# Questions tagged [camera-matrix]

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### Inverse value in a Perspective Matrix

I am a new leaner of computer graphics. I'm trying to understand a code I found online and I got stuck in the following formula: ...
218 views

### Camera Model View transformation in Ray Tracing

I am implementing my own simple ray tracing and I came across some sort of confusion. When defining the verticies in the world I multiply them by the modelView transformation system (the matrix ...
1k views

### My perspective projection is messed up?

So I've been messing with perspective projection matrices recently. I used numpy and GTK/Cairo to make a very small Python renderer. I'm very confused with the results I'm getting though. I took this ...
131 views

### Correctness of logical steps for create the matrix of viewing transformation

In general, I understand the creation of viewing transformation matrix, but I have my doubts. For example, let's say that a world coordinate (called $A$) has a center at $(1,1,1)$, and the view ...
126 views

### Modify camera matrix so that it renders a “chunk” of the frustum

Given a perspective projection matrix. How can one from it derive a set of matrices representing "chunks" of the viewport? So that the rendered chunks can be "stiched" to form an image "chunk times ...
198 views

### Do straight lines always remain straight when projected with a perspective camera?

If I have a straight line in 3D space and I use a camera matrix to do a perspective projection into a 2D plane/screen will the resulting line always be straight too? If I project the start point and ...
4k views

### Correcting my “look-at” matrix so that it works on non-camera objects?

I'm familiar with the "look-at" matrix and the goal of being able to rotate a Camera at a specific location towards a specified target. When I tell the ...
350 views

### Inverted yaw angle in the view matrix

I'm trying to construct a FPS view matrix for my OpenGL renderer using yaw and pitch angles instead of the typical LookAt view matrix. The view matrix is the ...
178 views

### Calculate Camera parameters and HandEyeCalibration

I'm trying to calculate camera paramters and a hand eye calibration (Transformation from camera to eye (display) coordinates) for rendering on a see-through HMD. I have already calculated a ...
213 views

### Building a lookat camera matrix

I was reading this article and found something that caught my attention. They say they are using column-major for their matrices so, in the code they have under the section Look At Camera they ...
152 views

### With OpenGL, is it correct to apply model transformation to rotate the camera?

Having taken a basic CG course, I remember that transformations are relative, so rotating the camera is identical to rotating the view in the opposite direction. Right now I want to implement camera ...
69 views

### worldViewProjection doesn't work for a single component

I have implemented a couple of classes which are drawn using shaders where the vertex position is always calculated the same way: ...
335 views

### How to rotate a camera?

So I am doing a simple FPS camera with openGL. I store the camera as 4 vector, a position vector, a lookAt vector, an up vector and a right vector. When the user presses a key, I create a rotation ...
172 views

### Is there something wrong with a column camera matrix?

I am writing a simple ray tracer. I was working on my camera matrix when I encountered a problem. When I changed the look vector, so that it headed down, the image, which was supposed to go up, ...
118 views

### Intrinsic Matrix vs Perspective projection matrix

I was going through the camera matrix explained in the wikipedia article and understand how the matrix K \begin{bmatrix}f_x&s&x_0\\0&f_y&y_0\\0&0&1\end{bmatrix} is built. The ...
32 views

### Difference between a spherical camera and a trackball camera

A spherical camera is pretty easy to define. We have an anchor point C the camera always looks at and a relative position P where the camera is, which can be expressed in spherical coordinates, ...
160 views

### Help with understanding the look-at function (the view matrix)

I've been reading this article about the look-at function. I don't understand the part when they're trying to inverse the matrix N. They say that R is orthogonal because all its row and column ...
62 views

### Sampling a textureCube using a screen quad

I´m trying to use a screen quad to display the contents of a texture cube (instead of rendering a cube mesh in front of the view). I´m passing to my shader the camera view matrix. The pixel shader ...
449 views

### Getting improper undistorted images for stereo calibration

I am trying to calibrate stereocamera using left and right chessboard images available at github.com->opencv/opencv/tree/master/samples/data After undistorting them, left images seem to look right ...
51 views

### Shear(?) matrix projection along Z (depth) axis

I'm creating a primarily 2d game (platformer perspective) with 2d background parallax layers. The parallax effect falls out of the fact that I'm positioning a bunch of layers in 3d and using a ...
93 views

### Can pixels on the image plane be mapped to world space coordinates?

I'm trying to learn the fundamentals of 3d computer graphics by writing a toy framework in WebGL. I'm currently working on mouse based camera controls. There are plenty of good resources in the ACM ...
29 views

### How to calculate position from depth pass of the ZED camera?

I'm using the ZED 2 camera, and although the API provides a means of getting a point cloud position from a specific pixel, for my project I need to be able to perform this calculation myself from the ...