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By : user2955890
Date : November 22 2020, 10:48 AM
may help you . Well your problem has nothing to do with whether or not your are developing a console or GUI application. Images are stored and processed as matrices of pixels. When you rotate the image, the resulting position for a specific pixel is usually not integers.
The idea is to go the other way around. code : ## Obtaining an invertible square matrix from a non-square matrix of full rank in numpy or matlab

By : user2237357
Date : March 29 2020, 07:55 AM
help you fix your problem Assume you have an NxM matrix A of full rank, where M>N. If we denote the columns by C_i (with dimensions Nx1), then we can write the matrix as , Easy, peasy in MATLAB. Use QR, specifically, the pivoted QR.
code :
``````M = [3 0 0 0 0;
0 0 1 0 0;
0 0 0 0 1;
0 2 0 0 0]

[Q,R,E] = qr(M)
Q =
1     0     0     0
0     0     1     0
0     0     0     1
0     1     0     0

R =
3     0     0     0     0
0     2     0     0     0
0     0     1     0     0
0     0     0     1     0

E =
1     0     0     0     0
0     1     0     0     0
0     0     1     0     0
0     0     0     0     1
0     0     0     1     0
``````
``````M*E
ans =
3     0     0     0     0
0     0     1     0     0
0     0     0     1     0
0     2     0     0     0
`````` ## Generic Simple 3D Matrix Rotation Issue

Date : March 29 2020, 07:55 AM
help you fix your problem It appears you have a problem with the order of transformations. Unlike numerical multiplication, matrix multiplication is not commutative. 3D applications are very sensitive to the order of transformations.
In English: ## simple Inplace square matrix clockwise rotation in java - what is wrong with my code

By : fuse
Date : March 29 2020, 07:55 AM
I think the issue was by ths following , In your second for loop, you are using the wrong variable. Change this:
code :
``````for (int i=0; i<m;i++) {
for (int k=0; k<m;k++) {
^
int temp = arr[i][k];
arr[i][k] = arr[k][i];
arr[k][i] = temp;
``````
``````for (int i=0; i<m;i++) {
for (int k=i; k<m;k++) {
^
int temp = arr[i][k];
arr[i][k] = arr[k][i];
arr[k][i] = temp;
`````` ## matrix non uniform scale rotation issue

By : Cf Ayfa
Date : March 29 2020, 07:55 AM
With these it helps It depends upon what type of output you want, you have to see when you are rotating the object , around what axis you want to rotate the object. If you want to rotate the object around its own axis, better translate back to origin and then do your transformations and then again translate back to original position. if you can post video, it will be better to visualize what you exactly want. Also order of transformation can make things reaaly wonky :) ## Why android.Matrix.setRotateM returns a matrix whose rotation direction is the opposite of the expected rotation matrix?

By : user2916414
Date : March 29 2020, 07:55 AM
To fix this issue It is because OpenGL (ES) matrices are specified by vectors in column major order.
See android.opengl.Matrix:
code :
``````m[offset +  0] m[offset +  4] m[offset +  8] m[offset + 12]
m[offset +  1] m[offset +  5] m[offset +  9] m[offset + 13]
m[offset +  2] m[offset +  6] m[offset + 10] m[offset + 14]
m[offset +  3] m[offset +  7] m[offset + 11] m[offset + 15]
``````
``````mat4(float, float, float, float,  // first column
float, float, float, float,  // second column
float, float, float, float,  // third column
float, float, float, float); // fourth column
``````
``````mat4 m44 = mat4(
vec4( Xx, Xy, Xz, 0.0),
vec4( Yx, Xy, Yz, 0.0),
vec4( Zx  Zy  Zz, 0.0),
vec4( Tx, Ty, Tz, 1.0) );
``````
`````` 0  1  0  0   // x axis vector
-1  0  0  0   // y axis vector
0  0  1  0   // z axis vector
0  0  0  1   // translation vector
`````` 