Branching

branch one

varying vec2 vUv;
uniform sampler2D tDiffuse;
uniform float isPicking;
uniform vec3 pickingColor;

void main() {

	vec3 color = texture2D(tDiffuse, vUv).rgb;

	gl_FragColor = vec4(color, 1.0);
}

branch two

varying vec2 vUv;
uniform sampler2D tDiffuse;
uniform float isPicking;
uniform vec3 pickingColor;

void main() {

	gl_FragColor = vec4(pickingColor, 1.0);

}

original

varying vec2 vUv;
uniform sampler2D tDiffuse;
uniform float isPicking;
uniform vec3 pickingColor;

void main() {

	if( isPicking == 0.0 ) {

		vec3 color = texture2D(tDiffuse, vUv).rgb;

		gl_FragColor = vec4(color, 1.0);
	}

	else {

		gl_FragColor = vec4(pickingColor, 1.0);
	}

}