ios – 在顶点着色器内记录变量的值

我是OpenGL ES编程的新手,我正在尝试调试我的着色器编程,我想知道是否有任何方法可以记录特定变量的值.例如,在下面的顶点着色器程序中,我想测试正常返回的值,基本上,我正在寻找类似于NSLog的东西……

attribute vec4 position;
attribute vec3 normal;
attribute vec2 texture;
varying vec2 v_texCoord;
varying float LighTintensity;

uniform mat4 modelViewProjectionMatrix;
uniform mat3 normalMatrix;

void main()
{
    vec3 eyeNormal = normalize(normalMatrix * normal);
    vec3 lightPosition = vec3(-1.0,0.0,3.0);

    float nDotVP = max(0.0,dot(eyeNormal,normalize(lightPosition)));
    LighTintensity = nDotVP;

    v_texCoord = texture;

    gl_Position = modelViewProjectionMatrix * position;
}