I am working on a shader that creates a white border around red objects. I am checking every diagonal pixel. If a current pixel is not red and one of diagonal pixels is red then making it white. To increase the size of the border I am checking further distanced diagonal pixles.
here is the shader code
shader_type canvas_item;
void fragment(){
vec4 col = texture(SCREEN_TEXTURE, SCREEN_UV);
COLOR = col;
int size = 4;
bool is_found = false;
vec2 points[4] = {vec2(1.0, 1.0), vec2(-1.0, 1.0), vec2(-1.0, -1.0), vec2(1.0, -1.0)};
for(int i = 1; i < size && !is_found; i++){
for(int j = 0; j < 4; j++){
vec2 pixel_off = float(i) * points[j];
vec4 tex = texture(SCREEN_TEXTURE, SCREEN_UV + pixel_off * SCREEN_PIXEL_SIZE);
if(tex.rgb == vec3(1.0, 0.0, 0.0) && col.rgb != vec3(1.0, 0.0, 0.0)){
is_found = true;
COLOR.rgb = vec3(1.0);
}
}
}
}
But I get some pixels off in border.
Check attachment for a project.
