Do not bake ambient lighting into cached per-face light data

Fixes #2806

common/src/main/java/net/caffeinemc/mods/sodium/client/model/light/smooth/SmoothLightPipeline.java

@@ -6,10 +6,10 @@
 import net.caffeinemc.mods.sodium.client.model.light.data.QuadLightData;
 import net.caffeinemc.mods.sodium.client.model.quad.ModelQuadView;
 import net.caffeinemc.mods.sodium.client.model.quad.properties.ModelQuadFlags;
+import net.caffeinemc.mods.sodium.client.util.DirectionUtil;
 import net.minecraft.core.BlockPos;
 import net.minecraft.core.Direction;
 import net.minecraft.util.Mth;
-import net.minecraft.world.level.material.FluidState;
 import org.joml.Vector3f;
 
 /**
@@ -58,12 +58,23 @@ public class SmoothLightPipeline implements LightPipeline {
      */
     private final float[] weights = new float[4];
 
+    // Cached per-face brightness received from the dimension's ambient lighting.
+    // This data is static for a given world and dimension.
+    private final float[] ambientBrightnessShaded = new float[6];
+    private final float[] ambientBrightnessUnshaded = new float[6];
+
     public SmoothLightPipeline(LightDataAccess cache) {
         this.lightCache = cache;
 
         for (int i = 0; i < this.cachedFaceData.length; i++) {
             this.cachedFaceData[i] = new AoFaceData();
         }
+
+        for (Direction direction : DirectionUtil.ALL_DIRECTIONS) {
+            var level = cache.getLevel();
+            this.ambientBrightnessShaded[direction.ordinal()] = level.getShade(direction, true);
+            this.ambientBrightnessUnshaded[direction.ordinal()] = level.getShade(direction, false);
+        }
     }
 
     @Override
@@ -102,6 +113,8 @@ public void calculate(ModelQuadView quad, BlockPos pos, QuadLightData out, Direc
     private void applyAlignedFullFace(AoNeighborInfo neighborInfo, BlockPos pos, Direction dir, QuadLightData out, boolean shade) {
         AoFaceData faceData = this.getCachedFaceData(pos, dir, true, shade);
         neighborInfo.mapCorners(faceData.lm, faceData.ao, out.lm, out.br);
+
+        this.applyAmbientLighting(out.br, dir, shade);
     }
 
     /**
@@ -119,6 +132,8 @@ private void applyAlignedPartialFace(AoNeighborInfo neighborInfo, ModelQuadView
             neighborInfo.calculateCornerWeights(cx, cy, cz, weights);
             this.applyAlignedPartialFaceVertex(pos, dir, weights, i, out, true, shade);
         }
+
+        this.applyAmbientLighting(out.br, dir, shade);
     }
 
     /**
@@ -150,6 +165,8 @@ private void applyParallelFace(AoNeighborInfo neighborInfo, ModelQuadView quad,
                 this.applyInsetPartialFaceVertex(pos, dir, depth, 1.0f - depth, weights, i, out, shade);
             }
         }
+
+        this.applyAmbientLighting(out.br, dir, shade);
     }
 
     /**
@@ -178,6 +195,8 @@ private void applyNonParallelFace(AoNeighborInfo neighborInfo, ModelQuadView qua
                 this.applyInsetPartialFaceVertex(pos, dir, depth, 1.0f - depth, weights, i, out, shade);
             }
         }
+
+        this.applyAmbientLighting(out.br, dir, shade);
     }
 
     private void applyAlignedPartialFaceVertex(BlockPos pos, Direction dir, float[] w, int i, QuadLightData out, boolean offset, boolean shade) {
@@ -257,7 +276,7 @@ private void applyIrregularFace(BlockPos blockPos, ModelQuadView quad, QuadLight
                 final AoFaceData fd = gatherInsetFace(quad, blockPos, i, face, shade);
                 AoNeighborInfo.get(face).calculateCornerWeights(quad.getX(i), quad.getY(i), quad.getZ(i), w);
                 final float n = x * x;
-                final float a = fd.getBlendedShade(w);
+                final float a = fd.getBlendedShade(w) * this.getAmbientBrightness(face, shade);
                 final float s = fd.getBlendedSkyLight(w);
                 final float b = fd.getBlendedBlockLight(w);
                 ao += n * a;
@@ -275,7 +294,7 @@ private void applyIrregularFace(BlockPos blockPos, ModelQuadView quad, QuadLight
                 final AoFaceData fd = gatherInsetFace(quad, blockPos, i, face, shade);
                 AoNeighborInfo.get(face).calculateCornerWeights(quad.getX(i), quad.getY(i), quad.getZ(i), w);
                 final float n = y * y;
-                final float a = fd.getBlendedShade(w);
+                final float a = fd.getBlendedShade(w) * this.getAmbientBrightness(face, shade);
                 final float s = fd.getBlendedSkyLight(w);
                 final float b = fd.getBlendedBlockLight(w);
                 ao += n * a;
@@ -293,7 +312,7 @@ private void applyIrregularFace(BlockPos blockPos, ModelQuadView quad, QuadLight
                 final AoFaceData fd = gatherInsetFace(quad, blockPos, i, face, shade);
                 AoNeighborInfo.get(face).calculateCornerWeights(quad.getX(i), quad.getY(i), quad.getZ(i), w);
                 final float n = z * z;
-                final float a = fd.getBlendedShade(w);
+                final float a = fd.getBlendedShade(w) * this.getAmbientBrightness(face, shade);
                 final float s = fd.getBlendedSkyLight(w);
                 final float b = fd.getBlendedBlockLight(w);
                 ao += n * a;
@@ -309,29 +328,42 @@ private void applyIrregularFace(BlockPos blockPos, ModelQuadView quad, QuadLight
         }
     }
 
-    private void applySidedBrightness(AoFaceData out, Direction face, boolean shade) {
-        float brightness = this.lightCache.getLevel().getShade(face, shade);
-        float[] ao = out.ao;
+    /**
+     * Applies the "ambient" lighting from the dimension to a quad that is parallel with the block grid.
+     * @param brightness The array of brightnesses for each quad vertex
+     * @param face The facing of the quad
+     * @param shade Whether the quad should receive directional lighting
+     */
+    private void applyAmbientLighting(final float[] brightness, Direction face, boolean shade) {
+        final float multiplier = this.getAmbientBrightness(face, shade);
 
-        for (int i = 0; i < ao.length; i++) {
-            ao[i] *= brightness;
+        for (int i = 0; i < brightness.length; i++) {
+            brightness[i] *= multiplier;
         }
     }
 
+    /**
+     * Returns the "ambient" brightness a block face receives in the world.
+     * @param face The block face
+     * @param shade Whether the block face is receiving directional light
+     */
+    private float getAmbientBrightness(Direction face, boolean shade) {
+        return (shade ? this.ambientBrightnessShaded : this.ambientBrightnessUnshaded)[face.ordinal()];
+    }
+
     /**
      * Returns the cached data for a given facing or calculates it if it hasn't been cached.
      */
     private AoFaceData getCachedFaceData(BlockPos pos, Direction face, boolean offset, boolean shade) {
         AoFaceData data = this.cachedFaceData[offset ? face.ordinal() : face.ordinal() + 6];
 
-        if (!data.hasLightData()) {
-            data.initLightData(this.lightCache, pos, face, offset);
-
-            this.applySidedBrightness(data, face, shade);
-
-            data.unpackLightData();
+        if (data.hasLightData()) {
+            return data;
         }
 
+        data.initLightData(this.lightCache, pos, face, offset);
+        data.unpackLightData();
+
         return data;
     }