chromatic aberration shader

chromatic_aberration.glsl

//this is the vertex shader
attribute vec3 in_Position;
attribute vec4 in_Colour;
attribute vec2 in_Texture_Coordinate;

varying vec2 vertex_texture_coordinate;

void main() {
    
    vec4 vertex_model_position = vec4(in_Position, 1.0);
    
    vertex_texture_coordinate = in_Texture_Coordinate;
    
    gl_Position = gm_Matrices[MATRIX_WORLD_VIEW_PROJECTION] * vertex_model_position;
    
}

//this is the fragment shader
varying vec2 vertex_texture_coordinate;

uniform vec2 texel_dimensions;

//x and y are vector components for direction -1 to 1, and z is the number of texels
uniform vec3 red_bleed;
uniform vec3 green_bleed;
uniform vec3 blue_bleed;

void main() {
    
    float red = texture2D(gm_BaseTexture, vertex_texture_coordinate + ((red_bleed.xy * red_bleed.z) * texel_dimensions)).r;
    float green = texture2D(gm_BaseTexture, vertex_texture_coordinate + ((green_bleed.xy * green_bleed.z) * texel_dimensions)).g;
    float blue = texture2D(gm_BaseTexture, vertex_texture_coordinate + ((blue_bleed.xy * blue_bleed.z) * texel_dimensions)).b;
    
    float alpha = texture2D(gm_BaseTexture, vertex_texture_coordinate).a;
    
    gl_FragColor = vec4(red, green, blue, alpha);
    
}