Sprite Basics
by Mark Quinn


Before you can create your own skins for Legacy, you must know about how to make sprites.  Here is a quick primer.
 

Naming Format:

All sprite graphics in DooM, DooM II, Strife, Heretic, and Hexen follow the same naming format.  Here it is:

NameX#Y#

Name is a four letter name used for all sprite graphics in a sprite family.  The name used by all the player sprite graphics is PLAY, for example.

X is a letter that identifies the current moving phase represented by the sprite graphic.  Here is an example showing the phases used by the player when he walks:
 

PLAYA1
PLAYB1
PLAYC1
PLAYD1

# is the viewing angle from which the sprite graphic is meant to be seen.  There are eight different viewing angles used by DooM.  They are arranged in 45º increments.

There is also a special angle, angle 0 (a note on that shortly).

Y and #(optional).  This second phase and viewing angle tell DooM that the sprite graphic is also to be used for phase Y and viewing angle #, and that it will be mirrored when drawn on screen.

This is used by DooM as a way of cutting down the number of sprite graphics that need to be drawn.

id, for example, only created marine sprite graphics for angles 1, 2, 3, 4, and 5.  There are no marine sprite graphics for angle 6, 7, or 8.  In order to allow the marine to be seen from all angles, the second phase and angle are used so that the sprite graphics for angles 2, 3, and 4 will be mirrored and used for angles 6, 7, and 8.

 
PLAYA1
PLAYA2A8
PLAYA3A7
PLAYA4A6
PLAYA5
PLAYA4A6 (mirrored)
PLAYA3A7 (mirrored)
PLAYA2A8
(mirrored)
In this manner,  the DooM marine only requires 20 sprite graphics for his walking sequence, instead of 32.
 
Angle 0

In addition to the eight regular angles mentioned above, there is one special angle, angle 0.  A sprite graphic marked with an angle of 0 will always be displayed from the same view, regardless of which way it is facing.  Dead bodies, and all other stationary objects in DooM use angle 0.

Why have a sprite that always faces the same way?

There are two reasons for this:

The first reason is simply that it is a lot easier to create one sprite drawing, than it is to create eight.  The existing DooM marine uses angle 0 for his death sequence and his exploding death sequence.  This cuts the number of sprite drawings he uses down considerably.

The second reason for having angle 0 is that the 45º turning increments used by DooM are too coarse to look effective on stationary objects in the game.  As the player moves around an object, it will appear to keep the same pose for a full 45º, then suddenly jump to a new angle.  This is very jarring to look at.  Imagine what it would be like if all of the scenery objects in the game jumped around like this.  It wouldnít be very much fun.  It would be very distracting.  0 angle sprites donít jump between views, and tend to look much better in the game.
 

Note:  If you use angle 0 for the angle of your current sprite phase, you can not use sprite graphics with other angles for the same phase.  You may use either the eight angles, or you can use angle 0, but you may not use them together.
(DooM gets really ticked off if you do.)

Transparent Areas:

This may seem really basic to those of you who already know, but in case you donít, I should point out that the areas you wish to be transparent in your sprite graphics must be painted entirely in cyan (Colour 247 on the DooM palette).

X and Y Offsets:

There is one more thing you must remember when adding sprites to a wad; an x and y offset must be provided for each and every sprite graphic you add.

DooM draws all of its sprite graphics in relation to the ground spot on which the creature/player/object is standing.  The x and y offsets  adjust the position of the sprite graphic so that it displays correctly in relation to this ground spot.   Without the x and y offsets, your sprite graphic will be drawn with its upper left hand corner at the ground spot, and the sprite will  appear to be burried in the floor!


Whoops!

Below is a shot of the wad editing screen in Wintex 4.2.  In the upper right hand corner is a pair of slider bars to help position the sprite graphic.  A black cross hair indicates the position on the ground spot.

You will notice that the graphic is intentionally set slightly lower than the ground spot.  This is to ensure that the sprite appears to be firmly planted on the ground, and not floating just above it.
 

Thatís it for sprite editing basics.  Pretty easy, eh?  I hope this gets you up and running on your sprite editing projects.

Good Luck!