godot_color_replace.shader

// from https://godotengine.org/qa/15718/how-to-change-a-specific-color-using-shaders

shader_type canvas_item;
 
void fragment()
{
  vec4 curr_color = texture(TEXTURE, UV); // Get current color of pixel

  if (curr_color == vec4(0, 0, 0, 1))
  {
    COLOR = vec4(0, 0, 0, 0);
  }
  else
  {
    COLOR = curr_color;
  }
}