Uber smooth

- Add material shader component to specify smooth lighting behavior
- Allows much easier composition of smooth lighting/material shader
  effects, and potentially gives backends the option to specialize
  shaders on the complexity of shader lighting
- Pack fog, cutout, and light into a single uint

common/src/api/java/dev/engine_room/flywheel/api/material/LightShader.java

@@ -0,0 +1,11 @@
+package dev.engine_room.flywheel.api.material;
+
+import dev.engine_room.flywheel.api.internal.FlwApiLink;
+import dev.engine_room.flywheel.api.registry.Registry;
+import net.minecraft.resources.ResourceLocation;
+
+public interface LightShader {
+	Registry<LightShader> REGISTRY = FlwApiLink.INSTANCE.createRegistry();
+
+	ResourceLocation source();
+}

common/src/api/java/dev/engine_room/flywheel/api/material/Material.java

@@ -9,6 +9,8 @@ public interface Material {
 
 	CutoutShader cutout();
 
+	LightShader light();
+
 	ResourceLocation texture();
 
 	/**

common/src/backend/java/dev/engine_room/flywheel/backend/MaterialShaderIndices.java

@@ -8,6 +8,7 @@ import org.jetbrains.annotations.Unmodifiable;
 
 import dev.engine_room.flywheel.api.material.CutoutShader;
 import dev.engine_room.flywheel.api.material.FogShader;
+import dev.engine_room.flywheel.api.material.LightShader;
 import dev.engine_room.flywheel.api.material.MaterialShaders;
 import dev.engine_room.flywheel.api.registry.Registry;
 import it.unimi.dsi.fastutil.objects.Object2IntMap;
@@ -25,6 +26,8 @@ public final class MaterialShaderIndices {
 	private static Index fogSources;
 	@Nullable
 	private static Index cutoutSources;
+	@Nullable
+	private static Index lightSources;
 
 	private MaterialShaderIndices() {
 	}
@@ -57,6 +60,13 @@ public final class MaterialShaderIndices {
 		return cutoutSources;
 	}
 
+	public static Index lightSources() {
+		if (lightSources == null) {
+			lightSources = indexFromRegistry(LightShader.REGISTRY, LightShader::source);
+		}
+		return lightSources;
+	}
+
 	public static int vertexIndex(MaterialShaders shaders) {
 		return vertexSources().index(shaders.vertexSource());
 	}
@@ -73,6 +83,10 @@ public final class MaterialShaderIndices {
 		return cutoutSources().index(cutoutShader.source());
 	}
 
+	public static int lightIndex(LightShader lightShader) {
+		return lightSources().index(lightShader.source());
+	}
+
 	private static <T> Index indexFromRegistry(Registry<T> registry, Function<T, ResourceLocation> sourceFunc) {
 		if (!registry.isFrozen()) {
 			throw new IllegalStateException("Cannot create index from registry that is not frozen!");

common/src/backend/java/dev/engine_room/flywheel/backend/compile/FlwPrograms.java

@@ -46,15 +46,16 @@ public final class FlwPrograms {
 		var fragmentMaterialComponent = createFragmentMaterialComponent(loader);
 		var fogComponent = createFogComponent(loader);
 		var cutoutComponent = createCutoutComponent(loader);
+		var lightComponent = createLightComponent(loader);
 
-		if (stats.errored() || vertexComponentsHeader == null || fragmentComponentsHeader == null || vertexMaterialComponent == null || fragmentMaterialComponent == null || fogComponent == null || cutoutComponent == null) {
+		if (stats.errored() || vertexComponentsHeader == null || fragmentComponentsHeader == null || vertexMaterialComponent == null || fragmentMaterialComponent == null || fogComponent == null || cutoutComponent == null || lightComponent == null) {
 			// Probably means the shader sources are missing.
 			stats.emitErrorLog();
 			return;
 		}
 
 		List<SourceComponent> vertexComponents = List.of(vertexComponentsHeader, vertexMaterialComponent);
-		List<SourceComponent> fragmentComponents = List.of(fragmentComponentsHeader, fragmentMaterialComponent, fogComponent, cutoutComponent);
+		List<SourceComponent> fragmentComponents = List.of(fragmentComponentsHeader, fragmentMaterialComponent, fogComponent, cutoutComponent, lightComponent);
 
 		var pipelineKeys = createPipelineKeys();
 		InstancingPrograms.reload(sources, pipelineKeys, vertexComponents, fragmentComponents);
@@ -118,4 +119,17 @@ public final class FlwPrograms {
 				.switchOn(GlslExpr.variable("_flw_uberCutoutIndex"))
 				.build(loader);
 	}
+
+	@Nullable
+	private static UberShaderComponent createLightComponent(SourceLoader loader) {
+		return UberShaderComponent.builder(Flywheel.rl("light"))
+				.materialSources(MaterialShaderIndices.lightSources()
+						.all())
+				.adapt(FnSignature.create()
+						.returnType("void")
+						.name("flw_shaderLight")
+						.build())
+				.switchOn(GlslExpr.variable("_flw_uberLightIndex"))
+				.build(loader);
+	}
 }

common/src/backend/java/dev/engine_room/flywheel/backend/engine/MaterialEncoder.java

@@ -52,10 +52,11 @@ public final class MaterialEncoder {
 		return ((1 << bitLength) - 1) << bitOffset;
 	}
 
-	public static int packFogAndCutout(Material material) {
+	public static int packUberShader(Material material) {
 		var fog = MaterialShaderIndices.fogIndex(material.fog());
 		var cutout = MaterialShaderIndices.cutoutIndex(material.cutout());
-		return fog & 0xFFFF | (cutout & 0xFFFF) << 16;
+		var light = MaterialShaderIndices.lightIndex(material.light());
+		return (light & 0x3FF) | (cutout & 0x3FF) << 10 | (fog & 0x3FF) << 20;
 	}
 
 	// Packed format:

common/src/backend/java/dev/engine_room/flywheel/backend/engine/indirect/IndirectDraw.java

@@ -34,7 +34,7 @@ public class IndirectDraw {
 
 		this.materialVertexIndex = MaterialShaderIndices.vertexIndex(material.shaders());
 		this.materialFragmentIndex = MaterialShaderIndices.fragmentIndex(material.shaders());
-		this.packedFogAndCutout = MaterialEncoder.packFogAndCutout(material);
+		this.packedFogAndCutout = MaterialEncoder.packUberShader(material);
 		this.packedMaterialProperties = MaterialEncoder.packProperties(material);
 	}
 
@@ -88,7 +88,7 @@ public class IndirectDraw {
 
 		MemoryUtil.memPutInt(ptr + 24, MaterialShaderIndices.vertexIndex(materialOverride.shaders())); // materialVertexIndex
 		MemoryUtil.memPutInt(ptr + 28, MaterialShaderIndices.fragmentIndex(materialOverride.shaders())); // materialFragmentIndex
-		MemoryUtil.memPutInt(ptr + 32, MaterialEncoder.packFogAndCutout(materialOverride)); // packedFogAndCutout
+		MemoryUtil.memPutInt(ptr + 32, MaterialEncoder.packUberShader(materialOverride)); // packedFogAndCutout
 		MemoryUtil.memPutInt(ptr + 36, MaterialEncoder.packProperties(materialOverride)); // packedMaterialProperties
 	}
 

common/src/backend/java/dev/engine_room/flywheel/backend/engine/instancing/InstancedDrawManager.java

@@ -206,7 +206,7 @@ public class InstancedDrawManager extends DrawManager<InstancedInstancer<?>> {
 		int uniformLocation = program.getUniformLocation("_flw_packedMaterial");
 		int vertexIndex = MaterialShaderIndices.vertexIndex(material.shaders());
 		int fragmentIndex = MaterialShaderIndices.fragmentIndex(material.shaders());
-		int packedFogAndCutout = MaterialEncoder.packFogAndCutout(material);
+		int packedFogAndCutout = MaterialEncoder.packUberShader(material);
 		int packedMaterialProperties = MaterialEncoder.packProperties(material);
 		GL32.glUniform4ui(uniformLocation, vertexIndex, fragmentIndex, packedFogAndCutout, packedMaterialProperties);
 	}

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

@@ -47,6 +47,10 @@ void _flw_main() {
 
     vec4 color = flw_fragColor;
 
+    if (flw_discardPredicate(color)) {
+        discard;
+    }
+
     float diffuseFactor = _flw_diffuseFactor();
     color.rgb *= diffuseFactor;
 
@@ -57,14 +61,12 @@ void _flw_main() {
 
     vec4 lightColor = vec4(1.);
     if (flw_material.useLight) {
+        flw_shaderLight();
+
         lightColor = texture(flw_lightTex, clamp(flw_fragLight, 0.5 / 16.0, 15.5 / 16.0));
         color *= lightColor;
     }
 
-    if (flw_discardPredicate(color)) {
-        discard;
-    }
-
     switch (_flw_debugMode) {
         case 1u:
         color = vec4(flw_vertexNormal * .5 + .5, 1.);

common/src/backend/resources/assets/flywheel/flywheel/internal/components_header.frag

@@ -1,3 +1,4 @@
 uint _flw_uberMaterialFragmentIndex;
 uint _flw_uberFogIndex;
 uint _flw_uberCutoutIndex;
+uint _flw_uberLightIndex;

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

@@ -6,7 +6,7 @@ flat in uvec3 _flw_packedMaterial;
 
 void main() {
     _flw_uberMaterialFragmentIndex = _flw_packedMaterial.x;
-    _flw_unpackUint2x16(_flw_packedMaterial.y, _flw_uberCutoutIndex, _flw_uberFogIndex);
+    _flw_unpackUint3x10(_flw_packedMaterial.y, _flw_uberFogIndex, _flw_uberCutoutIndex, _flw_uberLightIndex);
     _flw_unpackMaterialProperties(_flw_packedMaterial.z, flw_material);
 
     _flw_main();

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

@@ -5,7 +5,7 @@ uniform uvec4 _flw_packedMaterial;
 
 void main() {
     _flw_uberMaterialFragmentIndex = _flw_packedMaterial.y;
-    _flw_unpackUint2x16(_flw_packedMaterial.z, _flw_uberCutoutIndex, _flw_uberFogIndex);
+    _flw_unpackUint3x10(_flw_packedMaterial.z, _flw_uberFogIndex, _flw_uberCutoutIndex, _flw_uberLightIndex);
     _flw_unpackMaterialProperties(_flw_packedMaterial.w, flw_material);
 
     _flw_main();

common/src/backend/resources/assets/flywheel/flywheel/internal/packed_material.glsl

@@ -53,3 +53,9 @@ void _flw_unpackUint2x16(uint s, out uint hi, out uint lo) {
     hi = (s >> 16) & 0xFFFFu;
     lo = s & 0xFFFFu;
 }
+
+void _flw_unpackUint3x10(uint s, out uint hi, out uint mi, out uint lo) {
+    hi = (s >> 20) & 0x3FFu;
+    mi = (s >> 10) & 0x3FFu;
+    lo = s & 0x3FFu;
+}

common/src/lib/java/dev/engine_room/flywheel/lib/material/LightShaders.java

@@ -0,0 +1,19 @@
+package dev.engine_room.flywheel.lib.material;
+
+import org.jetbrains.annotations.ApiStatus;
+
+import dev.engine_room.flywheel.api.Flywheel;
+import dev.engine_room.flywheel.api.material.LightShader;
+
+public class LightShaders {
+	public static final LightShader SMOOTH_WHEN_EMBEDDED = LightShader.REGISTRY.registerAndGet(new SimpleLightShader(Flywheel.rl("light/smooth_when_embedded.glsl")));
+	public static final LightShader SMOOTH = LightShader.REGISTRY.registerAndGet(new SimpleLightShader(Flywheel.rl("light/smooth.glsl")));
+	public static final LightShader FLAT = LightShader.REGISTRY.registerAndGet(new SimpleLightShader(Flywheel.rl("light/flat.glsl")));
+
+	private LightShaders() {
+	}
+
+	@ApiStatus.Internal
+	public static void init() {
+	}
+}

common/src/lib/java/dev/engine_room/flywheel/lib/material/SimpleLightShader.java

@@ -0,0 +1,7 @@
+package dev.engine_room.flywheel.lib.material;
+
+import dev.engine_room.flywheel.api.material.LightShader;
+import net.minecraft.resources.ResourceLocation;
+
+public record SimpleLightShader(@Override ResourceLocation source) implements LightShader {
+}

common/src/lib/java/dev/engine_room/flywheel/lib/material/SimpleMaterial.java

@@ -3,6 +3,7 @@ package dev.engine_room.flywheel.lib.material;
 import dev.engine_room.flywheel.api.material.CutoutShader;
 import dev.engine_room.flywheel.api.material.DepthTest;
 import dev.engine_room.flywheel.api.material.FogShader;
+import dev.engine_room.flywheel.api.material.LightShader;
 import dev.engine_room.flywheel.api.material.Material;
 import dev.engine_room.flywheel.api.material.MaterialShaders;
 import dev.engine_room.flywheel.api.material.Transparency;
@@ -14,6 +15,7 @@ public class SimpleMaterial implements Material {
 	protected final MaterialShaders shaders;
 	protected final FogShader fog;
 	protected final CutoutShader cutout;
+	protected final LightShader light;
 
 	protected final ResourceLocation texture;
 	protected final boolean blur;
@@ -33,6 +35,7 @@ public class SimpleMaterial implements Material {
 		shaders = builder.shaders();
 		fog = builder.fog();
 		cutout = builder.cutout();
+		light = builder.light();
 		texture = builder.texture();
 		blur = builder.blur();
 		mipmap = builder.mipmap();
@@ -69,6 +72,11 @@ public class SimpleMaterial implements Material {
 		return cutout;
 	}
 
+	@Override
+	public LightShader light() {
+		return light;
+	}
+
 	@Override
 	public ResourceLocation texture() {
 		return texture;
@@ -128,6 +136,7 @@ public class SimpleMaterial implements Material {
 		protected MaterialShaders shaders;
 		protected FogShader fog;
 		protected CutoutShader cutout;
+		protected LightShader light;
 
 		protected ResourceLocation texture;
 		protected boolean blur;
@@ -147,6 +156,7 @@ public class SimpleMaterial implements Material {
 			shaders = StandardMaterialShaders.DEFAULT;
 			fog = FogShaders.LINEAR;
 			cutout = CutoutShaders.OFF;
+			light = LightShaders.SMOOTH_WHEN_EMBEDDED;
 			texture = InventoryMenu.BLOCK_ATLAS;
 			blur = false;
 			mipmap = true;
@@ -197,6 +207,11 @@ public class SimpleMaterial implements Material {
 			return this;
 		}
 
+		public Builder light(LightShader value) {
+			this.light = value;
+			return this;
+		}
+
 		public Builder texture(ResourceLocation value) {
 			this.texture = value;
 			return this;
@@ -267,6 +282,11 @@ public class SimpleMaterial implements Material {
 			return cutout;
 		}
 
+		@Override
+		public LightShader light() {
+			return light;
+		}
+
 		@Override
 		public ResourceLocation texture() {
 			return texture;

common/src/lib/resources/assets/flywheel/flywheel/light/flat.glsl

@@ -0,0 +1,6 @@
+void flw_shaderLight() {
+    vec2 embeddedLight;
+    if (flw_lightFetch(ivec3(floor(flw_vertexPos.xyz)), embeddedLight)) {
+        flw_fragLight = max(flw_fragLight, embeddedLight);
+    }
+}

common/src/lib/resources/assets/flywheel/flywheel/light/smooth.glsl

@@ -0,0 +1,6 @@
+void flw_shaderLight() {
+    vec2 embeddedLight;
+    if (flw_light(flw_vertexPos.xyz, flw_vertexNormal, embeddedLight)) {
+        flw_fragLight = max(flw_fragLight, embeddedLight);
+    }
+}

common/src/lib/resources/assets/flywheel/flywheel/light/smooth_when_embedded.glsl

@@ -0,0 +1,8 @@
+void flw_shaderLight() {
+    #ifdef FLW_EMBEDDED
+    vec2 embeddedLight;
+    if (flw_light(flw_vertexPos.xyz, flw_vertexNormal, embeddedLight)) {
+        flw_fragLight = max(flw_fragLight, embeddedLight);
+    }
+    #endif
+}

common/src/lib/resources/assets/flywheel/flywheel/material/default.frag

@@ -1,8 +1,2 @@
 void flw_materialFragment() {
-    #ifdef FLW_EMBEDDED
-    vec2 embeddedLight;
-    if (flw_light(flw_vertexPos.xyz, flw_vertexNormal, embeddedLight)) {
-        flw_fragLight = max(flw_fragLight, embeddedLight);
-    }
-    #endif
 }

common/src/main/java/dev/engine_room/flywheel/impl/FlwImpl.java

@@ -10,6 +10,7 @@ import dev.engine_room.flywheel.impl.registry.RegistryImpl;
 import dev.engine_room.flywheel.lib.instance.InstanceTypes;
 import dev.engine_room.flywheel.lib.material.CutoutShaders;
 import dev.engine_room.flywheel.lib.material.FogShaders;
+import dev.engine_room.flywheel.lib.material.LightShaders;
 import dev.engine_room.flywheel.lib.material.StandardMaterialShaders;
 import dev.engine_room.flywheel.lib.util.ShadersModHandler;
 import dev.engine_room.flywheel.vanilla.VanillaVisuals;
@@ -30,6 +31,7 @@ public final class FlwImpl {
 		InstanceTypes.init();
 		CutoutShaders.init();
 		FogShaders.init();
+		LightShaders.init();
 		StandardMaterialShaders.init();
 
 		// backend