OpenGL 纹理到 AhardwareBuffer

Question

I came across AHardwareBuffer in Android. I wanted to make use of AHardwareBuffer to store textures so that I can use them on different threads where I don't have an OpenGL context. Currently, I'm doing the following:

• Generate a texture and bind it to GL_TEXTURE_2D .
• Create EGLClientBuffer and EGLImageKHR from it. Attach the EGLImage as texture target.
• Generate an FBO and bind it to the texture using glFramebufferTexture2D .
• To draw the texture (say tex ), I'm rendering it onto the AHardwareBuffer using shaders

However, I wanted away so that I don't need to rerender it onto hardwarebuffer but instead directly store data of the texture onto hardwarebuffer.

I was thinking of using glCopyTexImage2d for doing this. Is this fine and would it work?

Also (a dumb question but I cannot get over it) if I attach my EGLImage which is from the Hardwarebuffer to GL_TEXTURE_2D and define the texture using glTexImage2D, would it not store the data of the texture which is a parameter of glTexImage2D into the hardwarebuffer?

Answer 1

I solved this issue using glSubTexImage2D .

First create a opengl texture and bind it to GL_TEXTURE_2D . Then use glEGLImageTargetTexture2DOES to bind texture to EGLImageKHR created from EGLClientBuffer. This is similar to glTexImage2D . Any subsequent call to glTexImage2D will break the relationship between the texture and EGLClientBuffer.

refer: https://www.khronos.org/registry/OpenGL/extensions/OES/OES_EGL_image_external.txt

However glSubTexImage2D preserves the relationship. Hence we can load data with this API and store it in AHardwareBuffer .

PS: This might me one way and if there are other ways i'll be accepting the answer.