Quake II (id Software's GPL source release, 3.19)

id Software's GPL source release of Quake II calls itself "the complete source code for Quake 2, version 3.19", and qcommon.h sets VERSION to 3.19, so the code read here is the 3.19 point release rather than the 1997 retail build. quake-ii/source-version

Value: 3.19

Player movement is qcommon/pmove.c, engine code that the server and the client's prediction both run; weapons, damage, monsters, and items are the game library in game/.

Cited by: Quake II

On the ground, Quake II's Pmove runs PM_Friction, which lowers the speed by step time × 6 (pm_friction) × the larger of the speed and 100 (pm_stopspeed) on any ground that isn't slick, and then PM_Accelerate with pm_accelerate 10: if the speed along the wish direction is under the wish speed, it adds 10 × step time × wish speed, no more than the shortfall. The wish velocity's length is capped at 300 (pm_maxspeed), or 100 ducked. These are the numbers Quake III keeps (friction 6, acceleration 10), where Quake's friction is 4. Computed, not measured: since 10 outpaces 6, a run settles at exactly 300 units/s. The movement constants are C globals, not cvars. quake-ii/ground-move

About: Quake II Running

{
 "pm_friction": 6,
 "pm_accelerate": 10,
 "pm_stopspeed": 100,
 "pm_maxspeed": 300
}

At 300 a step's friction removes 1800 × step time and the acceleration could add 3000 × step time, so the cap at the shortfall returns the speed to 300 at any step length. Water friction adds to the same drop. After each command PM_SnapPosition truncates each velocity axis to an eighth of a unit (L1089-L1091), which leaves 300 unchanged.

Cited by: Quake II

Quake II's keyboard moves are cl_forwardspeed, cl_sidespeed, and cl_upspeed 200, all doubled while running, which the speed key toggles: with cl_run 0 holding the key runs, and with cl_run 1 holding it walks. The movement code builds the wish velocity from the view's forward and right vectors, with the pitch first divided by 3, then zeroes its vertical part and caps its length at 300. Computed from these, with the view level (pitch 0): walking forward wishes 200 and walking forward with a strafe about 283, but a run wishes 400 forward and about 566 on the diagonal, both cut to 300, so a strafe adds nothing to a run on the ground. Looking up or down shortens the forward part before the cap. quake-ii/move-speeds

About: Quake II Strafe-running

{
 "walk": 200,
 "walk_diagonal": 283,
 "run": 300
}

The diagonal figure is √(200² + 200²). The forward vector isn't renormalized after the vertical part is dropped, so at pitch p its horizontal length is cos(p/3). A joystick or mouse move can give other values; this is the keyboard.

Cited by: Quake II, Strafe-running

In the air, Quake II's PM_AirMove calls the ground's PM_Accelerate with an acceleration of 1 while pm_airaccelerate is 0: the push is 1 × step time × wish speed (up to 300), and it stops only when the velocity's component along the wish direction reaches the full wish speed. Quake III keeps this rule, with pm_airaccelerate 1 and a PM_Accelerate commented "q2 style". In deathmatch the server copies its latched cvar sv_airaccelerate (default 0) into pm_airaccelerate, and any nonzero value switches to PM_AirAccelerate, which is Quake's air rule: the wish speed capped at 30 for the shortfall, the push from the uncapped wish speed × pm_accelerate (10) × step time. The server's movement code uses the value only as a nonzero test, so it acts as an on-off switch; outside deathmatch it is forced to 0. The server also sends the value to clients as the CS_AIRACCEL config string, for their prediction, in code not read here. quake-ii/air-accelerate

About: Quake II Strafe-running

{
 "air_accelerate": 1,
 "dm_switch_cap": 30
}

The client's use of CS_AIRACCEL is in client/cl_pred.c, outside the files pinned here and not read for this claim. Within pmove.c, pm_airaccelerate is used only in the test at L654.

Cited by: Quake II, Strafe-running

Quake II's PM_CheckJump, which Pmove runs before friction, does nothing while the landing timer flag is set; otherwise it needs an up move of at least 10 and the jump-held flag clear, which only a command with the key released clears, so holding the key never jumps twice. On ground it adds 270 to the vertical velocity, raising it to at least 270, and clears the ground entity; in water at level 2 or more it sets an upward swim speed instead (100 in water, 80 in slime, 50 in lava). Quake's QuakeC jump and QuakeWorld's movement code also add 270. Gravity is sv_gravity, 800. quake-ii/jump

About: Quake II Jump

Value: 270 units/s

Because the jump adds to the vertical velocity, a jump made while moving upward (up stairs or a ramp, whose climb the stepping move leaves in the velocity) takes off faster than 270. The swim-up branch also returns early when the player is sinking at 300 units/s or more (L802).

Cited by: Quake II

Quake II checks the jump before friction: Pmove calls PM_CheckJump, which clears the ground entity, and then PM_Friction, whose ground friction needs a ground entity, so a hop on the first command that starts on the ground loses no speed to friction. QuakeWorld's PlayerMove has the same order: JumpButton clears onground before PM_Friction, whose ground friction needs it. Two conditions apply. The jump key must be released and pressed again (the jump claim). And when the position check first finds ground with the vertical speed below −200, it sets a landing timer of 18 units, or 25 below −400, that blocks the jump until it runs out; each command lowers it by its length in ms divided by 8, rounded down and at least 1, so 18 units last 144 ms at 8 or 16 ms commands and 180 ms at 10 ms (computed). By the atlas's reading the slide move clips the velocity along a floor it runs into, and the stepping move keeps that clipped vertical speed, so a landing step that reaches the floor would not set the timer; how often a hop's landing sets it has not been measured. quake-ii/hop-friction

About: Quake II Bunny hopping

The landing timer also restores the unclipped velocity at the end of each slide move while it runs (L259-L262). The reading that clipped landings skip the timer follows the code paths, not a run; a probe that steps Pmove through a hop chain would settle it.

Cited by: Quake II

Quake II's bullets, pellets, and railgun are hitscan: fire_lead, which fire_bullet (the machine gun and chaingun) and fire_shotgun (once per pellet, for both shotguns) call, traces a line 8192 units long in the frame the gun fires, bent by a random spread (crandom × the spread, each way) for each bullet or pellet, and fire_rail traces 8192 units and keeps tracing past every monster or player it hits, damaging each. The blaster, grenades, and rockets launch entities that travel: the player's blaster bolt at 1000 units/s, the launcher's grenade at 600, and the rocket at 650. quake-ii/hitscan-projectiles

About: Quake II Hitscan

A bullet that enters water is re-aimed with twice the spread. The shotgun's line at L1213 is its deathmatch pellet count; single player uses the line after it.

Cited by: Quake II

A Quake II rocket's direct hit does 100 + (int)(random() * 20.0) damage, 100 to 119, the roll made when it is fired; the explosion then does radius damage to everything else within 120 units, the rocket's 120 less half the distance from the explosion to the center of the target's box, and the target hit directly takes no splash. A quad damage multiplies both by 4. The railgun's damage is a constant, 150 in single player and 100 in deathmatch. quake-ii/rocket-damage

About: Quake II Damage formula

{
 "direct": "100–119",
 "splash": 120,
 "splash_radius": 120
}

findradius also skips non-solid entities. A wall between the explosion and the target blocks the splash (CanDamage, L569). Armor and power armor then take their share in T_Damage.

Cited by: Quake II

Quake II's radius damage halves the points for the entity that caused it, so a player takes half splash from their own rocket or grenade, and T_Damage pushes a player who hurt themselves with 1600 × knockback / mass instead of 500 ×, commented "the rocket jump hack...". The player's mass is 200, so a self-inflicted push is 8 units/s per point against 2.5 from anyone else, and the radius damage passes its points as the knockback. Computed: a rocket exploding on the floor directly under a standing player, 28 units below the center of the player's box, does 120 − 14 = 106, halved to 53, which adds 424 units/s upward, against a jump's 270. quake-ii/self-damage

About: Quake II Rocket jumping

{
 "self_scale": 0.5,
 "self_knockback": 1600,
 "other_knockback": 500,
 "mass": 200
}

The box runs from 24 below the origin to 32 above, so its center is 4 above the origin and the floor 28 below the center. The push direction is from the explosion to the player's origin. The worked case ignores armor, which lowers the damage taken but not the push, and the rocket's own offset from the eye.

Cited by: Quake II, Rocket jumping

On Easy (skill 0) outside deathmatch, Quake II's T_Damage halves the damage a player takes, to no less than 1; the knockback is worked out separately and isn't halved. Levels also pick their entities by skill: an entity flagged not-easy, not-medium, or not-hard is removed at load on that skill, with Nightmare (3) counted as hard. quake-ii/easy-damage

About: Quake II Difficulty level

Value: 0.5 ×

The damage is an int, so an odd amount rounds down. The skill filter is the non-deathmatch branch; deathmatch removes entities flagged not-deathmatch instead (L578).

Cited by: Difficulty level, Quake II

Quake II's T_Damage doubles the damage a player does to a living monster that has no enemy yet, commented "bonus damage for suprising a monster", unless the damage is radius damage; the doubling comes after Easy's halving, which applies only to players. quake-ii/surprise-damage

About: Quake II Damage formula

Value: 2 ×

A rocket's direct hit is not radius damage, so it doubles on a monster that hasn't noticed anyone; its splash does not.

Cited by: Quake II

In the four Quake II monsters read, a flinch is a cooldown rather than a roll: the soldier's, infantry's, and gunner's pain functions play a pain animation unless one started within the last 3 seconds (pain_debounce_time), choosing which at random (soldier, infantry) or by the damage (gunner), and on Nightmare (skill 3) they return before the animation. The soldier has an exception both ways: knocked upward faster than 100, it switches to a fourth pain animation even within the cooldown (if already in one of the other three) and even on Nightmare. On Nightmare the cooldown is 5 seconds, not 3: T_Damage resets it to 5 after each hit that calls the pain function. The tank adds a roll: it ignores hits of 10 or less, and flinches from 11 to 30 only when random() is at most 0.2; on hard and Nightmare it doesn't flinch during two of its attacks. quake-ii/pain-cooldown

About: Quake II Pain chance

Only four of the monster files were read; the others' pain functions may differ. A ducked monster skips its pain function altogether (g_combat.c L509).

Cited by: Pain chance, Quake II

When a monster survives damage from another monster, Quake II's M_ReactToDamage makes the attacker its enemy if both move the same way (walking, flying, or swimming), their class names differ, and the attacker isn't a tank, super tank, Makron, or Jorg; failing that, it fights back only if the attacker was targeting it, and otherwise takes on the attacker's enemy, unless that enemy is itself. Nothing happens when it hurt itself or the attacker is already its enemy. A player it was chasing is kept as the old enemy. Quake's rule, in the version 1.01 QuakeC of id's Quake-Tools release, is simpler: a monster turns on any attacker of a different class, and soldiers turn on each other too. quake-ii/infighting

About: Quake II Monster infighting

T_Damage calls it only when the monster survives (a kill returns at L497-L502). Two monsters of the same class skip the first branch, but one still fights back if the other was targeting it, and otherwise joins the other's target. Damage from a player always makes the player the enemy, except that a good-guy monster ignores players, and in coop a monster chasing a visible player keeps it (L303-L332).

Cited by: Monster infighting, Quake II

A Quake II weapon pickup adds the weapon to the player's inventory, which keeps every weapon taken, and gives that weapon's ammo with it unless the item carries the DROPPED_ITEM flag. The player switches to it only when it is the first of its kind carried, and in deathmatch only while the blaster is in hand. In coop, or in deathmatch with weapons-stay set, a player who already has the weapon can't take a placed one. A placed weapon picked up in deathmatch stays where it is with weapons-stay set and otherwise respawns after 30 seconds, and in coop it stays; a weapon flagged DROPPED_PLAYER_ITEM, which a dying player's weapon is, gives its ammo but neither stays nor respawns. quake-ii/weapon-pickup

About: Quake II Weapon pickup

With infinite ammo set, the pickup gives 1000 rounds instead of the item's quantity (L138-L139). Drop_Item (g_items.c) flags what it drops DROPPED_ITEM; a dying player's weapon then has its flags replaced by DROPPED_PLAYER_ITEM alone, so it passes the ammo test at L134. After a pickup, Touch_Item clears a set FL_RESPAWN and leaves the item, and frees it otherwise; SetRespawn (g_items.c) is the code that hides it for 30 seconds.

Cited by: Quake II, Weapon pickup