Add existing to tracked

node_modules/@cesium/engine/Source/Shaders/Voxels/Megatexture.glsl

@@ -0,0 +1,55 @@
+// See Octree.glsl for the definitions of SampleData
+
+/* Megatexture defines (set in Scene/VoxelRenderResources.js)
+#define SAMPLE_COUNT ###
+#define PADDING
+*/
+
+uniform ivec3 u_megatextureTileCounts; // number of tiles in the megatexture, along each axis
+
+vec3 index1DTo3DTexCoord(int index)
+{
+    int tilesPerZ = u_megatextureTileCounts.x * u_megatextureTileCounts.y;
+    int iz = index / tilesPerZ;
+    int remainder = index - iz * tilesPerZ;
+    int iy = remainder / u_megatextureTileCounts.x;
+    int ix = remainder - iy * u_megatextureTileCounts.x;
+    return vec3(ix, iy, iz) / vec3(u_megatextureTileCounts);
+}
+
+Properties getPropertiesFromMegatexture(in SampleData sampleData) {
+    int tileIndex = sampleData.megatextureIndex;
+
+    vec3 voxelCoord = sampleData.inputCoordinate;
+
+    // UV coordinate of the lower corner of the tile in the megatexture
+    vec3 tileUvOffset = index1DTo3DTexCoord(tileIndex);
+
+    // Voxel location
+    vec3 tileDimensions = vec3(u_inputDimensions);
+    vec3 clampedVoxelCoord = clamp(voxelCoord, vec3(0.5), tileDimensions - vec3(0.5));
+    vec3 voxelUv = clampedVoxelCoord / tileDimensions / vec3(u_megatextureTileCounts);
+
+    return getPropertiesFromMegatextureAtUv(tileUvOffset + voxelUv);
+}
+
+// Convert an array of sample datas to a final weighted properties.
+Properties accumulatePropertiesFromMegatexture(in SampleData sampleDatas[SAMPLE_COUNT]) {
+    #if (SAMPLE_COUNT == 1)
+        return getPropertiesFromMegatexture(sampleDatas[0]);
+    #else
+        // When more than one sample is taken the accumulator needs to start at 0
+        Properties properties = clearProperties();
+        for (int i = 0; i < SAMPLE_COUNT; ++i) {
+            float weight = sampleDatas[i].weight;
+
+            // Avoid reading the megatexture when the weight is 0 as it can be costly.
+            if (weight > 0.0) {
+                Properties tempProperties = getPropertiesFromMegatexture(sampleDatas[i]);
+                tempProperties = scaleProperties(tempProperties, weight);
+                properties = sumProperties(properties, tempProperties);
+            }
+        }
+        return properties;
+    #endif
+}