正确删除纹理

Question

I am trying to delete a texture when I'm done with it on android running opengl es 1.1

On Galaxy S (phone) and Droid X, everything seems to work fine. In fact it works too well, I don't seem to even need to delete the texture when I'm done with it, I never seem to run out of memory...

On another device (not allowed to name at the moment) it seems like glDeleteTextures doesn't work. After I load 6 large texture (and a number of other small ones) no new textures can be loaded, they just come out white.

On a nexus one, I have a report that it turns white and throws the following error log

E/Adreno200-EGL( 632): eglLockWindowSurface: failed to map the memory for fd=37 offs=4796416 E/Adreno200-EGL( 632): eglLockWindowSurface: failed to map the memory for fd=38 offs=1662976 E/Adreno200-EGL( 632): eglLockWindowSurface: failed to map the memory for fd=37 offs=4796416 E/Adreno200-EGL( 632): eglLockWindowSurface: failed to map the memory for fd=38 offs=1662976 E/Adreno200-EGL( 632): eglLockWindowSurface: failed to map the memory for fd=37 offs=4796416 E/Adreno200-EGL( 632): eglLockWindowSurface: failed to map the memory for fd=38 offs=1662976 E/Adreno200-EGL( 632): eglLockWindowSurface: failed to map the memory for fd=37 offs=4796416 E/Adreno200-EGL( 632): eglLockWindowSurface: failed to map the memory for fd=38 offs=1662976

I'm far from an expert on OpenGL, but: a) I can't find a complete example that both creates and deletes textures to ensure my code is correct b) the exact same methodology works perfectly on iPhone

The only thing I can think of is I am using a fair amount of threading so perhaps my unbinds are escaping the correct thread, or in some way not being timed correctly. I don't have any hardware at the moment that has the error so I can't test this theory until I get another device myself.

Do you need to do anything special before deleting a texture, or should you be able to just slip a glDeleteTextures() in wherever in your flow and it should work?

Apologies for not posting any example code, I currently have some restrictions on it.

Answer 1

So far as I know, all OpenGL functions must be called in the same thread as the device is created. Both OpenGL and OpenGL ES applies.

Answer 2

I seem to have solved this. Some devices (unsure if it's the graphics chipsets or something else with the device) apparently can only delete textures from the graphics context thread. My textures were being deleted in a cleanup call to my main texture variable which apparently wasn't getting executed in the right place. Now my glDeleteTexuters() gets qued in an event under the GLSurface so it's executed in the right thread in the right context.

Not sure if it's related but the device I have that was having the problem creates textureID's in linear order (eg 1, 2, 3, 4 then I delete 2, it will create 2, 5, 6, etc.) where as the galaxy S with no problems seems to create texture ID's that are random. Might be an indication of how the chipset handles the textures? just a guess.