As far as I know, rendering Stuff using GDI or OpenGL doesn‘t directly make the pixels on my monitor light up, but rather map onto a bitmap which is then later send by windows to the GPU so it can actually draw the pixels on my screen.
For this to happen, Windows must somehow tell the GPU „Hey, please draw all this stuff onto the monitor which is connected with this computer“.
But how does it do that? Does Windows just have direct access to the video memory, as it were a pointer where you can write data into? Or are there specific API calls that are provided by the GPU, but only accessible by the operating system and not by the user (programmer)?
