Added slang shaders for ssao sample

Author: SaschaWillems

shaders/slang/ssao/blur.slang

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+/* Copyright (c) 2025, Sascha Willems
+ *
+ * SPDX-License-Identifier: MIT
+ *
+ */
+
+import types;
+
+Sampler2D samplerSSAO;
+
+[shader("fragment")]
+float4 fragmentMain(VSOutput input)
+{
+	const int blurRange = 2;
+	int n = 0;
+    int2 texDim;
+    samplerSSAO.GetDimensions(texDim.x, texDim.y);
+	float2 texelSize = 1.0 / (float2)texDim;
+	float result = 0.0;
+	for (int x = -blurRange; x <= blurRange; x++)
+	{
+		for (int y = -blurRange; y <= blurRange; y++)
+		{
+            float2 offset = float2(float(x), float(y)) * texelSize;
+            result += samplerSSAO.Sample(input.UV + offset).r;
+			n++;
+		}
+	}
+	return result / (float(n));
+}

shaders/slang/ssao/composition.slang

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+/* Copyright (c) 2025, Sascha Willems
+ *
+ * SPDX-License-Identifier: MIT
+ *
+ */
+
+import types;
+
+Sampler2D samplerposition;
+Sampler2D samplerNormal;
+Sampler2D samplerAlbedo;
+Sampler2D samplerSSAO;
+Sampler2D samplerSSAOBlur;
+
+struct UBO
+{
+	float4x4 _dummy;
+	int ssao;
+	int ssaoOnly;
+	int ssaoBlur;
+};
+ConstantBuffer<UBO> uboParams;
+
+[shader("fragment")]
+float4 fragmentMain(VSOutput input)
+{
+    float3 fragPos = samplerposition.Sample(input.UV).rgb;
+    float3 normal = normalize(samplerNormal.Sample(input.UV).rgb * 2.0 - 1.0);
+    float4 albedo = samplerAlbedo.Sample(input.UV);
+
+    float ssao = (uboParams.ssaoBlur == 1) ? samplerSSAOBlur.Sample(input.UV).r : samplerSSAO.Sample(input.UV).r;
+
+	float3 lightPos = float3(0.0, 0.0, 0.0);
+	float3 L = normalize(lightPos - fragPos);
+	float NdotL = max(0.5, dot(normal, L));
+
+	float4 outFragColor;
+	if (uboParams.ssaoOnly == 1)
+	{
+		outFragColor.rgb = ssao.rrr;
+	}
+	else
+	{
+		float3 baseColor = albedo.rgb * NdotL;
+
+		if (uboParams.ssao == 1)
+		{
+			outFragColor.rgb = ssao.rrr;
+
+			if (uboParams.ssaoOnly != 1)
+				outFragColor.rgb *= baseColor;
+		}
+		else
+		{
+			outFragColor.rgb = baseColor;
+		}
+	}
+	return outFragColor;
+}

shaders/slang/ssao/fullscreen.slang

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+/* Copyright (c) 2025, Sascha Willems
+ *
+ * SPDX-License-Identifier: MIT
+ *
+ */
+
+import types;
+
+[shader("vertex")]
+VSOutput vertexMain(uint VertexIndex : SV_VertexID)
+{
+	VSOutput output;
+	output.UV = float2((VertexIndex << 1) & 2, VertexIndex & 2);
+	output.Pos = float4(output.UV * 2.0f - 1.0f, 0.0f, 1.0f);
+	return output;
+}

shaders/slang/ssao/gbuffer.slang

@@ -0,0 +1,73 @@
+/* Copyright (c) 2025, Sascha Willems
+ *
+ * SPDX-License-Identifier: MIT
+ *
+ */
+
+struct VSInput
+{
+    float4 Pos;
+    float2 UV;
+    float3 Color;
+    float3 Normal;
+};
+
+struct VSOutput
+{
+    float4 Pos : SV_POSITION;
+    float3 Normal;
+    float2 UV;
+    float3 Color;
+    float3 WorldPos;
+};
+
+struct FSOutput
+{
+    float4 Position : SV_TARGET0;
+    float4 Normal : SV_TARGET1;
+    float4 Albedo : SV_TARGET2;
+};
+
+struct UBO
+{
+    float4x4 projection;
+    float4x4 model;
+    float4x4 view;
+    float nearPlane;
+    float farPlane;
+};
+ConstantBuffer<UBO> ubo;
+
+[[vk::binding(0, 1)]] Texture2D textureColorMap;
+[[vk::binding(0, 1)]] SamplerState samplerColorMap;
+
+[shader("vertex")]
+VSOutput vertexMain(VSInput input)
+{
+    VSOutput output;
+    output.Pos = mul(ubo.projection, mul(ubo.view, mul(ubo.model, input.Pos)));
+    output.UV = input.UV;
+    // Vertex position in view space
+    output.WorldPos = mul(ubo.view, mul(ubo.model, input.Pos)).xyz;
+    // Normal in view space
+    float3x3 normalMatrix = (float3x3)mul(ubo.view, ubo.model);
+    output.Normal = mul(normalMatrix, input.Normal);
+    output.Color = input.Color;
+    return output;
+}
+
+float linearDepth(float depth)
+{
+	float z = depth * 2.0f - 1.0f;
+	return (2.0f * ubo.nearPlane * ubo.farPlane) / (ubo.farPlane + ubo.nearPlane - z * (ubo.farPlane - ubo.nearPlane));
+}
+
+[shader("fragment")]
+FSOutput fragmentMain(VSOutput input)
+{
+	FSOutput output;
+	output.Position = float4(input.WorldPos, linearDepth(input.Pos.z));
+	output.Normal = float4(normalize(input.Normal) * 0.5 + 0.5, 1.0);
+	output.Albedo = textureColorMap.Sample(samplerColorMap, input.UV) * float4(input.Color, 1.0);
+	return output;
+}

shaders/slang/ssao/ssao.slang

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+/* Copyright (c) 2025, Sascha Willems
+ *
+ * SPDX-License-Identifier: MIT
+ *
+ */
+
+import types;
+
+Sampler2D samplerPositionDepth;
+Sampler2D samplerNormal;
+Sampler2D ssaoNoiseSampler;
+
+struct UBOSSAOKernel
+{
+	float4 samples[64];
+};
+ConstantBuffer<UBOSSAOKernel> uboSSAOKernel;
+
+struct UBO
+{
+	float4x4 projection;
+};
+ConstantBuffer<UBO> ubo;
+
+[[SpecializationConstant]] const int SSAO_KERNEL_SIZE = 64;
+[[SpecializationConstant]] const float SSAO_RADIUS = 0.5;
+
+[shader("fragment")]
+float fragmentMain(VSOutput input)
+{
+    // Get G-Buffer values
+    float3 fragPos = samplerPositionDepth.Sample(input.UV).rgb;
+    float3 normal = normalize(samplerNormal.Sample(input.UV).rgb * 2.0 - 1.0);
+
+	// Get a random vector using a noise lookup
+    int2 texDim;
+    samplerPositionDepth.GetDimensions(texDim.x, texDim.y);
+    int2 noiseDim;
+    ssaoNoiseSampler.GetDimensions(noiseDim.x, noiseDim.y);
+    const float2 noiseUV = float2(float(texDim.x) / float(noiseDim.x), float(texDim.y) / (noiseDim.y)) * input.UV;
+    float3 randomVec = ssaoNoiseSampler.Sample(noiseUV).xyz * 2.0 - 1.0;
+
+	// Create TBN matrix
+	float3 tangent = normalize(randomVec - normal * dot(randomVec, normal));
+	float3 bitangent = cross(tangent, normal);
+	float3x3 TBN = transpose(float3x3(tangent, bitangent, normal));
+
+	// Calculate occlusion value
+	float occlusion = 0.0f;
+	for(int i = 0; i < SSAO_KERNEL_SIZE; i++)
+	{
+		float3 samplePos = mul(TBN, uboSSAOKernel.samples[i].xyz);
+		samplePos = fragPos + samplePos * SSAO_RADIUS;
+
+		// project
+		float4 offset = float4(samplePos, 1.0f);
+		offset = mul(ubo.projection, offset);
+		offset.xyz /= offset.w;
+		offset.xyz = offset.xyz * 0.5f + 0.5f;
+
+        float sampleDepth = -samplerPositionDepth.Sample(offset.xy).w;
+
+		float rangeCheck = smoothstep(0.0f, 1.0f, SSAO_RADIUS / abs(fragPos.z - sampleDepth));
+		occlusion += (sampleDepth >= samplePos.z ? 1.0f : 0.0f) * rangeCheck;
+	}
+	occlusion = 1.0 - (occlusion / float(SSAO_KERNEL_SIZE));
+
+	return occlusion;
+}
+

shaders/slang/ssao/types.slang

@@ -0,0 +1,13 @@
+/* Copyright (c) 2025, Sascha Willems
+ *
+ * SPDX-License-Identifier: MIT
+ *
+ */
+
+module types;
+
+public struct VSOutput
+{
+    public float4 Pos : SV_POSITION;
+    public float2 UV;
+};