MD2 - Revision history

Corbin: /* Features */ MD2 clarifications

2017-08-31T18:54:02Z

‎Features: MD2 clarifications

Corbin: /* Limitations */ Changed, since we have a lighting system that affects models now.

2016-04-29T21:39:52Z

‎Limitations: Changed, since we have a lighting system that affects models now.

UsernameAK at 08:52, 29 April 2016

2016-04-29T08:52:56Z

Corbin: Created page with "The MD2 model file format was introduced by id Software when releasing Quake 2 in November 1997. It's a file format quite simple to use and understand. MD2 models' charact..."

2015-01-27T06:59:54Z

Created page with "The MD2 model file format was introduced by id Software when releasing Quake 2 in November 1997. It's a file format quite simple to use and understand. MD2 models' charact..."

New page

The MD2 model file format was introduced by id Software when releasing [[Quake 2]] in November 1997. It's a file format quite simple to use and understand. MD2 models' characteristics are these:

* Model's geometric data (triangles);
* Frame-by-frame animations;
* Structured data for drawing the model using GL_TRIANGLE_FAN and GL_TRIANGLE_STRIP primitives (called “OpenGL commands”).
* Model's texture is in a separate file. One MD2 model can have only one texture at the same time.

MD2 model file's extension is “md2”. A MD2 file is a binary file divided in two part: the header dans the data. The header contains all information needed to use and manipulate the data.

=Constants=

Here are some constant values defining maximal dimensions, so do not exceed these amounts, or 3DGE will fail to render the model:

* Maximum number of triangles: 4096
* Maximum number of vertices: 2048
* Maximum number of texture coordinates: 2048
* Maximum number of frames: 512
* Maximum number of skins: 32
* Number of precalculated normal vectors: 162

=Use in 3DGE=
Both ports can utilize MD2, but there are a few key additions that become helpful, as the engine supports higher-resolution/color textures,
==Features==
EDGE, and by extension, 3DGE, can load MD2s from either a LUMP in the wadfile, or externally as a plain file. While Quake 2 imposes harsh limits on the format, 3DGE enhances it beyond what was normally capable:

* Ability to use PNG, JPG, and TGA file formats for skins (original PCX is not supported)
* Able to define up to 9 skins-per-model and switch them out on-the-fly through DDF
* Able to use animations as either frame number or reference name, or both if desired
* Can control the bias, aspect, scale, and placement of the model, both for environment and HUD (weapons)

==Limitations==
While those features are handy, there are currently limitations of the format:

* No linear interpolation, so the "jelly-like" vertex animation carries over from Quake 2
* No internal shader system, so the models are lit uniformly, even in the presence of [[dynamic lights]]

==Explanation==
===Model===
Any state frame can specify a model by using the special '@123' or '@framename' syntax for the frame (instead of a letter). The number is the absolute frame number in the MD2 model, beginning at 1, or you can use the frame name.

Examples:
<TABLE WIDTH=95% BORDER=1 CELLSPACING=0 CELLPADDING=3 FRAME="box" BGCOLOR="#C2D6D6" >
<TR><TD>
<FONT SIZE=2>
STATES(IDLE)=TROO:@5:7:NORMAL:NOTHING; // the 5th frame

STATES(IDLE)=TROO:@run3:7:NORMAL:NOTHING; // frame called "run3"
</FONT>
</TD></TR>
</TABLE>
<div style="background: #f2e0ce; border: 2px solid #bfb1a3; padding: 0.6em; margin-top: 0.8em;">The model itself must be stored in a wad, and the lump name is the sprite base ("TROO") plus "MD2" on the end --> "TROOMD2".</div>

===Skins===
The skin of the model is the sprite base ("TROO") plus "SKN1" on the end --> "TROOSKN1". There should be a definition for it in IMAGES.DDF using the sprite namespace --> [spr:TROOSKN1].

<div style="background: #f2e0ce; border: 2px solid #bfb1a3; padding: 0.6em; margin-top: 0.8em;">Other skins can be used. The command "MODEL_SKIN=3" in a thing or weapon definition will use the third skin --> "TROOSKN3". Up to nine skins can currently be used (1 to 9). The skin can also be changed dynamically by using the SET_SKIN(##) action in the state frames.</div>

=USAGE=
Below describes the commands needed to manipulate and use the models in the game engine via DDF:

===THINGS.DDF===
{| border="1" cellpadding="2" BGCOLOR="#C8F4FF"
! COMMAND
! EXPLANATION
|-
| MODEL_SCALE
| Draw the model bigger, for example: MODEL_SCALE=1.5;
|-
| MODEL_ASPECT
| make the model fatter/skinnier: MODEL_ASPECT=0.7;
|-
| MODEL_BIAS
| add this to every z coordinate: MODEL_BIAS=24.0; Useful if you don't want to position from Quake 2's original 24 units in an external editor.
|}

===WEAPONS.DDF===

{| border="1" cellpadding="2" BGCOLOR="#C8F4FF"
! COMMAND
! EXPLANATION
|-
| MODEL_ASPECT
| make the weapon fatter/skinnier
|-
| MODEL_BIAS
| add this to every z coordinate
|-
| MODEL_FORWARD
| move the weapon forward/backward: MODEL_FORWARD=2.2;
|-
| MODEL_SIDE
| move the weapon right/left: MODEL_SIDE=-3.5;
|}

<div style="background: #f2e0ce; border: 2px solid #bfb1a3; padding: 0.6em; margin-top: 0.8em;">Note: there is no MODEL_SCALE command for WEAPONS.DDF (scaling has no effect because the model is drawn at the camera point). Changing MODEL_FORWARD, MODEL_SIDE and/or MODEL_BIAS can have a huge impact on the apparent size of the weapon.</div>

Also see [[MD3]] and [[MD5]].

@@ Line 22: / Line 22: @@
 Both ports can utilize MD2, but there are a few key additions that become helpful, as the engine supports higher-resolution/color textures,
 ==Features==
-EDGE, and by extension, 3DGE, can load MD2s from either a LUMP in the wadfile, or externally as a plain file. While Quake 2 imposes harsh limits on the format, 3DGE enhances it beyond what was normally capable:
+[[EDGE]], and by extension, 3DGE, can load MD2s from either a LUMP in the wadfile, or externally as a plain file. While Quake 2 imposes harsh limits on the format, 3DGE enhances it beyond what was normally capable:
 * Ability to use PNG, JPG, and TGA file formats for skins (original PCX is not supported)
@@ Line 32: / Line 32: @@
 While those features are handy, there are currently limitations of the format:
-* No linear interpolation, so the "jelly-like" vertex animation carries over from Quake 2
+* No linear interpolation implementation, so the "jelly-like" vertex animation carries over from Quake 2
 ==Explanation==
@@ Line 39: / Line 39: @@
 Examples:
-<TABLE WIDTH=95% BORDER=1 CELLSPACING=0 CELLPADDING=3 FRAME="box" BGCOLOR="#C2D6D6" >
+<TABLE width="95%" border="1" cellspacing="0" cellpadding="3" frame="box" bgcolor="#C2D6D6">
 <TR><TD>
-<FONT SIZE=2>
+<FONT size="2">
 STATES(IDLE)=TROO:@5:7:NORMAL:NOTHING;  // the 5th frame
@@ Line 61: / Line 61: @@
 ===THINGS.DDF===
-{| border="1" cellpadding="2" BGCOLOR="#C8F4FF"
+{| border="1" cellpadding="2" bgcolor="#C8F4FF"
 ! COMMAND
 ! EXPLANATION
@@ Line 74: / Line 74: @@
 | add this to every z coordinate: MODEL_BIAS=24.0; Useful if you don't want to position from Quake 2's original 24 units in an external editor.
 |}
 ===WEAPONS.DDF===
-{| border="1" cellpadding="2" BGCOLOR="#C8F4FF"
+{| border="1" cellpadding="2" bgcolor="#C8F4FF"
 ! COMMAND
 ! EXPLANATION

← Older revision		Revision as of 21:39, 29 April 2016
Line 33:		Line 33:

	* No linear interpolation, so the "jelly-like" vertex animation carries over from Quake 2		* No linear interpolation, so the "jelly-like" vertex animation carries over from Quake 2
−	* No internal shader system, so the models are lit uniformly, even in the presence of [[dynamic lights]]

	==Explanation==		==Explanation==

@@ Line 53: / Line 53: @@
 ===Skins===
 The skin of the model is the sprite base ("TROO") plus "SKN1" on the end --> "TROOSKN1".  There should be a definition for it in IMAGES.DDF using the sprite namespace --> [spr:TROOSKN1].
 <div style="background: #f2e0ce; border: 2px solid #bfb1a3; padding: 0.6em; margin-top: 0.8em;">Other skins can be used.  The command "MODEL_SKIN=3" in a thing or weapon definition will use the third skin --> "TROOSKN3". Up to nine skins can currently be used (1 to 9).  The skin can also be changed dynamically by using the SET_SKIN(##) action in the state frames.</div>
 =USAGE=