grimepoch
Posts: 95
Joined: Thu May 12, 2016 1:57 am

PBO Support on with Raspberry Pi?

Mon Aug 13, 2018 2:53 pm

Does anyone know if PBO are supported through extension on the Pi with GLES2.0? I searched the header files and see the defines in GL/glext.h that I would expect, but before I go down that path, I want to make sure it works.

What I am specifically working on is looking at experimenting with pushing video frames into a texture, and using a PBO so I can have asynchronous GL usage of that data. I want to see how well that performs since the current method I am using blocks the GL pipeline until the transfer is complete.

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Paeryn
Posts: 2169
Joined: Wed Nov 23, 2011 1:10 am
Location: Sheffield, England

Re: PBO Support on with Raspberry Pi?

Mon Aug 13, 2018 4:14 pm

There's no appropriate extension for PBO reported by the driver. GL/glext.h won't tell you anything about GLES2 extensions, for that you need GLES2/gl2ext.h but that still won't tell you if the driver actually implements any of them, for that you need to query the driver with

Code: Select all

const GLubyte* available_extensions = glGetString(GL_EXTENSIONS);
and see if the required extension GL_NV_pixel_buffer_object is listed in the string. The ones supported by the Broadcom driver are :-

Code: Select all

GL_OES_compressed_ETC1_RGB8_texture GL_OES_compressed_paletted_texture GL_OES_texture_npot GL_OES_depth24 GL_OES_vertex_half_float GL_OES_EGL_image GL_OES_EGL_image_external GL_EXT_discard_framebuffer GL_OES_rgb8_rgba8 GL_OES_depth32 GL_OES_mapbuffer GL_EXT_texture_format_BGRA8888 GL_APPLE_rgb_422 GL_EXT_debug_marker
The example code in /opt/vc/src/hello_pi/hello_videocube shows video decoding into a texture.
She who travels light — forgot something.

grimepoch
Posts: 95
Joined: Thu May 12, 2016 1:57 am

Re: PBO Support on with Raspberry Pi?

Mon Aug 13, 2018 5:50 pm

The example code in /opt/vc/src/hello_pi/hello_videocube shows video decoding into a texture.
My project is based on V4L2, so I am not using OMX. I spent some time trying to get glCreateImageKHR and it doesn't appear to be supported.

My curiosity with PBO was for reading in/out asynchronously, but not seeing it in the list means that is probably a dead end for now. Thanks.

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