# Tagged Questions

72 views

### Trying to project a point onto a cubemap

I've got a simple test program with a camera within a cubemap (skybox). You can look around, and it feels like you're in a 3D room, but really it's just a cubemap image. Now I want to draw a point ...
58 views

### Perspective projection computation

I'm learning OpenGL from arcsynthesis and I don't understand something about perspective projection (http://www.arcsynthesis.org/gltut/Positioning/Tut04%20Perspective%20Projection.html). When the ...
101 views

### Stereo 3D: drawing 2D elements at apparent screen depth

I'm developing an application making use of DirectX11's stereoscopic features. At such I am not relying on nVidia's automatic implementation. That means I have to replicate a way to render 2d elements ...
98 views

### Which is the right way to build a OpenGL Projection Matrix

This time I'm trying to learn the core of matrix transformations. I dont like the idea to using a Math library and dont understand what is hapening on background, because this I'm having some ...
154 views

### What kind of projection is ScreenX=X/Z, ScreenY=Y/Z?

I have an existing class which transforms 3D vectors and projects them on a 2D plane (Camera). The code is all written in C without help from an external library. To project a single vector (X,Y,Z) ...
129 views

### Keeping raycast on the same level

I want my raycast to end at certain height(red line). But as the game is 3D and the camera rotates I can't use a fixed magnitude. What I thought was a stroke of genius, I figured I'd project the ...
263 views

### How to do perspective projection “parallax” but without changing the scale or offset of objects?

Hello everyone I have this problem that I have tried everything I could think of. The problem: I am making a 2D game with parallax effect but I am using 3d space so am not simulating the parallax but ...
316 views

### Unproject mouse position to tile — extremely jumpy position?

I'm trying to unproject the mouse position to get the position on the X-Z plane of a ray cast from the mouse. The camera is fully controllable by the user. Right now, the algorithm I'm using is... ...
351 views

### Orthographic unit translation mismatch on grid (e.g. 64 pixels translates incorrectly)

I am looking for some insight into a small problem with unit translations on a grid. Update and Solved I solved my own issue. See below for details. Everything in this part of the post turned out to ...
406 views

### Silly question about perspective correct texture mapping

OK, I'll admit, the math on a perspective projection matrix is quite hairy for me, but I get the general gist of it: morph the object so that it looks... perspective-ish. But there is one thing which ...
131 views

### What is the connection between an isometric angle and scale

I am trying to work out an isometric projection matrix for a custom angle. In the engine I'm using there's a projection matrix defined like so: projection.rotate(45 * (Math.PI / 180) ); scale = ...
843 views

### Arbitrary projection matrix from 6 arbitrary frustum planes

A projection matrix represent a tranformation from the camera view space to the rendering system clip space. In other words, it defines the transormation between a 6-sided frustum to the clip cube. ...
902 views

### What's a pre-multiplied 4x4 matrix?

I'm using a 3d game engine, that uses a 4x4 matrix to modify the camera projection. The matrix is in the regular 4x4 format: r r r x r r r y r r r z - - - zoom The description for the ...
643 views

### How to create projection/view matrix for hole in the monitor effect

Lets say I have my XNA app window that is sized at 640 x 480 pixels. Now lets say I have a cube model with its poly's facing in to make a room. This cube is sized 640 units wide by 480 units high by ...
2k views

### Faking isometric graphics in a 2D space game

First off, I know exactly what my drawing problem is, and I have various ideas on how to approach solving it. I am here to figure out how to adjust which frame is drawn so that the isometric ...