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fgdata/Shaders/HDR/envmap.vert

25 lines
876 B
GLSL

#version 330 core
out vec3 cubemap_coord0;
out vec3 cubemap_coord1;
out vec3 cubemap_coord2;
out vec3 cubemap_coord3;
out vec3 cubemap_coord4;
out vec3 cubemap_coord5;
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
cubemap_coord0 = vec3( 1.0, -pos.y, -pos.x);
cubemap_coord1 = vec3(- 1.0, -pos.y, pos.x);
cubemap_coord2 = vec3( pos.x, 1.0, pos.y);
cubemap_coord3 = vec3( pos.x, - 1.0, -pos.y);
cubemap_coord4 = vec3( pos.x, -pos.y, 1.0);
cubemap_coord5 = vec3(-pos.x, -pos.y, - 1.0);
}