I've never used VBOs before, nor researched them very much; but I do have a guess for you nonetheless.
I would assume that your use of GL_DYNAMIC_DRAW is preventing the card from storing the data in an maximally optimized form.
Trying to adapt your application to use GL_STATIC_DRAW, or display lists might be a fruitful venture. (If you haven't heard of display lists yet then don't be afraid to give them a go; they're certainly no more complicated than VBOs).
Also, googling "Vertex Buffers versus Display Lists" will likely be of use as well.
-Patrick
P.S. I don't think you need to use the ARB suffixed functions as you do in the source you posted. GenBuffers, BindBuffers, and BufferData have been in OpenGL since 1.5. You can find the standard here:
On May 23, 2008, at 12:34 PM, Mike wrote: Hello,
I am learning OpenGL and building a simple particle demo with velocity, friction, forces, etc.
I started with immediate mode and drew each particle with glVertex() and it went up to 200k particles with about 50fps (2.4Ghz iMac & ati 2600 pro & no vsync).
Then I learned about VBO's and how much faster they're supposed to be. I modified my code to use VBO instead but the speed difference is only about 10% more compared to glBegin/end() with zillion individual glColor() glVertex() pairs ?!?
I am using 4 threads to calculate the math and timer to render the scene. Is there anything to speed up things or is GLSL -> FBO -> VBO only possible solution? (well, frankly that is my next goal and questions anyway).
But for now; Is it possible that there is something wrong in my VBO usage or can driver somehow optimize the glVertex() calls and thus no huge gains visible?
Thank You.
Here's how I do it:
// build VBO's once bool buildVBO(int vertexCount,float* pVerArray,float* pColArray ) { if (pVerArray && pColArray) { glGenBuffersARB( 1, &m_nVBOVertices ); glBindBufferARB( GL_ARRAY_BUFFER_ARB, m_nVBOVertices ); glBufferDataARB( GL_ARRAY_BUFFER_ARB, vertexCount * 3 * sizeof(GLfloat),pVerArray, GL_DYNAMIC_DRAW );
glGenBuffersARB( 1, &m_nVBOColors ); glBindBufferARB( GL_ARRAY_BUFFER_ARB, m_nVBOColors ); glBufferDataARB( GL_ARRAY_BUFFER_ARB, vertexCount * 3 * sizeof(GLfloat), pColArray, GL_DYNAMIC_DRAW ); if (m_nVBOVertices && m_nVBOColors) return true; }
return false; }
// update new vertex-data void refreshData(int vertexCount,float* pVerArray,float* pColArray ) { glBindBufferARB(GL_ARRAY_BUFFER_ARB, m_nVBOVertices); glBufferDataARB(GL_ARRAY_BUFFER_ARB, vertexCount * 3 * sizeof(GLfloat), pVerArray, GL_DYNAMIC_DRAW );
glBindBufferARB(GL_ARRAY_BUFFER_ARB, m_nVBOColors); glBufferDataARB(GL_ARRAY_BUFFER_ARB, vertexCount * 3 * sizeof(GLfloat), pColArray, GL_DYNAMIC_DRAW ); }
// draw VBO's void drawVbo(int vertexCount) { glEnableClientState( GL_VERTEX_ARRAY ); glEnableClientState( GL_COLOR_ARRAY );
glBindBufferARB( GL_ARRAY_BUFFER_ARB, m_nVBOVertices ); glVertexPointer( 3, GL_FLOAT, 0, 0 ); glBindBufferARB( GL_ARRAY_BUFFER_ARB, m_nVBOColors ); glColorPointer( 3, GL_FLOAT, 0, 0 );
// Render glDrawArrays( GL_POINTS, 0, vertexCount );
glDisableClientState( GL_COLOR_ARRAY ); glDisableClientState( GL_VERTEX_ARRAY ); }
Do not post admin requests to the list. They will be ignored.
Mac-opengl mailing list (email@hidden)
Help/Unsubscribe/Update your Subscription:
http://lists.apple.com/mailman/options/mac-opengl/email@hidden
This email sent to email@hidden
|
