varying vec2 v_vTexcoord;
varying vec4 v_vColour;

uniform float alp; // 0 = 原样, 1 = 完全白

void main() {
    vec4 base = texture2D(gm_BaseTexture, v_vTexcoord);
    vec4 white = vec4(1.0, 1.0, 1.0, base.a);
    gl_FragColor = mix(base, white, alp) * v_vColour;
}