I'm using a camera control in my 2D platformer game (using BlitzMax if that matters) to 'handle' my image drawing; ie drawing images at (image.x - camera.x),(image.y - camera.y).

Then I had the idea to use layers, which also works OK; drawing to ((image.x*image.layer) - camera.x),((image.y*image.layer) - camera.y)

Now I'd like to add in zooming, and I seem to have hit a brick wall. I thought it would be something like (((image.x*image.layer) - camera.x)*size),(((image.y*image.layer) - camera.y)*size), but that doesn't seem to work right . I've tried a few other cominations, but no luck.

Does anyone have any advice?

Thanks in advance

So things on layer 2 are to be twice as big, for example?

Do an OpenGL and use 3x3 matrices for everything, you can do rotation, translation and scaling with it no problem.

If you don't know OpenGL, use the math from here for now: http://easyweb.easynet.co.uk/~mrmeanie/persp/persp.htm

Aye, that's a good tutorial; I'll look into it thanks.

I'd use

apparentX=window.width/2.0+(image.x - camera.x)/distance
apparentY=window.height/2.0+(image.y - camera.y)/distance

where distance is the distance between the camera and the object (which changes depending on the "layer" and if you zoom in-out)

Also you will have to scale the objects inversely to the distance