Raster Effects

[oompa loompa]

Here's an example of how to do rasters with basiegaxorz. For the 12 uSec allocated for hblank, basic is only able to load 1 pallette =P. If i try to change more than one pallette, the screen will either start to oscillate, or have the same color for some amount of lines. later i'll make a faster command specific for "loading" rasters


for a=0 to 25
locate a, 0: print chr$(&h41+a);
locate a, 36: print chr$(&h41+a);
next
locate 5, 5: print "Rasters"
locate 6, 7: print "Test"
locate 7, 9: print "In"
locate 8, 11: print "Just"
locate 9, 13: print "Like"
locate 10, 15: print "On"
locate 11, 17: print "The"
locate 12, 19: print "Atari 2600!"
raster=0
valt
' waitraster 6
while 1
dalt
if raster=8 then
raster=0
reload
endif
halt
pallette readint(), 0, 1
raster++
wend

dataint &h00EE
dataint &h0E00
dataint &h0E0E
dataint &h0EE0
dataint &h0EEE
dataint &h0000
dataint &h000E
dataint &h00E0


[Tulio Adriano]

Great! I love the idea of having a command to work with Raster Effects, since they are a need when we think about making a decent game, scroling backgrounds, water effects, etc.

Excelent idea! ;D

[oompa loompa]

heh, i get flickering when i run it on real hardware, i still don't think i'm doing it right =P. but if it be okay on emulators, i guess its okay for everyone else =D

[Tulio Adriano]

Well well... I use to compile my games in SCD format and play them in the real thing...

[oompa loompa]

Tulio said:

Well well... I use to compile my games in SCD format and play them in the real thing...

scd games made with basiegaxorz =o?

i never tested sega cd boot up isos made in bex on the real hardware x.x

[Tulio Adriano]

Well, so you can raise your hands up to the sky and enjoy your brilliance, 'cause it works as fine as any official Sega CD game!

In fact, the most exciting feature I found on BEX was this ability to compile a SCD ISO. Just burn it in a CD-RW and test it in the real hardware. Very cool! ;D

[oompa loompa]

i use to test sega cd images using gens, and not all things that run on gens will run on the real system =P. now that fusion has come out, i tested some of the stuff i've compiled, and things like the interrupters and 68k exceptions didn't work x.x

[Garlo]

Cool! Thanks for the code!

Also, I wasn't sure I understood what rasters were or how were they used for games. Turns our wikipedia does know a lot hehe

en.wikipedia.org/wiki/Parallax_scrolling

[oompa loompa]

=P, i think the term "raster" is used differently in wikipedia =D

for this program, rasters are used to produce more colors than the sega genesis can display on one frame. to do this, we use "raster effects", which change the values in color memory while the screen is drawing