Print Page - No light in my scene

Title: No light in my scene
Post by: strange on January 21, 2004, 20:42:52

Hi,

I have a problem with setting up the light in my scene. I just want to have some nice flat surfaces without textures that get shaded by a light.
Is there anyting I did forget or did wrong in my code because the objects stay totaly black:

GL.glLightModel(GL.GL_LIGHT_MODEL_AMBIENT, temp.asFloatBuffer().put(ambientLight));
GL.glEnable(GL.GL_COLOR_MATERIAL);

GL.glLightfv(GL.GL_LIGHT0, GL.GL_AMBIENT, temp.asFloatBuffer().put(ambientLight0));
GL.glLightfv(GL.GL_LIGHT0, GL.GL_DIFFUSE, temp.asFloatBuffer().put(diffuseLight0));
GL.glLightfv(GL.GL_LIGHT0, GL.GL_POSITION,temp.asFloatBuffer().put(lightPos0));
GL.glEnable(GL.GL_LIGHT0);
GL.glEnable(GL.GL_LIGHTING);

and this in front of my objects:

GL.glColorMaterial(GL.GL_FRONT, GL.GL_AMBIENT_AND_DIFFUSE);

Thanks for help

Title: No light in my scene
Post by: Mojomonkey on January 21, 2004, 21:33:59

Are you setting up your normals?

Title: No light in my scene
Post by: princec on January 21, 2004, 22:15:42

You must flip() your buffers after put()ting stuff in them. This sets the buffer's position and limit correctly which is what we pass into OpenGL.

Cas :)

Title: No light in my scene
Post by: strange on January 21, 2004, 22:17:10

That sounds pretty much like a problem :wink:

I did the necesary changes in my code but now I have compilingproblems. An exception occured in the native code.

The code looks like:
public static FloatBuffer fbuff = FloatBuffer.allocate(16);
fbuff.put(diffuseLight0).flip();
GL.glLightfv(GL.GL_LIGHT0, GL.GL_DIFFUSE, fbuff);

Oh my god!

Title: No light in my scene
Post by: Optus on January 21, 2004, 23:50:28

Don't know if it will be your end-all fix, but buffers passed to OpenGL must be allocated with allocateDirect(), not the allocate() method.

Title: No light in my scene
Post by: cfmdobbie on January 22, 2004, 00:03:25

Try this instead:

Code Select

public static FloatBuffer fbuff = ByteBuffer.allocateDirect(16).order(ByteOrder.nativeOrder()).asFloatBuffer();
fbuff.put(diffuseLight0).flip();
GL.glLightfv(GL.GL_LIGHT0, GL.GL_DIFFUSE, fbuff);

Title: No light in my scene
Post by: strange on January 22, 2004, 01:28:43

Great, finaly the light works. I thank you guys very much.

But this is a very complicated way of seting up the light.
Does anyone have a more "normal" way of doing this?

Title: No light in my scene
Post by: Optus on January 22, 2004, 04:27:07

I haven't used any of OpenGL's lighting for any lighting purposes in my current project. I have either used lightmapping, using ARB multitexture, or by calculating shade values and coloring geometry with the glColor3f() method at render-time.

Title: No light in my scene
Post by: princec on January 22, 2004, 09:36:43

There is no easier way of setting up lights in OpenGL. However, coz you're a Java programmer, you will write a Light class that does it for you and squirrels away the nasty code so you can't see it any more, and you'll forget all about how it works in a few weeks and just get on with some other problem :)

Cas :)

LWJGL Forum

Programming => Lightweight Java Gaming Library => Topic started by: strange on January 21, 2004, 20:42:52