hi all forum folks,
I have been a newbie in opengl stuff for more than an year, now i am feeling kinda it is time to face some serious stuff.
My first question is: where i may find some good book teaching the adv uses of opengl? Stuff like doing your own lighting, computing radiosity algorithms and so on.
Next there are a few questions i am facing right now: what is exactly a cubemap? I have a nice tutorial, but unfortunately i am not understanding it very much. For example in the rendering loop there is something like:
compute cube map
glClear(GL_DEPTH_BUFFER_BIT);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
//some scene rotations
//no big deal here
glRotate(…);
glRotate(…);
//render world
RenderSkyBox();
glTranslatef(camera position);
//enable cube mapping
glEnable(GL_TEXTURE_CUBE_MAP_ARB);
//enable the texture
g_cubemap->bind();
//enable cube mapping
glEnable(GL_TEXTURE_GEN_S);
glEnable(GL_TEXTURE_GEN_T);
glEnable(GL_TEXTURE_GEN_R);
>ok, first big question:
>what happens when i switch to
>TEXTURE matrix? Am i rendering
>the scene on a special texture
>that i will use to make the
>reflection map? I just used
>modelview for all my (short)
>opengl career, so i am a bit lost.
glMatrixMode(GL_TEXTURE);
glPushMatrix();
//here is the viewport corrected. NOTE that
//we are in TEXTURE matrix mode
glRotate(-yangle…);
glRotate(-xangle…);
//rendere the sphere
>ok now where am i rendering this sphere?
>I thought i was just putting all the sphere
>stuff in a sort of texture buffer, but it
>actually renders it in the middle of my
>scene… puzzling
gluSphere(shere,6.0f,64,64);
//restore texture matrix
glPopMatrix();
glMatrixMode(GL_MODELVIEW);
glDisable(GL_TEXTURE_GEN_S);
glDisable(GL_TEXTURE_GEN_T);
glDisable(GL_TEXTURE_GEN_R);
//render the objects
*render 2 cubes and a sphere…
that is the chunk i am having some trouble to undersand. I hope i am not too much off theme for an advanced forum, but actually i do need to start somewhere after all, no?
Thank you to all who’ll help me
The Gunslinger