This is the development thread for the F18A racing demo.
Only a few weeks ago I had no idea how 8-bit racing games like Pole Position were created. I had a vague idea that the screen was drawn from polygons like most 3D games today. Then I found this excellent page that explains a lot.
The starting point is an image of the road:
road3.png 1.68KB 10 downloads
The image is 512 pixels wide - twice as wide as a normal TI screen - so if we center the view this gives us 128 pixels on each side for scrolling the view from side to side. The F18A allows us to create such a view by setting the page size to 2X1 in VREG 29 (>1D). Once we have done that we can scroll the entire screen left and right by varying the horizontal scroll offset in VREG 27 (>1B) between 0 and 255 (128 is the center).
Note that there are no stripes in the road yet, these will be added later by changing the palette.
More to follow...