Some drivers (at least the Intel drivers on Windows) are slow at
incrementally updating a VBO with hundreds of calls to glBufferSubData
every frame. Performance is significantly better if you use
glBufferData(NULL) to tell it to discard all the previous contents, and
then re-upload all the data at once.
Update CVertexBuffer so that GL_DYNAMIC_DRAW/GL_STREAM_DRAW buffers are
handled with the new mechanism. This requires the caller to hold onto
the backing store so it can be re-uploaded when necessary, and needs a
bit more signalling to indicate exactly what needs uploading.
I see an improvement from roughly 60 to 75 fps on Intel HD Graphics
3000, Windows, 1024x768, Siwa Oasis.
This was SVN commit r16241.
the old debug_assert always ran and tested the expression, which slows
down release builds. wrapping them in #ifndef NDEBUG is clumsy. the new
ASSERT behaves like assert and ENSURE like the old debug_assert. Let's
change any time-critical but not-super-important ENSURE to ASSERT to
speed up release builds. (already done in bits.h and unique_range.h)
This was SVN commit r9362.
Use index VBOs in model renderers, for performance.
Be more explicit about static/dynamic VBOs.
Add VBO usage to renderer stats.
Clean up some obsolete unused code.
This was SVN commit r9052.
Add Ogl_Shader and Ogl_Program handle types for shaders/programs loaded
from
files.
In the vertexshader render path, use a vertex program for lighting for
optimization.
This was SVN commit r2853.
