256 Colour Tutorial Part 2(V2.62): Difference between revisions

'''Palette effects using pre-defined functions'''

(by [[user:Gilbert|Gilbert Cheung]])

==Palette related functions==

If you had seen the stunning colour effects like in old VGA or Amiga games created in the early 90's this tutorial is for you, I'll demonstrate some simple ways of doing these effects using palette here.

Now, how does this function work? Read the manual first:

(You may have noticed, that I omitted a paragraph from the manual text, which was about the colours cycling in both directions. I did that because there's a bug in AGS which prevents the colour cycling in backward direction to work properly, this bug is fixed in AGS V2.71.)

Don't get confused, yet, it's not really that hard, let me demonstrate it with an example. You may still remember that I made [[media:8bittut_dizzy.pcx|this background]] in Part 1, and its palette is like:

You may have noticed that, I used the "rainbow" colours in slots #240 through #253 (the first 14 slots in the last line of the above palette) to draw the "warping frame" of the background, if the colours of these slots are altered the colours of that "warping frame" will be changed accordingly (you can load the background into a graphics programme and play with the colours of these slots and see what will happen). To make an animated effect, you may try using the function '''CyclePalette()''' with ''starting slot'' #240 and ''ending slot'' #253. Here's a graphical illustration of what will happen if you do that:

Whenever the function CyclePalette(240, 253) is executed, the colours in these slots are shifted to the left by one slot, and the original colour in the first slot (#240) will be warped to the last slot (#253).

==Changing an individual colour==

Sometimes you may want to change the colour of a particular slot for some reasons, in such case you may check out the function '''SetPalRGB()''', again, let me just copy something from the AGS manual to bloat this space a bit:

Well, I won't bother explaining the above word by word, basically what this function does, is to change the colour of a slot directly, ''all'' pixels on screen which use this slot will be changed to the new colour immediately.

If you check, you'll see that the red tips of her antennae were drawn using colour slot #32. Suppose you want them to alter between black and red colours endlessly throughout the ''whole game'', what we can do is, in each game loop, if the colour of slot #32 is currently <font color='FF0000'>red</font> change it to <font color='000000'>black</font> (where (r, g, b) tuple equals (0, 0, 0) ) , ''else'' change it to <font color='FF0000'>red</font> (where (r, g, b) tuple equals (63, 0, 0) ). This logic can be visualised as follow:

Which is merely just the above materials put together into an AGS "game". To test it just unzip it into an empty folder and load up '''ac2game.dta''' via the AGS editor and ''save'' a game. ('''room1.crm''' is the "dizzy" room, where you can click to transport you to '''room2.crm''', which is the "disco" room, you can click on the door(way) to toggle between opening and closing of the door, you'll notice also the door lock light will change colour according to the status of the door, you can read the room script for more info on how to do this. If you're having enough "fun" just press '''ctrl-Q''' to quit.)  

(Return to [[Using 256 colour graphics in AGS]])

[[Category:Intermediate Tutorials:Graphics Related:256 colour]]