input View {
  mat4 mvp,
  mat4 proj,
  mat4 proj_inverse,
  mat4 view,
  mat4 world, //geometry.world atm
  float2 fov, //fov.x, fov.y
  float2 resolution,
  float4 target_region,
  float4 target_region_size
}

input MaskedSprite {
    float4 uv,
    float4 color,
    float2 skew,
    bool2 uv_flip,
    #0 image2D image,
    #1 image2D mask
    // bool flipy
}

stage vertex vert(
		input { View view, MaskedSprite sprite },
		vertex in { #0 float4 pos, #1 float4 color, #2 float2 uv },
		fragment out { float4 color, float2 uv})
{
		out.color = in.color;
		out.uv = in.uv;

		mat4 skew = mat4(
				float4(1,input.sprite.skew.x,0,0),
				float4(input.sprite.skew.y,1,0,0),
				float4(0,0,1,0),
				float4(0,0,0,1)
		);

		stage.pos = input.view.mvp * (skew * float4(in.pos.xyz, 1.0));
}

stage fragment frag(
		input { MaskedSprite sprite },
		fragment in { float4 color, float2 uv })
{
		float4 uv = input.sprite.uv;

		if(input.sprite.uv_flip.x) {
				uv.x = input.sprite.uv.z; //left
				uv.z = input.sprite.uv.x; //right
		}

		if(input.sprite.uv_flip.y) {
				uv.y = input.sprite.uv.w; //top
				uv.w = input.sprite.uv.y; //bottom
		}

		float4 color = texture(input.sprite.image, uv.xy + (in.uv.xy * (uv.zw - uv.xy)));
		color.a *= texture(input.sprite.mask, in.uv.xy).a;

		if(color.a <= 0.0) {
				discard;
				return;
		}

		stage.color[0] = color * in.color * input.sprite.color;
}