Laurent Ostiz

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.

object-opengl-shadows

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 

https://cycling74.com/forums/index.php?t=msg&goto=47810&rid=0&srch=

>
> 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.

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:

https://cycling74.com/forums/index.php?t=msg&goto=47810&rid=0&srch= 
%22jitter+shadows%22#msg_47810

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 ;-)

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)

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.

> 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)

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 

Starting Build for minjitglplato.pat-build...

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 

Thank you very much for any advice, even it seems trivial

jmbeal@telefonica.net +34932857046 +34696538403. 

caos->sonoscop. cccb. montalegre, 5. 08001 barcelona

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 :

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.

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


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 ?

Object OpenGL shadows