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opengl-esyuvrgba

How to read back opengl processed data from GPU to host memory

I want to convert my yuv420 image into rgb888 image. i got below link for this. http://www.fourcc.org/source/YUV420P-OpenGL-GLSLang.c

This program works fine for me. Now i want to read back my processed rgb data from GPU into host memory. i have tried to do glGetTexImage but it gives me only last binded texture data.

Can any one tell how can i read back my processed RGB data from GPU into host memory?

I also have another question that if i will get success to read back my data from GPU into host memory then it will be RGB or RGBA?

Solution

  • Use the glReadPixels command. The syntax is `glReadPixels(GLint x, GLint y, GLsizei width, GLsizei height, GLenum format, GLenum type, GLvoid * data)

    x and y specify the location of the lower left corner of the rectangle you to read from thr framebuffer, format accepts GL_ALPHA, GL_RGB, and GL_RGBA, type is the type of the pixel data, data is a pointer to the returned data array. format specifies if the data will be RGB, RGBA or alpha.

    You can get more information at the Khronos specification page.