Optimize DDGI software raytracing with point sampler

Source/Shaders/GI/DDGI.shader

@@ -9,6 +9,10 @@
 // "Scaling Probe-Based Real-Time Dynamic Global Illumination for Production", https://jcgt.org/published/0010/02/01/
 // "Dynamic Diffuse Global Illumination with Ray-Traced Irradiance Fields", https://jcgt.org/published/0008/02/01/
 
+// Use point sampling in software raytracing
+#define GLOBAL_SURFACE_ATLAS_SAMPLER SamplerPointClamp
+#define GLOBAL_SDF_SAMPLER SamplerPointClamp
+
 #include "./Flax/Common.hlsl"
 #include "./Flax/Math.hlsl"
 #include "./Flax/Noise.hlsl"

Source/Shaders/GI/GlobalSurfaceAtlas.hlsl

@@ -25,6 +25,9 @@
 #define GLOBAL_SURFACE_ATLAS_TILE_NORMAL_WEIGHT_ENABLED 0
 #define GLOBAL_SURFACE_ATLAS_TILE_NORMAL_THRESHOLD 0
 #endif
+#ifndef GLOBAL_SURFACE_ATLAS_SAMPLER
+#define GLOBAL_SURFACE_ATLAS_SAMPLER SamplerLinearClamp
+#endif
 
 struct GlobalSurfaceTile
 {
@@ -119,9 +122,9 @@ struct GlobalSurfaceAtlasData
 
 float3 SampleGlobalSurfaceAtlasTex(Texture2D atlas, float2 atlasUV, float4 bilinearWeights)
 {
-    float4 sampleX = atlas.GatherRed(SamplerLinearClamp, atlasUV);
-    float4 sampleY = atlas.GatherGreen(SamplerLinearClamp, atlasUV);
-    float4 sampleZ = atlas.GatherBlue(SamplerLinearClamp, atlasUV);
+    float4 sampleX = atlas.GatherRed(GLOBAL_SURFACE_ATLAS_SAMPLER, atlasUV);
+    float4 sampleY = atlas.GatherGreen(GLOBAL_SURFACE_ATLAS_SAMPLER, atlasUV);
+    float4 sampleZ = atlas.GatherBlue(GLOBAL_SURFACE_ATLAS_SAMPLER, atlasUV);
     return float3(dot(sampleX, bilinearWeights), dot(sampleY, bilinearWeights), dot(sampleZ, bilinearWeights));
 }
 
@@ -154,7 +157,7 @@ float4 SampleGlobalSurfaceAtlasTile(const GlobalSurfaceAtlasData data, GlobalSur
     bilinearWeights.w = (1 - bilinearWeightsUV.x) * (1 - bilinearWeightsUV.y);
 
     // Tile depth weight based on sample position occlusion
-    float4 tileZ = depth.Gather(SamplerLinearClamp, atlasUV);
+    float4 tileZ = depth.Gather(GLOBAL_SURFACE_ATLAS_SAMPLER, atlasUV);
     float depthThreshold = 2.0f * surfaceThreshold / tile.ViewBoundsSize.z;
     float4 depthVisibility = 1.0f;
     UNROLL

Source/Shaders/GlobalSignDistanceField.hlsl

@@ -11,7 +11,9 @@
 #define GLOBAL_SDF_WORLD_SIZE 60000.0f
 #define GLOBAL_SDF_MIN_VALID 0.9f
 #define GLOBAL_SDF_CHUNK_MARGIN_SCALE 4.0f
+#ifndef GLOBAL_SDF_SAMPLER
 #define GLOBAL_SDF_SAMPLER SamplerLinearClamp
+#endif
 
 // Global SDF data for a constant buffer
 struct GlobalSDFData