Object OpenGL shadows


    Jul 21 2006 | 7:55 pm
    Hi !
    I am drawing a scene consisting only of planes in OpenGL with some gridshape objects. Is there anybody here that can explain to me how to have shadows of those planes onto other planes as I move the light ? I looked in the forum and know that it is not automatic but I did not understand how to do it simply.
    Thanks.

    • Jul 21 2006 | 8:22 pm
      On Jul 21, 2006, at 12:55 PM, Laurent Ostiz wrote:
      > > I am drawing a scene consisting only of planes in OpenGL with some > gridshape objects. Is there anybody here that can explain to me how > to have shadows of those planes onto other planes as I move the > light ? I looked in the forum and know that it is not automatic but > I did not understand how to do it simply.
      Sorry, but in OpenGL, there isn't a way to do it *simply*.
      We're looking at some yet more complicated ways to get better quality shadows in future release, but currently I would suggest the texture approach posted by Randy Jones:
      -Joshua
    • Jul 23 2006 | 11:34 am
      Hi !
      I have studied this example, but it works well only when scene is static. If I move the light, and of course move at the same time the camera in the render that create the shadow texture, I do not get a realistic shadow. The shadow is not projected from the light point of view. I have read that there could be solutions with GLSL shaders. Does anyone has already tried to write one ? What about stencils ? Does Jitter 1.5.x support stencils ? Another problem with this solution is that writing a texture to a matrix, turn rendering in software mode. Is there a way to render in a texture directly in OpenGL ? I know many questions, but perhaps do you have some clues of answer ;-)
      Best regards
      Laurent
    • Jul 23 2006 | 12:18 pm
      Hi again
      Continuing my investigations, is there a way to read the z-buffer directly in Jitter, and render it ? (method of shadow mapping described here and there on the Internet)
      Best regards
      Laurent
    • Jul 24 2006 | 5:34 pm
      On Jul 23, 2006, at 5:18 AM, Laurent Ostiz wrote:
      > Continuing my investigations, is there a way to read the z-buffer > directly in Jitter, and render it ? (method of shadow mapping > described here and there on the Internet)
      Not currently, but this is being actively worked on.
      -Joshua
    • Jul 24 2006 | 7:34 pm
      hello
      i'm trying (without any success) to build a minimal jitter-opengl application (shown below) in a Macintel MacBookPro 2.0 GHz under WXP.
      after including all needed files (cg.dll, cgGL.dll, jitlib.dll and jitter shaders), pushing the build button in the collective editor, choosing "Application (*.exe)" option and pushing save button in the file browser, max window and collective editor display the following message :
      Starting Build for minjitglplato.pat-build...
      But this starting process never ends ...
      When object jit.gl.plato and include file jitter shaders are removed, after relaunching max, the building process ends normally
      I've tried building some help patches of jitter objects. I get exactly the same behavior.
      Is this a known issue?
      Thank you very much for any advice, even it seems trivial
      jose manuel
      ________________
      jose manuel berenguer jmbeal@telefonica.net +34932857046 +34696538403. http:// www.sonoscop.net/jmb/ jmberenguer@sonoscop.net +34933064128. http://www.sonoscop.net/ caos->sonoscop. cccb. montalegre, 5. 08001 barcelona spain
    • Jul 25 2006 | 9:08 am
    • Jul 26 2006 | 10:10 am
      Hi !
      I have read the documentation about the new Jitter SDK 1.6.0 (thanks for this) and, wonder this : since from the C API we have a direct access to the full (yes ?) OpenGL 2.0 API, do you think now that it could be possible to implement soft shadows algorithm directly in an external that can interact with other jit.gl.* objects ? More precisely, is it possible to setup a multipass object with "private" renderings contexts to perform complex calculations ?
      Thanks a lot.
      Laurent