
-		SourceFile contextShaderSource = contextShader.getFile();
-
-		Optional<ShaderFunction> maybeContextVertex = contextShaderSource.findFunction("flw_contextVertex");
-
-		if (maybeContextVertex.isEmpty()) {
-			ErrorReporter.generateMissingFunction(contextShaderSource, "flw_contextVertex", "\"flw_contextVertex\" function not defined");
-			throw new ShaderLoadingException();
-		}
-
-		ShaderFunction contextVertex = maybeContextVertex.get();
-		params = contextVertex.getParameters();
-
-		if (params.size() != 0) {
-			ErrorReporter.generateSpanError(contextVertex.getArgs(), "\"flw_contextVertex\" function must not have any arguments");
-			throw new ShaderLoadingException();
-		}
+		// CONTEXT
 
+		var contextShaderSource = contextShader.getFile();
 		contextShaderSource.generateFinalSource(index, finalSource);
 
-		//
+		// MAIN
 
-		finalSource.append(generateFooter(key.vertexType, instance));
+		var instanceStruct = instanceShader.findFunction("flw_instanceVertex")
+				.flatMap(f -> f.getParameterType(0)
+						.findStruct())
+				.orElseThrow();
+		finalSource.append(generateFooter(key.vertexType, instanceStruct));
 
-		return new GlShader(instanceShader.name, ShaderType.VERTEX, finalSource.toString());
+		return new GlShader(finalSource.toString(), ShaderType.VERTEX, ImmutableList.of(layoutShader.name, instanceShader.name, materialShader.name, contextShaderSource.name), shaderConstants);
 	}
 
 	protected String generateFooter(VertexType vertexType, ShaderStruct instance) {
@@ -203,45 +131,12 @@ public class VertexCompiler extends Memoizer<VertexCompiler.Context, GlShader> {
 		value.delete();
 	}
 
-	public static class Context {
-		/**
-		 * The vertex type to use.
-		 */
-		private final VertexType vertexType;
-
-		/**
-		 * The instance shader source.
-		 */
-		private final SourceFile instanceShader;
-
-		/**
-		 * The vertex material shader source.
-		 */
-		private final SourceFile materialShader;
-
-		/**
-		 * The shader constants to apply.
-		 */
-		private final StateSnapshot ctx;
-
-		public Context(VertexType vertexType, SourceFile instanceShader, SourceFile materialShader, StateSnapshot ctx) {
-			this.vertexType = vertexType;
-			this.instanceShader = instanceShader;
-			this.materialShader = materialShader;
-			this.ctx = ctx;
-		}
-
-		@Override
-		public boolean equals(Object o) {
-			if (this == o) return true;
-			if (o == null || getClass() != o.getClass()) return false;
-			var that = (Context) o;
-			return vertexType == that.vertexType && instanceShader == that.instanceShader && materialShader == that.materialShader && ctx.equals(that.ctx);
-		}
-
-		@Override
-		public int hashCode() {
-			return Objects.hash(vertexType, instanceShader, materialShader, ctx);
-		}
+	/**
+	 * @param vertexType The vertex type to use.
+	 * @param instanceShader The instance shader source.
+	 * @param materialShader The vertex material shader source.
+	 * @param ctx The shader constants to apply.
+	 */
+	public record Context(VertexType vertexType, SourceFile instanceShader, SourceFile materialShader, StateSnapshot ctx) {
 	}
 }

src/main/java/com/jozufozu/flywheel/core/material/MaterialShaders.java

@@ -2,8 +2,7 @@ package com.jozufozu.flywheel.core.material;
 
 import com.jozufozu.flywheel.Flywheel;
 import com.jozufozu.flywheel.core.source.FileResolution;
-import com.jozufozu.flywheel.core.source.Resolver;
-import com.jozufozu.flywheel.event.GatherContextEvent;
+import com.jozufozu.flywheel.core.source.SourceChecks;
 import com.jozufozu.flywheel.util.ResourceUtil;
 
 import net.minecraft.resources.ResourceLocation;
@@ -13,10 +12,16 @@ public class MaterialShaders {
 	public static FileResolution DEFAULT_FRAGMENT;
 	public static FileResolution SHADED_VERTEX;
 
-	public static void flwInit(GatherContextEvent event) {
-		DEFAULT_VERTEX = Resolver.INSTANCE.get(ResourceUtil.subPath(Names.DEFAULT, ".vert"));
-		DEFAULT_FRAGMENT = Resolver.INSTANCE.get(ResourceUtil.subPath(Names.DEFAULT, ".frag"));
-		SHADED_VERTEX = Resolver.INSTANCE.get(ResourceUtil.subPath(Names.SHADED, ".vert"));
+	public static void init() {
+		var checkVert = SourceChecks.checkFunctionArity("flw_materialVertex", 0);
+		var checkFrag = SourceChecks.checkFunctionArity("flw_materialFragment", 0);
+
+		DEFAULT_VERTEX = FileResolution.get(ResourceUtil.subPath(Names.DEFAULT, ".vert"))
+				.validateWith(checkVert);
+		DEFAULT_FRAGMENT = FileResolution.get(ResourceUtil.subPath(Names.DEFAULT, ".frag"))
+				.validateWith(checkFrag);
+		SHADED_VERTEX = FileResolution.get(ResourceUtil.subPath(Names.SHADED, ".vert"))
+				.validateWith(checkVert);
 	}
 
 	public static class Names {

src/main/java/com/jozufozu/flywheel/core/shader/ShaderConstants.java

@@ -3,6 +3,7 @@ package com.jozufozu.flywheel.core.shader;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 
 /**
  * A class for manipulating a list of {@code #define} directives.
@@ -52,4 +53,17 @@ public class ShaderConstants {
 			acc.append('\n');
 		}
 	}
+
+	@Override
+	public boolean equals(Object o) {
+		if (this == o) return true;
+		if (o == null || getClass() != o.getClass()) return false;
+		ShaderConstants that = (ShaderConstants) o;
+		return Objects.equals(definitions, that.definitions);
+	}
+
+	@Override
+	public int hashCode() {
+		return Objects.hash(definitions);
+	}
 }

src/main/java/com/jozufozu/flywheel/core/source/FileIndexImpl.java

@@ -33,7 +33,7 @@ public class FileIndexImpl implements FileIndex {
 
 	@Override
 	public boolean exists(SourceFile sourceFile) {
-		return files.indexOf(sourceFile) != -1;
+		return files.contains(sourceFile);
 	}
 
 	@Override
@@ -68,10 +68,7 @@ public class FileIndexImpl implements FileIndex {
 	@Nullable
 	private ErrorBuilder parseCompilerError(String line) {
 		try {
-			ErrorBuilder error = ErrorBuilder.fromLogLine(this, line);
-			if (error != null) {
-				return error;
-			}
+			return ErrorBuilder.fromLogLine(this, line);
 		} catch (Exception ignored) {
 		}
 

src/main/java/com/jozufozu/flywheel/core/source/FileResolution.java

@@ -1,11 +1,13 @@
 package com.jozufozu.flywheel.core.source;
 
 import java.util.ArrayList;
+import java.util.HashMap;
 import java.util.List;
-import java.util.function.Consumer;
+import java.util.Map;
+import java.util.function.BiConsumer;
 
-import com.jozufozu.flywheel.backend.Backend;
 import com.jozufozu.flywheel.core.source.error.ErrorBuilder;
+import com.jozufozu.flywheel.core.source.error.ErrorReporter;
 import com.jozufozu.flywheel.core.source.span.Span;
 
 import net.minecraft.resources.ResourceLocation;
@@ -21,17 +23,73 @@ import net.minecraft.resources.ResourceLocation;
  */
 public class FileResolution {
 
+	private static final Map<ResourceLocation, FileResolution> ALL = new HashMap<>();
+	private static boolean tooLate = false;
+
 	/**
-	 * Extra info about where this resolution is required. Includes ProgramSpecs and shader Spans.
+	 * Extra info about where this resolution is required. Includes shader Spans.
 	 */
-	private final List<Consumer<ErrorBuilder>> extraCrashInfoProviders = new ArrayList<>();
+	private final List<Span> neededAt = new ArrayList<>();
+	private final List<BiConsumer<ErrorReporter, SourceFile>> checks = new ArrayList<>();
+
 	private final ResourceLocation fileLoc;
+
 	private SourceFile file;
 
 	FileResolution(ResourceLocation fileLoc) {
 		this.fileLoc = fileLoc;
 	}
 
+	public static FileResolution get(ResourceLocation file) {
+		if (!tooLate) {
+			return ALL.computeIfAbsent(file, FileResolution::new);
+		} else {
+			// Lock the map after resolution has run.
+			FileResolution fileResolution = ALL.get(file);
+
+			// ...so crash immediately if the file isn't found.
+			if (fileResolution == null) {
+				throw new ShaderLoadingException("could not find source for file: " + file);
+			}
+
+			return fileResolution;
+		}
+	}
+
+	/**
+	 * Try and resolve all referenced source files, printing errors if any aren't found.
+	 */
+	public static void run(ErrorReporter errorReporter, SourceFinder sources) {
+		for (FileResolution resolution : ALL.values()) {
+			resolution.resolveAndCheck(errorReporter, sources);
+		}
+
+		tooLate = true;
+	}
+
+	private void resolveAndCheck(ErrorReporter errorReporter, SourceFinder sources) {
+		file = sources.findSource(fileLoc);
+
+		if (file == null) {
+			ErrorBuilder builder = errorReporter.error(String.format("could not find source for file %s", fileLoc));
+			for (Span location : neededAt) {
+				builder.pointAtFile(location.getSourceFile())
+						.pointAt(location, 1);
+			}
+		} else {
+			runChecks(errorReporter);
+		}
+
+		// Let the GC do its thing
+		neededAt.clear();
+	}
+
+	private void runChecks(ErrorReporter errorReporter) {
+		for (var check : checks) {
+			check.accept(errorReporter, file);
+		}
+	}
+
 	public ResourceLocation getFileLoc() {
 		return fileLoc;
 	}
@@ -53,45 +111,13 @@ public class FileResolution {
 	 * @param span A span where this file is referenced.
 	 */
 	public FileResolution addSpan(Span span) {
-		extraCrashInfoProviders.add(builder -> builder.pointAtFile(span.getSourceFile())
-				.pointAt(span, 1));
+		neededAt.add(span);
 		return this;
 	}
 
-	public void addSpec(ResourceLocation name) {
-		extraCrashInfoProviders.add(builder -> builder.extra("needed by spec: " + name + ".json"));
-	}
-
-	/**
-	 * Check to see if this file actually resolves to something.
-	 *
-	 * <p>
-	 *     Called after all files are loaded. If we can't find the file here, it doesn't exist.
-	 * </p>
-	 *
-	 * @return True if this file is resolved.
-	 */
-	boolean resolve(SourceFinder sources) {
-		file = sources.findSource(fileLoc);
-
-		if (file == null) {
-			ErrorBuilder builder = ErrorBuilder.error(String.format("could not find source for file %s", fileLoc));
-			for (Consumer<ErrorBuilder> consumer : extraCrashInfoProviders) {
-				consumer.accept(builder);
-			}
-			Backend.LOGGER.error(builder.build());
-
-			return false;
-		}
-
-		// Let the GC do its thing
-		extraCrashInfoProviders.clear();
-		return true;
-	}
-
-	void invalidate() {
-		extraCrashInfoProviders.clear();
-		file = null;
+	public FileResolution validateWith(BiConsumer<ErrorReporter, SourceFile> check) {
+		checks.add(check);
+		return this;
 	}
 
 	@Override

src/main/java/com/jozufozu/flywheel/core/source/Resolver.java

@@ -1,70 +0,0 @@
-package com.jozufozu.flywheel.core.source;
-
-import java.util.HashMap;
-import java.util.Map;
-
-import net.minecraft.resources.ResourceLocation;
-
-/**
- * Manages deferred file resolution.
- *
- * <p>
- *     Interns all file names in shader sources and program specs, deduplicating the final lookups and allowing for more
- *     dev-friendly error reporting.
- * </p>
- *
- * @see FileResolution
- */
-public class Resolver {
-
-	public static final Resolver INSTANCE = new Resolver();
-
-	private final Map<ResourceLocation, FileResolution> resolutions = new HashMap<>();
-	private boolean hasRun = false;
-
-	public FileResolution get(ResourceLocation file) {
-		if (!hasRun) {
-			return resolutions.computeIfAbsent(file, FileResolution::new);
-		} else {
-			// Lock the map after resolution has run.
-			FileResolution fileResolution = resolutions.get(file);
-
-			// ...so crash immediately if the file isn't found.
-			if (fileResolution == null) {
-				throw new RuntimeException("could not find source for file: " + file);
-			}
-
-			return fileResolution;
-		}
-	}
-
-	/**
-	 * Try and resolve all referenced source files, printing errors if any aren't found.
-	 */
-	public void run(SourceFinder sources) {
-		boolean needsCrash = false;
-		for (FileResolution resolution : resolutions.values()) {
-			if (!resolution.resolve(sources)) {
-				needsCrash = true;
-			}
-		}
-
-		if (needsCrash) {
-			throw new ShaderLoadingException("Failed to resolve all source files, see log for details");
-		}
-
-		hasRun = true;
-	}
-
-	/**
-	 * Invalidates all FileResolutions.
-	 *
-	 * <p>
-	 *     Called on resource reload.
-	 * </p>
-	 */
-	public void invalidate() {
-		resolutions.values().forEach(FileResolution::invalidate);
-		hasRun = false;
-	}
-}

src/main/java/com/jozufozu/flywheel/core/source/ShaderLoadingException.java

@@ -2,9 +2,6 @@ package com.jozufozu.flywheel.core.source;
 
 public class ShaderLoadingException extends RuntimeException {
 
-	public ShaderLoadingException() {
-	}
-
 	public ShaderLoadingException(String message) {
 		super(message);
 	}

src/main/java/com/jozufozu/flywheel/core/source/ShaderSources.java

@@ -9,6 +9,7 @@ import java.util.Map;
 import org.jetbrains.annotations.Nullable;
 
 import com.google.common.collect.Lists;
+import com.jozufozu.flywheel.core.source.error.ErrorReporter;
 import com.jozufozu.flywheel.util.ResourceUtil;
 import com.jozufozu.flywheel.util.StringUtil;
 
@@ -20,14 +21,14 @@ import net.minecraft.server.packs.resources.ResourceManager;
  * The main object for loading and parsing source files.
  */
 public class ShaderSources implements SourceFinder {
-	public static final String SHADER_DIR = "flywheel/shaders/";
+	public static final String SHADER_DIR = "flywheel/";
 	public static final ArrayList<String> EXTENSIONS = Lists.newArrayList(".vert", ".vsh", ".frag", ".fsh", ".glsl");
 
 	private final Map<ResourceLocation, SourceFile> shaderSources = new HashMap<>();
 
 	public final Index index;
 
-	public ShaderSources(ResourceManager manager) {
+	public ShaderSources(ErrorReporter errorReporter, ResourceManager manager) {
 		Collection<ResourceLocation> allShaders = manager.listResources(SHADER_DIR, s -> {
 			for (String ext : EXTENSIONS) {
 				if (s.endsWith(ext)) return true;
@@ -41,7 +42,7 @@ public class ShaderSources implements SourceFinder {
 
 				ResourceLocation name = ResourceUtil.removePrefixUnchecked(location, SHADER_DIR);
 
-				shaderSources.put(name, new SourceFile(this, name, source));
+				shaderSources.put(name, new SourceFile(errorReporter, this, name, source));
 			} catch (IOException e) {
 				//
 			}

src/main/java/com/jozufozu/flywheel/core/source/SourceChecks.java

@@ -0,0 +1,57 @@
+package com.jozufozu.flywheel.core.source;
+
+import java.util.Optional;
+import java.util.function.BiConsumer;
+
+import org.jetbrains.annotations.Nullable;
+
+import com.google.common.collect.ImmutableList;
+import com.jozufozu.flywheel.core.source.error.ErrorReporter;
+import com.jozufozu.flywheel.core.source.parse.ShaderFunction;
+import com.jozufozu.flywheel.core.source.parse.Variable;
+
+public class SourceChecks {
+
+	public static BiConsumer<ErrorReporter, SourceFile> checkFunctionArity(String name, int arity) {
+		return (errorReporter, file) -> checkFunctionArity(errorReporter, file, name, arity);
+	}
+
+	public static BiConsumer<ErrorReporter, SourceFile> checkFunctionParameterTypeExists(String name, int arity, int param) {
+		return (errorReporter, file) -> {
+			var func = checkFunctionArity(errorReporter, file, name, arity);
+
+			if (func == null) {
+				return;
+			}
+
+			var maybeStruct = func.getParameterType(param)
+					.findStruct();
+
+			if (maybeStruct.isEmpty()) {
+				errorReporter.generateMissingStruct(file, func.getParameterType(param), "struct not defined");
+			}
+		};
+	}
+
+	/**
+	 * @return {@code null} if the function doesn't exist, or if the function has the wrong arity.
+	 */
+	@Nullable
+	private static ShaderFunction checkFunctionArity(ErrorReporter errorReporter, SourceFile file, String name, int arity) {
+		Optional<ShaderFunction> maybeFunc = file.findFunction(name);
+
+		if (maybeFunc.isEmpty()) {
+			errorReporter.generateMissingFunction(file, name, "\"" + name + "\" function not defined");
+			return null;
+		}
+
+		ShaderFunction func = maybeFunc.get();
+		ImmutableList<Variable> params = func.getParameters();
+		if (params.size() != arity) {
+			errorReporter.generateFunctionArgumentCountError(name, arity, func.getArgs());
+			return null;
+		}
+
+		return func;
+	}
+}

src/main/java/com/jozufozu/flywheel/core/source/SourceFile.java

@@ -11,9 +11,11 @@ import java.util.regex.Matcher;
 
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
+import com.jozufozu.flywheel.core.source.error.ErrorReporter;
 import com.jozufozu.flywheel.core.source.parse.Import;
 import com.jozufozu.flywheel.core.source.parse.ShaderFunction;
 import com.jozufozu.flywheel.core.source.parse.ShaderStruct;
+import com.jozufozu.flywheel.core.source.parse.Variable;
 import com.jozufozu.flywheel.core.source.span.ErrorSpan;
 import com.jozufozu.flywheel.core.source.span.Span;
 import com.jozufozu.flywheel.core.source.span.StringSpan;
@@ -55,7 +57,7 @@ public class SourceFile {
 	 */
 	public final ImmutableList<Import> imports;
 
-	public SourceFile(ShaderSources parent, ResourceLocation name, String source) {
+	public SourceFile(ErrorReporter errorReporter, ShaderSources parent, ResourceLocation name, String source) {
 		this.parent = parent;
 		this.name = name;
 		this.source = source;
@@ -64,7 +66,7 @@ public class SourceFile {
 
 		List<Span> elisions = new ArrayList<>();
 
-		this.imports = parseImports(elisions);
+		this.imports = parseImports(errorReporter, elisions);
 		this.functions = parseFunctions();
 		this.structs = parseStructs();
 
@@ -233,7 +235,7 @@ public class SourceFile {
 	 * Records the contents of the directive into an {@link Import} object, and marks the directive for elision.
 	 * @param elisions
 	 */
-	private ImmutableList<Import> parseImports(List<Span> elisions) {
+	private ImmutableList<Import> parseImports(ErrorReporter errorReporter, List<Span> elisions) {
 		Matcher uses = Import.PATTERN.matcher(source);
 
 		Set<String> importedFiles = new HashSet<>();
@@ -245,9 +247,9 @@ public class SourceFile {
 
 			String fileName = file.get();
 			if (importedFiles.add(fileName)) {
-				Import import1 = Import.create(Resolver.INSTANCE, use, file);
-				if (import1 != null) {
-					imports.add(import1);
+				var checked = Import.create(errorReporter, use, file);
+				if (checked != null) {
+					imports.add(checked);
 				}
 			}
 
@@ -280,4 +282,15 @@ public class SourceFile {
 	public String toString() {
 		return name.toString();
 	}
+
+	@Override
+	public boolean equals(Object o) {
+		// SourceFiles are only equal by reference.
+		return this == o;
+	}
+
+	@Override
+	public int hashCode() {
+		return System.identityHashCode(this);
+	}
 }

src/main/java/com/jozufozu/flywheel/core/source/error/ErrorReporter.java

@@ -1,5 +1,6 @@
 package com.jozufozu.flywheel.core.source.error;
 
+import java.util.ArrayList;
 import java.util.List;
 import java.util.Optional;
 
@@ -13,58 +14,78 @@ import com.jozufozu.flywheel.util.FlwUtil;
 
 public class ErrorReporter {
 
-	public static void generateSpanError(Span span, String message) {
-		SourceFile file = span.getSourceFile();
+	private final List<ErrorBuilder> reportedErrors = new ArrayList<>();
 
-		String error = ErrorBuilder.error(message)
-				.pointAtFile(file)
-				.pointAt(span, 2)
-				.build();
-
-		Backend.LOGGER.error(error);
-	}
-
-	public static void generateFileError(SourceFile file, String message) {
-		String error = ErrorBuilder.error(message)
-				.pointAtFile(file)
-				.build();
-
-		Backend.LOGGER.error(error);
-	}
-
-	public static void generateMissingStruct(SourceFile file, Span vertexName, CharSequence msg) {
+	public void generateMissingStruct(SourceFile file, Span vertexName, CharSequence msg) {
 		generateMissingStruct(file, vertexName, msg, "");
 	}
 
-	public static void generateMissingStruct(SourceFile file, Span vertexName, CharSequence msg, CharSequence hint) {
+	public void generateMissingStruct(SourceFile file, Span vertexName, CharSequence msg, CharSequence hint) {
 		Optional<Span> span = file.parent.index.getStructDefinitionsMatching(vertexName)
 				.stream()
 				.findFirst()
 				.map(ShaderStruct::getName);
 
-		ErrorBuilder error = ErrorBuilder.error(msg)
+		this.error(msg)
 				.pointAtFile(file)
 				.pointAt(vertexName, 1)
 				.hintIncludeFor(span.orElse(null), hint);
-
-		Backend.LOGGER.error(error.build());
 	}
 
-	public static void generateMissingFunction(SourceFile file, CharSequence functionName, CharSequence msg) {
+	public void generateMissingFunction(SourceFile file, CharSequence functionName, CharSequence msg) {
 		generateMissingFunction(file, functionName, msg, "");
 	}
 
-	public static void generateMissingFunction(SourceFile file, CharSequence functionName, CharSequence msg, CharSequence hint) {
+	public void generateMissingFunction(SourceFile file, CharSequence functionName, CharSequence msg, CharSequence hint) {
 		Optional<Span> span = file.parent.index.getFunctionDefinitionsMatching(functionName)
 				.stream()
 				.findFirst()
 				.map(ShaderFunction::getName);
 
-		ErrorBuilder error = ErrorBuilder.error(msg)
+		this.error(msg)
 				.pointAtFile(file)
 				.hintIncludeFor(span.orElse(null), hint);
+	}
 
-		Backend.LOGGER.error(error.build());
+	public ErrorBuilder generateFunctionArgumentCountError(String name, int requiredArguments, Span span) {
+		var msg = '"' + name + "\" function must ";
+
+		if (requiredArguments == 0) {
+			msg += "not have any arguments";
+		} else {
+			msg += "have exactly " + requiredArguments + " argument" + (requiredArguments == 1 ? "" : "s");
+		}
+
+		return generateSpanError(span, msg);
+	}
+
+	public ErrorBuilder generateSpanError(Span span, String message) {
+		SourceFile file = span.getSourceFile();
+
+		return error(message)
+				.pointAtFile(file)
+				.pointAt(span, 2);
+	}
+
+	public ErrorBuilder generateFileError(SourceFile file, String message) {
+		return error(message)
+				.pointAtFile(file);
+	}
+
+	public ErrorBuilder error(CharSequence msg) {
+		var out = ErrorBuilder.error(msg);
+		reportedErrors.add(out);
+		return out;
+	}
+
+	public boolean hasErrored() {
+		return !reportedErrors.isEmpty();
+	}
+
+	public void dump() {
+		for (var error : reportedErrors) {
+			Backend.LOGGER.error(error.build());
+		}
 	}
 
 	public static void printLines(CharSequence source) {

src/main/java/com/jozufozu/flywheel/core/source/parse/Import.java

@@ -6,7 +6,6 @@ import java.util.regex.Pattern;
 import org.jetbrains.annotations.Nullable;
 
 import com.jozufozu.flywheel.core.source.FileResolution;
-import com.jozufozu.flywheel.core.source.Resolver;
 import com.jozufozu.flywheel.core.source.SourceFile;
 import com.jozufozu.flywheel.core.source.error.ErrorReporter;
 import com.jozufozu.flywheel.core.source.span.Span;
@@ -26,16 +25,16 @@ public class Import extends AbstractShaderElement {
 	}
 
 	@Nullable
-	public static Import create(Resolver resolver, Span self, Span file) {
+	public static Import create(ErrorReporter errorReporter, Span self, Span file) {
 		ResourceLocation fileLocation;
 		try {
 			fileLocation = new ResourceLocation(file.get());
 		} catch (ResourceLocationException e) {
-			ErrorReporter.generateSpanError(file, "malformed source location");
+			errorReporter.generateSpanError(file, "malformed source location");
 			return null;
 		}
 
-		return new Import(self, resolver.get(fileLocation), file);
+		return new Import(self, FileResolution.get(fileLocation), file);
 	}
 
 	public FileResolution getResolution() {

src/main/java/com/jozufozu/flywheel/core/source/parse/ShaderFunction.java

@@ -52,6 +52,10 @@ public class ShaderFunction extends AbstractShaderElement {
 		return name + "(" + String.join(", ", args) + ")";
 	}
 
+	public Span getParameterType(int index) {
+		return parameters.get(index).type;
+	}
+
 	public ImmutableList<Variable> getParameters() {
 		return parameters;
 	}

src/main/java/com/jozufozu/flywheel/core/source/span/Span.java

@@ -1,8 +1,11 @@
 package com.jozufozu.flywheel.core.source.span;
 
+import java.util.Optional;
 import java.util.regex.Matcher;
 
 import com.jozufozu.flywheel.core.source.SourceFile;
+import com.jozufozu.flywheel.core.source.parse.ShaderFunction;
+import com.jozufozu.flywheel.core.source.parse.ShaderStruct;
 
 /**
  * A segment of code in a {@link SourceFile}.
@@ -121,4 +124,18 @@ public abstract class Span implements CharSequence {
 	public static Span fromMatcher(Span superSpan, Matcher m) {
 		return superSpan.subSpan(m.start(), m.end());
 	}
+
+	public Optional<ShaderStruct> findStruct() {
+		if (isErr()) {
+			return Optional.empty();
+		}
+		return in.findStruct(this);
+	}
+
+	public Optional<ShaderFunction> findFunction() {
+		if (isErr()) {
+			return Optional.empty();
+		}
+		return in.findFunction(this);
+	}
 }

src/main/java/com/jozufozu/flywheel/core/structs/InstanceShaders.java

@@ -2,8 +2,7 @@ package com.jozufozu.flywheel.core.structs;
 
 import com.jozufozu.flywheel.Flywheel;
 import com.jozufozu.flywheel.core.source.FileResolution;
-import com.jozufozu.flywheel.core.source.Resolver;
-import com.jozufozu.flywheel.event.GatherContextEvent;
+import com.jozufozu.flywheel.core.source.SourceChecks;
 import com.jozufozu.flywheel.util.ResourceUtil;
 
 import net.minecraft.resources.ResourceLocation;
@@ -12,9 +11,13 @@ public class InstanceShaders {
 	public static FileResolution MODEL;
 	public static FileResolution ORIENTED;
 
-	public static void flwInit(GatherContextEvent event) {
-		MODEL = Resolver.INSTANCE.get(ResourceUtil.subPath(Names.MODEL, ".vert"));
-		ORIENTED = Resolver.INSTANCE.get(ResourceUtil.subPath(Names.ORIENTED, ".vert"));
+	public static void init() {
+		var check = SourceChecks.checkFunctionParameterTypeExists("flw_instanceVertex", 1, 0);
+
+		MODEL = FileResolution.get(ResourceUtil.subPath(Names.MODEL, ".vert"))
+				.validateWith(check);
+		ORIENTED = FileResolution.get(ResourceUtil.subPath(Names.ORIENTED, ".vert"))
+				.validateWith(check);
 	}
 
 	public static class Names {

src/main/java/com/jozufozu/flywheel/core/vertex/LayoutShaders.java

@@ -2,8 +2,7 @@ package com.jozufozu.flywheel.core.vertex;
 
 import com.jozufozu.flywheel.Flywheel;
 import com.jozufozu.flywheel.core.source.FileResolution;
-import com.jozufozu.flywheel.core.source.Resolver;
-import com.jozufozu.flywheel.event.GatherContextEvent;
+import com.jozufozu.flywheel.core.source.SourceChecks;
 import com.jozufozu.flywheel.util.ResourceUtil;
 
 import net.minecraft.resources.ResourceLocation;
@@ -12,9 +11,14 @@ public class LayoutShaders {
 	public static FileResolution BLOCK;
 	public static FileResolution POS_TEX_NORMAL;
 
-	public static void flwInit(GatherContextEvent event) {
-		BLOCK = Resolver.INSTANCE.get(ResourceUtil.subPath(Names.BLOCK, ".vert"));
-		POS_TEX_NORMAL = Resolver.INSTANCE.get(ResourceUtil.subPath(Names.POS_TEX_NORMAL, ".vert"));
+	public static void init() {
+		var check = SourceChecks.checkFunctionArity("flw_layoutVertex", 0);
+
+		BLOCK = FileResolution.get(ResourceUtil.subPath(Names.BLOCK, ".vert"))
+				.validateWith(check);
+
+		POS_TEX_NORMAL = FileResolution.get(ResourceUtil.subPath(Names.POS_TEX_NORMAL, ".vert"))
+				.validateWith(check);
 	}
 
 	public static class Names {

src/main/java/com/jozufozu/flywheel/event/ForgeEvents.java

@@ -6,6 +6,7 @@ import com.jozufozu.flywheel.light.LightUpdater;
 import com.jozufozu.flywheel.util.WorldAttached;
 
 import net.minecraft.client.Minecraft;
+import net.minecraft.client.player.LocalPlayer;
 import net.minecraftforge.api.distmarker.Dist;
 import net.minecraftforge.client.event.RenderGameOverlayEvent;
 import net.minecraftforge.event.TickEvent;
@@ -32,8 +33,10 @@ public class ForgeEvents {
 
 	@SubscribeEvent
 	public static void tickLight(TickEvent.ClientTickEvent e) {
-		if (e.phase == TickEvent.Phase.END && Backend.isGameActive())
-			LightUpdater.get(Minecraft.getInstance().level).tick();
+		if (e.phase == TickEvent.Phase.END && Backend.isGameActive()) {
+			LightUpdater.get(Minecraft.getInstance().level)
+					.tick();
+		}
 	}
 
 }

src/main/java/com/jozufozu/flywheel/event/GatherContextEvent.java

@@ -1,20 +0,0 @@
-package com.jozufozu.flywheel.event;
-
-import net.minecraftforge.eventbus.api.Event;
-import net.minecraftforge.fml.event.IModBusEvent;
-
-public class GatherContextEvent extends Event implements IModBusEvent {
-
-	private final boolean firstLoad;
-
-	public GatherContextEvent(boolean firstLoad) {
-		this.firstLoad = firstLoad;
-	}
-
-	/**
-	 * @return true iff it is the first time the event is fired.
-	 */
-	public boolean isFirstLoad() {
-		return firstLoad;
-	}
-}