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Questions tagged [projection-matrix]

234 questions
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DirectX 11 Direct Texel Mapping

I am trying to render to a texture in DirectX 11 (C++ API) using an orthographic projection matrix. In the horizontal dimension, I am taking advantage of the "projection" that occurs, but in the vertical dimension, I am wanting my vertices to map…
Tim Coolman
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Why linear transformation improves accuracy and efficiency of classification for high-dimensional data?

Let X be an m×n (m: number of records, and n: number of attributes) dataset. When the number of attributes n is large and the dataset X is noisy, classification gets more complicated and the classification accuracy decreases. One way to over come…
user1468089
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Creating an OpenGL projection matrix to shear an object

I'm trying to render a box where the near face stays perfectly aligned to the corners of the display, but the rest can shear (with perspective) kind of like a parallax effect. Basically exactly like this one. I found that multiplying my projection…
user252406
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Image to world projection

I have a RGB image and 8-bit depth data of the same scene from two different cameras and need to generate point cloud in 3D space. I used this paper to understand how to do it. As mentioned in Eq. 1 we can find non-homogeneous coordinates of the…
Huá dé ní 華得尼
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Projection matrix: combining transition and fertility matrices for second stage group

I would like to ask how to combine the following information into the projectio matrix. I do have data for transition (T) and fertility (F) matrices, so the projection matrix (A) is equal to the sum of these two matrices, i.e. A=T+F. Concerning…
user3152197
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How to compute fundamental matrix using a stereo pair?

referring to the question about fundamental matrix,If I had a stereo pair (2 jpeg) and I want to apply Peter Kovesi's or Zisserman's function on order to obtain F, how can I retrieve P1 and P2 ? these two matrices are 3x4 matrices from the two…
user2614596
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Proper calculation for the first element of an OpenGL projection Matrix?

Almost all the theoretical stuff I read about projection matrices have the first element being 2n/(r-l), but most of the open source implementations I've seen have it as 2n/((t-b)*a), -- which makes sense to me at first since (r-l) should be…
Chad Mourning
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2D Screen coordinate to 3D position Directx 9 / Box Select

I am trying to implement box select in a 3d world. Basically, click, hold mouse, and then unpress mouse, get a box, and then box select. To start, I'm trying to figure out how to get the coordinates of the clicks in 3d. I have raypicking, and…
Mary Ellen Bench
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File not appearing in IOS programming

I am using Xcode to program a new application that is of the game sorts, and when I run it the file that I am using as a main character does not appear. It is just a basic script, but I want it to all be right the first time. Here is the code I…
MAS
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Projection of 3D Coordinates onto a 2D image with known points

I'm writing a .NET program that allows a user to register an image by identifying specific points on an image and then specifying the real world coordinates associated with each of those points. http://www.ironbyte.ca/temp/mountain.jpg The image…
jacobya
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Perspective projection matrix in OpenGL

I an new to perspective division phenomenon. I am rendering a simple square in 3D space using following code : void MatrixPersp(Mat4& matrix,const float fovy, const float aspect, const float zNear, const float zFar) { float sine,…
maverick9888
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OpenGL ES 2.0 cuts the screen in landscape mode

I'm starting to learn OpenGL, and are using the following site: http://www.learnopengles.com/android-lesson-one-getting-started/ But it seems that I got a problem at this part (works fine in portrait mode): private float[] mViewMatrix = new…
Araw
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Orthographic projection with origin at screen bottom left

I'm using the python OpenGL bindings, and trying to only use modern opengl calls. I have a VBO with verticies, and I am trying to render with an orthographic projection matrix passed to the vertex shader. At present I am calculating my projection…
Shootfast
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OpenGL matrix issue

I have an NSOpenGLView setup and working great, but I need to draw a rectangle that always completely fills the view and is not clipped (does that make sense?). I have a view that is always going to be 1100x850 pixels in size. Basically, what I am…
Justin
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Setting Up a Coordinate System For Perspective Viewing?

I understand the concept behind a frustrum viewing system; it's shaped like a pyramid, and as objects get closer to the center, they get smaller until they're finally clipped off. However, when using a viewing projecting in say, OpenGL (heads up: I…
Shokwav
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