Hot links

- Do not specify layout qualifier for vertex attributes
- Bind attribute locations before linking programs
- Delete gl programs when linking fails

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

@@ -81,7 +81,7 @@ public class IndirectPrograms extends AbstractPrograms {
 						.withComponent(IndirectComponent::create)
 						.withResource(InstanceType::cullShader)
 						.withResource(CULL_SHADER_MAIN))
-				.then((key, program) -> program.setUniformBlockBinding("_FlwFrameUniforms", 0))
+				.postLink((key, program) -> program.setUniformBlockBinding("_FlwFrameUniforms", 0))
 				.harness("culling", sources);
 	}
 

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

@@ -50,7 +50,14 @@ public class PipelineCompiler {
 						.withResource(key -> key.contextShader()
 								.fragmentShader())
 						.withResource(pipeline.fragmentMain()))
-				.then((key, program) -> {
+				.preLink((key, program) -> {
+					program.bindAttribLocation("_flw_a_pos", 0);
+					program.bindAttribLocation("_flw_a_color", 1);
+					program.bindAttribLocation("_flw_a_texCoord", 2);
+					program.bindAttribLocation("_flw_a_overlay_light", 3);
+					program.bindAttribLocation("_flw_a_normal", 4);
+				})
+				.postLink((key, program) -> {
 					program.setUniformBlockBinding("_FlwFrameUniforms", 0);
 					program.setUniformBlockBinding("_FlwFogUniforms", 1);
 

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

@@ -42,7 +42,10 @@ public class Compile<K> {
 
 	public static class ProgramStitcher<K> implements CompilationHarness.KeyCompiler<K> {
 		private final Map<ShaderType, ShaderCompiler<K>> compilers = new EnumMap<>(ShaderType.class);
-		private BiConsumer<K, GlProgram> onLink = (k, p) -> {
+		private BiConsumer<K, GlProgram> postLink = (k, p) -> {
+
+		};
+		private BiConsumer<K, GlProgram> preLink = (k, p) -> {
 		};
 
 		public CompilationHarness<K> harness(String marker, ShaderSources sources) {
@@ -57,8 +60,13 @@ public class Compile<K> {
 			return this;
 		}
 
-		public ProgramStitcher<K> then(BiConsumer<K, GlProgram> onLink) {
+		public ProgramStitcher<K> postLink(BiConsumer<K, GlProgram> postLink) {
-			this.onLink = onLink;
+			this.postLink = postLink;
+			return this;
+		}
+
+		public ProgramStitcher<K> preLink(BiConsumer<K, GlProgram> preLink) {
+			this.preLink = preLink;
 			return this;
 		}
 
@@ -84,10 +92,10 @@ public class Compile<K> {
 				return null;
 			}
 
-			var out = programLinker.link(shaders);
+			var out = programLinker.link(shaders, p -> preLink.accept(key, p));
 
 			if (out != null) {
-				onLink.accept(key, out);
+				postLink.accept(key, out);
 			}
 
 			return out;

src/main/java/com/jozufozu/flywheel/backend/compile/core/ProgramLinker.java

@@ -9,6 +9,7 @@ import static org.lwjgl.opengl.GL20.glGetProgrami;
 import static org.lwjgl.opengl.GL20.glLinkProgram;
 
 import java.util.List;
+import java.util.function.Consumer;
 
 import org.jetbrains.annotations.Nullable;
 
@@ -23,26 +24,30 @@ public class ProgramLinker {
 	}
 
 	@Nullable
-	public GlProgram link(List<GlShader> shaders) {
+	public GlProgram link(List<GlShader> shaders, Consumer<GlProgram> preLink) {
 		// this probably doesn't need caching
-		var linkResult = linkInternal(shaders);
+		var linkResult = linkInternal(shaders, preLink);
 		stats.linkResult(linkResult);
 		return linkResult.unwrap();
 	}
 
-	private LinkResult linkInternal(List<GlShader> shaders) {
+	private LinkResult linkInternal(List<GlShader> shaders, Consumer<GlProgram> preLink) {
 		int handle = glCreateProgram();
+		var out = new GlProgram(handle);
 
 		for (GlShader shader : shaders) {
 			glAttachShader(handle, shader.handle());
 		}
 
+		preLink.accept(out);
+
 		glLinkProgram(handle);
 		String log = glGetProgramInfoLog(handle);
 
 		if (linkSuccessful(handle)) {
-			return LinkResult.success(new GlProgram(handle), log);
+			return LinkResult.success(out, log);
 		} else {
+			out.delete();
 			return LinkResult.failure(log);
 		}
 	}

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

@@ -1,5 +1,6 @@
 package com.jozufozu.flywheel.backend.gl.shader;
 
+import static org.lwjgl.opengl.GL20.glBindAttribLocation;
 import static org.lwjgl.opengl.GL20.glDeleteProgram;
 import static org.lwjgl.opengl.GL20.glGetUniformLocation;
 import static org.lwjgl.opengl.GL20.glUniform1f;
@@ -170,6 +171,10 @@ public class GlProgram extends GlObject implements Shader {
 		glUniformBlockBinding(handle(), index, binding);
 	}
 
+	public void bindAttribLocation(String attribute, int binding) {
+		glBindAttribLocation(handle(), binding, attribute);
+	}
+
 	@Override
 	protected void deleteInternal(int handle) {
 		glDeleteProgram(handle);

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

@@ -1,8 +1,8 @@
-layout(location = 0) in vec3 _flw_a_pos;
+in vec3 _flw_a_pos;
-layout(location = 1) in vec4 _flw_a_color;
+in vec4 _flw_a_color;
-layout(location = 2) in vec2 _flw_a_texCoord;
+in vec2 _flw_a_texCoord;
-layout(location = 3) in ivec4 _flw_a_overlay_light;
+in ivec4 _flw_a_overlay_light;
-layout(location = 4) in vec3 _flw_a_normal;
+in vec3 _flw_a_normal;
 
 void _flw_layoutVertex() {
     flw_vertexPos = vec4(_flw_a_pos, 1.0);