93 lines
3.4 KiB
HLSL
93 lines
3.4 KiB
HLSL
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#ifndef UNITY_SHADER_VARIABLES_FUNCTIONS_INCLUDED
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#define UNITY_SHADER_VARIABLES_FUNCTIONS_INCLUDED
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#include "Packages/com.unity.render-pipelines.core/ShaderLibrary/SpaceTransforms.hlsl"
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// Note: '_WorldSpaceCameraPos' is set by the legacy Unity code.
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float3 GetPrimaryCameraPosition()
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{
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#if (SHADEROPTIONS_CAMERA_RELATIVE_RENDERING != 0)
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return float3(0, 0, 0);
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#else
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return _WorldSpaceCameraPos;
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#endif
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}
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// Could be e.g. the position of a primary camera or a shadow-casting light.
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float3 GetCurrentViewPosition()
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{
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#if defined(SHADERPASS) && (SHADERPASS != SHADERPASS_SHADOWS)
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return GetPrimaryCameraPosition();
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#else
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// This is a generic solution.
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// However, for the primary camera, using '_WorldSpaceCameraPos' is better for cache locality,
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// and in case we enable camera-relative rendering, we can statically set the position is 0.
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return UNITY_MATRIX_I_V._14_24_34;
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#endif
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}
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// Returns the forward (central) direction of the current view in the world space.
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float3 GetViewForwardDir()
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{
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float4x4 viewMat = GetWorldToViewMatrix();
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return -viewMat[2].xyz;
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}
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// Returns 'true' if the current view performs a perspective projection.
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bool IsPerspectiveProjection()
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{
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#if defined(SHADERPASS) && (SHADERPASS != SHADERPASS_SHADOWS)
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return (unity_OrthoParams.w == 0);
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#else
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// TODO: set 'unity_OrthoParams' during the shadow pass.
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return UNITY_MATRIX_P[3][3] == 0;
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#endif
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}
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// Computes the world space view direction (pointing towards the viewer).
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float3 GetWorldSpaceNormalizeViewDir(float3 positionWS)
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{
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if (IsPerspectiveProjection())
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{
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// Perspective
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float3 V = GetCurrentViewPosition() - positionWS;
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return normalize(V);
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}
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else
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{
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// Orthographic
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return -GetViewForwardDir();
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}
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}
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// UNITY_MATRIX_V defines a right-handed view space with the Z axis pointing towards the viewer.
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// This function reverses the direction of the Z axis (so that it points forward),
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// making the view space coordinate system left-handed.
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void GetLeftHandedViewSpaceMatrices(out float4x4 viewMatrix, out float4x4 projMatrix)
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{
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viewMatrix = UNITY_MATRIX_V;
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viewMatrix._31_32_33_34 = -viewMatrix._31_32_33_34;
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projMatrix = UNITY_MATRIX_P;
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projMatrix._13_23_33_43 = -projMatrix._13_23_33_43;
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}
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#if UNITY_REVERSED_Z
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#if (defined(SHADER_API_GLCORE) && !defined(SHADER_API_SWITCH)) || defined(SHADER_API_GLES) || defined(SHADER_API_GLES3)
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//GL with reversed z => z clip range is [near, -far] -> should remap in theory but dont do it in practice to save some perf (range is close enough)
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#define UNITY_Z_0_FAR_FROM_CLIPSPACE(coord) max(-(coord), 0)
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#else
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//D3d with reversed Z => z clip range is [near, 0] -> remapping to [0, far]
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//max is required to protect ourselves from near plane not being correct/meaningfull in case of oblique matrices.
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#define UNITY_Z_0_FAR_FROM_CLIPSPACE(coord) max(((1.0-(coord)/_ProjectionParams.y)*_ProjectionParams.z),0)
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#endif
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#elif UNITY_UV_STARTS_AT_TOP
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//D3d without reversed z => z clip range is [0, far] -> nothing to do
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#define UNITY_Z_0_FAR_FROM_CLIPSPACE(coord) (coord)
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#else
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//Opengl => z clip range is [-near, far] -> should remap in theory but dont do it in practice to save some perf (range is close enough)
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#define UNITY_Z_0_FAR_FROM_CLIPSPACE(coord) (coord)
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#endif
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#endif // UNITY_SHADER_VARIABLES_FUNCTIONS_INCLUDED
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