Top Left vs Bottom Left Coordinates Origin
-
I've noticed that that in Pixelwave, like flash and most other 2d graphics applications, the 0,0 origin point is located int he top left and positive y values move down the screen. This seems like a good idea, especially since Pixelwave is trying to emulate that flash APIs. I've also noted that OpenGL's default coordinate system starts in the bottom left with positive y values moving up the screen, this matches the more mathematically traditional approche.
I've been looking thew the Pixelwave code base to see how it is doing the coordinates translation but so far I haven't been able to figure it out. Could anyone here point me in the right direction? It would make integrating third party code with Pixelwave easier and vice versa. -
PXGL.m, lines 2280-2285:
glOrthof(0, // xMin pxGLWidthInPoints, // xMax pxGLHeightInPoints, // yMin 0, // yMax -100.0f, // zMin 100.0f); // zMax
Note how pxGLHeightInPoints is given for bottom, and 0 is given for top. This flips the OpenGL coordinate system such that (0, 0) is in the top left.
