How do I dynamically create an array at runtime in Objective-C (iOS)?

Question

I have recently started doing some things in my iOS app using OpenGL.

I found this tutorial which has been a tremendous help:

www.raywenderlich.com/3664/opengl-es-2-0-for-iphone-tutorial .

typedef struct
{
    float Position[3];
    float Color[4];
} Vertex;

const Vertex Vertices[] = { ... };
const GLubyte Indices[] = { ... };

glBufferData(GL_ARRAY_BUFFER, sizeof(Vertices), Vertices, GL_STATIC_DRAW);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(Indices), Indices, GL_STATIC_DRAW);

I need an array of variables/structs since the content is dependent on what happens at runtime and is not static.

How do I define and create a dynamic array when I don't know the number of elements in the array until runtime?

Do I need to use malloc or something like that? I haven't come across any examples of allocating memory for an iPhone app before so I'm a little wary. Any advice or direction would be appreciated.

Yes, you'll need malloc(). Alternatively you can rely on a GCC extension and write GLFloat vertices[someVariable]; — user529758
– user529758, Commented Jul 19, 2012 at 7:23

SteveL · Accepted Answer · 2012-07-21 18:40:28Z

3

With malloc:

    Vertex* verts;
    void Load()
    {
        int SIZE=200;
        verts=(Vertex*)malloc(sizeof(Vertex)*SIZE);//in c you dont need (Vertex*)
    }

answered Jul 21, 2012 at 18:40

SteveL

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1 Comment

Jim True Over a year ago

Can you show how you stock verts using this? I've tried assigning the verts to Vertices but it won't allow (expected expression).

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