#version 430 core

//reference https://learnopengl.com/Advanced-Lighting/Bloom
out vec4 FragColor;

in vec2 TexCoords;

uniform sampler2D image;

uniform bool horizontal;
uniform float weight[5] = float[] (0.2270270270, 0.1945945946, 0.1216216216, 0.0540540541, 0.0162162162);

void main()
{

		vec2 tex_offset = 1.0 / textureSize(image, 0); // gets size of single texel
		vec3 result = texture(image, TexCoords).rgb * weight[0];

		if(horizontal)
		{
			for(int i = 1; i < 5; ++i)
			{
			result += texture(image, TexCoords + vec2(tex_offset.x * i, 0.0)).rgb * weight[i];
			result += texture(image, TexCoords - vec2(tex_offset.x * i, 0.0)).rgb * weight[i];
			}
		}
		else
		{
			for(int i = 1; i < 5; ++i)
			{
				result += texture(image, TexCoords + vec2(0.0, tex_offset.y * i)).rgb * weight[i];
				result += texture(image, TexCoords - vec2(0.0, tex_offset.y * i)).rgb * weight[i];
			}
		}
		FragColor = vec4(result, 1.0);

}