I have an OpenGL engine set up, and have added OpenGL ES support to it recently. Currently I am targeting android, and in an effort to speed up debugging I have added OpenGL ES support to the windows side of things using the MALI GLES 3.0 Emulator.
I am using the GL_OES_mapbuffer extension if it is available for sprite rendering, falling back to glBufferData if it isn't. This works on both my test phone, which supports the extension, and the android emulator, which doesn't. However running this on my main computer results in the call to glMapBufferOES to return null and calling glGetError returns GL_INVALID_VALUE. I find this strange, since glMapBuffer shouldn't even return GL_INVALID_VALUE, so I assume this is a bug.
I am calling glMapBufferOES with these arguments, it should be valid for OpenGL ES. glMapBufferOES(GL_ARRAY_BUFFER, GL_WRITE_ONLY);
Does anyone have any idea why this would be happening, any help would be appreciated.
Hi Programmdude,
Firstly, thank you for bringing this to our attention. I noticed that you wrote in your message that you are using glMapBufferOES(GL_ARRAY_BUFFER, GL_WRITE_ONLY). I am guessing you meant GL_WRITE_ONLY_OES, as GL_WRITE_ONLY is not a valid argument for this function. This also may explain why you are seeing an unusual error code as our OpenGL ES 3.0 Emulator works by converting function calls and parameters to their Open GL equivalents. It could be that the emulator tries to convert GL_WRITE_ONLY and is unsure how to convert correctly.
If this is not the case and you are using GL_WRITE_ONLY_OES would it be possible to get a small reproducer of the issue so that we can investigate further and possibly raise a bug on the tool?
Many thanks in advance,
Stephen
The values for GL_WRITE_ONLY_OES and GL_WRITE_ONLY are the same, but I did mean _OES. My program has a gl dispatch system, which is used for both desktop GL and mobile GLES. I wrote a small example based off the cube example, and it still crashes on the call to glMapBufferOES. It's compiled with VC++ 17.00.60610.1 and gnumake 3.82.90, though should compile with any VC++ and possibly any gcc.
My build system is set up differently, so I just copied over the headers, bin and lib files.
Uploaded to dropbox
https://www.dropbox.com/s/d6t6fjun8rydr2f/cube2.zip
Thank you for the code reproducer you have sent. I have managed to recreate the issue in house. This has now been filed as a bug under the OpenGL ES 3.0 Emulator and passed to the Mali Tools team. I will update you with any updates to the bug being fixed as soon as they arise.
Thank you again for bringing this to our attention.
Cheers,
Just letting you know that the OpenGL ES Emulator v1.4 has now been released. This should fix the issue that you have reported.
It still gives GL_INVALID_ENUM for target GL_ELEMENT_ARRAY_BUFFER, though it works fine with GL_ARRAY_BUFFER. Please confirm if it is the case or Its not working only for me.
I will raise this with the Tools team and get back to you.
Having looked at the specification for glMapBufferOES extension. It says that it is based on the OpenGL 2.0 function glMapBuffer. In the OpenGL2.0 spec there is no support for GL_ELEMENT_ARRAY_BUFFER this was introduced later. As a result it is also not supported in the emulator.
Kind regards,
Dear programmdude,
As there's been no activity on this post for a month I'm going to mark the question as assumed answered. Let us know if you want to open it back up.
Thanks,
Ellie