How do you calculate UVW coordinates?

Posted by Jenko on Game Development See other posts from Game Development or by Jenko
Published on 2011-11-17T15:22:25Z Indexed on 2011/11/17 18:10 UTC
Read the original article Hit count: 355

Filed under:

3d-engines

|

triangles

|

uvw-mapping

|

perspective

I'm working on a 3d engine and I'm calculating UVT coordinates, where U and V represent pixels on the texture measured in 0-1, and T is:

T = perspective / Z

But I'm trying to use this perspective-correct triangle rasteriser, which requires a W, per vertex. How do I calculate the W for each vertex for the drawPerspectiveTexturedPolygon() function?

Hint: The code comments refer to W as the "homogenous coordinate" ... does that mean anything?

© Game Development or respective owner

Related posts about 3d-engines

Loading Obj Files in Soya3d engine

as seen on Game Development - Search for 'Game Development'
I recently just found soya3d and from what i have seen through the tutorials i will be able to make exactly what i wanted with python skills. Now i have built this map generator. The only issue is that i can not manage to understand from any documents how to load obj files. At first i figured that… >>> More
Ideas for extending tic-tac-toe game?

as seen on Game Development - Search for 'Game Development'
I'm building a 3D tic-tac-toe game and this is what I've implemented so far: 3D renderer with texture mapping Playing against the computer Playing online (multiplayer) Now I'm a little lost what I could add. Obviously, tic-tac-toe isn't that exciting or advanced, but I just miss something to salt… >>> More
Ogre3D, OGRE_NEW gives editor errors

as seen on Game Development - Search for 'Game Development'
Hello Game Developers, I am trying to get more experienced with OGRE3D and I am following the basic tutorials on the website. All the code samples compile just fine. The first time I encountered a "error" was in Basic Tutorurial 3. The code line where visual studio says something is not right is… >>> More
What's the standard location of a 3D clipping box?

as seen on Game Development - Search for 'Game Development'
The way I understand 3D rendering, polygons are transformed using several matrices, and they are then clipped if they are not inside a certain box, before projecting the box onto the screen. Before transformation, the visible area is typically a frustum, and after transformation, I am guessing it's… >>> More
Game engine help

as seen on Game Development - Search for 'Game Development'
So, I am looking to start designing a video game. My biggest problem right now is choosing the right game engine. I am hiring a programmer, so the language doesn't really matter as much. What I need is an engine with these features, for very, very cheap: -Ability to create very realistic AI -Ability… >>> More

Related posts about triangles

Adding Vertices to a dynamic mesh via Method Call

as seen on Game Development - Search for 'Game Development'
I have a C# Struct with a static method, "Get Shape" which populates a List with the vertices of a polyhedron. Method Signature: public static void GetShape(Block b, int x, int y, int z, List<Vector3> vertices, List<int> triangles, … >>> More
Polygonal Triangulation - algorithm with O(n log n) complexity

as seen on Game Development - Search for 'Game Development'
I wish to triangulate a polygon I only have the outline of (p0, p1, p2 ... pn) like described in this question: polygon triangulation algorithm and this webpage: http://cgm.cs.mcgill.ca/~godfried/teaching/cg-projects/97/Ian/algorithm2.html I do not wish to learn the subject and have a deep understanding… >>> More
Triangle - Rectangle Intersection in 2D

as seen on Game Development - Search for 'Game Development'
I had previously asked this for 3D but now I changed my strategy and would like to do the intersection in 2D. The Rectangle is axis aligned and will always be in a fixed position, and has a constant shape and size, basically I want to clip the red areas of the triangles that extend outside the bounds… >>> More
Dynamically creating astar node map by triangular polygonal map

as seen on Game Development - Search for 'Game Development'
My game's map format uses a bunch of triangles to make up the platforms and terrain in 2d. Right now I can set up a 2d array of nodes for the astar algorithm that basically is a bunch of rectangles across the maps x and y that can be set to "wall" if the a* algorithm should try to go around it. However… >>> More
Triangulation A* (TA*) pathfinding algorithm

as seen on Game Development - Search for 'Game Development'
I need help understanding the Triangle A* (TA*) algorithm that is described by Demyen in his paper Efficient Triangulation-Based Pathfinding, on pages 76-81. He describes how to adapt the regular A* algorithm for triangulation, to search for other possibly more optimal paths, even after the final… >>> More