$input v_texcoord0

/*
 * Copyright 2018 Eric Arnebäck. All rights reserved.
 * License: https://github.com/bkaradzic/bgfx#license-bsd-2-clause
 */

#include "../common/common.sh"

SAMPLER2D(s_tex, 0);

// pixel size of the target texture.
uniform vec4 u_pixelSize;

void main()
{
   vec2 halfpixel = 0.5 * vec2(u_pixelSize.x, u_pixelSize.y);
   vec2 oneepixel = 1.0 * vec2(u_pixelSize.x, u_pixelSize.y);
    
	vec2 uv = v_texcoord0.xy;
	
	vec4 sum = vec4(0.0, 0.0, 0.0, 0.0);
	
	sum += (4.0/32.0) * texture2D(s_tex, uv).rgba;
	
    sum += (4.0/32.0) * texture2D(s_tex, uv + vec2(-halfpixel.x, -halfpixel.y));
	sum += (4.0/32.0) * texture2D(s_tex, uv + vec2(+halfpixel.x, +halfpixel.y));
    sum += (4.0/32.0) * texture2D(s_tex, uv + vec2(+halfpixel.x, -halfpixel.y));
    sum += (4.0/32.0) * texture2D(s_tex, uv + vec2(-halfpixel.x, +halfpixel.y)	);
			
	sum += (2.0/32.0) * texture2D(s_tex, uv + vec2(+oneepixel.x, 0.0));
	sum += (2.0/32.0) * texture2D(s_tex, uv + vec2(-oneepixel.x, 0.0));
	sum += (2.0/32.0) * texture2D(s_tex, uv + vec2(0.0, +oneepixel.y));
	sum += (2.0/32.0) * texture2D(s_tex, uv + vec2(0.0, -oneepixel.y));
	
	sum += (1.0/32.0) * texture2D(s_tex, uv + vec2(+oneepixel.x, +oneepixel.y));
	sum += (1.0/32.0) * texture2D(s_tex, uv + vec2(-oneepixel.x, +oneepixel.y));
	sum += (1.0/32.0) * texture2D(s_tex, uv + vec2(+oneepixel.x, -oneepixel.y));
	sum += (1.0/32.0) * texture2D(s_tex, uv + vec2(-oneepixel.x, -oneepixel.y));
	
	gl_FragColor.xyzw = sum;
}