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 Font {
	image2D page0,
	image2D page1,
	image2D page2,
	image2D page3,
	image2D page4,
	image2D page5,
	image2D page6,
	image2D page7
}

stage vertex vert(
    input { View view },
    vertex in { #0 float4 pos, #1 float4 color, #2 float2 uv },
    fragment out { float4 color, float2 uv, float page })
{
    out.color = in.color;
    out.uv = in.uv;
    out.page = in.pos.w;
    stage.pos = input.view.mvp * float4(in.pos.xyz, 1.0);
}

stage fragment frag(
    input { Font font },
    fragment in { float4 color, float2 uv, float page })
{
  int page = int(in.page);
	float4 msdf_sample = texture(input.font.page0, in.uv.xy);
	if(page == 1) { msdf_sample = texture(input.font.page1, in.uv.xy); }
	if(page == 2) { msdf_sample = texture(input.font.page2, in.uv.xy); }
	if(page == 3) { msdf_sample = texture(input.font.page3, in.uv.xy); }
	if(page == 4) { msdf_sample = texture(input.font.page4, in.uv.xy); }
	if(page == 5) { msdf_sample = texture(input.font.page5, in.uv.xy); }
	if(page == 6) { msdf_sample = texture(input.font.page6, in.uv.xy); }
	if(page == 7) { msdf_sample = texture(input.font.page7, in.uv.xy); }

	float r = msdf_sample.r;
	float g = msdf_sample.g;
	float b = msdf_sample.b;
	float median = max(min(r, g), min(max(r, g), b));
	float opacity = step(0.5, median);

	stage.color[0] = float4(in.color.rgb, in.color.a * opacity);
}