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Type: Posts; User: wmelgaard

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by wmelgaard
Replies
4
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272

### 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
272

### 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
272

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,...
4. ## Thread: glOrtho in GL_PROJECTION vs GL_MODELVIEW?

by wmelgaard
Replies
2
Views
278

### 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...
5. ## Thread: glOrtho in GL_PROJECTION vs GL_MODELVIEW?

by wmelgaard
Replies
2
Views
278

### 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...
6. ## Thread: glTranslate( 0, 0, something ) ineffectual on VBO

by wmelgaard
Replies
8
Views
801

### 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...
7. ## Thread: glTranslate( 0, 0, something ) ineffectual on VBO

by wmelgaard
Replies
8
Views
801

### 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...
8. ## Thread: glTranslate( 0, 0, something ) ineffectual on VBO

by wmelgaard
Replies
8
Views
801

### 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...
9. ## Thread: glTranslate( 0, 0, something ) ineffectual on VBO

by wmelgaard
Replies
8
Views
801

### My objective is to rotate the entire model about...

My objective is to rotate the entire model about the center of the second VBO.
I am running Debian oldstable

KDE reports OpenGL version 2.1 Mesa 7.7.1, and GLX version 1.4 Mesa. I understand that...
10. ## Thread: glTranslate( 0, 0, something ) ineffectual on VBO

by wmelgaard
Replies
8
Views
801

### glTranslate( 0, 0, something ) ineffectual on VBO

I constructed two widgets, one centered on z =0, and another at z = offset, and wrote them both to VBO[1] and VBO[2].

glMatrixMode(GL_MODELVIEW);
glColor( 1, 0, 0 );
glPushMatrix();...
11. ## Thread: glTranslate & glRotate deprecated

by wmelgaard
Replies
1
Views
344

### glTranslate & glRotate deprecated

that glTranslate and glRotate are being deprecated in favor of OpenGL Mathmatics (GLM).
This may fine and...
12. ## Thread: Triangulating a surface constructed by 3D curves

by wmelgaard
Replies
5
Views
633

### Again without having seen your data, it sounds...

Again without having seen your data, it sounds like the same problem as meshing a Finite Element Analysis (FEA) model. The Finite Element Method Its Basis And Fundamentals , by Ziendiewicz, Taylor &...
13. ## Thread: Simple iOS 3D drawing app

by wmelgaard
Replies
1
Views
604

### A few tutorials are nice, but if you really want...

A few tutorials are nice, but if you really want to get into OpenGL, you need "The Red Book" OpenGL Programming Guide, available from your favorite book seller. This forum is not an adequate...
14. ## Thread: Triangulating a surface constructed by 3D curves

by wmelgaard
Replies
5
Views
633

### The example that I provided (creating a sphere...

The example that I provided (creating a sphere from a single triangle strip) in this forum sounds close to what you are trying to do.
assume:
float curve[n][npoints][3]; // this assumes that all...
15. ## Thread: Rotate object around its local coordinate system

by wmelgaard
Replies
4
Views
612

glTranslatef(ctrx,ctry, ctrz);
glRotatef((pitch, 0, 1, 0);
glRotatef((roll, 1, 0, 0);
glRotate(yaw, 0,0,1);

model();

...
16. ## Thread: trying to draw a sphere in a single triangle strip

by wmelgaard
Replies
7
Views
1,404

### See the attached program for (hemisphere) from a...

See the attached program for (hemisphere) from a single line strip. If the limit in line 38 is changed from 180 - 360, you will get the entire sphere
Left click and drag rotates the model.1235

by wmelgaard
Replies
1
Views
383

### Incidentally, the ctrz for my current model is...

Incidentally, the ctrz for my current model is ~1000, and the model maximum radius is 710. My VBO rendering appears be rotating about z=0 (?) regardless of translation of ctrz = +/- 1000

by wmelgaard
Replies
1
Views
383

### rotating VBO about x,y axes

My problem is that the model is not rotating about any recognizable z coordinate. I expect it to rotate about z = ctrz.

Since my data is in a linked list instead of an array, I built the VBO using...
19. ## Thread: rotating large models

by wmelgaard
Replies
11
Views
1,308

### Thank you. It will take me a few days...

Thank you. It will take me a few days experimenting, but it looks rather straight forward.

Is there a callback function that will tell me how much buffer array space I have in the GPU?
My sample...
20. ## Thread: rotating large models

by wmelgaard
Replies
11
Views
1,308

### My model() function is very efficient in terms of...

My model() function is very efficient in terms of memory, but not speed. That was not a problem until I tried to rotate it. if I generate a Vertex Buffer Object as malexander suggests, that would...
21. ## Thread: rotating large models

by wmelgaard
Replies
11
Views
1,308

### I have not learned to use VBOs, Example 2-28 in...

I have not learned to use VBOs, Example 2-28 in OpenGL Programming Guide 7th ed. mentions VBOs, but what I see is VAOs loaded into the kernel via glDrawElements(PrimType[i], NumElements[i],...
22. ## Thread: rotating large models

by wmelgaard
Replies
11
Views
1,308

### void move(int x, int y){ // creates dynamic...

void move(int x, int y){ // creates dynamic display from mouse drag
int dx, dy, dz;
dx = downx -x; dy = downy - y;
glutSwapBuffers();
glMatrixMode(GL_MODELVIEW);
glClearColor(1.0, 1.0,...
23. ## Thread: rotating large models

by wmelgaard
Replies
11
Views
1,308

### rotating large models

I am writing what I intend to be an Open Source implementation of NASTRAN. My sample model has 5,000 lines, 5,000 triangles, 10,000 quadrilaterals and 10,000 points. I am trying to rotate the model...
24. ## Thread: tagging occlluded primitives

by wmelgaard
Replies
1
Views
646

### tagging occlluded primitives

I am writing a GUI for a finite element program. I want to be able to highlight/choose a primitive from a list, where the list is limited to those primitives which are visible. Bounding boxes really...
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