Getting pixels data from image on iPhone

Question

I want to use bitmap images as a "map" for levels in iphone game. Basicly it's all about the location of obstacles in the rectangular world. The obstacles would be color-coded -- where the white pixel is, there's no obstacle. Black means there is one at this point.

Now I need to use this data to do 2 things: (a) display the level map, (b) for in-game calculations. So, in general, I need a way to read the data from the bitmap and create some data structure (matrix-like) with those information - to both overlay the bitmap onto the level graphics as well as to calculate collisions and such.

How should I do it? Is there any easy way to read the data from image? And what's the best format to keep the images for this?

Answer 1

Have you looked at how Texture2D translates an image file to an OpenGL Texture ?

Tip: take a look at this Method in Texture2D.m:

- (id) initWithCGImage:(CGImageRef)image orientation:(UIImageOrientation)orientation sizeToFit:(BOOL)sizeToFit pixelFormat:(Texture2DPixelFormat)pixelFormat filter:(GLenum) filter

In 3D apps, it's quite common to use this kind of representation for height maps, in a height map, you use a Texture with colors that range from black to white ( white represents the maximum altitude )

For example, from this:

To this:

That was just to tell you that your representation is not that crazy :).

About reading the bitmap, I would also recommend you to read this (just in case you want to go deeper)

Hope I helped a bit!