A shady API

- Remove storage qualifiers and compile guards from api sources.
- Replace api sources with empty stubs by poisoning the ShaderSources
  cache.
- Pipelines redefine the shader api and are inserted at the top of a
  compilation.
- Declare shader api methods in api sources.
- Fix crash in ErrorBuilder#pointAtLine

src/main/java/com/jozufozu/flywheel/backend/compile/CompilationHarness.java

@@ -59,4 +59,28 @@ public class CompilationHarness<K> {
 	public interface KeyCompiler<K> {
 		@Nullable GlProgram compile(K key, SourceLoader loader, ShaderCompiler shaderCompiler, ProgramLinker programLinker);
 	}
+
+	public static class Builder<K> {
+		private final ShaderSources sources;
+		private ImmutableList<K> keys;
+		private KeyCompiler<K> compiler;
+
+		public Builder(ShaderSources sources) {
+			this.sources = sources;
+		}
+
+		public Builder<K> keys(ImmutableList<K> keys) {
+			this.keys = keys;
+			return this;
+		}
+
+		public Builder<K> compiler(KeyCompiler<K> compiler) {
+			this.compiler = compiler;
+			return this;
+		}
+
+		public CompilationHarness<K> build() {
+			return new CompilationHarness<>(sources, keys, compiler);
+		}
+	}
 }

src/main/java/com/jozufozu/flywheel/backend/compile/Compile.java

@@ -19,19 +19,34 @@ import com.jozufozu.flywheel.gl.shader.GlProgram;
 import com.jozufozu.flywheel.gl.shader.GlShader;
 import com.jozufozu.flywheel.gl.shader.ShaderType;
 import com.jozufozu.flywheel.glsl.GLSLVersion;
+import com.jozufozu.flywheel.glsl.ShaderSources;
 import com.jozufozu.flywheel.glsl.SourceComponent;
 
 import net.minecraft.resources.ResourceLocation;
 
-public class Compile {
-	public static <K> ShaderCompilerBuilder<K> shader(GLSLVersion glslVersion, ShaderType shaderType) {
+/**
+ * A typed provider for shader compiler builders.
+ * <br>
+ * This could just be a static utility class, but creating an instance of Compile
+ * and calling the functors on it prevents you from having to specify the key type everywhere.
+ * <br>
+ * Consider {@code Compile.<PipelineKey>shader(...)} vs {@code PIPELINE.shader(...)}
+ *
+ * @param <K> The type of the key used to compile shaders.
+ */
+public class Compile<K> {
+	public ShaderCompilerBuilder<K> shader(GLSLVersion glslVersion, ShaderType shaderType) {
 		return new ShaderCompilerBuilder<>(glslVersion, shaderType);
 	}
 
-	public static <K> ProgramLinkBuilder<K> program() {
+	public ProgramLinkBuilder<K> program() {
 		return new ProgramLinkBuilder<>();
 	}
 
+	public CompilationHarness.Builder<K> harness(ShaderSources sources) {
+		return new CompilationHarness.Builder<>(sources);
+	}
+
 	public static class ProgramLinkBuilder<K> implements CompilationHarness.KeyCompiler<K> {
 		private final Map<ShaderType, ShaderCompilerBuilder<K>> compilers = new EnumMap<>(ShaderType.class);
 		private BiConsumer<K, GlProgram> onLink = (k, p) -> {

src/main/java/com/jozufozu/flywheel/backend/compile/FlwPrograms.java

@@ -1,5 +1,7 @@
 package com.jozufozu.flywheel.backend.compile;
 
+import java.util.List;
+
 import com.google.common.collect.ImmutableList;
 import com.jozufozu.flywheel.Flywheel;
 import com.jozufozu.flywheel.api.context.Context;
@@ -22,7 +24,8 @@ public class FlwPrograms {
 	}
 
 	public static void reload(ResourceManager resourceManager) {
-		var sources = new ShaderSources(resourceManager);
+		var empty = List.of(Flywheel.rl("api/fragment.glsl"), Flywheel.rl("api/vertex.glsl"));
+		var sources = new ShaderSources(resourceManager, empty);
 
 		var preLoadStats = new CompilerStats();
 		var loadChecker = new SourceLoader(sources, preLoadStats);

src/main/java/com/jozufozu/flywheel/backend/compile/IndirectPrograms.java

@@ -22,6 +22,7 @@ import net.minecraft.resources.ResourceLocation;
 
 public class IndirectPrograms {
 	public static IndirectPrograms instance;
+	private static final Compile<InstanceType<?>> CULL = new Compile<>();
 	private final Map<PipelineProgramKey, GlProgram> pipeline;
 	private final Map<InstanceType<?>, GlProgram> culling;
 
@@ -74,16 +75,17 @@ public class IndirectPrograms {
 	}
 
 	private static CompilationHarness<InstanceType<?>> createCullingCompiler(UniformComponent uniformComponent, ShaderSources sources) {
-		return new CompilationHarness<>(sources, createCullingKeys(), Compile.<InstanceType<?>>program()
-				.link(Compile.<InstanceType<?>>shader(GLSLVersion.V460, ShaderType.COMPUTE)
-						.define("FLW_SUBGROUP_SIZE", GlCompat.SUBGROUP_SIZE)
-						.withComponent(uniformComponent)
-						.withComponent(IndirectComponent::create)
-						.withResource(InstanceType::instanceShader)
-						.withResource(Files.INDIRECT_CULL))
-				.then((InstanceType<?> key, GlProgram program) -> {
-					program.setUniformBlockBinding("FLWUniforms", 0);
-				}));
+		return CULL.harness(sources)
+				.keys(createCullingKeys())
+				.compiler(CULL.program()
+						.link(CULL.shader(GLSLVersion.V460, ShaderType.COMPUTE)
+								.define("FLW_SUBGROUP_SIZE", GlCompat.SUBGROUP_SIZE)
+								.withComponent(uniformComponent)
+								.withComponent(IndirectComponent::create)
+								.withResource(Files.INDIRECT_CULL)
+								.withResource(InstanceType::instanceShader))
+						.then((key, program) -> program.setUniformBlockBinding("FLWUniforms", 0)))
+				.build();
 	}
 
 	public GlProgram getIndirectProgram(VertexType vertexType, InstanceType<?> instanceType, Context contextShader) {

src/main/java/com/jozufozu/flywheel/backend/compile/Pipeline.java

@@ -2,12 +2,12 @@ package com.jozufozu.flywheel.backend.compile;
 
 import com.jozufozu.flywheel.api.instance.InstanceType;
 import com.jozufozu.flywheel.api.vertex.VertexType;
-import com.jozufozu.flywheel.backend.compile.Pipeline.InstanceAssembler;
 import com.jozufozu.flywheel.glsl.GLSLVersion;
 import com.jozufozu.flywheel.glsl.SourceComponent;
 
 import net.minecraft.resources.ResourceLocation;
 
+// TODO: move shader api redefinition to a separate file?
 public record Pipeline(GLSLVersion glslVersion, ResourceLocation vertexShader, ResourceLocation fragmentShader, InstanceAssembler assembler) {
 	@FunctionalInterface
 	public interface InstanceAssembler {

src/main/java/com/jozufozu/flywheel/backend/compile/PipelineCompiler.java

@@ -3,36 +3,40 @@ package com.jozufozu.flywheel.backend.compile;
 import com.google.common.collect.ImmutableList;
 import com.jozufozu.flywheel.backend.compile.component.MaterialAdapterComponent;
 import com.jozufozu.flywheel.backend.compile.component.UniformComponent;
-import com.jozufozu.flywheel.gl.shader.GlProgram;
 import com.jozufozu.flywheel.gl.shader.ShaderType;
 import com.jozufozu.flywheel.glsl.ShaderSources;
 
 public class PipelineCompiler {
+	private static final Compile<PipelineProgramKey> PIPELINE = new Compile<>();
+
 	static CompilationHarness<PipelineProgramKey> create(ShaderSources sources, Pipeline pipeline, ImmutableList<PipelineProgramKey> pipelineKeys, UniformComponent uniformComponent, MaterialAdapterComponent vertexMaterialComponent, MaterialAdapterComponent fragmentMaterialComponent) {
-		return new CompilationHarness<>(sources, pipelineKeys, Compile.<PipelineProgramKey>program()
-				.link(Compile.<PipelineProgramKey>shader(pipeline.glslVersion(), ShaderType.VERTEX)
-						.withComponent(uniformComponent)
-						.withComponent(vertexMaterialComponent)
-						.withComponent(key -> pipeline.assembler()
-								.assemble(new Pipeline.InstanceAssemblerContext(key.vertexType(), key.instanceType())))
-						.withResource(key -> key.vertexType()
-								.layoutShader())
-						.withResource(key -> key.instanceType()
-								.instanceShader())
-						.withResource(key -> key.contextShader()
-								.vertexShader())
-						.withResource(pipeline.vertexShader()))
-				.link(Compile.<PipelineProgramKey>shader(pipeline.glslVersion(), ShaderType.FRAGMENT)
-						.enableExtension("GL_ARB_conservative_depth")
-						.withComponent(uniformComponent)
-						.withComponent(fragmentMaterialComponent)
-						.withResource(key -> key.contextShader()
-								.fragmentShader())
-						.withResource(pipeline.fragmentShader()))
-				.then((PipelineProgramKey key, GlProgram program) -> {
-					key.contextShader()
-							.onProgramLink(program);
-					program.setUniformBlockBinding("FLWUniforms", 0);
-				}));
+		return PIPELINE.harness(sources)
+				.keys(pipelineKeys)
+				.compiler(PIPELINE.program()
+						.link(PIPELINE.shader(pipeline.glslVersion(), ShaderType.VERTEX)
+								.withComponent(uniformComponent)
+								.withComponent(key -> pipeline.assembler()
+										.assemble(new Pipeline.InstanceAssemblerContext(key.vertexType(), key.instanceType())))
+								.withResource(pipeline.vertexShader())
+								.withComponent(vertexMaterialComponent)
+								.withResource(key -> key.vertexType()
+										.layoutShader())
+								.withResource(key -> key.instanceType()
+										.instanceShader())
+								.withResource(key -> key.contextShader()
+										.vertexShader()))
+						.link(PIPELINE.shader(pipeline.glslVersion(), ShaderType.FRAGMENT)
+								.enableExtension("GL_ARB_conservative_depth")
+								.withComponent(uniformComponent)
+								.withResource(pipeline.fragmentShader())
+								.withComponent(fragmentMaterialComponent)
+								.withResource(key -> key.contextShader()
+										.fragmentShader()))
+						.then((key, program) -> {
+							key.contextShader()
+									.onProgramLink(program);
+							program.setUniformBlockBinding("FLWUniforms", 0);
+						}))
+				.build();
 	}
 }

src/main/java/com/jozufozu/flywheel/backend/compile/SourceLoader.java

@@ -10,7 +10,7 @@ import net.minecraft.resources.ResourceLocation;
 
 public class SourceLoader {
 
-	public final ShaderSources sources;
+	private final ShaderSources sources;
 	private final CompilerStats stats;
 
 	public SourceLoader(ShaderSources sources, CompilerStats stats) {

src/main/java/com/jozufozu/flywheel/glsl/ShaderSources.java

@@ -35,6 +35,18 @@ public class ShaderSources {
 		this.manager = manager;
 	}
 
+	public ShaderSources(ResourceManager manager, Map<ResourceLocation, LoadResult> preloadCache) {
+		this.manager = manager;
+		cache.putAll(preloadCache);
+	}
+
+	public ShaderSources(ResourceManager manager, List<ResourceLocation> preloadEmpty) {
+		this.manager = manager;
+		for (ResourceLocation rl : preloadEmpty) {
+			cache.put(rl, SourceFile.empty(rl));
+		}
+	}
+
 	@NotNull
 	public LoadResult find(ResourceLocation location) {
 		if (findStack.contains(location)) {

src/main/java/com/jozufozu/flywheel/glsl/SourceFile.java

@@ -67,6 +67,10 @@ public class SourceFile implements SourceComponent {
 		this.finalSource = finalSource;
 	}
 
+	public static LoadResult empty(ResourceLocation name) {
+		return new LoadResult.Success(new SourceFile(name, new SourceLines(name, ""), ImmutableMap.of(), ImmutableMap.of(), ImmutableList.of(), ImmutableMap.of(), ImmutableList.of(), ""));
+	}
+
 	public static LoadResult parse(ShaderSources sourceFinder, ResourceLocation name, String stringSource) {
 		var source = new SourceLines(name, stringSource);
 

src/main/java/com/jozufozu/flywheel/glsl/error/ErrorBuilder.java

@@ -122,7 +122,7 @@ public class ErrorBuilder {
 
 	public ErrorBuilder pointAtLine(SourceLines lines, int spanLine, int ctxLines, int firstCol, int lastCol) {
 		int firstLine = Math.max(0, spanLine - ctxLines);
-		int lastLine = Math.min(lines.count(), spanLine + ctxLines);
+		int lastLine = Math.min(lines.count() - 1, spanLine + ctxLines);
 
 
 		for (int i = firstLine; i <= lastLine; i++) {

src/main/resources/assets/flywheel/flywheel/api/fragment.glsl

@@ -1,22 +1,16 @@
-#ifdef FRAGMENT_SHADER
-in vec4 flw_vertexPos;
-in vec4 flw_vertexColor;
-in vec2 flw_vertexTexCoord;
-flat in ivec2 flw_vertexOverlay;
-in vec2 flw_vertexLight;
-in vec3 flw_vertexNormal;
+/*const*/ vec4 flw_vertexPos;
+/*const*/ vec4 flw_vertexColor;
+/*const*/ vec2 flw_vertexTexCoord;
+/*const*/ ivec2 flw_vertexOverlay;
+/*const*/ vec2 flw_vertexLight;
+/*const*/ vec3 flw_vertexNormal;
 
-in float flw_distance;
+/*const*/ float flw_distance;
 
-in vec4 flw_var0;
-in vec4 flw_var1;
-in vec4 flw_var2;
-in vec4 flw_var3;
-
-flat in uint _flw_materialFragmentID;
-flat in uint _flw_packedMaterialProperties;
-
-//
+/*const*/ vec4 flw_var0;
+/*const*/ vec4 flw_var1;
+/*const*/ vec4 flw_var2;
+/*const*/ vec4 flw_var3;
 
 /*const*/ vec4 flw_sampleColor;
 
@@ -24,13 +18,11 @@ vec4 flw_fragColor;
 ivec2 flw_fragOverlay;
 vec2 flw_fragLight;
 
-/*
- * Must be implemented by materials.
- */
+// To be implemented by material shaders.
 vec4 flw_fogFilter(vec4 color);
-
-/*
- * Must be implemented by materials.
- */
 bool flw_discardPredicate(vec4 finalColor);
-#endif
+void flw_materialFragment();
+
+// To be implemented by the context shader.
+void flw_initFragment();
+void flw_contextFragment();

src/main/resources/assets/flywheel/flywheel/api/vertex.glsl

@@ -1,19 +1,27 @@
-#ifdef VERTEX_SHADER
-uint _flw_materialVertexID;
+vec4 flw_vertexPos;
+vec4 flw_vertexColor;
+vec2 flw_vertexTexCoord;
+ivec2 flw_vertexOverlay;
+vec2 flw_vertexLight;
+vec3 flw_vertexNormal;
 
-out vec4 flw_vertexPos;
-out vec4 flw_vertexColor;
-out vec2 flw_vertexTexCoord;
-flat out ivec2 flw_vertexOverlay;
-out vec2 flw_vertexLight;
-out vec3 flw_vertexNormal;
+float flw_distance;
 
-out float flw_distance;
+vec4 flw_var0;
+vec4 flw_var1;
+vec4 flw_var2;
+vec4 flw_var3;
 
-out vec4 flw_var0;
-out vec4 flw_var1;
-out vec4 flw_var2;
-out vec4 flw_var3;
-flat out uint _flw_materialFragmentID;
-flat out uint _flw_packedMaterialProperties;
-#endif
+// To be implemented by the layout shader.
+void flw_layoutVertex();
+
+// To be implemented by the instance shader.
+void flw_transformBoundingSphere(in FlwInstance i, inout vec3 center, inout float radius);
+void flw_instanceVertex(FlwInstance i);
+
+// To be implemented by material shaders.
+void flw_materialVertex();
+
+// To be implemented by the context shader.
+void flw_initVertex();
+void flw_contextVertex();

src/main/resources/assets/flywheel/flywheel/instance/oriented.vert

@@ -9,11 +9,9 @@ void flw_transformBoundingSphere(in FlwInstance i, inout vec3 center, inout floa
     center = rotateVertexByQuat(center - pivot, rotation) + pivot + pos;
 }
 
-#ifdef VERTEX_SHADER
 void flw_instanceVertex(in FlwInstance i) {
     flw_vertexPos = vec4(rotateVertexByQuat(flw_vertexPos.xyz - i.pivot, i.rotation) + i.pivot + i.position, 1.0);
     flw_vertexNormal = rotateVertexByQuat(flw_vertexNormal, i.rotation);
     flw_vertexColor = i.color;
     flw_vertexLight = i.light / 15.0;
 }
-#endif

src/main/resources/assets/flywheel/flywheel/instance/transformed.vert

@@ -8,11 +8,9 @@ void flw_transformBoundingSphere(in FlwInstance i, inout vec3 center, inout floa
     radius *= scale;
 }
 
-    #ifdef VERTEX_SHADER
 void flw_instanceVertex(in FlwInstance i) {
     flw_vertexPos = i.pose * flw_vertexPos;
     flw_vertexNormal = i.normal * flw_vertexNormal;
     flw_vertexColor = i.color;
     flw_vertexLight = i.light / 15.0;
 }
-    #endif

src/main/resources/assets/flywheel/flywheel/internal/draw.frag

@@ -1,4 +1,33 @@
-#include "flywheel:api/fragment.glsl"
+in vec4 flw_vertexPos;
+in vec4 flw_vertexColor;
+in vec2 flw_vertexTexCoord;
+flat in ivec2 flw_vertexOverlay;
+in vec2 flw_vertexLight;
+in vec3 flw_vertexNormal;
+
+in float flw_distance;
+
+in vec4 flw_var0;
+in vec4 flw_var1;
+in vec4 flw_var2;
+in vec4 flw_var3;
+
+flat in uint _flw_materialFragmentID;
+flat in uint _flw_packedMaterialProperties;
+
+vec4 flw_sampleColor;
+
+vec4 flw_fragColor;
+ivec2 flw_fragOverlay;
+vec2 flw_fragLight;
+
+vec4 flw_fogFilter(vec4 color);
+
+bool flw_discardPredicate(vec4 finalColor);
+
+void flw_initFragment();
+void flw_materialFragment();
+void flw_contextFragment();
 
 void main() {
     flw_initFragment();

src/main/resources/assets/flywheel/flywheel/internal/indirect_cull.glsl

@@ -2,6 +2,21 @@ layout(local_size_x = FLW_SUBGROUP_SIZE) in;
 
 #include "flywheel:internal/indirect_draw_command.glsl"
 
+// need to add stubs so the instance shader compiles.
+vec4 flw_vertexPos;
+vec4 flw_vertexColor;
+vec2 flw_vertexTexCoord;
+ivec2 flw_vertexOverlay;
+vec2 flw_vertexLight;
+vec3 flw_vertexNormal;
+float flw_distance;
+vec4 flw_var0;
+vec4 flw_var1;
+vec4 flw_var2;
+vec4 flw_var3;
+
+void flw_transformBoundingSphere(in FlwInstance i, inout vec3 center, inout float radius);
+
 struct Object {
     uint batchID;
     FlwPackedInstance instance;

src/main/resources/assets/flywheel/flywheel/internal/indirect_draw.vert

@@ -1,6 +1,23 @@
-#include "flywheel:api/vertex.glsl"
 #include "flywheel:internal/indirect_draw_command.glsl"
 
+out vec4 flw_vertexPos;
+out vec4 flw_vertexColor;
+out vec2 flw_vertexTexCoord;
+flat out ivec2 flw_vertexOverlay;
+out vec2 flw_vertexLight;
+out vec3 flw_vertexNormal;
+
+out float flw_distance;
+
+out vec4 flw_var0;
+out vec4 flw_var1;
+out vec4 flw_var2;
+out vec4 flw_var3;
+
+uint _flw_materialVertexID;
+flat out uint _flw_materialFragmentID;
+flat out uint _flw_packedMaterialProperties;
+
 struct Object {
     uint batchID;
     FlwPackedInstance instance;
@@ -19,6 +36,14 @@ layout(std430, binding = 2) restrict readonly buffer DrawCommands {
     MeshDrawCommand drawCommands[];
 };
 
+FlwInstance _flw_unpackInstance(FlwPackedInstance i);
+
+void flw_layoutVertex();
+void flw_initVertex();
+void flw_instanceVertex(FlwInstance i);
+void flw_materialVertex();
+void flw_contextVertex();
+
 void main() {
     uint instanceIndex = objectIDs[gl_BaseInstance + gl_InstanceID];
     uint batchID = objects[instanceIndex].batchID;

src/main/resources/assets/flywheel/flywheel/internal/instanced_arrays_draw.vert

@@ -1,7 +1,30 @@
-#include "flywheel:api/vertex.glsl"
+out vec4 flw_vertexPos;
+out vec4 flw_vertexColor;
+out vec2 flw_vertexTexCoord;
+flat out ivec2 flw_vertexOverlay;
+out vec2 flw_vertexLight;
+out vec3 flw_vertexNormal;
+
+out float flw_distance;
+
+out vec4 flw_var0;
+out vec4 flw_var1;
+out vec4 flw_var2;
+out vec4 flw_var3;
+
+uint _flw_materialVertexID;
+flat out uint _flw_materialFragmentID;
+flat out uint _flw_packedMaterialProperties;
+
 
 uniform uvec3 _flw_material_instancing;
 
+void flw_layoutVertex();
+void flw_initVertex();
+void flw_instanceVertex(FlwInstance i);
+void flw_materialVertex();
+void flw_contextVertex();
+
 void main() {
     _flw_materialVertexID = _flw_material_instancing.x;
     _flw_materialFragmentID = _flw_material_instancing.y;