#version 450
#extension GL_ARB_separate_shader_objects : enable

layout(std140, push_constant) uniform CameraData
{
    mat4 viewProjection;
    mat4 view;
    mat4 projection;
    vec4 camPos;
    float nearPlane;
    float farPlane;
    float width;
    float height;
    float fov;
    float aspect;
} cam;

// Grid position are in clipped space
vec4 gridPlane[4] = vec4[] (
    vec4(1, 1, 0, 1), vec4(-1, 1, 0, 1), vec4(1, -1, 0, 1), vec4(-1, -1, 0, 1)
);

float realFov = 53;
float realAspect = 1.33333333;

void main() {
    float virtualAspect = cam.width / cam.height;
    vec4 position = gridPlane[gl_VertexIndex];

    // Calculate the scaling factors for width and height
    float scaleX = tan(radians(cam.fov * 0.5)) / tan(radians(realFov * 0.5));
    float scaleY = virtualAspect / realAspect * scaleX;

    // Scale the quad's position
    position.xy *= vec2(scaleX, scaleY);

    // Pass the transformed position to the fragment shader
    gl_Position = position;
}