SDL2 - Draw Bottom Left

SDL2 uses a top-level (0,0) configuration with a positive y-axis pointing down. How can I change this for y pointing up from the bottom left? Note that the area covered by the input coordinates may or may not be the same as the screen area.

Usually I would just change the projection matrix to whatever I need, but I don't have access to that through the SDL API?


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How about a function that transforms it for you?

float convertPointY(float y) {
     return -y + WINDOW_HEIGHT;


And if the window resizes without having a constant height:

float convertPointY(float y) {
     int width = 0, height = 0;
     SDL_GetWindowSize(window, &width, &height);

     return -y + height;




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