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OpenMW/files/shaders/shadows_vertex.glsl

53 lines
2.1 KiB
GLSL

#define SHADOWS @shadows_enabled
#if SHADOWS
@foreach shadow_texture_unit_index @shadow_texture_unit_list
uniform int shadowTextureUnit@shadow_texture_unit_index;
varying vec4 shadowSpaceCoords@shadow_texture_unit_index;
#if @perspectiveShadowMaps
uniform mat4 validRegionMatrix@shadow_texture_unit_index;
varying vec4 shadowRegionCoords@shadow_texture_unit_index;
#endif
@endforeach
// Enabling this may reduce peter panning. Probably unnecessary.
const bool onlyNormalOffsetUV = false;
#endif // SHADOWS
void setupShadowCoords(vec4 viewPos, vec3 viewNormal)
{
#if SHADOWS
// This matrix has the opposite handedness to the others used here, so multiplication must have the vector to the left. Alternatively it could be transposed after construction, but that's extra work for the GPU just to make the code look a tiny bit cleaner.
mat4 eyePlaneMat;
vec4 shadowOffset;
@foreach shadow_texture_unit_index @shadow_texture_unit_list
eyePlaneMat = mat4(gl_EyePlaneS[shadowTextureUnit@shadow_texture_unit_index], gl_EyePlaneT[shadowTextureUnit@shadow_texture_unit_index], gl_EyePlaneR[shadowTextureUnit@shadow_texture_unit_index], gl_EyePlaneQ[shadowTextureUnit@shadow_texture_unit_index]);
#if @perspectiveShadowMaps
shadowRegionCoords@shadow_texture_unit_index = validRegionMatrix@shadow_texture_unit_index * viewPos;
#endif
#if @disableNormalOffsetShadows
shadowSpaceCoords@shadow_texture_unit_index = viewPos * eyePlaneMat;
#else
shadowOffset = vec4(viewNormal * @shadowNormalOffset, 0.0);
if (onlyNormalOffsetUV)
{
shadowSpaceCoords@shadow_texture_unit_index = viewPos * eyePlaneMat;
vec4 lightSpaceXY = viewPos + shadowOffset;
lightSpaceXY = lightSpaceXY * eyePlaneMat;
shadowSpaceCoords@shadow_texture_unit_index.xy = lightSpaceXY.xy;
}
else
{
vec4 offsetViewPosition = viewPos + shadowOffset;
shadowSpaceCoords@shadow_texture_unit_index = offsetViewPosition * eyePlaneMat;
}
#endif
@endforeach
#endif // SHADOWS
}