rhythmbullet/android/assets/shaders/combine.fsh

#ifdef GL_ES
#define LOWP lowp
precision mediump float;
#else
#define LOWP
#endif

varying LOWP vec4 vColor;
varying vec2 vTexCoord;


uniform sampler2D u_texture;
uniform sampler2D u_texture1;
uniform float exposure;

void main() {
	vec3 origColor = texture2D(u_texture, vTexCoord).rgb;
	vec3 blurredColor = texture2D(u_texture1, vTexCoord).rgb;
	
    const float gamma = 2.2;
    origColor += blurredColor; // additive blending
    // tone mapping
    vec3 result = vec3(1.0) - exp(-origColor * exposure);
    // also gamma correct while we're at it       
    result = pow(result, vec3(1.0 / gamma));
    gl_FragColor = vec4(result, 1.0);

}