Issues using GL Vertex Buffers

[rsodre]

Hello,

I was not happy with the performance using BaseDraw::LineStripBegin() / BaseDraw::LineStrip() / BaseDraw::LineStripEnd() to draw thousands of strands on the viewport, so I tried using GlProgramFactory and GlVertexBuffer from gl.h, exemplified on the sdk source gl_test_object.cpp. The performance improved was amazing, viewport fps raised up to 3 times.

But those functions are marked as undocumented, and I hope that's very different from the private, that shall never be commented, because some issues arised that I'm unable to solve.

First, bd->SetDrawParam( DRAW_PARAMETER_LINEWIDTH, 2 ); does not work when drawing with DrawSubBuffer().
DRAW_PARAMETER_LINEWIDTH is marked in the docs as (OpenGL only), but actually looks like is the inverse.
How can I set like width for DrawSubBuffer()?
What OpenGL does DRAW_PARAMETER_LINEWIDTH refers to?

And some lines seem broken, with gaps in between, usually on concave surfaces. Looks like some depth precision problem.
How to control depth read/write using those functions?

[a_block]

Hello,

again it's me who has provide the unsatisfactory answer. We currently have nothing more to contribute to this topic besides the examples you have already found. I am terribly sorry.

Cheers,
Andreas

[rsodre]

This post is deleted!

[rsodre]

Just found my problem, nothing to do with the drawing API...

bd->SetDrawParam( DRAW_PARAMETER_SETZ, DRAW_Z_ALWAYS );

It was setting the depth fragment on all the strands, occluding itself sometimes!

[a_block]

Hi Roger,

I'm glad you were able to identify the issue and made some progress. And thanks for taking the time to share your findings with the forum. Much appreciated!

Cheers,
Andreas