Question

Im trying to encode into a NSValue an multidimensional array of structs.

This is the struct:

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

const Vertex Vertices[] = {
    // Front
    {{1, -1, 0}, {1, 0, 0, 1}},
    {{1, 1, 0}, {1, 0, 0, 1}},
(etc...)

I need to encode into a NSValue to store it in the object “Block”.

This is what I do to store:

Block *newBlock = [[Block alloc] init];
newBlock.blockVertices = [NSValue value:&Vertices withObjCType:@encode(Vertex)];

And to get it back:

Vertex tempVertices[24];
[newBlock.blockVertices getValue:&tempVertices];

Everything seems to work fine, then I try to compare values like this:

for (int i = 0; i < 24; i++){
    NSLog(@"%f = %f", Vertices[i].Position[0], tempVertices[i].Position[0]);
    NSLog(@"%f = %f", Vertices[i].Position[1], tempVertices[i].Position[1]);
    NSLog(@"%f = %f", Vertices[i].Position[2], tempVertices[i].Position[2]);
    NSLog(@" ");
}

And I’m getting weird results, like:
-1.000000 = -1.998905

where could be the problem? Any help would be appreciated.

Answer 1

You need to tell @encode how many Vertex structs are being encoded, for example:

[NSValue value:&Vertices withObjCType:@encode(Vertex[24])];