I am just getting started with LJGL.
I am struggling to pull all the pieces together.
I am hoping I can ask questions here on the forum.
I will be fine when I get rolling
Here is my first questions....
I am trying to draw a four triangles that meet at a point.
Like a pyramid on its side, with out a bottom.
When I draw it and then move around it, the sides will sometimes disappear.
It seems like I have to be facing it from the right direction to see it.
It seems like the surface is only seen from one direction
Can some explain, I am sure it is something stupid.
Here is the code segment
GL11.glBegin(GL11.GL_TRIANGLES);
GL11.glNormal3f( 0.0f, 0.0f, 1.0f);
GL11.glVertex3f(size, size, size);
GL11.glVertex3f( size, -size, size);
GL11.glVertex3f( 2 * size, 0, 0);
GL11.glNormal3f( 0.0f, 0.0f, 1.0f);
GL11.glVertex3f(size, size, -size);
GL11.glVertex3f( size, -size, -size);
GL11.glVertex3f( 2 * size, 0, 0);
GL11.glNormal3f( 0.0f, 0.0f, 1.0f);
GL11.glVertex3f(size, size, +size);
GL11.glVertex3f( size, size, -size);
GL11.glVertex3f( 2 * size, 0, 0);
GL11.glNormal3f( 0.0f, 0.0f, 1.0f);
GL11.glVertex3f( size, -size, -size);
GL11.glVertex3f(size, -size, +size);
GL11.glVertex3f( 2 * size, 0, 0);
GL11.glEnd();
When you move "behind" a triangle, the default behaviour in OpenGL is to "cull" it from the scene, that is, not draw it. To draw both the front and back of a triangle you need to use glCullFace() (http://www.opengl.org/sdk/docs/man/xhtml/glCullFace.xml).
Cas :)