Added Stochastic Sampling material node

Source/Editor/Surface/Archetypes/Textures.cs

@@ -405,6 +405,24 @@ namespace FlaxEditor.Surface.Archetypes
                     NodeElementArchetype.Factory.Output(0, "Color", typeof(Float3), 3)
                 }
             },
+            new NodeArchetype
+            {
+                TypeID = 17,
+                Title = "Stochastic Sample Texture",
+                Description = "Projects a texture using world-space coordinates instead of UVs.",
+                Flags = NodeFlags.MaterialGraph,
+                Size = new Float2(240, 60),
+                DefaultValues = new object[]
+                {
+                    new Float2(1.0f, 1.0f),
+                },
+                Elements = new[]
+                {
+                    NodeElementArchetype.Factory.Input(0, "Texture", true, typeof(FlaxEngine.Object), 0),
+                    NodeElementArchetype.Factory.Input(1, "UV", true, typeof(Float2), 1, 0),
+                    NodeElementArchetype.Factory.Output(0, "Color", typeof(Float4), 2),
+                }
+            },
         };
     }
 }

Source/Engine/Tools/MaterialGenerator/MaterialGenerator.Textures.cpp

@@ -669,6 +669,115 @@ void MaterialGenerator::ProcessGroupTextures(Box* box, Node* node, Value& value)
         _writer.Write(*triplanarTexture);
         value = result;
     }
+    case 17:
+    {
+        auto textureBox = node->GetBox(0);
+        auto uvsBox = node->GetBox(1);
+
+        Value uvs;
+        const bool useCustomUVs = uvsBox->HasConnection();
+        if (useCustomUVs)
+        {
+            // Get custom UVs
+            uvs = eatBox(uvsBox->GetParent<Node>(), uvsBox->FirstConnection());
+        }
+        else
+        {
+            // Use default UVs
+            uvs = getUVs;
+        }
+
+        if (!textureBox->HasConnection())
+        {
+            // No texture to sample
+            value = Value::Zero;
+            break;
+        }
+
+        if (!CanUseSample(_treeType))
+        {
+            // Must sample texture in pixel shader
+            value = Value::Zero;
+            break;
+        }
+
+        const auto texture = eatBox(textureBox->GetParent<Node>(), textureBox->FirstConnection());
+        const auto textureParam = findParam(texture.Value);
+        const bool isNormalMap = textureParam->Type == MaterialParameterType::NormalMap;
+
+        auto result = writeLocal(Value::InitForZero(ValueType::Float4), node);
+        createGradients(node);
+
+        auto proceduralSample = String::Format(TEXT(
+            "   {{\n"
+            "   float W1, W2, W3;\n"
+            "   float2 vertex1, vertex2, vertex3;\n"
+            "   float2 uv = {0} * 3.464; // 2 * sqrt (3);\n"
+            "   float2 UV1, UV2, UV3;\n"
+            "   const float2x2 gridToSkewedGrid = float2x2( 1.0, 0.0, -0.57735027, 1.15470054 );\n"
+            "   float2 skewedCoord = mul( gridToSkewedGrid, uv );\n"
+            "   int2 baseId = int2( floor( skewedCoord ) );\n"
+            "   float3 temp = float3( frac( skewedCoord ), 0 );\n"
+            "   temp.z = 1.0 - temp.x - temp.y;\n"
+            "   if ( temp.z > 0.0 )\n"
+            "   {{\n"
+            "   	W1 = temp.z;\n"
+            "   	W2 = temp.y;\n"
+            "   	W3 = temp.x;\n"
+            "   	vertex1 = baseId;\n"
+            "   	vertex2 = baseId + int2( 0, 1 );\n"
+            "   	vertex3 = baseId + int2( 1, 0 );\n"
+            "   }}\n"
+            "   else\n"
+            "   {{\n"
+            "   	W1 = -temp.z;\n"
+            "   	W2 = 1.0 - temp.y;\n"
+            "   	W3 = 1.0 - temp.x;\n"
+            "   	vertex1 = baseId + int2( 1, 1 );\n"
+            "   	vertex2 = baseId + int2( 1, 0 );\n"
+            "   	vertex3 = baseId + int2( 0, 1 );\n"
+            "   }}\n"
+            "   UV1 = {0} + frac( sin( mul( float2x2( 127.1, 311.7, 269.5, 183.3 ), vertex1 ) ) * 43758.5453 );\n"
+            "   UV2 = {0} + frac( sin( mul( float2x2( 127.1, 311.7, 269.5, 183.3 ), vertex2 ) ) * 43758.5453 );\n"
+            "   UV3 = {0} + frac( sin( mul( float2x2( 127.1, 311.7, 269.5, 183.3 ), vertex3 ) ) * 43758.5453 );\n"
+            "   float4 tex1 = {1}.SampleGrad(SamplerLinearWrap, UV1, {2}, {3});\n"
+            "   float4 tex2 = {1}.SampleGrad(SamplerLinearWrap, UV2, {2}, {3});\n"
+            "   float4 tex3 = {1}.SampleGrad(SamplerLinearWrap, UV3, {2}, {3});\n"
+        ),
+            uvs.Value, // {0}
+            texture.Value, // {1}
+            _ddx.Value, // {2}
+            _ddy.Value // {3}
+        );
+
+        // Decode normal map vector
+        if (isNormalMap)
+        {
+            proceduralSample += String::Format(TEXT(
+            "   tex1.xy = tex1.xy * 2.0 - 1.0;\n"
+            "   tex1.z = sqrt(saturate(1.0 - dot(tex1.xy, tex1.xy))); \n"
+            "   tex2.xy = tex2.xy * 2.0 - 1.0;\n"
+            "   tex2.z = sqrt(saturate(1.0 - dot(tex2.xy, tex2.xy))); \n"
+            "   tex3.xy = tex3.xy * 2.0 - 1.0;\n"
+            "   tex3.z = sqrt(saturate(1.0 - dot(tex3.xy, tex3.xy))); \n"
+            ));
+        }
+
+        proceduralSample += String::Format(TEXT(
+            "   tex1 *= W1;\n"
+            "   tex2 *= W2;\n"
+            "   tex3 *= W3;\n"
+            "   {0} = tex1 + tex2 + tex3;\n"
+            "	}}\n"
+        ),
+            result.Value // {0}
+        );
+
+        _writer.Write(*proceduralSample);
+        value = result;
+
+        break;
+    }
     default:
         break;
     }