for our application we need a ping-pong rendering functionality - render into offscreen buffers (or anywhere else) and use the result as a texture again.
currently we bind textures, glsl shaders and render into framebuffer objects. but the performance is very poor so far, using
10.4.3
powerbook ati 9700
are FBOs accelerated?
if they are not, what is the fastest way to
realize a ping-pong rendering system?
Those numbers look a lot like your video rendering is syncrhonized to something – the fact that doubling the number of clips halves the frame-rate. How are you getting the video frames?
well, it turned out that we uploaded textures
using GL_TEXTURE_2D, but using GL_TEXTURE_RECT
is a LOT faster … fully accelerated.
the (not so …) funny point about
this is, that i removed GL_TEXTURE_RECT from
the code base a year ago, because
GL_TEXTURE_RECT and GLSL was not supported
under win32 and ati (last september) and now
we have to pull it back in again to get good
performance with ati in macs. sigh.