First looking at making backgounds and doing some scribbling.
Using a third screen we let a ball bounce and recover the background from the third screen. The lower screen is slowly replaced by the third screen as the image of the ball on the lower screen is updated. The upper screen shows the normal behavior, where the ball if moving like a sprite.
The third example shows a splash, than clicking twice at the lower screen two words are copied to the upper screen and an explanation is given with a special image that serves as a font. This is an imitation of a typewriter where the characters are not on one line anymore.
After the explanation the upper screen is wiped clean and one can choose two other words.
There are some tricks shown in these examples:
- the way to make your own character set and use it with a transparent color.
- for instance download this bmp
- the difference between dmacopy and copying of bits
- a way to use a double buffer to get a bouncing ball updated