Objective-C：如何分配GLuint数组

Question

I have an array of GLuint with fixed size:

GLuint textures[10];

Now I need to set a size of array dynamically. I wrote something like this:

*.h:

GLuint *textures; 

*.m:

textures = malloc(N * sizeof(GLuint)); 

where N - needed size.

Then it used like this:

glGenTextures(N, &textures[0]);
// load texture from image

-(GLuint)getTexture:(int)index{
    return textures[index];
}

I used the answer from here , but program fell in runtime. How to fix this?

Program is written on Objective-C and uses OpenGL ES.

Answer 1

I figured out this issue.

This code is valid but seems like not working. This problem is described here , but it's not so clear.

The solution that works for me is to create separate class with GLuint property:

@interface Texture : NSObject
    GLuint texture;
@end

@property (nonatomic, readwrite) GLuint texture;

Then we can create NSMutableArray of Textures:

NSMutableArray *textures;

In *.m file we should fill our array:

for(int i=0;i<N;i++){
    Texture *t = [[Texture alloc] init];
    t.texture = i;
    GLuint l = t.texture;
    [textures addObject:t];
    glGenTextures(1, &l);
}

If you use other array(s) with textures you have to shift GLuint indexes, eg:

t.texture = i+M;

where M - size of earlier used array of GLuint's.

Then getTexture will be rewritten as following:

-(GLuint)getTexture:(int)index{
    return textures[index].texture;
}

I am not excited with this approach but it's a single one I make work.

Answer 2

If you set the value of N to 10, then the behavior of the two methods will be identical. You should therefore look for the reason for the failure in different places.

Answer 3

void glGenTextures( GLsizei n, GLuint * textures);

accepts an array of unsigned ints, and it looks like you are passing a pointer to the first element in the array, which I think is not what you want to do or what the function accepts

maybe just try

glGenTextures(N, textures);