# Search:

Type: Posts; User: yoyonel

1. ## Thread: 3d rendering - strange curved lines

by yoyonel
Replies
3
Views
2,015

### Yep it's a filtering problem. You need to...

Yep it's a filtering problem.

You need to understand what you do when you're rendering a 'pixel' with your voxel engine.

In a few words, you need to consider a pixel like a mini frustum from...
2. ## Thread: how to Calculate the Irradiated area?

by yoyonel
Replies
7
Views
1,726

### Irradiated area on Plane with z=0 ... mmmMMMmm...

Irradiated area on Plane with z=0 ... mmmMMMmm ...
you want to compute the area of the projection of the xy-plane (z=0) on the near plane of your camera ?
3. ## Thread: how to Calculate the Irradiated area?

by yoyonel
Replies
7
Views
1,726

### lol it's a joke yanasdf789 ;) The xy-plane(z=0)...

lol it's a joke yanasdf789 ;)
The xy-plane(z=0) is infinite, like all planes of "space" (dimension(s) >= 1).
4. ## Thread: Making an arbitrary polygon look darker towards the edges

by yoyonel
Replies
9
Views
3,540

### Sound like a good idea ! Please send your...

Sound like a good idea !
5. ## Thread: Making an arbitrary polygon look darker towards the edges

by yoyonel
Replies
9
Views
3,540

### A simple way => Use a shader (pixel shader,...

A simple way =>
Use a shader (pixel shader, fragment shader) when you're rendering your triangle to compute the distance between the pixel/point and the "base"-edge of your triangle.
Point-Line...
6. ## Thread: Making an arbitrary polygon look darker towards the edges

by yoyonel
Replies
9
Views
3,540

### Hello, For visual effect, you can: - [1] Use...

Hello,

For visual effect, you can:
- [1] Use a Stencil Buffer (and stencil operations) and render your polygons and mark them (for example 1 for 'inside" polygon)
- [2] Render in a target your...
7. ## Thread: Fitting a model appropirately

by yoyonel
Replies
2
Views
796

### Hello, Yes i think it's the good way (BBox and...

Hello,
Yes i think it's the good way (BBox and fitting the view frustum).

But i can't see how this can be a 'slightly heavy' calculations ^^ (for 1 object -> 1 (AA)BBox and a frustum camera).
...
8. ## Thread: What are some concepts every OpenGL programer should know from memory?

by yoyonel
Replies
4
Views
1,734

### - Matrix transformations : ModelView, Projection,...

- Matrix transformations : ModelView, Projection, Viewport settings
- Basic Shaders: all stuffs mentionned previously (transformations, animation, camera control, lighting, ...) with a GLSL shaders...
9. ## Thread: Need help on shadow mapping

by yoyonel
Replies
7
Views
2,395

### For the resolution, with hardware support, i...

For the resolution, with hardware support, i think the limit is 4096² or 8192² (not more).
But you can subdivise your light viewport and have the size that you want (independtly of your...
10. ## Thread: Need help on shadow mapping

by yoyonel
Replies
7
Views
2,395

### Oki i see, i think it's the "acnee problem" with...

Oki i see, i think it's the "acnee problem" with shadow mapping.
Look here => http://msdn.microsoft.com/en-us/library/windows/desktop/ee416324(v=vs.85).aspx
Very useful page, it's for DirectX but...
11. ## Thread: Need help on shadow mapping

by yoyonel
Replies
7
Views
2,395

### Not sure to understand well your problem. ...

Not sure to understand well your problem.

Some possible ways to know what happens:
- Draw your 2D Depth Buffer (using for Shadow-Map...
12. ## Thread: glVertex3i Z can only be -1, 0, or 1. Why?

by yoyonel
Replies
7
Views
3,648

### You can use a custom Orthogonal Projection...

You can use a custom Orthogonal Projection matrix, explain here: http://www.songho.ca/opengl/gl_projectionmatrix.html (Orthographic Projection section))
So => ...
13. ## Thread: "Backface culling" GL_LINES

by yoyonel
Replies
6
Views
3,919

### Aestivae: Perspective projection don't "bend" a...

Aestivae: Perspective projection don't "bend" a plane, you need to rethink about visibility with projection transformation.
Good Luck
14. ## Thread: "Backface culling" GL_LINES

by yoyonel
Replies
6
Views
3,919

### If you want to do this in device side (gpu), you...

If you want to do this in device side (gpu),
you can simply add normal information for all vertex that define yours lines (the plane normal)
and compute the culling a vertex shader (just transform...
15. ## Thread: "Backface culling" GL_LINES

by yoyonel
Replies
6
Views
3,919

### Hello ! I'm not sure to really understand...

Hello !

I'm not sure to really understand your problem ...
The plane (who contains 'all the line') is visible or not visible (cull or not cull), even with a perspective projection.
So, when...
16. ## Thread: Character collision

by yoyonel
Replies
3
Views
2,571

### Hi ! You need to apply your transformation...

Hi !

You need to apply your transformation local object space -> world space to your AABBOX to have the AABBOX in world space (it's the space where you're compute the interaction with others...
17. ## Thread: creating 3D rect angle using opengl Qt

by yoyonel
Replies
2
Views
1,385

### Re: creating 3D rect angle using opengl Qt

Hi !

Your problem is about the orientation of the first face (quad).

Try this:

glColor3f (0.0f,1.0f,0.0f); // Set The Color To Green
glVertex3f( 1.0f, 1.0f,-1.0f); ...
18. ## Thread: Compilation error (beginner, c++, netbeans)!

by yoyonel
Replies
2
Views
2,436

### Re: Compilation error (beginner, c++, netbeans)!

Hello !

Try to include BMPLoader.c in your project (like source code file) and not with the preprocessor instruction #include (it's for header file).
Maybe that solve yours compiler errors.
...
19. ## Thread: Is there effective way of storing distance data?

by yoyonel
Replies
6
Views
1,359

### Re: Is there effective way of storing distance data?

You can exploit the Z-Buffer with the distance to the camera's Z-Plane and add the distance to the camera's center (projection center (0,0,0)) and the intersection of the view ray (center to you 3D...
20. ## Thread: Vector through poly intersection...

by yoyonel
Replies
6
Views
3,370

### Re: Vector through poly intersection...

Hi :)

"could do some collision detection to see if the lumel is obstructed by any of the polygons" it's already happen with depth shadow map.
The problem is not the intersection himself but what...
21. ## Thread: can GL_COMBINE implement a expression with if else

by yoyonel
Replies
2
Views
1,517

### Re: can GL_COMBINE implement a expression with if else

Hi !

You can try this:
float f_test = v2 < 128;
float f_result = f_test * (2 * v1 * v2 / 255) + (1-f_test) * (255 - 2 * (255-v1) * (255-v2) / 255);

Good Luck !

YoYOOOoOO
22. ## Thread: waht's the "Stencil Test" Compare

by yoyonel
Replies
2
Views
1,658

### Re: waht's the "Stencil Test" Compare

Wikipedia is your friend:
"A stencil buffer is an EXTRA BUFFER, in addition to the color buffer (pixel buffer) and depth buffer (z-buffering) ..."
=> http://en.wikipedia.org/wiki/Stencil_buffer...
23. ## Thread: VBO with flat shading

by yoyonel
Replies
5
Views
6,780

### Re: VBO with flat shading

Hi !

You can see this: http://www.opengl.org/sdk/docs/man3/xhtml/glProvokingVertex.xml
I think it's what you search !

good luck,
YoYooOoOOoO
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