GP32 Outrun/hang-on Race Track Graphic Effect?


Nitro

Member
Joined
Jan 22, 2003
Messages
172
Okay, so it's probably a bit strange to see me asking how the Outrun/Hang-on race track effect is done, seeing as how old and out of date it is etc ;)

Funny thing is, I can understand and code Mode-7 and voxel stuff, but I'm not sure how to recreate this kind of graphics effect. I'm pretty sure it was a raster effect, but does anyone know where I can find any info on this effect? It's been bugging me for quite some time now :blink:

I'm also interested in how the level data is saved for the tracks... is it just X & Y data for the X position of the road and Y position of the horizon ?

Any help would be much appreciated :D

-Nitro
 
Its a clever trick, you make a picture of an arched road, going straight into the distance as if on a hill.

Then as the screen is drawn you move the offsets of each line.

To make hills and such you alter what lines of the picture are shown and where.

If you don't want hills you just draw the road flat and going into the distance.

I'm sure if you view the memory of a racing game you will be able to find the pic of the road somewhere.

-Craig

www.gbax.com
 
and to give the motion, it's just a palette rotation, look carefully at those game and u'll see that the road is always stripped in 2 colors, the pixels height of each line represent how much color are cycled. that's all ;)
 
I am pretty sure you can find those graphics in the jar of MotoGP (or something similar, I don't remember the name) for cellular phones.
 
How is it you do that offset trick then?

And is there an easy blit routine for scaling down the other riders in the distance, or are they dirrefent sprites for each distance?
 
Is this the "Mode7" method? Cause if it is, there is a tutorial about it for flash... mayb it helps understanding. CLICK
 
These examples are for flash, flash already has scaling and rotation.
 
It's a different effect than Mode 7. I can't seem to find anything on the internet about it, either. Guess it doesn't help when I don't know what the effect is called :rolleyes:
 
Just looked into outrun. Its not a palette rotation. its a raster effekt. you can see this if you drive slow.
 
The actual road is a raster effect (manipulation of an existing image in memory), but the impression of it rolling towards you is acheived with palette manipulation.
 
Just look at the road in curves! the white-gray borders remain horizontally. thats a sign of a raster! that old machines had 16 maybe 32 colors. There are no much palette places for rotation!
you need at least 32 Plalette entries to get it smooth!
 
Think we're talking bout the same thing with different names.
4 me a raster effect is changing one palette value during screen update ( Display list Atari800/RasterIRQ on C64) thats indeed a palette modification.

The best thing to have a similar effect on GP is to reserve ec 32 Palette entries and rotate 'cause there is no horizontal raster. GP refreshes screen vertically, right?
 
I'm still not sure how the track data is stored though. I'm pretty sure it's not one giant texture like it would be for a mode 7 effect. I'm still none the wiser on how to achieve this effect, even if its all done in software (not using real raster lines) ;)

I think the image is distored using the same kind of perspective method that Mode 7 uses, but apart from that, I'm not sure how the rest of it is done..
 
Back
Top