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Type: Posts; User: wmelgaard

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1. ## Thread: extrude along an arbitrary vector?

by wmelgaard
Replies
2
Views
415

### That works For my example, polygon in Y-Z plane,...

That works
For my example, polygon in Y-Z plane, extruding in X; origin at GLfloat x,y,z:

GLfloat matrix[16];
glPushMatrix();
glTranslatef(x, y, z);
matrix[0] = Y[0]; matrix[1] =...
2. ## Thread: extrude along an arbitrary vector?

by wmelgaard
Replies
2
Views
415

### extrude along an arbitrary vector?

I have arbitrary orthogonal vectors float X[3], Y[3], Z[3];
where X is the vector that I want to extrude a polygon that is in Y, Z coordinates.
For example, I have a polygon (-.25,3; 2,3; 2,2.5;...
3. ## Thread: problem de-rotating a model

by wmelgaard
Replies
6
Views
1,017

### Thank you. Thankyouthankyouthankyou!

Thank you.
Thankyouthankyouthankyou!
4. ## Thread: problem de-rotating a model

by wmelgaard
Replies
6
Views
1,017

### problem labeling a rotated model

I have tried to implement your suggestion, unsuccessfully.
The matrix multiplication algorithm that I presented works. I have verified that using Octave. Even accounting for the fact that OpenGL...
5. ## Thread: problem de-rotating a model

by wmelgaard
Replies
6
Views
1,017

### problem labeling a rotated model

My problem is that I don't know the location of the rotated and spun vertex.
Commenting out the transform command and placing the grid location into the printtext command utilizes the same...
6. ## Thread: problem de-rotating a model

by wmelgaard
Replies
6
Views
1,017

### problem labeling a rotated model

The following program writes an 8 line cube, allows a mouse drag to rotate it, and then attempts to label the corners in their rotated location.
However, the more the model is rotated, the farther...
7. ## Thread: Drawing a bezier spline

by wmelgaard
Replies
1
Views
1,283

### If all that you want is an increment and...

If all that you want is an increment and decrement, then draw a pair of boxes (somewhere) with a "+" in one box and a "_" in the other box.
In main, create a glutMouseFunc(mouse);
within mouse(int...
8. ## Thread: Can't reshape subwindow

by wmelgaard
Replies
2
Views
877

Your answer sounds like a style issue. Within my project, "windowheight" is a computed number. For the test problem, I merely toggled between two heights. In practice, "windowheight" can be any one...
9. ## Thread: 3D Poisson distribution

by wmelgaard
Replies
3
Views
2,468

### Assume that your box is bounded by [0,0,0; 0,0,1;...

Assume that your box is bounded by [0,0,0; 0,0,1; 0,1,0; 0,1,1; 1,0,1; 1,1,1]. Compute your point [x,y,z] where (0 <= x <= 1); (0 <= y <= 1); (0 <= z <= 1) and plot your point within your cube. ...
10. ## Thread: 3D Poisson distribution

by wmelgaard
Replies
3
Views
2,468

### I don't understand what you are trying to do. ...

I don't understand what you are trying to do.
Are you using a random number generator with a poisson distribution to pick points off an OpenGL cube?
Or are you plotting points within that cube?
11. ## Thread: Can't reshape subwindow

by wmelgaard
Replies
2
Views
877

### Can't reshape subwindow

I am running Debian Stable (Jessie), with GLU1.3, and am trying to reshape a subwindow.
The following program writes a subwindow in the top, left corner of the main window. If you left-click on that...
12. ## Thread: gluLookAt & depth culling

by wmelgaard
Replies
1
Views
972

### gluLookAt & depth culling

I have a model 0.0 < z < 30.0. The default gluLookAt(0,-100,0, 0,0,0, 0,1,0); looks at the bottom of the model. If I rotate the model, the bottom of the model occludes anything above it.
If I...
13. ## Thread: Graphics disappear under certain geometries.

by wmelgaard
Replies
2
Views
1,291

### see...

see https://www.opengl.org/sdk/docs/man3/xhtml/glCullFace.xml
The default is to cull a polygon whose back is to the viewer.
Add the disable, and those faces should reappear

by wmelgaard
Replies
0
Views
772

### glutDewstroyWindow cleanup

My situation is that I have a subwindow in mainwindow which creates another subwindow in mainwindow. The second subwindow provides a template for inputting data. Upon completion of data entry, I...

by wmelgaard
Replies
3
Views
1,761

### The window was created with subWindow =...

The window was created with
subWindow = glutCreateSubWindow(mainWindow, margin, margin, width, height);
glViewport(0, 0, (GLsizei) width, (GLsizei) height);

Basically, I want to change...

by wmelgaard
Replies
3
Views
1,761

### resizing subwindow

I have an existing subwindow that is to be replaced by a different one.
Should I destroy the original and then create a new one, or merely change the size of the existing one?
How do I change the...
17. ## Thread: Identifying a specific vertex

by wmelgaard
Replies
0
Views
827

### Identifying a specific vertex

If I mouse-click on s specific pixel, that will give me the x & y of the mouse, which is the projected location of the vertex which drew that pixel. Similarly, glReadPixels(x, y, 1, 1,...

by wmelgaard
Replies
4
Views
3,689

### That works. Problems solved. Thanx. FYI for...

That works. Problems solved. Thanx.

given

glMatrixMode(GL_PROJECTION);
glOrtho(xmin, xmax, ymin, ymax, zmin, zmax);
...

by wmelgaard
Replies
4
Views
3,689

### Changing the 0 to 1 helps. I misinterpreted the...

Changing the 0 to 1 helps. I misinterpreted the glReadPixels() definition to be (target) + width & (target) + height.
Leaving the glutSwapBuffers() where it is, I get z = 0.25194 and bgr = 0. Since...

by wmelgaard
Replies
4
Views
3,689

The following program gives a value of (some random number) for the red point, but 0.0000 for the z-value of the point.
How do I get a return of z != 0.0000, given that the point is located at 50,...
21. ## Thread: glOrtho in GL_PROJECTION vs GL_MODELVIEW?

by wmelgaard
Replies
2
Views
1,868

### From the tutorial, "do you want to move the...

From the tutorial, "do you want to move the camera in one direction, or move the object in the opposite direction?" All of the examples in Chapter 3 move the model. Nate Robins' robot arm is drawn...
22. ## Thread: glOrtho in GL_PROJECTION vs GL_MODELVIEW?

by wmelgaard
Replies
2
Views
1,868

### glOrtho in GL_PROJECTION vs GL_MODELVIEW?

I have a model xmin = -264.000000, xmax = 384.000000; ymin = -263.942993, ymax = 330.480591; zmin = 673.751099, zmax = 1345.000000
If I include glOrtho((xmin -margin), (xmax +margin), (ymin...
23. ## Thread: glTranslate( 0, 0, something ) ineffectual on VBO

by wmelgaard
Replies
8
Views
4,240

### Back to basics, I have recently learned that my...

Back to basics, I have recently learned that my push, transform and pops affect the transformation matrix, not the contents of the framebuffer. You say, "well, duh?"

Google NASTRAN for what I am...
24. ## Thread: glTranslate( 0, 0, something ) ineffectual on VBO

by wmelgaard
Replies
8
Views
4,240

### Wow. I am mostly self taught, and my background...

Wow. I am mostly self taught, and my background is as a structural engineer (PE), and incidentally as a computer programmer. I have the Red Book; I should probably get a copy of the Blue Book rather...
25. ## Thread: glTranslate( 0, 0, something ) ineffectual on VBO

by wmelgaard
Replies
8
Views
4,240

### I am writing an open source version of NASTRAN....

I am writing an open source version of NASTRAN. Think of it as a CAD model undergoing computer analysis. My test file is from a real life project that has 10,000 points. My current objective is to...
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