I don't get why having multiple drawindexedprimitive seems to stall

Marv G · 2004-02-29T16:34:36

so let me be a bit brief as I can, I did two experiments using vertex and index buffers. The common base for both experiments is this: 27 DrawPrimitive calls of 801 vertices(267 triangles - TRIANGLELIST ) Shader = fixedcolor out + a little vertex tweening here is what both tests look like: http://www.mojo9.com/~wickedewok/scene.gif Now, for test A, I put all 801*27 vertices in 1 STATIC( don't change it after the first init ) vertex buffer and used DrawPrimitive() to render them all. This is the throughput I get: FPS:71.3466 Number of vertices/second = 1.54301e+006( divide by 3 to get tris/sec ) number dps: 27 verts: 801 Now for test B, I compact the 801 vertices into roughly 535 vertices and put them in the one Static vertex buffer. I use a Static index buffer to look into this vertex buffer. I render with 27 DrawIndexedPrimitive() calls and here is my result: FPS:7.18518 Number of vertices/second = 155394 number vbs: 27 verts: 801 Ok what looks a litle weird are the numbers, I'm getting almost exactly 10 times less than the first experiment, but here is the calllist from D3D Spy for both: testa) http://www.mojo9.com/~wickedewok/VertexBufferRender.gif testb) http://www.mojo9.com/~wickedewok/IndexBufferRender.gif I have not done anything else in between. When I use 1 Drawprimitive for both test A and B and 9000 vertices, there throughput is identical. Only when I start using many DPs and DIPs do two methods diverge in speed. any ideas? thanks -Marv edit- links were fine, just the link headings were copied and pasted, fixed now. [edited by - Wicked Ewok on February 28, 2004 8:10:55 PM]