Sierra's old AGI games used vector graphics. On earliest versions of Kings Quest, you could watch the new screen get drawn line by line when you changed screens.
Later DOS versions would do this rendering off-screen, and copy the results into graphics memory.
#retrocomputing #sierra #ibmpc
Later DOS versions would do this rendering off-screen, and copy the results into graphics memory.
#retrocomputing #sierra #ibmpc
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But it's a bit weirder than that. Take a look at the how the back buffer for Space Quest I here looks, in false color.
This is the control bitmap, that defines important regions of the playfield. It's actually interleaved with the graphics.
It's not a fast movsw at all, but a rather complex loop where we mask and shift out the graphics.