Taken from https://github.com/prabindh/sgxperf/blob/master/sgxperf_gles20_vg.cpp (test17)

offscreen sgxperf

                //Bind offscreen texture
                GL_CHECK(glBindTexture(GL_TEXTURE_2D, 0));
                GL_CHECK(glBindTexture(GL_TEXTURE_2D, fboTextureId[i]));
                GL_CHECK(glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, inTextureWidth, inTextureHeight, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL));
                GL_CHECK(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR));
                GL_CHECK(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR));

                GL_CHECK(glBindFramebuffer(GL_FRAMEBUFFER, fboId[i]));
                GL_CHECK(glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, fboTextureId[i], 0));

                if(glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE)
                {
                        printf("FB is not complete for rendering offscreen\n");
                        goto err;
                }
                //Bind regular texture
                GL_CHECK(glBindTexture(GL_TEXTURE_2D, 0));
                GL_CHECK(glBindTexture(GL_TEXTURE_2D, regularTextureId));
                add_texture(inTextureWidth, inTextureHeight, textureData, inPixelFormat);
                GL_CHECK(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR));
                GL_CHECK(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR));
                 //Draw with regular draw calls to FBO
                GL_CHECK(_test17(1));

                //Now get back display framebuffer and unbind the FBO
                GL_CHECK(glBindFramebuffer(GL_FRAMEBUFFER, 0));
                GL_CHECK(glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, 0, 0));
                if(glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE)
                {
                        printf("FB is not complete for rendering to display\n");
                        goto err;
                }
                //bind to texture
                GL_CHECK(glBindTexture(GL_TEXTURE_2D, 0));
                GL_CHECK(glBindTexture(GL_TEXTURE_2D, fboTextureId[i]));

                GL_CHECK(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR));
                GL_CHECK(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR));
                //draw to display buffer
                _test17(0);