Frag shader go brr

- Add flw_vertexDiffuse and flw_fragDiffuse to glsl api.
- Compute/apply diffuse in the fragment shader.
- Move common glsl between instancing/indirect to common.vert/.frag.
- Add a pittance more documentation to api spec.
- Sneak in a block to build.gradle to always download sources/javadoc.

build.gradle

@@ -122,6 +122,14 @@ mixin {
     debug.export = true
 }
 
+idea {
+    // Tell IDEA to always download sources/javadoc artifacts from maven.
+    module {
+        downloadJavadoc = true
+        downloadSources = true
+    }
+}
+
 // Workaround for SpongePowered/MixinGradle#38
 afterEvaluate {
     tasks.configureReobfTaskForReobfJar.mustRunAfter(tasks.compileJava)

docs/shader-api/fragment.glsl

@@ -13,14 +13,19 @@
 
 /*const*/ float flw_distance;
 
+/*const*/ bool flw_vertexDiffuse;
+
+bool flw_fragDiffuse;
 vec4 flw_fragColor;
 ivec2 flw_fragOverlay;
 vec2 flw_fragLight;
 
 // To be implemented by the material fragment shader.
-vec4 flw_fogFilter(vec4 color);
-bool flw_discardPredicate(vec4 finalColor);
 void flw_materialFragment();
+// To be implement by fog shaders.
+vec4 flw_fogFilter(vec4 color);
+// To be implemented by discard shaders.
+bool flw_discardPredicate(vec4 finalColor);
 
 // To be implemented by the context shader.
 void flw_beginFragment();

docs/shader-api/vertex.glsl

@@ -7,12 +7,16 @@ ivec2 flw_vertexOverlay;
 vec2 flw_vertexLight;
 vec3 flw_vertexNormal;
 
+bool flw_vertexDiffuse;
+
 /*const*/ FlwMaterial flw_material;
 
 // 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 the instance cull shader.
+void flw_transformBoundingSphere(in FlwInstance i, inout vec3 center, inout float radius);
+
 // To be implemented by the material vertex shader.
 void flw_materialVertex();
 

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

@@ -0,0 +1,57 @@
+#include "flywheel:internal/packed_material.glsl"
+#include "flywheel:internal/diffuse.glsl"
+
+// optimize discard usage
+#ifdef GL_ARB_conservative_depth
+layout (depth_greater) out float gl_FragDepth;
+#endif
+
+uniform sampler2D _flw_diffuseTex;
+uniform sampler2D _flw_overlayTex;
+uniform sampler2D _flw_lightTex;
+
+flat in uint _flw_vertexDiffuse;
+
+out vec4 _flw_outputColor;
+
+void _flw_main() {
+    flw_sampleColor = texture(_flw_diffuseTex, flw_vertexTexCoord);
+    flw_fragColor = flw_vertexColor * flw_sampleColor;
+    flw_fragOverlay = flw_vertexOverlay;
+    flw_fragLight = flw_vertexLight;
+
+    flw_vertexDiffuse = bool(_flw_vertexDiffuse);
+    flw_fragDiffuse = flw_vertexDiffuse;
+
+    flw_beginFragment();
+    flw_materialFragment();
+    flw_endFragment();
+
+    vec4 color = flw_fragColor;
+
+    if (flw_fragDiffuse) {
+        float diffuseFactor;
+        if (flywheel.constantAmbientLight == 1) {
+            diffuseFactor = diffuseNether(flw_vertexNormal);
+        } else {
+            diffuseFactor = diffuse(flw_vertexNormal);
+        }
+        color.rgb *= diffuseFactor;
+    }
+
+    if (flw_material.useOverlay) {
+        vec4 overlayColor = texelFetch(_flw_overlayTex, flw_fragOverlay, 0);
+        color.rgb = mix(overlayColor.rgb, color.rgb, overlayColor.a);
+    }
+
+    if (flw_material.useLight) {
+        vec4 lightColor = texture(_flw_lightTex, (flw_fragLight * 15.0 + 0.5) / 16.0);
+        color *= lightColor;
+    }
+
+    if (flw_discardPredicate(color)) {
+        discard;
+    }
+
+    _flw_outputColor = flw_fogFilter(color);
+}

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

@@ -0,0 +1,20 @@
+#include "flywheel:internal/fog_distance.glsl"
+
+flat out uint _flw_vertexDiffuse;
+
+void _flw_main(in FlwInstance instance) {
+    flw_vertexDiffuse = flw_material.diffuse;
+
+    _flw_layoutVertex();
+    flw_beginVertex();
+    flw_instanceVertex(instance);
+    flw_materialVertex();
+    flw_endVertex();
+
+    flw_vertexNormal = normalize(flw_vertexNormal);
+
+    _flw_vertexDiffuse = uint(flw_vertexDiffuse);
+
+    flw_distance = fogDistance(flw_vertexPos.xyz, flywheel.cameraPos.xyz, flywheel.fogShape);
+    gl_Position = flywheel.viewProjection * flw_vertexPos;
+}

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

@@ -9,10 +9,13 @@ in vec3 flw_vertexNormal;
 
 in float flw_distance;
 
+bool flw_vertexDiffuse;
+
 vec4 flw_sampleColor;
 
 FlwMaterial flw_material;
 
+bool flw_fragDiffuse;
 vec4 flw_fragColor;
 ivec2 flw_fragOverlay;
 vec2 flw_fragLight;

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

@@ -1,5 +1,6 @@
 #include "flywheel:internal/material.glsl"
 
+// TODO: can we combine some of these internally to use fewer in/out slots?
 out vec4 flw_vertexPos;
 out vec4 flw_vertexColor;
 out vec2 flw_vertexTexCoord;
@@ -9,4 +10,6 @@ out vec3 flw_vertexNormal;
 
 out float flw_distance;
 
+bool flw_vertexDiffuse;
+
 FlwMaterial flw_material;

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

@@ -1,47 +1,11 @@
-#include "flywheel:internal/packed_material.glsl"
+#include "flywheel:internal/common.frag"
-
-// optimize discard usage
-#ifdef GL_ARB_conservative_depth
-layout (depth_greater) out float gl_FragDepth;
-#endif
-
-uniform sampler2D _flw_diffuseTex;
-uniform sampler2D _flw_overlayTex;
-uniform sampler2D _flw_lightTex;
 
 flat in uvec3 _flw_packedMaterial;
 
-out vec4 _flw_outputColor;
-
 void main() {
     _flw_uberMaterialFragmentIndex = _flw_packedMaterial.x;
     _flw_unpackUint2x16(_flw_packedMaterial.y, _flw_uberCutoutIndex, _flw_uberFogIndex);
     _flw_unpackMaterialProperties(_flw_packedMaterial.z, flw_material);
 
-    flw_sampleColor = texture(_flw_diffuseTex, flw_vertexTexCoord);
+    _flw_main();
-    flw_fragColor = flw_vertexColor * flw_sampleColor;
-    flw_fragOverlay = flw_vertexOverlay;
-    flw_fragLight = flw_vertexLight;
-
-    flw_beginFragment();
-    flw_materialFragment();
-    flw_endFragment();
-
-    vec4 color = flw_fragColor;
-
-    if (flw_material.useOverlay) {
-        vec4 overlayColor = texelFetch(_flw_overlayTex, flw_fragOverlay, 0);
-        color.rgb = mix(overlayColor.rgb, color.rgb, overlayColor.a);
-    }
-
-    if (flw_material.useLight) {
-    	vec4 lightColor = texture(_flw_lightTex, (flw_fragLight * 15.0 + 0.5) / 16.0);
-        color *= lightColor;
-    }
-
-    if (flw_discardPredicate(color)) {
-        discard;
-    }
-
-    _flw_outputColor = flw_fogFilter(color);
 }

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

@@ -1,5 +1,4 @@
-#include "flywheel:internal/diffuse.glsl"
+#include "flywheel:internal/common.vert"
-#include "flywheel:internal/fog_distance.glsl"
 #include "flywheel:internal/packed_material.glsl"
 #include "flywheel:internal/indirect/buffers.glsl"
 #include "flywheel:internal/indirect/draw_command.glsl"
@@ -33,24 +32,5 @@ void main() {
     uint objectIndex = objectIndices[gl_BaseInstance + gl_InstanceID];
     FlwInstance instance = _flw_unpackInstance(objects[objectIndex].instance);
 
-    _flw_layoutVertex();
+    _flw_main(instance);
-    flw_beginVertex();
-    flw_instanceVertex(instance);
-    flw_materialVertex();
-    flw_endVertex();
-
-    flw_vertexNormal = normalize(flw_vertexNormal);
-
-    if (flw_material.diffuse) {
-        float diffuseFactor;
-        if (flywheel.constantAmbientLight == 1) {
-            diffuseFactor = diffuseNether(flw_vertexNormal);
-        } else {
-            diffuseFactor = diffuse(flw_vertexNormal);
-        }
-        flw_vertexColor = vec4(flw_vertexColor.rgb * diffuseFactor, flw_vertexColor.a);
-    }
-
-    flw_distance = fogDistance(flw_vertexPos.xyz, flywheel.cameraPos.xyz, flywheel.fogShape);
-    gl_Position = flywheel.viewProjection * flw_vertexPos;
 }

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

@@ -1,47 +1,11 @@
-#include "flywheel:internal/packed_material.glsl"
+#include "flywheel:internal/common.frag"
-
-// optimize discard usage
-#ifdef GL_ARB_conservative_depth
-layout (depth_greater) out float gl_FragDepth;
-#endif
-
-uniform sampler2D _flw_diffuseTex;
-uniform sampler2D _flw_overlayTex;
-uniform sampler2D _flw_lightTex;
 
 uniform uvec4 _flw_packedMaterial;
 
-out vec4 _flw_outputColor;
-
 void main() {
     _flw_uberMaterialFragmentIndex = _flw_packedMaterial.y;
     _flw_unpackUint2x16(_flw_packedMaterial.z, _flw_uberCutoutIndex, _flw_uberFogIndex);
     _flw_unpackMaterialProperties(_flw_packedMaterial.w, flw_material);
 
-    flw_sampleColor = texture(_flw_diffuseTex, flw_vertexTexCoord);
+    _flw_main();
-    flw_fragColor = flw_vertexColor * flw_sampleColor;
-    flw_fragOverlay = flw_vertexOverlay;
-    flw_fragLight = flw_vertexLight;
-
-    flw_beginFragment();
-    flw_materialFragment();
-    flw_endFragment();
-
-    vec4 color = flw_fragColor;
-
-    if (flw_material.useOverlay) {
-        vec4 overlayColor = texelFetch(_flw_overlayTex, flw_fragOverlay, 0);
-        color.rgb = mix(overlayColor.rgb, color.rgb, overlayColor.a);
-    }
-
-    if (flw_material.useLight) {
-        vec4 lightColor = texture(_flw_lightTex, (flw_fragLight * 15.0 + 0.5) / 16.0);
-        color *= lightColor;
-    }
-
-    if (flw_discardPredicate(color)) {
-        discard;
-    }
-
-    _flw_outputColor = flw_fogFilter(color);
 }

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

@@ -1,5 +1,4 @@
-#include "flywheel:internal/diffuse.glsl"
+#include "flywheel:internal/common.vert"
-#include "flywheel:internal/fog_distance.glsl"
 #include "flywheel:internal/packed_material.glsl"
 
 uniform uvec4 _flw_packedMaterial;
@@ -10,24 +9,5 @@ void main() {
 
     FlwInstance instance = _flw_unpackInstance();
 
-    _flw_layoutVertex();
+    _flw_main(instance);
-    flw_beginVertex();
-    flw_instanceVertex(instance);
-    flw_materialVertex();
-    flw_endVertex();
-
-    flw_vertexNormal = normalize(flw_vertexNormal);
-
-    if (flw_material.diffuse) {
-        float diffuseFactor;
-        if (flywheel.constantAmbientLight == 1) {
-            diffuseFactor = diffuseNether(flw_vertexNormal);
-        } else {
-            diffuseFactor = diffuse(flw_vertexNormal);
-        }
-        flw_vertexColor = vec4(flw_vertexColor.rgb * diffuseFactor, flw_vertexColor.a);
-    }
-
-    flw_distance = fogDistance(flw_vertexPos.xyz, flywheel.cameraPos.xyz, flywheel.fogShape);
-    gl_Position = flywheel.viewProjection * flw_vertexPos;
 }