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

[binding]
name: mesh
rate: vertex
[attribute]
name: position
type: vec3
[attribute]
name: normal
type: vec3
[attribute]
name: tangent
type: vec3
[attribute]
name: uv
type: vec2

[interpolator]
name: uv
type: vec2
[interpolator]
name: position
type: vec4
[interpolator]
name: normal
type: vec3
[interpolator]
name: tbn
type: mat3

[struct]
name: MVP
[variable]
name: model
type: mat4
[variable]
name: view_projection
type: mat4

[struct]
name: Material
[variable]
name: albedo
type: vec3
[variable]
name: metalness
type: float
[variable]
name: roughness
type: float
[variable]
name: ao
type: float

[cbuffer]
name: c_mvp
type: MVP
stage: vertex

[cbuffer]
name: material
type: Material
stage: fragment

[texture]
name: albedo
stage: fragment
dimension: 2
[texture]
name: ao
stage: fragment
dimension: 2
[texture]
name: metal
stage: fragment
dimension: 2
[texture]
name: rough
stage: fragment
dimension: 2
[texture]
name: normal
stage: fragment
dimension: 2

[target]
name: colour
type: vec4

#endif

#ifdef VERTEX_SHADER

void main() {
	vec4 pos = c_mvp.model * vec4(position, 1.0);
	vec3 t = normalize((c_mvp.model * vec4(tangent, 0.0)).xyz);
	vec3 n = normalize((c_mvp.model * vec4(normal, 0.0)).xyz);
	vec3 b = cross(t, n);
	interpolator.normal = n;
	interpolator.tbn = mat3(t, b, n);
	interpolator.uv = uv;
	interpolator.position = pos;
	interpolator.tbn = mat3(t, b, n);
	gl_Position = c_mvp.view_projection * pos;
}

#endif

#ifdef FRAGMENT_SHADER

void main() {
	vec2 uv = interpolator.uv;

	vec3 nrmsample = texture(normal, uv).rgb;

	vec2 nrmxy = nrmsample.xy * 2.0 - 1.0;
	vec3 nrm = normalize(vec3(nrmxy, 1.0));
	if (nrmsample.b == 1.0) /* default texture */
		nrm = vec3(0, 0, 1);
	nrm = normalize(interpolator.tbn * nrm);

	float light = max(dot(nrm, vec3(0, 0, 1)), 0.0);

	vec3 ambient = 0.05.xxx * texture(ao, uv).r;
	vec3 col = ambient + light * material.albedo;
	col *= texture(albedo, uv).rgb;
	colour = vec4(col, 1.0);
}

#endif