glDrawBuffer

glDrawBuffer: man3/glDrawBuffer.xml

When colors are written to the frame buffer, they are written into the color buffers specified by glDrawBuffer. The specifications are as follows: If more than one color buffer is selected for drawing, then blending or logical operations are computed and applied independently for each color buffer and can produce different results in each buffer. Monoscopic contexts include only buffers, and stereoscopic contexts include both and buffers. Likewise, single-buffered contexts include only buffers, and double-buffered contexts include both and buffers. The context is selected at GL initialization.