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uto314

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About uto314

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  1. hi, i wrote a program that uses the nv_occlusion_query extension. Basicaly I perform about 256000 occlusion queries, n at the time, consecutively. if n == 100, the result gets wrong after a while, the occlusion query always returns 0. if n == 1000 it works fine. I think it might be because of asynchronous nature of the occlusion query, but I can't find a way to make it work with n == 100. So if someone has any experience with this extension or any idea, it would be really helpfull. thanks.
  2. Thanks for the reply, the thread option is pretty much what I will do. Cool. -u.
  3. Try glGetIntegerv(GL_MAX_TEXTURE_IMAGE_UNITS), it returns the actual number of texture units. -u.
  4. Hi, I'm wondering if there is a common way to load texture into the graphics hardware (glTexImage2D) in a asychrone way. For instance if I know that at time T I'll need a texture to be accessible, I'd like to start transfering the data at T - t to not slow down the frame rate of the application. My idea is to use a specialized thread that cares only about the textures management, but if someone knows a simplest way that would be greaaat :) Thanks.
  5. uto314

    Fragment shader - GL_BLEND

    Thanks a lot, actually it seems to be the case. It works for 64 bits textures. -cf.
  6. Hi, I draw in a floating point pbuffer (128 bits/pixel) with stencil and depth buffer. Everything works fine. Once I enable GL_BLEND, it goes insanely slow. I'd like to know if someone ever had a trouble such this one. The graphics I use is a NVidia Quadro FX 4400 with the driver 77.18 Any comment would help a lot, Thanks, -uto-
  7. uto314

    Maya 6.5 OBJ Loader

    Hi, I'm trying to load an .obj in Maya 6.5 but it doesn't load the texture specify in the .mtl file. Then I tryed to model a simple textured quad, export it to an .obj file. Even this file doesn't load properly with Maya 6.5, the texture is missing. But it does ok with Maya 6.0. Does anyone knows something about that, that would be great, Thanks. -uto-
  8. Thanks for you reply, but I'm not sure that the depth buffer sampling is linear, in which case a constant offset will not work. I'm sure that is very known problem but I haven't found some good documentation about how to solve it. ... after googling... [http://www.codesampler.com/oglsrc.htm] -uto- [Edited by - uto314 on March 31, 2005 5:38:29 PM]
  9. Hi, I'm trying to get ride of a Z-fighting against two polygon which overlap one the other and belong to the same plane. First I enable GL_POLYGON_OFFSET_FILL, then I set glPolygonOffset(k,u); and I draw the 2 polygons. But I can't find the propers k and u unit to make the thing work, there is always a point of view (distance / perspective) which involves a z-fight between the 2 polygons. So if someone knows something about that a little help would be great... Thanks, -uto-
  10. Thanks Gulgi. As you might have seen I use rectangular texture. And I can't perform (I mean it's not working) rectangular texture lookup from a glsl fragment shader with a sampler2DRect and the texture2DRect lookup function on a ATI card, I don't know why because it's supposed to support it. If you have a piece of code to access rectangular texture with a sampler2DRect which works on ATI your welcome :)! Thanks, -uto-
  11. silvermace : isn't this approach the same a the one on Paul's Project ? -uto-
  12. Thanks to you for you replies, Radod : As Kalidor said the render to depth texture is not supported by the ATI cards. And I was actually trying to render to a pbuffer and copy its depth buffer to a depth texture, as in the Paul's tutorial. The issue with this approach is that it's not really suitable for a dynamic scene. But I am trying to understand why the call glCopyTexSubImage2D() is 10 times slower if I initialize my texture as : glTexImage2D( GL_TEXTURE_RECTANGLE_ARB, 0, GL_LUMINANCE16, m_width, m_height, 0,GL_DEPTH_COMPONENT, GL_UNSIGNED_BYTE, 0L); than glTexImage2D( GL_TEXTURE_RECTANGLE_ARB, 0, GL_DEPTH_COMPONENT, m_width, m_height, 0,GL_DEPTH_COMPONENT, GL_UNSIGNED_BYTE, 0L); (in the first case it copies the frame buffer to the texture, in the second case it should copy the depth buffer to the texture) Kalidor : I'll try to work arround you solution, thanks.
  13. Hi, I am looking for a way to implement some dynamic shadow maps for ATI cards. For the nVidia I use the render to depth texture extension but I didn't found an equivalent that can work for ATI cards. So if someone has a link to a sample code or knows how to deal with it, that that would be great. Thanks, -uto-
  14. [EDIT :] I just realize the the wrong forum to post it (it would be better in Graphics, sorry) Hi, let summary, I have a shadow map and a depth value corresponding to the projection of a 3D point in the light space. The depth value is the actual value, but the value picked in the shadow is dependent of the shadow map resolution. The error between the two value is big each time there is a depth step (you can see the pictures if it's not clear, the links are below). Moreover, the error value is more or less equal to the depth step value. I don't have a real solution, I try to quantify the error to use a epsilon, but the major problem is the foreshortening, I am thinking about validating the point if the depth is in the range defines by the [min,max] value of the shadowMap's corresponding pixel's neighbourhood (But that implies 9 texture accesses :( ).(I use a fragment shader) So anyone with any comments or links is welcome. Thanks, -uto- 3D point depth variation in the light space [link]http://members.gamedev.net/uto/ShadowMap/PointDepthGradient.jpg[/link] Shadow depth variation [link]http://members.gamedev.net/uto/ShadowMap/shadowDepthGradient.jpg[/link] Difference between the two [link]http://members.gamedev.net/uto/ShadowMap/DepthError.jpg[/link]
  15. That's true :) But I didn't get the "just with translation included but this should not be the problem i guess". -uto-
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