opengl - GLSL for-loop array index

Question

I'm having some trouble using variable indices in GLSL. The folowing GLSL code is working fine on NVidia cards. But its not working on my Intel HD 4000:

for(int i=0;i<int(uLightCount);++i)
{
    vec3 lightPos = uLightsPos[i];
    ....
}

There is no Shader-Compiler Error. The program simply crashes on glUseProgram

How can I fix this?

Edit:

uLightCount and uLightsPos are uniforms:

#define MAX_LIGHTS 10
uniform float uLightCount;
uniform vec3 uLightsPos[MAX_LIGHTS];

Edit 2:

I have found a strange workaround:

#define i0  0
#define i1  1
#define i2  2
...

for(int i=0;i<int(uLightCount);++i)
{
    vec3 lightPos;

    if (i==i0) 
        lightPos = uLightsPos[i0];
    if (i==i1) 
        lightPos = uLightsPos[i1];
    ....
}

Any idea why this is working?

Answer 1

索引必须是常数。这就是您的解决方法有效的原因。

所以不可能这么写

for(int i=0;i<10;++i)
{
  result += uLightsPos[i];
}

Answer 2

在循环内部，我这样做了：

for(int i=0;i<n;i++) {
    int j = i;
    and use myArray[j];
}

它编译...所以你可以在你的代码中尝试。