#version 410

in vec2 xy;

out vec3 xyzV;

uniform mat4 cameraMatrix;
uniform float eyePos;

void main(void)
{
    // screen location is rectangle set at the far Z.
    vec4 pos = vec4(xy, 0.99999, 1.0);
    gl_Position = pos;

    // fragment shader renders the infinite sphere with this
    xyzV = inverse(mat3(cameraMatrix)) * vec3(xy, -eyePos);
}