57 lines
1.6 KiB
Text
57 lines
1.6 KiB
Text
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/* Copyright (c) 2024, Sascha Willems
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*
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* SPDX-License-Identifier: MIT
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*
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*/
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struct Attributes
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{
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float2 bary;
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};
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struct Payload
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{
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[[vk::location(0)]] float3 hitValue;
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};
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struct UBO
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{
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float4x4 viewInverse;
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float4x4 projInverse;
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float4 lightPos;
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};
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cbuffer ubo : register(b2)
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{
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UBO ubo;
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};
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[[vk::ext_extension("SPV_KHR_ray_tracing_position_fetch")]]
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[shader("closesthit")]
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void main(inout Payload p, in Attributes attribs)
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{
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// We need the barycentric coordinates to calculate data for the current position
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const float3 barycentricCoords = float3(1.0f - attribs.bary.x - attribs.bary.y, attribs.bary.x, attribs.bary.y);
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// With VK_KHR_ray_tracing_position_fetch we can access the vertices for the hit triangle in the shader
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// We need to use special syntax for SPIR-V inlines
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#define HitTriangleVertexPositionsKHR 5391
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[[vk::ext_builtin_output(HitTriangleVertexPositionsKHR)]]
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static float3 gl_HitTriangleVertexPositions[3];
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float3 vertexPos0 = gl_HitTriangleVertexPositions[0];
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float3 vertexPos1 = gl_HitTriangleVertexPositions[1];
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float3 vertexPos2 = gl_HitTriangleVertexPositions[2];
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float3 currentPos = vertexPos0 * barycentricCoords.x + vertexPos1 * barycentricCoords.y + vertexPos2 * barycentricCoords.z;
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// Calcualte the normal from above values
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float3 normal = normalize(cross(vertexPos1 - vertexPos0, vertexPos2 - vertexPos0));
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normal = normalize(mul(float4(normal, 1.0), WorldToObject4x3()));
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// Basic lighting
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float3 lightDir = normalize(ubo.lightPos.xyz - currentPos);
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float diffuse = max(dot(normal, lightDir), 0.0);
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p.hitValue.rgb = 0.1 + diffuse;
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}
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