rhythmbullet/android/assets/shaders/invert_frag.glsl

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

varying LOWP vec4 vColor;
varying vec2 vTexCoord;

uniform sampler2D u_texture;

void main() {
	vec4 texColor = texture2D(u_texture, vTexCoord);
	texColor.rgb = 1.0 - texColor.rgb;
	gl_FragColor = texColor * vColor;
}