#ifdef DESC
[program]
type: graphics
vertex: main
fragment: main

[binding]
name: verts
rate: vertex
[attribute]
name: position
type: vec2
[attribute]
name: uv
type: vec2

[interpolator]
name: uv
type: vec2

[struct]
name: Config
[variable]
name: iview
type: mat4
[variable]
name: iprojection
type: mat4

[cbuffer]
name: config_buffer
type: Config
stage: fragment

[texture]
name: picture
stage: fragment
dimension: 2

[target]
name: colour
type: vec4
#endif

#ifdef VERTEX_SHADER
void main() {
	interpolator.uv = uv;
	gl_Position = vec4(position, 1.0, 1.0);
}
#endif

#ifdef FRAGMENT_SHADER
void main() {
	float pi = 3.14159265358979323846;
	vec2 uv = interpolator.uv;
	vec4 ndc = vec4(uv * 2.0 - 1.0, -1.0, 1.0);
	vec4 dir = config_buffer.iprojection * ndc;
	dir.w = 0.0;
	dir = config_buffer.iview * dir;
	dir.xyz = normalize(dir.xyz);
	uv = vec2(
		0.5f + 0.5f * atan(dir.z, dir.x) / pi,
		acos(dir.y) / pi
	);
	colour = texture(picture, uv);
}
#endif