片段着色器:"no matching overloaded function found" 错误

Fragment shader: "no matching overloaded function found" error

问题来自 mandelbrot 函数:

vec3 mandelbrot (vec2 coord){
    vec2 z0 = vec2(0.0, 0.0);
    int number = fractal (z0, coord, 10000);    
    float v = float(number);
    float factor = 0.0;
    return paletize (v, factor);
}

int fractal (vec2 z0, vec2 c, int maxIterations){
 //doesn't matter
}

vec3 paletize (float v, float factor){
   doesn't matter
}

这是错误消息:https://gyazo.com/5516853ee2600b58a303fd609530fafe

片段着色器编译失败:错误日志为:

ERROR:0:13 ´fractal´:no matching overloaded function found
ERROR:0.13: '=' : cannot convert from const float to mediump int
ERROR:0:19: ´paletize´: no matching overloaded function found
ERROR:0:19: ´return´: function return is not matching type: 

尝试将分形和调色板函数移到 mandelbrot 上。