On 1/23/08, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote: > > Hi, > > I'm sorry if this is the wrong place to post this, but this was the > only place I could find to discuss pyglet programming. I'm currently > trying to move a 2d game system over to pyglet from pygame. In the > pygame code, collision is checked for using a bitmap, allowing the > level to contain arbitrary curves and still react correctly. I am > trying to replicate this behavior.
You'll get much better performance by using some OpenGL tricks. For example, use the selection buffer to check for the intersection between a rectangle (or point) and an arbitrary image. Use a combination of the stencil buffer and occlusion query tests to check for intersection between two arbitrary images. > The way I am currently doing it is as follows: I read an image in > from file. I convert that image to its data. I take a region of the > data which is one pixel known to be fully transparent. I change the > format for that region to 'A' (Alpha). Then, whenever I'm checking > for collision, I take a one pixel region at the x and y coordinates, > convert the format of that to 'A', and compare the value of its data > to the value of the sample pixel's data. If they aren't equal, a > collision has occurred. > > Converting the format of an ImageData or ImageDataRegion is very > expensive, though, and slows my program down to a crawl. Is there any > way to get the Alpha without performing this operation, or is there a > better way to do this? You can use the data in its existing format. i.e., it will probably be in something standard like 'RGBA'. Then to get the alpha component at x, y: image.data[y * image.pitch + x * 4 + 3] Alex. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "pyglet-users" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/pyglet-users?hl=en -~----------~----~----~----~------~----~------~--~---
