Questions tagged [projection-matrix]
234 questions
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How to set an ortographic camera to project like described?
I would like the projection to be like this:
That is, (x,y,z) -> (x-y/sqrt(2),y/sqrt(2)-z)
How to find the projection matrix?
MaiaVictor
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Why are two elements of my inverse projection matrix always 0?
I'm writing a ray tracer for which I need to cast rays from the screen into the world. I'm using the inverse of the view-projection-viewport matrix to get back from screen pixel coordinates to world space coordinates.
I noticed by accident that two…
Boann
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how to perform perspective transform in CSS given perspectiveTransform matrix from openCV
I ran this openCV command to get a perspective transformation matrix:
projective_matrix = cv2.getPerspectiveTransform(src_points, dst_points)
The output (projective_matrix):
[[ 0.35330902 -0.20574606 222. ]
[ 0. 0.12791606 0. …
user2401856
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Unity wants a Y-flipped projection matrix when rendering under Direct3D
First of all, hello,
I have several questions tied together to this title, because I can't summarize all into one good question.
To put the settings, I am using Unity 2020.1.2f1 URP and I am trying to rebuild myself the Unity's projection matrix…
Chacal
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glm::perspective function's near plane and far plane and aspect ratio
two questions but the first one is, in the learnopengl.com website, for the glm::perspective function, it tells me to input 0.1f for the near plane, and 100.0f for the far plane. Why do I supply positive numbers. Isn't OpenGL using a right handed…
programmerdude
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2 answers
Sequentially multiply matrices from a list by a vector at time t-1 (recursively)
I am trying to multiply a list of matrices, in the order they appear within the list starting with matrix 1, by an initial vector and then recursively; so matrix 2 from the list multiplied by that resulting vector. I have tried various iteration of…
user11057680
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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 matrix (I believe it's also called model matrix) by…
uorbe001
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Perspective projection turns cube into weird tv shaped cuboid
This is my perspective projection matrix code
inline m4
Projection(float WidthOverHeight, float FOV)
{
float Near = 1.0f;
float Far = 100.0f;
float f = 1.0f/(float)tan(DegToRad(FOV / 2.0f));
float fn = 1.0f / (Near - Far);
…
vk123
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Perspective projection inverting x axis (glm::perspective)
When I use a perspective projection in OpenGL, my X axis gets inverted as seen in the image below. The code below might not be valid because I changed it a lot in order to make it less obscure. It might not work, so just keep that in mind. Here is…
Serket
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how to use JOML to simulate OpenGL like Model, View Matrices on 3D projection to 2D plane?
After years of taking beginner courses in OpenGL and linear algebra courses, I recently finally understood the point of the Model, View and Projection Matrices. Basically the Model Matrix converts the vertex coordinates of an 3D model into vertex…
Paiku Han
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Building a Perspective Projection Matrix
my first post here but hopefully I can explain my dilemma with building a perspective projection matrix similar to the one in OpenGL. Being new to the 3D graphics space, I'm having trouble understanding what to do after multiplying my matrix after…
majesticglue
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How to retrieve the camera origin/position from the view projection matrix? (OpenGL)
Is there any way to retrieve the camera origin/position from the view projection matrix? (OpenGL)
I'm trying to draw the camera's frustum and I have no problems calculating corners for the Far and the Near planes.
But I can't figure out how to…
Gediminas
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OpenGL How to calculate worldspace coordinates from frustum aligned vectors?
I am a graphics programming beginner working on my own engine and tried to implement frustum-aligned volume rendering.
The idea was to render multiple planes as vertical slices across the view frustum and then use the world coordinates of those…
Blendurian
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Where is the returning values of cv2.solvePnP actually holding the camera's position?
There's a cube and a camera in the real world. Each point coordinates are shown in the following figure. It is clear that the camera's coordinate is at [0,0,1].
We can calculate each position's displayed coordinates on screen.
import numpy as…
Izumi Kawashima
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Oblique perspective - projection matrizes in processing
I want to extend processing in order to be able to render 3D stuff with oblique projections (cabinet or cavalier). After looking around source of the camera(), perspective() and ortho() methods I was able to set up an orthographic perspective and…
hlg
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