Singularity/Library/PackageCache/com.unity.render-pipelines..../Shaders/CameraMotionVectors.shader
2024-05-06 11:45:45 -07:00

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Shader "Hidden/kMotion/CameraMotionVectors"
{
SubShader
{
Pass
{
Cull Off
ZWrite On
ZTest Always
HLSLPROGRAM
#pragma exclude_renderers d3d11_9x gles
#pragma target 3.5
#pragma vertex vert
#pragma fragment frag
// -------------------------------------
// Includes
#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Core.hlsl"
#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/DeclareDepthTexture.hlsl"
#if defined(USING_STEREO_MATRICES)
float4x4 _PrevViewProjMStereo[2];
#define _PrevViewProjM _PrevViewProjMStereo[unity_StereoEyeIndex]
#else
#define _PrevViewProjM _PrevViewProjMatrix
#endif
// -------------------------------------
// Structs
struct Attributes
{
uint vertexID : SV_VertexID;
};
struct Varyings
{
float4 position : SV_POSITION;
};
// -------------------------------------
// Vertex
Varyings vert(Attributes input)
{
Varyings output;
output.position = GetFullScreenTriangleVertexPosition(input.vertexID);
return output;
}
// -------------------------------------
// Fragment
half4 frag(Varyings input, out float outDepth : SV_Depth) : SV_Target
{
// Calculate PositionInputs
half depth = LoadSceneDepth(input.position.xy).x;
outDepth = depth;
half2 screenSize = _ScreenSize.zw;
PositionInputs positionInputs = GetPositionInput(input.position.xy, screenSize, depth, UNITY_MATRIX_I_VP, UNITY_MATRIX_V);
// Calculate positions
float4 previousPositionVP = mul(_PrevViewProjM, float4(positionInputs.positionWS, 1.0));
float4 positionVP = mul(UNITY_MATRIX_VP, float4(positionInputs.positionWS, 1.0));
previousPositionVP.xy *= rcp(previousPositionVP.w);
positionVP.xy *= rcp(positionVP.w);
// Calculate velocity
float2 velocity = (positionVP.xy - previousPositionVP.xy);
#if UNITY_UV_STARTS_AT_TOP
velocity.y = -velocity.y;
#endif
// Convert velocity from Clip space (-1..1) to NDC 0..1 space
// Note it doesn't mean we don't have negative value, we store negative or positive offset in NDC space.
// Note: ((positionVP * 0.5 + 0.5) - (previousPositionVP * 0.5 + 0.5)) = (velocity * 0.5)
return half4(velocity.xy * 0.5, 0, 0);
}
ENDHLSL
}
}
}