Part of the Khronos Group
OpenGL.org

The Industry's Foundation for High Performance Graphics

from games to virtual reality, mobile phones to supercomputers

Search:

Type: Posts; User: Lord crc

Page 1 of 8 1 2 3 4

Search: Search took 0.00 seconds.

  1. Replies
    17
    Views
    4,706

    Re: Request: tweak transform feedback

    I'm wondering the same thing. You seem to consistently miss the point he is making and instead try to make it sound as if he's implying stuff he is not. You're also resorting to kindergarden-level...
  2. Replies
    7
    Views
    2,241

    Re: Central-Difference Shader Problem?

    Right, took me a few moments, but I get your approach. You're assuming the current point is part of a level set and compute the gradient of the point, which is of course normal to the level set.
    ...
  3. Replies
    7
    Views
    2,241

    Re: Central-Difference Shader Problem?

    You're computing the gradient there, which can indeed be the zero vector, and which should in general not be confused with the normal vector of a surface.

    For a heightfield h(x, y) you find the...
  4. Replies
    6
    Views
    1,590

    Re: Performance Issue

    Have you tried a wider pencil?


    Seriously, if you want any sensible replies you will have to give a lot more detailed information on how you're currently drawing things.
  5. Replies
    2
    Views
    1,253

    Re: Implementing Bidirectional Ray Tracing?

    The second edition of PBRT is due this summer, and will include info on bidirectional path tracing IIRC.

    In the meantime you should read Veach's thesis, which explains it in great detail, it is...
  6. Replies
    17
    Views
    8,495

    Re: Extensions for stereoscopic rendering

    When considering a workstation from Dell, it was either an intel thing or a Quadro-line card. Nope, couldn't get anything in between, then we had to go for a non-workstation model (which was poor in...
  7. Thread: Dx11 catchup

    by Lord crc
    Replies
    73
    Views
    49,185

    Re: Dx11 catchup

    My gut feeling is that games are still the primary driver of GPU sales. However most gamers can play their games at max quality using "only" a low to midrange card.

    The lack of need for a high-end...
  8. Thread: MRTs

    by Lord crc
    Replies
    8
    Views
    2,203

    Re: MRTs

    Are you certain that glGetUniformLocation() is successful and returns a valid location? Your problems could indicate that it does not.
  9. Thread: MRTs

    by Lord crc
    Replies
    8
    Views
    2,203

    Re: MRTs

    Someone might spot your error. However it's usually easier to get replies if you know where the issue is.

    In order to determine the location of the problem I would start with determining if the...
  10. Re: Direction of normals associated to new vertices

    You're welcome. Hope it works out alright :)
  11. Re: Direction of normals associated to new vertices

    Regular linear interpolation should be used, so if you drop the division by two there it should work :)
  12. Re: Direction of normals associated to new vertices

    Well, if all normals point in the Z direction (I'm going to assume the same Z direction, since the mesh should be "nice"), then there's nothing to interpolate. If one of the normals does not point...
  13. Re: Direction of normals associated to new vertices

    I must admit I've only used the barycentric version of this method. The way I interpret that passage is that you pick one of the normals consistently for all points P within the quad. Which normal...
  14. Re: Direction of normals associated to new vertices

    The normal approach would be to use Phong normal interpolation. It's essentially using linear interpolation of the vertex normals, which is then normalized. You can read up on it here:...
  15. Re: Number of pixels in a fragment - possible to calc?

    I suggest you read the specifications, it's section 4.1.7 and 6.1.12 in the OpenGL 2.1 specs. To quote the relevant part:



    Also check out the extension text, it contains some more useful info...
  16. Re: Number of pixels in a fragment - possible to calc?

    Couldn't you use occlusion queries for this? Start an occlusion query, render the object, get the number of samples (which, afaik, equals to fragments if multi/super sampling is off). Then re-render...
  17. Replies
    2
    Views
    4,238

    Re: glMultMatrixd()

    Unless you're looking for ultimate speed, it's not that hard, a double loop should do... see http://mathworld.wolfram.com/MatrixMultiplication.html (equations 3-12 should give you enough to work...
  18. Re: Number of pixels in a fragment - possible to calc?

    Quoting chapter 3 in the spec's (2.1):



    From this one can induce that the area covered by a fragment will always be 1 in grid coordinates (ie pixels).

    This does not change with MSAA as MSAA...
  19. Replies
    4
    Views
    2,364

    Re: Mandelbrot shader - float accuracy problem

    So in other words floats aren't accurate enough.

    The article I mentioned describes how to compute the sum and dot products up to K times the working precision, using only working precision...
  20. Replies
    4
    Views
    2,364

    Re: Mandelbrot shader - float accuracy problem

    Perhaps you can use some techniques mentioned in this paper:

    "Accurate Sum and Dot Product" http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.2.1547
  21. Replies
    16
    Views
    7,843

    Re: rectangular and npot textures

    See the "Overview" section of http://www.opengl.org/registry/specs/ARB/texture_rectangle.txt

    A regular NPOT texture behaves like a normal POT texture. A texture rect has non-normalized texture...
  22. Replies
    10
    Views
    5,710

    Re: glDrawArray not seeing VBOs

    Excellent, well at least that you figured it out :D

    I suspect that internally the driver would have converted to float anyway, but perhaps I'm wrong.
  23. Replies
    10
    Views
    5,710

    Re: glDrawArray not seeing VBOs

    Have you tried using floats instead of ints, and three coords instead of two? Just to see if there's another nice bug in the ATI drivers :)

    Also, is this (in essence) the only code you've got? If...
  24. Replies
    10
    Views
    5,710

    Re: glDrawArray not seeing VBOs

    I don't see "glEnableClientState(GL_VERTEX_ARRAY);" in that code, did you omit it?
  25. Replies
    29
    Views
    10,827

    Re: More GPU Raycasting Questions

    Perhaps you could do your own "two-pass" technique. First use a somewhat large step, and find the last empty position before you hit the surface. Also find the first empty position on the back, which...
Results 1 to 25 of 180
Page 1 of 8 1 2 3 4