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14
votes
5answers
4k views

Do I need the 'w' component in my Vector class?

Assume you're writing matrix code that handles rotation, translation etc for 3d space. Now the transformation matrices have to be 4x4 to fit the translation component in. However, you don't actually ...
3
votes
1answer
2k views

How do I create a decal system?

I'm currently given the task to design & create a simple decal-system in C++/DirectX. Does anybody know a great tutorial, article or paper to start with? (Especially the part about 2D-texture to ...
8
votes
1answer
555 views

Projected trajectory of a vehicle?

In the game I am developing, I have to calculate if my vehicle (1) which in the example is travelling north with a speed V, can reach its target (2). The example depict the problem from atop: There ...
8
votes
1answer
467 views

Downprojecting an imaginary 4D mesh to the screen

As a mental exercise, I'm trying to imagine projecting an arbitrary 4D mesh onto the screen (2D). I'm guessing a single 4D triangle would still consist of only 3 points, however each of those 3 ...
7
votes
2answers
487 views

Portal Projection

Ok ok I admit, I'm bored and toying with a portal script like the one on steam. I've figured out the following: relative positioning of the mirrored cameras render to texture for the portal (the ...
3
votes
1answer
563 views

Perspective projection with 90 degrees between X-Y axis?

I'm trying to create a game that mimics Tibia's projection style: , As you can see, a 3d point is mapped to 2d like this: So I've downloaded Three.JS and a lib to create a Orthographic Camera. But ...
1
vote
1answer
94 views

Using gluUnProject to transform mouse position to world coordinates (LWJGL)?

I have a little LWJGL application and I have been trying to figure out how to successfully use the GLU.gluUnProject function in order to transform a given point on the screen (mouse position) to world ...
1
vote
1answer
59 views

Why are there different ways of building projection matrices?

Matrix.PerspectiveFovLH documentation page says that this method uses the following formula to build a perspective projection matrix. [w, 0, 0, 0] [0, h, 0, 0] [0, 0, zFar/(zFar - zNear), 1] [0, 0, ...
1
vote
1answer
1k views

Restoring projection matrix

I am learning to use FBOs and one of the things that I need to do when rendering something onto user defined FBO, I have to setup the projection, modelview and viewport for it. Once I am done ...
0
votes
1answer
154 views

Scanline filling of polygons that share edges and vertices

In this picture (a perspective projection of an icosahedron), the scanline (red) intersects that vertex at the top. In an icosahedron each edge belongs to two triangles. From edge a, only one triangle ...
0
votes
3answers
220 views

Understanding how to go from a scene to what's actually rendered to screen in OpenGL?

I want something that explains step by step how, after setting up a simple scene I can go from that 'world' space, to what's finally rendered on my screen (ie, actually implement something). I need ...