Structless instances

- Instance shaders define their own input variables
 - Input locations are transformed during compilation based on vertex type

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

@@ -1,5 +1,7 @@
 package com.jozufozu.flywheel.core.compile;
 
+import java.util.ArrayList;
+
 import com.google.common.collect.ImmutableList;
 import com.jozufozu.flywheel.api.vertex.VertexType;
 import com.jozufozu.flywheel.backend.gl.GLSLVersion;
@@ -8,9 +10,12 @@ import com.jozufozu.flywheel.backend.gl.shader.ShaderType;
 import com.jozufozu.flywheel.core.shader.StateSnapshot;
 import com.jozufozu.flywheel.core.source.FileIndex;
 import com.jozufozu.flywheel.core.source.FileResolution;
+import com.jozufozu.flywheel.core.source.ShaderField;
 import com.jozufozu.flywheel.core.source.SourceFile;
 import com.jozufozu.flywheel.core.source.parse.ShaderStruct;
 import com.jozufozu.flywheel.core.source.parse.StructField;
+import com.jozufozu.flywheel.core.source.span.Span;
+import com.jozufozu.flywheel.util.Pair;
 
 /**
  * Handles compilation and deletion of vertex shaders.
@@ -43,8 +48,21 @@ public class VertexCompiler extends Memoizer<VertexCompiler.Context, GlShader> {
 
 		// INSTANCE
 
+		int attributeBaseIndex = key.vertexType.getLayout()
+				.getAttributeCount();
+
 		var instanceShader = key.instanceShader;
-		instanceShader.generateFinalSource(index, finalSource);
+		var replacements = new ArrayList<Pair<Span, String>>();
+		for (ShaderField field : instanceShader.fields.values()) {
+			if (field.decoration != ShaderField.Decoration.IN) {
+				continue;
+			}
+
+			int location = Integer.parseInt(field.location.get());
+			int newLocation = location + attributeBaseIndex;
+			replacements.add(Pair.of(field.location, Integer.toString(newLocation)));
+		}
+		instanceShader.generateFinalSource(index, finalSource, replacements);
 
 		// MATERIAL
 
@@ -58,11 +76,17 @@ public class VertexCompiler extends Memoizer<VertexCompiler.Context, GlShader> {
 
 		// MAIN
 
-		var instanceStruct = instanceShader.findFunction("flw_instanceVertex")
-				.flatMap(f -> f.getParameterType(0)
-						.findStruct())
-				.orElseThrow();
-		finalSource.append(generateFooter(key.vertexType, instanceStruct));
+		finalSource.append("""
+				void main() {
+					flw_layoutVertex();
+
+					flw_instanceVertex();
+
+					flw_materialVertex();
+
+					flw_contextVertex();
+				}
+				""");
 
 		try {
 			return new GlShader(finalSource.toString(), ShaderType.VERTEX, ImmutableList.of(layoutShader.name, instanceShader.name, materialShader.name, contextShaderSource.name), shaderConstants);
@@ -71,65 +95,6 @@ public class VertexCompiler extends Memoizer<VertexCompiler.Context, GlShader> {
 		}
 	}
 
-	protected String generateFooter(VertexType vertexType, ShaderStruct instance) {
-		ImmutableList<StructField> fields = instance.getFields();
-
-		int attributeBinding = vertexType.getLayout()
-				.getAttributeCount();
-
-		StringBuilder footer = new StringBuilder();
-
-		for (StructField field : fields) {
-			footer.append("layout(location = ")
-					.append(attributeBinding)
-					.append(") in")
-					.append(' ')
-					.append(field.type)
-					.append(' ')
-					.append("_flw_a_i_")
-					.append(field.name)
-					.append(";\n");
-			attributeBinding += CompileUtil.getAttributeCount(field.type);
-		}
-		footer.append('\n');
-
-		footer.append(String.format("""
-						void main() {
-							flw_layoutVertex();
-
-							%s instance;
-							%s
-							flw_instanceVertex(instance);
-
-							flw_materialVertex();
-
-							flw_contextVertex();
-						}
-						""",
-				instance.name,
-				assignFields(instance, "instance.", "_flw_a_i_")
-		));
-
-		return footer.toString();
-	}
-
-	protected static StringBuilder assignFields(ShaderStruct struct, String prefix1, String prefix2) {
-		ImmutableList<StructField> fields = struct.getFields();
-
-		StringBuilder builder = new StringBuilder();
-
-		for (StructField field : fields) {
-			builder.append(prefix1)
-					.append(field.name)
-					.append(" = ")
-					.append(prefix2)
-					.append(field.name)
-					.append(";\n");
-		}
-
-		return builder;
-	}
-
 	@Override
 	protected void _destroy(GlShader value) {
 		value.delete();

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

@@ -0,0 +1,43 @@
+package com.jozufozu.flywheel.core.source;
+
+import java.util.regex.Pattern;
+
+import org.jetbrains.annotations.Nullable;
+
+import com.jozufozu.flywheel.core.source.parse.AbstractShaderElement;
+import com.jozufozu.flywheel.core.source.span.Span;
+
+public class ShaderField extends AbstractShaderElement {
+	public static final Pattern PATTERN = Pattern.compile("layout\\s+\\(location\\s+=\\s+(\\d+)\\)\\s+(in|out)\\s+([\\w\\d]+)\\s+" + "([\\w\\d]+)");
+
+	public final Span location;
+	public final @Nullable Decoration decoration;
+	public final Span type;
+	public final Span name;
+
+	public ShaderField(Span self, Span location, Span inOut, Span type, Span name) {
+		super(self);
+
+		this.location = location;
+		this.decoration = Decoration.fromSpan(inOut);
+		this.type = type;
+		this.name = name;
+	}
+
+	public enum Decoration {
+		IN,
+		OUT,
+		FLAT,
+		;
+
+		@Nullable
+		public static Decoration fromSpan(Span span) {
+			return switch (span.toString()) {
+				case "in" -> IN;
+				case "out" -> OUT;
+				case "flat" -> FLAT;
+				default -> null;
+			};
+		}
+	}
+}

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

@@ -1,6 +1,8 @@
 package com.jozufozu.flywheel.core.source;
 
 import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Comparator;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
@@ -18,6 +20,7 @@ import com.jozufozu.flywheel.core.source.parse.ShaderStruct;
 import com.jozufozu.flywheel.core.source.span.ErrorSpan;
 import com.jozufozu.flywheel.core.source.span.Span;
 import com.jozufozu.flywheel.core.source.span.StringSpan;
+import com.jozufozu.flywheel.util.Pair;
 
 import net.minecraft.resources.ResourceLocation;
 
@@ -34,10 +37,6 @@ public class SourceFile {
 
 	public final ShaderSources parent;
 	public final String source;
-	/**
-	 * Sections of the source that must be trimmed for compilation. Currently, it only contains the spans of imports.
-	 */
-	public final String elided;
 
 	public final SourceLines lines;
 
@@ -55,6 +54,8 @@ public class SourceFile {
 	 * Includes ordered as defined in the source.
 	 */
 	public final ImmutableList<Import> imports;
+	public final ImmutableMap<String, ShaderField> fields;
+	private final List<Span> elisions;
 
 	public SourceFile(ErrorReporter errorReporter, ShaderSources parent, ResourceLocation name, String source) {
 		this.parent = parent;
@@ -63,13 +64,12 @@ public class SourceFile {
 
 		this.lines = new SourceLines(source);
 
-		List<Span> elisions = new ArrayList<>();
+		this.elisions = new ArrayList<>();
 
-		this.imports = parseImports(errorReporter, elisions);
+		this.imports = parseImports(errorReporter);
 		this.functions = parseFunctions();
 		this.structs = parseStructs();
-
-		this.elided = elideSource(source, elisions).toString();
+		this.fields = parseFields();
 	}
 
 	public Span getLineSpan(int line) {
@@ -136,11 +136,15 @@ public class SourceFile {
 	}
 
 	public void generateFinalSource(FileIndex env, StringBuilder source) {
+		generateFinalSource(env, source, Collections.emptyList());
+	}
+
+	public void generateFinalSource(FileIndex env, StringBuilder source, List<Pair<Span, String>> replacements) {
 		for (Import include : imports) {
 			SourceFile file = include.getFile();
 
 			if (file != null && !env.exists(file)) {
-				file.generateFinalSource(env, source);
+				file.generateFinalSource(env, source, replacements);
 			}
 		}
 
@@ -151,7 +155,13 @@ public class SourceFile {
 				.append(" // ")
 				.append(name)
 				.append('\n');
-		source.append(elided);
+
+		var replacementsAndElisions = new ArrayList<>(replacements);
+		for (Span elision : elisions) {
+			replacementsAndElisions.add(Pair.of(elision, ""));
+		}
+
+		source.append(this.replace(replacementsAndElisions));
 		source.append('\n');
 	}
 
@@ -159,18 +169,27 @@ public class SourceFile {
 		return "Source for shader '" + name + "':\n" + lines.printLinesWithNumbers();
 	}
 
-	private static CharSequence elideSource(String source, List<Span> elisions) {
+	private CharSequence replace(List<Pair<Span, String>> replacements) {
 		StringBuilder out = new StringBuilder();
 
 		int lastEnd = 0;
 
-		for (Span elision : elisions) {
-			out.append(source, lastEnd, elision.getStartPos());
+		replacements.sort(Comparator.comparing(Pair::first));
 
-			lastEnd = elision.getEndPos();
+		for (var replacement : replacements) {
+			var loc = replacement.first();
+
+			if (loc.getSourceFile() != this) {
+				continue;
+			}
+
+			out.append(this.source, lastEnd, loc.getStartPos());
+			out.append(replacement.second());
+
+			lastEnd = loc.getEndPos();
 		}
 
-		out.append(source, lastEnd, source.length());
+		out.append(this.source, lastEnd, this.source.length());
 
 		return out;
 	}
@@ -179,7 +198,7 @@ public class SourceFile {
 	 * Scan the source for function definitions and "parse" them into objects that contain properties of the function.
 	 */
 	private ImmutableMap<String, ShaderFunction> parseFunctions() {
-		Matcher matcher = ShaderFunction.functionDeclaration.matcher(source);
+		Matcher matcher = ShaderFunction.PATTERN.matcher(source);
 
 		Map<String, ShaderFunction> functions = new HashMap<>();
 
@@ -229,12 +248,31 @@ public class SourceFile {
 		return structs.build();
 	}
 
+	/**
+	 * Scan the source for function definitions and "parse" them into objects that contain properties of the function.
+	 */
+	private ImmutableMap<String, ShaderField> parseFields() {
+		Matcher matcher = ShaderField.PATTERN.matcher(source);
+
+		ImmutableMap.Builder<String, ShaderField> fields = ImmutableMap.builder();
+		while (matcher.find()) {
+			Span self = Span.fromMatcher(this, matcher);
+			Span location = Span.fromMatcher(this, matcher, 1);
+			Span decoration = Span.fromMatcher(this, matcher, 2);
+			Span type = Span.fromMatcher(this, matcher, 3);
+			Span name = Span.fromMatcher(this, matcher, 4);
+
+			fields.put(location.get(), new ShaderField(self, location, decoration, type, name));
+		}
+
+		return fields.build();
+	}
+
 	/**
 	 * Scan the source for {@code #use "..."} directives.
 	 * Records the contents of the directive into an {@link Import} object, and marks the directive for elision.
-	 * @param elisions
 	 */
-	private ImmutableList<Import> parseImports(ErrorReporter errorReporter, List<Span> elisions) {
+	private ImmutableList<Import> parseImports(ErrorReporter errorReporter) {
 		Matcher uses = Import.PATTERN.matcher(source);
 
 		Set<String> importedFiles = new HashSet<>();
@@ -253,7 +291,7 @@ public class SourceFile {
 				}
 			}
 
-			elisions.add(use); // we have to trim that later
+			this.elisions.add(use); // we have to trim that later
 		}
 
 		return ImmutableList.copyOf(imports);

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

@@ -10,7 +10,7 @@ import com.jozufozu.flywheel.core.source.span.Span;
 public class ShaderFunction extends AbstractShaderElement {
 
 	// https://regexr.com/60n3d
-	public static final Pattern functionDeclaration = Pattern.compile("(\\w+)\\s+(\\w+)\\s*\\(([\\w,\\s]*)\\)\\s*\\{");
+	public static final Pattern PATTERN = Pattern.compile("(\\w+)\\s+(\\w+)\\s*\\(([\\w,\\s]*)\\)\\s*\\{");
 
 	public static final Pattern argument = Pattern.compile("(?:(inout|in|out) )?(\\w+)\\s+(\\w+)");
 	public static final Pattern assignment = Pattern.compile("(\\w+)\\s*=");

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

@@ -3,6 +3,8 @@ package com.jozufozu.flywheel.core.source.span;
 import java.util.Optional;
 import java.util.regex.Matcher;
 
+import org.jetbrains.annotations.NotNull;
+
 import com.jozufozu.flywheel.core.source.SourceFile;
 import com.jozufozu.flywheel.core.source.parse.ShaderFunction;
 import com.jozufozu.flywheel.core.source.parse.ShaderStruct;
@@ -14,7 +16,7 @@ import com.jozufozu.flywheel.core.source.parse.ShaderStruct;
  *     Spans are used for pretty-printing errors.
  * </p>
  */
-public abstract class Span implements CharSequence {
+public abstract class Span implements CharSequence, Comparable<Span> {
 
 	protected final SourceFile in;
 	protected final CharPos start;
@@ -138,4 +140,9 @@ public abstract class Span implements CharSequence {
 		}
 		return in.findFunction(this);
 	}
+
+	@Override
+	public int compareTo(@NotNull Span o) {
+		return Integer.compareUnsigned(getStartPos(), o.getStartPos());
+	}
 }

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

@@ -12,7 +12,7 @@ import com.jozufozu.flywheel.util.ResourceUtil;
 import net.minecraft.resources.ResourceLocation;
 
 public class InstanceShaders {
-	public static final BiConsumer<ErrorReporter, SourceFile> CHECK = SourceChecks.checkFunctionParameterTypeExists("flw_instanceVertex", 1, 0);
+	public static final BiConsumer<ErrorReporter, SourceFile> CHECK = SourceChecks.checkFunctionArity("flw_instanceVertex", 0);
 
 	public static final FileResolution TRANSFORMED = create(ResourceUtil.subPath(Names.TRANSFORMED, ".vert"));
 	public static final FileResolution ORIENTED = create(ResourceUtil.subPath(Names.ORIENTED, ".vert"));

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

@@ -2,17 +2,15 @@
 #use "flywheel:util/light.glsl"
 #use "flywheel:util/quaternion.glsl"
 
-struct Oriented {
-    vec2 light;
-    vec4 color;
-    vec3 pos;
-    vec3 pivot;
-    vec4 rotation;
-};
+layout (location = 0) in vec2 oriented_light;
+layout (location = 1) in vec4 oriented_color;
+layout (location = 2) in vec3 oriented_pos;
+layout (location = 3) in vec3 oriented_pivot;
+layout (location = 4) in vec4 oriented_rotation;
 
-void flw_instanceVertex(Oriented oriented) {
-    flw_vertexPos = vec4(rotateVertexByQuat(flw_vertexPos.xyz - oriented.pivot, oriented.rotation) + oriented.pivot + oriented.pos, 1.0);
-    flw_vertexNormal = rotateVertexByQuat(flw_vertexNormal, oriented.rotation);
-    flw_vertexColor = oriented.color;
-    flw_vertexLight = shiftLight(oriented.light);
+void flw_instanceVertex() {
+    flw_vertexPos = vec4(rotateVertexByQuat(flw_vertexPos.xyz - oriented_pivot, oriented_rotation) + oriented_pivot + oriented_pos, 1.0);
+    flw_vertexNormal = rotateVertexByQuat(flw_vertexNormal, oriented_rotation);
+    flw_vertexColor = oriented_color;
+    flw_vertexLight = shiftLight(oriented_light);
 }

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

@@ -1,16 +1,14 @@
 #use "flywheel:api/vertex.glsl"
 #use "flywheel:util/light.glsl"
 
-struct Instance {
-    vec2 light;
-    vec4 color;
-    mat4 transform;
-    mat3 normalMat;
-};
+layout (location = 0) in vec2 transformed_light;
+layout (location = 1) in vec4 transformed_color;
+layout (location = 2) in mat4 transformed_pose;
+layout (location = 6) in mat3 transformed_normal;
 
-void flw_instanceVertex(Instance instance) {
-    flw_vertexPos = instance.transform * flw_vertexPos;
-    flw_vertexNormal = instance.normalMat * flw_vertexNormal;
-    flw_vertexColor = instance.color;
-    flw_vertexLight = shiftLight(instance.light);
+void flw_instanceVertex() {
+    flw_vertexPos = transformed_pose * flw_vertexPos;
+    flw_vertexNormal = transformed_normal * flw_vertexNormal;
+    flw_vertexColor = transformed_color;
+    flw_vertexLight = shiftLight(transformed_light);
 }