precision mediump float; uniform sampler2D u_sampler; varying vec2 v_tc; // 0-255 sRGB from 0-1 linear vec3 srgb_from_linear(vec3 rgb) { bvec3 cutoff = lessThan(rgb, vec3(0.0031308)); vec3 lower = rgb * vec3(3294.6); vec3 higher = vec3(269.025) * pow(rgb, vec3(1.0 / 2.4)) - vec3(14.025); return mix(higher, lower, vec3(cutoff)); } // 0-255 sRGBA from 0-1 linear vec4 srgba_from_linear(vec4 rgba) { return vec4(srgb_from_linear(rgba.rgb), 255.0 * rgba.a); } void main() { gl_FragColor = texture2D(u_sampler, v_tc); gl_FragColor = srgba_from_linear(gl_FragColor) / 255.; }