gpu.md

GPU

init()

• create window & buffer surface

tick()

• update registers
• fire interrupts
• for each frame, call draw_line() 144 times and noop (vblank) 10 times
• we draw one line at a time because it's possible to update GPU settings multiple times per frame, eg adjusting x-offset for a parallax effect

draw_line()

• figure out what tiles are active on which layers (background, window, sprites) and call paint_tile_line() for each tile.

paint_tile_line()

• copy a line of pixels from a tile into the buffer