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improvement: better weapon shells physics #77

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improvement: better weapon shells physics #77

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c930a6e
fix: machinegun / shotgun shells initial angles
WofWca Jun 1, 2026
dfcbb0e
fix: make shotgun / machinegun shells rotate
WofWca Jun 1, 2026
2ad949e
fix: weapon shells: lie flat on the ground
WofWca Jun 1, 2026
825e024
feat: weapon shells: inherit player velocity
WofWca Jun 1, 2026
7793bed
fix: don't half-sink weapons shells in the ground
WofWca Jun 1, 2026
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42 changes: 41 additions & 1 deletion code/cgame/cg_localents.c
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Original file line number Diff line number Diff line change
Expand Up @@ -217,6 +217,24 @@ void CG_ReflectVelocity( localEntity_t *le, trace_t *trace ) {
}
}

static void GetFragmentMinsMaxs( const localEntity_t *le, vec3_t mins, vec3_t maxs ) {
VectorCopy( vec3_origin, mins );
VectorCopy( vec3_origin, maxs );

// can't use `le->leBounceSoundType` because for brass it gets unset
// after first impact
if ( le->refEntity.hModel == cgs.media.machinegunBrassModel ) {
// The primary point of this is to ensure
// that they don't half-sink into the the ground.
// Same for shotgun.
VectorSet(mins, -1, -1, -0.2);
VectorSet(maxs, 1, 1, 0.2);
} else if ( le->refEntity.hModel == cgs.media.shotgunBrassModel ) {
VectorSet(mins, -1, -1, -0.5);
VectorSet(maxs, 1, 1, 0.5);
}
}

/*
================
CG_AddFragment
Expand All @@ -225,6 +243,11 @@ CG_AddFragment
static void CG_AddFragment( localEntity_t *le ) {
vec3_t newOrigin;
trace_t trace;
vec3_t mins;
vec3_t maxs;

VectorCopy( vec3_origin, mins );
VectorCopy( vec3_origin, maxs );

if ( le->pos.trType == TR_STATIONARY ) {
// sink into the ground if near the removal time
Expand Down Expand Up @@ -252,8 +275,9 @@ static void CG_AddFragment( localEntity_t *le ) {
// calculate new position
BG_EvaluateTrajectory( &le->pos, cg.time, newOrigin );

GetFragmentMinsMaxs( le, mins, maxs );
// trace a line from previous position to new position
CG_Trace( &trace, le->refEntity.origin, NULL, NULL, newOrigin, -1, CONTENTS_SOLID );
CG_Trace( &trace, le->refEntity.origin, mins, maxs, newOrigin, -1, CONTENTS_SOLID );
if ( trace.fraction == 1.0 ) {
// still in free fall
VectorCopy( newOrigin, le->refEntity.origin );
Expand Down Expand Up @@ -283,6 +307,22 @@ static void CG_AddFragment( localEntity_t *le ) {
return;
}

// stop pitch spin so that when it settles it lies flat on the ground
if ( le->leBounceSoundType == LEBS_BRASS ) {
// save current as base
BG_EvaluateTrajectory( &le->angles, cg.time, le->angles.trBase );
le->angles.trTime = cg.time;

// "fall over" to nearest horizontal orientation
//
// FIXME: handle non-horizontal surfaces (see `trace.plane.normal`)
// (YAW would need to be taken into account then)
le->angles.trBase[PITCH] = 90 + 180 * floor( le->angles.trBase[PITCH] / 180 );
le->angles.trDelta[PITCH] = 0;

AnglesToAxis( le->angles.trBase, le->refEntity.axis );
}

// leave a mark
CG_FragmentBounceMark( le, &trace );

Expand Down
36 changes: 22 additions & 14 deletions code/cgame/cg_weapons.c
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Original file line number Diff line number Diff line change
Expand Up @@ -51,10 +51,12 @@ static void CG_MachineGunEjectBrass( centity_t *cent ) {
waterScale = 0.10f;
}

// don't inherit the full velocity, to emulate air resistance
VectorScale( cent->currentState.pos.trDelta, 0.75, le->pos.trDelta );
xvelocity[0] = velocity[0] * v[0][0] + velocity[1] * v[1][0] + velocity[2] * v[2][0];
xvelocity[1] = velocity[0] * v[0][1] + velocity[1] * v[1][1] + velocity[2] * v[2][1];
xvelocity[2] = velocity[0] * v[0][2] + velocity[1] * v[1][2] + velocity[2] * v[2][2];
VectorScale( xvelocity, waterScale, le->pos.trDelta );
VectorMA( le->pos.trDelta, waterScale, xvelocity, le->pos.trDelta );

AxisCopy( axisDefault, re->axis );
re->hModel = cgs.media.machinegunBrassModel;
Expand All @@ -63,12 +65,14 @@ static void CG_MachineGunEjectBrass( centity_t *cent ) {

le->angles.trType = TR_LINEAR;
le->angles.trTime = cg.time;
le->angles.trBase[0] = rand()&31;
le->angles.trBase[1] = rand()&31;
le->angles.trBase[2] = rand()&31;
le->angles.trDelta[0] = 2;
le->angles.trDelta[1] = 1;
le->angles.trDelta[2] = 0;
VectorCopy ( cent->lerpAngles, le->angles.trBase );
le->angles.trBase[PITCH] += 90;
le->angles.trBase[0] += rand()&31 - 15;
le->angles.trBase[1] += rand()&31 - 15;
le->angles.trBase[2] += rand()&31 - 15;
le->angles.trDelta[PITCH] = 1750 + rand()&511;
le->angles.trDelta[YAW] = le->angles.trDelta[0] / 2 * ((rand()&1)*2 - 1);
le->angles.trDelta[ROLL] = 0;

le->leFlags = LEF_TUMBLE;
le->leBounceSoundType = LEBS_BRASS;
Expand Down Expand Up @@ -128,23 +132,27 @@ static void CG_ShotgunEjectBrass( centity_t *cent ) {
waterScale = 0.10f;
}

// don't inherit the full velocity, to emulate air resistance
VectorScale( cent->currentState.pos.trDelta, 0.675, le->pos.trDelta );
xvelocity[0] = velocity[0] * v[0][0] + velocity[1] * v[1][0] + velocity[2] * v[2][0];
xvelocity[1] = velocity[0] * v[0][1] + velocity[1] * v[1][1] + velocity[2] * v[2][1];
xvelocity[2] = velocity[0] * v[0][2] + velocity[1] * v[1][2] + velocity[2] * v[2][2];
VectorScale( xvelocity, waterScale, le->pos.trDelta );
VectorMA( le->pos.trDelta, waterScale, xvelocity, le->pos.trDelta );

AxisCopy( axisDefault, re->axis );
re->hModel = cgs.media.shotgunBrassModel;
le->bounceFactor = 0.3f;

le->angles.trType = TR_LINEAR;
le->angles.trTime = cg.time;
le->angles.trBase[0] = rand()&31;
le->angles.trBase[1] = rand()&31;
le->angles.trBase[2] = rand()&31;
le->angles.trDelta[0] = 1;
le->angles.trDelta[1] = 0.5;
le->angles.trDelta[2] = 0;
VectorCopy( cent->lerpAngles, le->angles.trBase );
le->angles.trBase[PITCH] += 90;
le->angles.trBase[0] += rand()&31 - 15;
le->angles.trBase[1] += rand()&31 - 15;
le->angles.trBase[2] += rand()&31 - 15;
le->angles.trDelta[PITCH] = 750 + rand()&511;
le->angles.trDelta[YAW] = le->angles.trDelta[0] / 2 * ((rand()&1)*2 - 1);
le->angles.trDelta[ROLL] = 0;

le->leFlags = LEF_TUMBLE;
le->leBounceSoundType = LEBS_BRASS;
Expand Down