armorpaint/base/shaders/pass_viewray2.vert.glsl

#version 450

uniform mat4 invP;

in vec2 pos;

out vec2 tex_coord;
out vec3 view_ray;

void main() {
	// Scale vertex attribute to [0-1] range
	const vec2 madd = vec2(0.5, 0.5);
	tex_coord = pos.xy * madd + madd;

#ifdef GLSL
#else
	tex_coord.y = 1.0 - tex_coord.y;
#endif

	gl_Position = vec4(pos.xy, 0.0, 1.0);

	// NDC (at the back of cube)
	vec4 v = vec4(pos.x, pos.y, 1.0, 1.0);
	v = vec4(mul(v, invP));
	view_ray = vec3(v.xy / v.z, 1.0);
}