Single IBO and Single VBO or terrain rendering

OpenGL OpenGL: Basic Coding
1

I think and hope I am close to having this worked out, but I am not able to render the whole terrain correctly? I think I have it narrowed down to this

glVertexPointer(3, GL_FLOAT, vertexStride, BUFFER_OFFSET(0));
glDrawElements(GL_TRIANGLES, numberIndices, GL_UNSIGNED_SHORT, BUFFER_OFFSET(0));

the glVertexPointer() I need to somehow offset the BUFFER_OFFSET()

I have tried this

index = 0;
//loop here
glVertexPointer(3, GL_FLOAT, vertexStride, BUFFER_OFFSET(index)); glDrawElements(GL_TRIANGLES, numberIndices, GL_UNSIGNED_SHORT, BUFFER_OFFSET(0));
index +=vertexStride;

but that doesn’t work either??? I only get partially rendered terrain???

Thanks

2

How big is your terrain? If you’re using GL_UNSIGNED_SHORT, then the largest terrain you can have is 255 x 255. You can’t have anything bigger. Try using GL_UNSIGNED_INT instead if you can.

3

I am trying to use unsigned short to stay on the fast path as Nvidia suggests.

I am sure there is some way to use a single VBO and a single IBO and just offset the various pointers to render the mesh?

a IBO of say 33x33 patch size is well with in unsigned short range. I have a working unsigned int version, but that uses one large VBO with many many IBO’s…

4

This looks wrong. Surely your indices and your vertex data don’t live at the start of the same buffer?

5

This are different buffers. DrawElements takes the currently bound ekement array buffer, while *Pointer takes the vertex array buffer.

6

Right, thanks for the correction. Slipped my mind.