Tagged Questions
3
votes
2answers
110 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) ...
0
votes
1answer
61 views
Ways to “invert Z-axis” in shader-based core-profile OpenGL?
In my hobbyist shader-based (non-FFP) GL (3.2+ core) "engine", everything in world-space and model-space is by design "left-handed" (and to stay that way), so X-axis goes from -1 ("left") to 1 ...
0
votes
0answers
87 views
Camera Projection back Into 3D world, offset error
I'm using XNA to simulate a robot in a 3D world and then do image analysis on what the camera sees.
I have my camera looking down in front of the direction that the robot is going, and I have the ...
1
vote
1answer
271 views
How to do geometric projection shadows?
I have decided that since my game world is mostly flat I don't need better shadows than geometric projections - at least for now.
The only problem is I don't even know how to do those properly - that ...
0
votes
0answers
167 views
Unity3D - Projection matrix camera frustum
I've used off centre projection to create a custom projection matrix for my camera.
When I run the game I can see the scene correctly in the game view but in the editor view the camera frustum is not ...
1
vote
1answer
130 views
Orthogonal projection and world transform
I'm reading about projection matrix. Needs of perspective projection is obvious, but I'm not sure about orthogonal projection. Because orthogonal projection effect looks possible with only world ...
8
votes
1answer
1k views
Screen space to world space
I am writing a 2D game where my game world has x axis running left to right, y axis running top to bottom, and z axis out of the screen:
Whilst my game world is top-down, the game is rendered on a ...
0
votes
3answers
224 views
Project rendering onto a polygon in the scene
I have a function that renders a simple OpenGL scene. I want to display this scene on a polygon within another scene, without the function having to know about it. For example, to display the scene on ...
5
votes
3answers
614 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.
...
5
votes
3answers
647 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 ...
3
votes
1answer
1k views
Can a 4x4 matrix describe a camera's perspective?
I'm working with a closed-source 3D engine, and it only allows you to set the view projection via a 4x4 matrix. Can this matrix describe the camera's translation, rotation & perspective?
I turned ...
2
votes
1answer
557 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 ...
2
votes
2answers
953 views
How should I calculate world and projection matrices in this scenario?
I'm trying to understand transformation matrices. Suppose I use the camera from this StackOverflow answer, this is how my view matrix would look:
Matrix.Identity *
...
0
votes
0answers
794 views
Setting up perspective projection on Opengl ES 2.0 makes objects disappear
I'm working on a project using opengl-es 2.0, and I'm having some trouble setting up perspective projection.
If I don't set up the perspective projection and simply multiply the object-to-world ...
8
votes
1answer
379 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 ...
