OpenGL another question

SDL Development
1

Hello,

I have another question :

  • Does SDL uses AGP texturing in OpenGL mode with version 1.1.4 when drawing
    directly to the framebuffer ?
    Actually I draw on a offscreen SDL_Surface that I use as texture, but it’s
    slow for real time updating (for real time fire for instance)

Thanks a lot

Stephane

2

Can be wrong on this one, but I think that AGP texturing is up to the driver…
AGP is not really fast, you’d better store everything you can into locale video
RAM.

Ingenu.

Stephane Magnenat a ?crit :> Hello,

I have another question :

  • Does SDL uses AGP texturing in OpenGL mode with version 1.1.4 when drawing
    directly to the framebuffer ?
    Actually I draw on a offscreen SDL_Surface that I use as texture, but it’s
    slow for real time updating (for real time fire for instance)

Thanks a lot

Stephane

3

Stephane Magnenat schrieb am 18 Aug 2000:

Hello,

I have another question :

  • Does SDL uses AGP texturing in OpenGL mode with version 1.1.4 when drawing
    directly to the framebuffer ?
    Actually I draw on a offscreen SDL_Surface that I use as texture, but it’s
    slow for real time updating (for real time fire for instance)
  1. SDL can’t access the framebuffer in OpenGL mode
  2. SDL_OPENGL_BLIT uses TexSubImage2D a lot to draw your surfaces
    as textures
  3. the texture uploading methods are entirely the OpenGL drivers
    domain, not SDLs.

So, generally: Yes, your card will use AGP for texture uploads
when it’s available.

4

So when SDL uses TexSubImage2D we MUST keep the SDL_Surface in the memory ?
but to update it, we must rebind no ?
So, how does OpenGL know that it is the same texture ?
as version 1.1.4, SDL can access the frame bufffer
What is the SDL_OPENGL_BLIT flag ?
Actually I use thew example from the doc.

Thanks a lot

Stpehane

Stephane Magnenat <@Stephane_Magnenat> schrieb am 18 Aug 2000:

Hello,

I have another question :

  • Does SDL uses AGP texturing in OpenGL mode with version 1.1.4 when
    drawing

directly to the framebuffer ?
Actually I draw on a offscreen SDL_Surface that I use as texture, but
it’s> > slow for real time updating (for real time fire for instance)

  1. SDL can’t access the framebuffer in OpenGL mode
  2. SDL_OPENGL_BLIT uses TexSubImage2D a lot to draw your surfaces
    as textures
  3. the texture uploading methods are entirely the OpenGL drivers
    domain, not SDLs.

So, generally: Yes, your card will use AGP for texture uploads
when it’s available.