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fgdata/Shaders/HDR/envmap-prefilter.vert
2021-08-31 18:02:38 +02:00

24 lines
843 B
GLSL

#version 330 core
out vec3 cubemapCoord0;
out vec3 cubemapCoord1;
out vec3 cubemapCoord2;
out vec3 cubemapCoord3;
out vec3 cubemapCoord4;
out vec3 cubemapCoord5;
void main()
{
vec2 pos = vec2(gl_VertexID % 2, gl_VertexID / 2) * 4.0 - 1.0;
gl_Position = vec4(pos, 0.0, 1.0);
// Map the quad texture coordinates to a direction vector to sample
// the cubemap. This assumes that we are using the weird left-handed
// orientations given by the OpenGL spec.
// See https://www.khronos.org/opengl/wiki/Cubemap_Texture#Upload_and_orientation
cubemapCoord0 = vec3(1.0, -pos.y, -pos.x);
cubemapCoord1 = vec3(-1.0, -pos.y, pos.x);
cubemapCoord2 = vec3(pos.x, 1.0, pos.y);
cubemapCoord3 = vec3(pos.x, -1.0, -pos.y);
cubemapCoord4 = vec3(pos.x, -pos.y, 1.0);
cubemapCoord5 = vec3(-pos.x, -pos.y, -1.0);
}