Re: [Mesa-dev] Dmabuf based render buffers!?
Hi and thanks for your replies! Note though that I want to get hold of the image/pixels after they have been processed by shader(s). So not the raw texture being fed in. So maybe it would be the contents of a FBO or similar. Cheers Fred On Fri, Jan 15, 2021 at 3:59 AM Christian König < ckoenig.leichtzumer...@gmail.com> wrote: > Am 15.01.21 um 11:26 schrieb Michel Dänzer: > > On 2021-01-14 8:02 p.m., Blueroom wrote: > >> > >> Hi Everyone! > >> > >> I have a program that’s using dmabuf’s to create a zero copy > >> camera->GL texture pipeline and it’s working great on my RPi4. > >> > >> Now as a last step I want to access the pixels that Iv’e processed in > >> gl with shaders, on the cpu. > >> > >> Iv’e been told that on the Raspberry Pi OpenGL is sharing the same > >> memory as the cpu so I’m hoping it would be possible to do something > >> like a dmabuf on the ‘way out’ too? > >> > >> Does anyone have any pointers in how this could work? > > > > I'd recommend using glGetTexImage or other similar GL APIs for getting > > the data out of the GL texture. > > > > While mmap of a dma-buf file descriptor works in theory, direct CPU > > reads from GPU accessible memory can be very slow on some platforms. > > > > Yeah, agree. Additional to that you don't know the format of the DMA-buf > of the texture. > > The input image is most likely linear, but the output might be tiled. > > Christian. > ___ mesa-dev mailing list mesa-dev@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/mesa-dev
Re: [Mesa-dev] Dmabuf based render buffers!?
Am 15.01.21 um 11:26 schrieb Michel Dänzer: On 2021-01-14 8:02 p.m., Blueroom wrote: Hi Everyone! I have a program that’s using dmabuf’s to create a zero copy camera->GL texture pipeline and it’s working great on my RPi4. Now as a last step I want to access the pixels that Iv’e processed in gl with shaders, on the cpu. Iv’e been told that on the Raspberry Pi OpenGL is sharing the same memory as the cpu so I’m hoping it would be possible to do something like a dmabuf on the ‘way out’ too? Does anyone have any pointers in how this could work? I'd recommend using glGetTexImage or other similar GL APIs for getting the data out of the GL texture. While mmap of a dma-buf file descriptor works in theory, direct CPU reads from GPU accessible memory can be very slow on some platforms. Yeah, agree. Additional to that you don't know the format of the DMA-buf of the texture. The input image is most likely linear, but the output might be tiled. Christian. ___ mesa-dev mailing list mesa-dev@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/mesa-dev
Re: [Mesa-dev] Dmabuf based render buffers!?
On 2021-01-14 8:02 p.m., Blueroom wrote: Hi Everyone! I have a program that’s using dmabuf’s to create a zero copy camera->GL texture pipeline and it’s working great on my RPi4. Now as a last step I want to access the pixels that Iv’e processed in gl with shaders, on the cpu. Iv’e been told that on the Raspberry Pi OpenGL is sharing the same memory as the cpu so I’m hoping it would be possible to do something like a dmabuf on the ‘way out’ too? Does anyone have any pointers in how this could work? I'd recommend using glGetTexImage or other similar GL APIs for getting the data out of the GL texture. While mmap of a dma-buf file descriptor works in theory, direct CPU reads from GPU accessible memory can be very slow on some platforms. -- Earthling Michel Dänzer | https://redhat.com Libre software enthusiast | Mesa and X developer ___ mesa-dev mailing list mesa-dev@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/mesa-dev
[Mesa-dev] Dmabuf based render buffers!?
Hi Everyone! I have a program that’s using dmabuf’s to create a zero copy camera->GL texture pipeline and it’s working great on my RPi4. Now as a last step I want to access the pixels that Iv’e processed in gl with shaders, on the cpu. Iv’e been told that on the Raspberry Pi OpenGL is sharing the same memory as the cpu so I’m hoping it would be possible to do something like a dmabuf on the ‘way out’ too? Does anyone have any pointers in how this could work? Cheers Fred ___ mesa-dev mailing list mesa-dev@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/mesa-dev
