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fgdata/Shaders/shadows-include.vert
2020-12-06 14:44:03 +01:00

47 lines
1.4 KiB
GLSL

#version 120
uniform bool shadows_enabled;
uniform int sun_atlas_size;
uniform mat4 fg_LightMatrix_csm0;
uniform mat4 fg_LightMatrix_csm1;
uniform mat4 fg_LightMatrix_csm2;
uniform mat4 fg_LightMatrix_csm3;
varying vec4 lightSpacePos[4];
const float NORMAL_OFFSET_SCALE = 200.0;
void setupShadows(vec4 eyeSpacePos)
{
if (!shadows_enabled)
return;
vec3 normal = gl_NormalMatrix * gl_Normal;
vec3 toLight = normalize(gl_LightSource[0].position.xyz);
float costheta = dot(normal, toLight);
float slopeScale = clamp(1.0 - costheta, 0.0, 1.0);
float texelSize = 1.0 / sun_atlas_size;
float normalOffset = NORMAL_OFFSET_SCALE * slopeScale * texelSize;
vec4 offsetPos = eyeSpacePos + vec4(normal * normalOffset, 0.0);
vec4 offsets[4];
offsets[0] = fg_LightMatrix_csm0 * offsetPos;
offsets[1] = fg_LightMatrix_csm1 * offsetPos;
offsets[2] = fg_LightMatrix_csm2 * offsetPos;
offsets[3] = fg_LightMatrix_csm3 * offsetPos;
lightSpacePos[0] = fg_LightMatrix_csm0 * eyeSpacePos;
lightSpacePos[1] = fg_LightMatrix_csm1 * eyeSpacePos;
lightSpacePos[2] = fg_LightMatrix_csm2 * eyeSpacePos;
lightSpacePos[3] = fg_LightMatrix_csm3 * eyeSpacePos;
// Offset only in UV space
lightSpacePos[0].xy = offsets[0].xy;
lightSpacePos[1].xy = offsets[1].xy;
lightSpacePos[2].xy = offsets[2].xy;
lightSpacePos[3].xy = offsets[3].xy;
}