I have a task of rendering texts in OpenGL context in Windows and Linux environment. I am using FTGL + freetype which works good with one exception. In order to use FTGL I need to supply the font...

In the course of developing the application under Windows I often stop debugging while the application is running and one or more OpenGl windows is active. I assume this does not release the video...

So I really stuck with this one.
I have some impostor shaders that convert a reactangle into a complex geometric shape. Also the application uses frame buffer object for implmementing shadows. So I...

You need to normalize twice as it is possible (and likely) for the normal to become 'unnormalized' as it gets interpolated between the vertices.

Regards
elFarto [/QUOTE]
I am a bit lost. Why do...

There is quite a few things that you can do to optimize your code.
Somebody already gave you a good advice to pack the variables into arrays (which you unfortunately ignored ).
Secondly the bottom...

Yes, in my original post I mentioned that I split the mesh into smaller pieces, which did not help at all.

I am afraid the problem is somewhere else.
Below is the corrupted part of the mesh. Since the same code runs without problem on more recent videocards I do not expect an error in the mesh creating...

I have a piece code that renders a mesh using VBO. It works OK but when the number of vertices is getting close to a milion a part of the image gets corrupted. This does not happen for example on...

Useful note about hapfpixel business Dorbie.
(On the side note: nice performance at the Torrey Pines Gliderport :-)

First of all the code style you quote is far from perfect. Instead of duplicating each call for every shader and checking everything in the end a far better practice is to move the common code to a...

My fragment shader changes z coordinate of the fragment.
In order to implement shadows I need to get distance to the light source from that new fragment position.
Anyone has an idea how to do that...

So I can draw conclusions:
1. Nobody is using glslDevil.
or
2. Nobody pays attention to the varying variables.

Your shader seems to be quite large. There is a limit on the shader size and it could be you are running out of space on iphone.

I am using glslDevil for shader debugging. I had to buy a certain videocard to be able to do that though.
The vertex shader debugging is very good and actually is much better than I expected....

In other words - sort all data points in CPU. You understand that this is not always desirable or even possible due to performance consideration.


Same as above.

Yes that's what I ended up doing. The same value is calculated for each vertex of the primitive. The code grows significantly,
The volume of communication with CPU increases, plus there is extra...

That is all understandable. The question is HOW TO...
It if cannot be done the usability of shaders is severely limited. There is a lot of situations when a fragment shader wants to know values at...

Thanks Yar,
However I cannot use geometry shaders for portability reasons.
As for the buffer color: Is it just an varying variable ? If that the case it is not going to work - see OP.

Please correct me if I am wrong but they will be equal only when x and y equal 0;

A usual way to pass data from a vertex to a fragment shader is to use "varying" qualifier. However it works only in the case when the data is common for all vertices in a primitive.

Let's say I am...

For the majority of 3d solid objects you do not want to see both sides of a primitive so why spending resources on drawing them ?
For example if you draw a sphere there is no need to render inside...

So how do you do printf from a shader ? The only debugging technique that I managed to employ is changing the color of a fragment or a vertex, which is just a tool to kill interest in any GLSL...

I need to shift the depth of a fragment a little bit (converting circles to spheres). Can anyone explain me how the original gl_FragCoord.z value is calculatged ?

First of all even if you could somehomw take control of open gl from another process that would be quite a major undertaking with little benefits if any.
I doubt that opengl conext is thread safe....

I am afraid there is no such thing as camera in OpenGL. Actually there is but it is always at 0,0,0 coordinate.