Downgrade quad materials by scanning their textures

common/src/main/java/net/caffeinemc/mods/sodium/client/render/chunk/compile/pipeline/BlockRenderer.java

@@ -9,6 +9,7 @@
 import net.caffeinemc.mods.sodium.client.model.quad.properties.ModelQuadOrientation;
 import net.caffeinemc.mods.sodium.client.render.chunk.compile.ChunkBuildBuffers;
 import net.caffeinemc.mods.sodium.client.render.chunk.compile.buffers.ChunkModelBuilder;
+import net.caffeinemc.mods.sodium.client.render.chunk.terrain.DefaultTerrainRenderPasses;
 import net.caffeinemc.mods.sodium.client.render.chunk.terrain.material.DefaultMaterials;
 import net.caffeinemc.mods.sodium.client.render.chunk.terrain.material.Material;
 import net.caffeinemc.mods.sodium.client.render.chunk.translucent_sorting.TranslucentGeometryCollector;
@@ -28,6 +29,7 @@
 import net.fabricmc.fabric.api.util.TriState;
 import net.minecraft.client.renderer.ItemBlockRenderTypes;
 import net.minecraft.client.renderer.RenderType;
+import net.minecraft.client.renderer.texture.TextureAtlasSprite;
 import net.minecraft.client.resources.model.BakedModel;
 import net.minecraft.core.BlockPos;
 import net.minecraft.world.level.block.state.BlockState;
@@ -128,11 +130,9 @@ protected void processQuad(MutableQuadViewImpl quad) {
             material = DefaultMaterials.forRenderLayer(blendMode.blockRenderLayer == null ? type : blendMode.blockRenderLayer);
         }
 
-        ChunkModelBuilder builder = this.buffers.get(material);
-
         this.colorizeQuad(quad, colorIndex);
         this.shadeQuad(quad, lightMode, emissive, shadeMode);
-        this.bufferQuad(quad, this.quadLightData.br, material, builder);
+        this.bufferQuad(quad, this.quadLightData.br, material);
     }
 
     private void colorizeQuad(MutableQuadViewImpl quad, int colorIndex) {
@@ -152,7 +152,7 @@ private void colorizeQuad(MutableQuadViewImpl quad, int colorIndex) {
         }
     }
 
-    private void bufferQuad(MutableQuadViewImpl quad, float[] brightnesses, Material material, ChunkModelBuilder modelBuilder) {
+    private void bufferQuad(MutableQuadViewImpl quad, float[] brightnesses, Material material) {
         ModelQuadOrientation orientation = defaultLightMode == LightMode.FLAT ? ModelQuadOrientation.NORMAL : ModelQuadOrientation.orientByBrightness(brightnesses, quad);
         ChunkVertexEncoder.Vertex[] vertices = this.vertices;
         Vector3f offset = this.posOffset;
@@ -175,15 +175,31 @@ private void bufferQuad(MutableQuadViewImpl quad, float[] brightnesses, Material
             out.light = quad.lightmap(srcIndex);
         }
 
+        var atlasSprite = SpriteFinderCache.forBlockAtlas().find(quad.getTexU(0), quad.getTexV(0));
+        material = getDowngradedMaterial(atlasSprite, material);
+
         ModelQuadFacing normalFace = quad.normalFace();
 
         if (material.isTranslucent() && this.collector != null) {
             this.collector.appendQuad(quad.getFaceNormal(), vertices, normalFace);
         }
 
-        ChunkMeshBufferBuilder vertexBuffer = modelBuilder.getVertexBuffer(normalFace);
+        ChunkModelBuilder builder = this.buffers.get(material);
+
+        ChunkMeshBufferBuilder vertexBuffer = builder.getVertexBuffer(normalFace);
         vertexBuffer.push(vertices, material);
 
-        modelBuilder.addSprite(SpriteFinderCache.forBlockAtlas().find(quad.getTexU(0), quad.getTexV(0)));
+        builder.addSprite(atlasSprite);
+    }
+
+    private Material getDowngradedMaterial(TextureAtlasSprite sprite, Material material) {
+        var contents = (SpriteContentsExtension) (sprite.contents());
+        if (material.pass == DefaultTerrainRenderPasses.TRANSLUCENT && !contents.sodium$hasTranslucentPixels()) {
+            material = DefaultMaterials.CUTOUT_MIPPED;
+        }
+        if (material.pass == DefaultTerrainRenderPasses.CUTOUT && !contents.sodium$hasTransparentPixels()) {
+            material = DefaultMaterials.SOLID;
+        }
+        return material;
     }
 }

common/src/main/java/net/caffeinemc/mods/sodium/client/render/chunk/compile/pipeline/SpriteContentsExtension.java

@@ -0,0 +1,7 @@
+package net.caffeinemc.mods.sodium.client.render.chunk.compile.pipeline;
+
+public interface SpriteContentsExtension {
+    boolean sodium$hasTransparentPixels();
+
+    boolean sodium$hasTranslucentPixels();
+}

common/src/main/java/net/caffeinemc/mods/sodium/mixin/features/textures/mipmaps/SpriteContentsMixin.java

@@ -1,6 +1,7 @@
 package net.caffeinemc.mods.sodium.mixin.features.textures.mipmaps;
 
 import com.mojang.blaze3d.platform.NativeImage;
+import net.caffeinemc.mods.sodium.client.render.chunk.compile.pipeline.SpriteContentsExtension;
 import net.caffeinemc.mods.sodium.client.util.NativeImageHelper;
 import net.caffeinemc.mods.sodium.client.util.color.ColorSRGB;
 import net.minecraft.client.renderer.texture.SpriteContents;
@@ -20,12 +21,18 @@
  * This Mixin is ported from Iris at <a href="https://github.com/IrisShaders/Iris/blob/41095ac23ea0add664afd1b85c414d1f1ed94066/src/main/java/net/coderbot/iris/mixin/bettermipmaps/MixinTextureAtlasSprite.java">MixinTextureAtlasSprite</a>.
  */
 @Mixin(SpriteContents.class)
-public class SpriteContentsMixin {
+public class SpriteContentsMixin implements SpriteContentsExtension {
     @Mutable
     @Shadow
     @Final
     private NativeImage originalImage;
 
+    @Unique
+    public boolean sodium$hasTransparentPixels = false;
+
+    @Unique
+    public boolean sodium$hasTranslucentPixels = false;
+
     // While Fabric allows us to @Inject into the constructor here, that's just a specific detail of FabricMC's mixin
     // fork. Upstream Mixin doesn't allow arbitrary @Inject usage in constructor. However, we can use @ModifyVariable
     // just fine, in a way that hopefully doesn't conflict with other mods.
@@ -51,7 +58,7 @@ public class SpriteContentsMixin {
      * black color does not leak over into sampling.
      */
     @Unique
-    private static void sodium$fillInTransparentPixelColors(NativeImage nativeImage) {
+    private void sodium$fillInTransparentPixelColors(NativeImage nativeImage) {
         final long ppPixel = NativeImageHelper.getPointerRGBA(nativeImage);
         final int pixelCount = nativeImage.getHeight() * nativeImage.getWidth();
 
@@ -79,9 +86,18 @@ public class SpriteContentsMixin {
                 b += ColorSRGB.srgbToLinear(FastColor.ABGR32.blue(color)) * weight;
 
                 totalWeight += weight;
+
+                // track if this image has transparent or even translucent pixels
+                if (alpha < 255) {
+                    this.sodium$hasTranslucentPixels = true;
+                }
+            } else {
+                this.sodium$hasTransparentPixels = true;
             }
         }
 
+        this.sodium$hasTransparentPixels |= this.sodium$hasTranslucentPixels;
+
         // Bail if none of the pixels are semi-transparent.
         if (totalWeight == 0.0f) {
             return;
@@ -107,4 +123,14 @@ public class SpriteContentsMixin {
             }
         }
     }
+
+    @Override
+    public boolean sodium$hasTransparentPixels() {
+        return this.sodium$hasTransparentPixels;
+    }
+
+    @Override
+    public boolean sodium$hasTranslucentPixels() {
+        return this.sodium$hasTranslucentPixels;
+    }
 }