Another simple example with the online shadertoy tool. In this example, I will show you how to use a webcam with a heat predator effect. And how to combine this effect with the webcam image.
vec3 predatorHeat(float v) {
float value = 1.0 - v;
return (0.5+0.5*smoothstep(0.0, 0.1, value))*vec3(
smoothstep(0.5, 0.3, value),
value < 0.3 ? smoothstep(0.0, 0.3, value) : smoothstep(1.0, 0.6, value),
smoothstep(0.4, 0.6, value)
);
}
void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
// Normalized pixel coordinates (from 0 to 1)
vec2 uv = fragCoord/iResolution.xy;
vec4 temp = texture(iChannel0, uv);
vec4 temp2 = texture(iChannel1,uv);
float average = ((temp.r + temp.g + temp.b) / 2.5);
temp.rgb = vec3(predatorHeat(average));
if(uv.x > 0.5)
fragColor = temp;
else
fragColor = temp2;
}