thebookofshaders/16/operations.frag

// Author @patriciogv - 2015
// http://patriciogonzalezvivo.com

#ifdef GL_ES
precision mediump float;
#endif

uniform sampler2D u_tex0;
uniform sampler2D u_tex1;

uniform float u_time;
uniform vec2 u_mouse;
uniform vec2 u_resolution;

void main (void) {
    vec2 st = gl_FragCoord.xy/u_resolution.xy;
    vec3 color = vec3(0.);
    vec3 colorA = texture2D(u_tex0,st).rgb;
    vec3 colorB = texture2D(u_tex1,st).rgb;

    color = colorA+colorB;      // Add
    // color = colorA-colorB;      // Diff
    // color = abs(colorA-colorB); // Abs Diff
    // color = colorA*colorB;      // Mult
    // color = colorA/colorB;      // Div
    // color = max(colorA,colorB); // Ligther
    // color = min(colorA,colorB); // Darker

    gl_FragColor = vec4(color,1.0);
}