#version 330 layout (location = 0) in vec2 pos; out vec2 apos; layout (std140) uniform Projection { mat4 projection; }; void main() { mat4 iproj = inverse(projection); vec4 ipos = iproj * vec4(pos, 0.f, 1.f); apos = ipos.xy; gl_Position = vec4(pos, 0.f, 1.f); }