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View Full Version : Using IBO offset causing crash with OpenGLES 1.1



Ro_land
01-18-2012, 11:02 PM
Hello all,

I am using a mobile device with Adreno 205 ( HTC Desire HD ) and OpenGL ES 1.1 for my application ( no shaders involved ).
Thinking of improving performance I moved to using VBO/IBOs in my rendering but found out that glDrawElements crashes when I use its last parameter for rendering from a certain offset in the index buffer object. It is always working with zero offset but does not like index offsets different from zero. I over analyzed every aspect ( data, offsets ) and everything is ok, the same code is working perfectly on my desktop computer.
My vertex attributes are just float type coordinates GL_FLOAT ( 12 bytes total ) and index type is GL_UNSIGNED_SHORT ( 2 bytes ).
Is there an explanation for this behavior?

My system info is:
GL_VERSION OpenGL ES-CM 1.1
GL_VENDOR Qualcomm
GL_RENDERER Adreno 205/225


PS my latest tests shows that there is a strange 32k limit for offset + count. When the offset is different form zero and offset + count is pointing to less than 32k bytes, it crashes. Otherwise it is working fine.
I also tested the same code on a Samsung Galaxy S2 with Mali400 GPU and it is working fine. The problem persists with the Adreno GPUs.