The same bouncy ball as before, but the background is drawn as a wireframe. The co-ordinates for the room are in a few sprites that draw the walls. For the ball, one loop does all the 3D display. Another does the movement - bouncing and falling. To remix, try duplicating the ball (and its shadow), or putting in a different wireframe drawing. The old notes are here: To understand this, download it first (!). The ball has 3 co-ordinates in the room: x, y, z positions (z is depth away from you). First, we decide on the proportions of the space where we are working. I wanted the ball to be half the size when it's at the far end, so z is transformed following this formula: zfactor = 1+(z/400) This way, if - z=0, zfactor = 1 (max size) - z=400, zfactor = 2 (furthest away, min size) Now to place the ball we do: screen x = x/zfactor screen y = y/zfactor size % = 100/zfactor Simple, innit? It's the perspective formula. To get the ball to move, we use speed co-ordinates, like a ball in 2D, only there are 3 speeds, for the 3 axes. I added a co-ordinate to the "gravity ball" example provided with the samples. Enjoy scratching!
