source: downloads/Samples/Media/materials/programs/hdr_finalToneMapping.glsl @ 5

uniform sampler2D inRTT;
uniform sampler2D inBloom;
uniform sampler2D inLum;

varying vec2 uv;

// declare external function
vec4 toneMap(in vec4 inColour, in float lum);

void main(void)
{
        // Get main scene colour
    vec4 sceneCol = texture2D(inRTT, uv);

        // Get luminence value
        vec4 lum = texture2D(inLum, vec2(0.5, 0.5));

        // tone map this
        vec4 toneMappedSceneCol = toneMap(sceneCol, lum.r);
        
        // Get bloom colour
    vec4 bloom = texture2D(inBloom, uv);

        // Add scene & bloom
        gl_FragColor = vec4(toneMappedSceneCol.rgb + bloom.rgb, 1.0);
    
}