分别在r、b、g向量上叠加一个0~1之间的值。

#ifdef GL_ES
precision mediump float;
varying mediump vec2 v_texCoord;
#else
varying vec2 v_texCoord;
#endif

void main()
{
    vec4 c = texture2D(CC_Texture0, v_texCoord);
    if (c.a <= 0.0) {
        discard;
    }
    float param = 0.2;
    gl_FragColor = vec4(c.r + param, c.g + param, c.b + param, c.a);
}