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Editorial Team
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Asked: 2026-05-22T22:42:22+00:00

So I’m making an Android 2.2 app that uses GLSurfaceView. My question is, since

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So I’m making an Android 2.2 app that uses GLSurfaceView. My question is, since OpenGL tends to buffer commands, does that mean it requires associated memory (e.g. the bitmap in a call to glTexSubImage2D() ) to stick around until it is done? Or does it make itself a copy of any memory needed for buffered commands?

I ask as this code tends to cause a long stall and an eventual crash on hardware (HTC Desrire) but not on the emulator:

//bm is a Bitmap stored in a vector from previous commands
//pt is a Point stored at the same time
GLUtils.texSubImage2D(GL10.GL_TEXTURE_2D, 0, pt.x, pt.y, bm); 
bm.recycle();

Now if I add glFlush() like so:

//bm is a Bitmap stored in a vector from previous commands
//pt is a Point stored at the same time
GLUtils.texSubImage2D(GL10.GL_TEXTURE_2D, 0, pt.x, pt.y, bm); 
**AGL.glFlush();** //or glFinish
bm.recycle();

It appears to work great. Now is this an actual functionality for glFlush/glFinish, to prevent memory from being cleared out from underneath OpenGL?

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1 Answer

  1. Editorial Team

    Good question. With Textures, and Vertex Buffer Objects incidentally, once you have called the methods that actually load the image data for the Texture, you do not need to hold onto the buffer/array you have in client memory.

    Don’t mistake the rendering buffer with memory associated with Textures. The Texture graphics are saved in memory for the GPU, they are not part of the buffer that is being flushed to finally draw.

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