Texture Space to World Space (Heavy Math)

Newbie & Debugging Questions
#1

I’m trying to reverse engineer some methods used for drawing textured triangles. I’m having an issue identifying certain values so I can properly name them.

All of the top fields from “a” to “i” are the most concerning.

Can anyone help me identify these?

		// The difference between these points?
		sceneX1 = sceneX0 - sceneX1;
		sceneY1 = sceneY0 - sceneY1;
		sceneZ1 = sceneZ0 - sceneZ1;

		// Now what are these?
		sceneX2 -= sceneX0;
		sceneY2 -= sceneY0;
		sceneZ2 -= sceneZ0;

		// This is looking so difficult because I can't tell what the previous
		// values are about..
		int a = ((sceneX2 * sceneY0) - (sceneY2 * sceneX0)) << 14;
		int b = ((sceneX1 * sceneY0) - (sceneY1 * sceneX0)) << 14;
		int c = ((sceneY1 * sceneX2 - sceneX1 * sceneY2)) << 14;

		int d = ((sceneY2 * sceneZ0) - (sceneZ2 * sceneY0)) << 8;
		int e = ((sceneY1 * sceneZ0) - (sceneZ1 * sceneY0)) << 8;
		int f = ((sceneZ1 * sceneY2) - (sceneY1 * sceneZ2)) << 8;

		int g = ((sceneZ2 * sceneX0) - (sceneX2 * sceneZ0)) << 5;
		int h = ((sceneZ1 * sceneX0) - (sceneX1 * sceneZ0)) << 5;
		int i = ((sceneX1 * sceneZ2) - (sceneZ1 * sceneX2)) << 5;

(Was incredibly massive in my post so I puush’d it.)
Code: http://puu.sh/dBNEq/8060548eea.txt

#2

Hmm there’s so much code (plus my low level knowledge lacks). But if you’re interested in low level rendering stuffs this is a great reference:

#3

I watched his entire 3d software playlist. It’s very interesting and a learning experience. Although, the math is different here because all calculations are done with integers and fixed-points. You may have provided a very useful resource, but it still does not answer my question. Thanks for your input though. :slight_smile: