SRB2Kart/Actions/A SPBChase

A_SPBChase is an action exclusive to SRB2Kart. It is used by the Self Propelled Bomb. It causes the actor to target and chase the player with the best rank at the time of spawning and collide with the target if they slow down for too long. If the target is turning, on a conveyor, or in current, the actor will slow down to compensate. If the target dies, the actor will wait in place for a moment before chasing the target. If the target is not in first place for 7 seconds, the actor will set its target to the player that is now in first place.
Code – A_SPBChase
void A_SPBChase(mobj_t *actor)
{
	player_t *player = NULL;
	UINT8 i;
	UINT8 bestrank = UINT8_MAX;
	fixed_t dist;
	angle_t hang, vang;
	fixed_t wspeed, xyspeed, zspeed;
#ifdef HAVE_BLUA
	if (LUA_CallAction("A_SPBChase", actor))
		return;
#endif

	// Default speed
	wspeed = actor->movefactor;

	if (actor->threshold) // Just fired, go straight.
	{
		actor->lastlook = -1;
		spbplace = -1;
		P_InstaThrust(actor, actor->angle, wspeed);
		actor->flags &=  ~MF_NOCLIPTHING;	// just in case.
		return;
	}

	// Find the player with the best rank
	for (i = 0; i < MAXPLAYERS; i++)
	{
		if (!playeringame[i] || players[i].spectator || players[i].exiting)
			continue; // not in-game

		/*if (!players[i].mo)
			continue; // no mobj

		if (players[i].mo->health <= 0)
			continue; // dead

		if (players[i].kartstuff[k_respawn])
			continue;*/ // respawning

		if (players[i].kartstuff[k_position] < bestrank)
		{
			bestrank = players[i].kartstuff[k_position];
			player = &players[i];
		}
	}

	if (actor->extravalue1 == 1) // MODE: TARGETING
	{
		if (actor->tracer && actor->tracer->health)
		{

			fixed_t defspeed = wspeed;
			fixed_t range = (160*actor->tracer->scale);
			fixed_t cx = 0, cy =0;

			// we're tailing a player, now's a good time to regain our damage properties
			actor->flags &=  ~MF_NOCLIPTHING;

			// Play the intimidating gurgle
			if (!S_SoundPlaying(actor, actor->info->activesound))
				S_StartSound(actor, actor->info->activesound);

			// Maybe we want SPB to target an object later? IDK lol
			if (actor->tracer->player)
			{
				UINT8 fracmax = 32;
				UINT8 spark = ((10-actor->tracer->player->kartspeed) + actor->tracer->player->kartweight) / 2;
				fixed_t easiness = ((actor->tracer->player->kartspeed + (10-spark)) << FRACBITS) / 2;

				actor->lastlook = actor->tracer->player-players; // Save the player num for death scumming...

				if (!P_IsObjectOnGround(actor->tracer) /*&& !actor->tracer->player->kartstuff[k_pogospring]*/)
				{
					// In the air you have no control; basically don't hit unless you make a near complete stop
					defspeed = (7 * actor->tracer->player->speed) / 8;
				}
				else
				{
					// 7/8ths max speed for Knuckles, 3/4ths max speed for min accel, exactly max speed for max accel
					defspeed = FixedMul(((fracmax+1)<<FRACBITS) - easiness, K_GetKartSpeed(actor->tracer->player, false)) / fracmax;
				}

				// Be fairer on conveyors
				cx = actor->tracer->player->cmomx;
				cy = actor->tracer->player->cmomy;

				// Switch targets if you're no longer 1st for long enough
				if (actor->tracer->player->kartstuff[k_position] <= bestrank)
					actor->extravalue2 = 7*TICRATE;
				else if (actor->extravalue2-- <= 0)
					actor->extravalue1 = 0; // back to SEEKING

				spbplace = actor->tracer->player->kartstuff[k_position];
			}

			dist = P_AproxDistance(P_AproxDistance(actor->x-actor->tracer->x, actor->y-actor->tracer->y), actor->z-actor->tracer->z);

			wspeed = FixedMul(defspeed, FRACUNIT + FixedDiv(dist-range, range));
			if (wspeed < defspeed)
				wspeed = defspeed;
			if (wspeed > (3*defspeed)/2)
				wspeed = (3*defspeed)/2;
			if (wspeed < 20*actor->tracer->scale)
				wspeed = 20*actor->tracer->scale;
			if (actor->tracer->player->pflags & PF_SLIDING)
				wspeed = actor->tracer->player->speed/2;
			//  ^^^^ current section: These are annoying, and grand metropolis in particular needs this.

			hang = R_PointToAngle2(actor->x, actor->y, actor->tracer->x, actor->tracer->y);
			vang = R_PointToAngle2(0, actor->z, dist, actor->tracer->z);

			// Modify stored speed
			if (wspeed > actor->cvmem)
				actor->cvmem += (wspeed - actor->cvmem) / TICRATE;
			else
				actor->cvmem = wspeed;

			{
				// Smoothly rotate horz angle
				angle_t input = hang - actor->angle;
				boolean invert = (input > ANGLE_180);
				if (invert)
					input = InvAngle(input);

				// Slow down when turning; it looks better and makes U-turns not unfair
				xyspeed = FixedMul(actor->cvmem, max(0, (((180<<FRACBITS) - AngleFixed(input)) / 90) - FRACUNIT));

				input = FixedAngle(AngleFixed(input)/4);
				if (invert)
					input = InvAngle(input);

				actor->angle += input;

				// Smoothly rotate vert angle
				input = vang - actor->movedir;
				invert = (input > ANGLE_180);
				if (invert)
					input = InvAngle(input);

				// Slow down when turning; might as well do it for momz, since we do it above too
				zspeed = FixedMul(actor->cvmem, max(0, (((180<<FRACBITS) - AngleFixed(input)) / 90) - FRACUNIT));

				input = FixedAngle(AngleFixed(input)/4);
				if (invert)
					input = InvAngle(input);

				actor->movedir += input;
			}

			actor->momx = cx + FixedMul(FixedMul(xyspeed, FINECOSINE(actor->angle>>ANGLETOFINESHIFT)), FINECOSINE(actor->movedir>>ANGLETOFINESHIFT));
			actor->momy = cy + FixedMul(FixedMul(xyspeed, FINESINE(actor->angle>>ANGLETOFINESHIFT)), FINECOSINE(actor->movedir>>ANGLETOFINESHIFT));
			actor->momz = FixedMul(zspeed, FINESINE(actor->movedir>>ANGLETOFINESHIFT));

			// Red speed lines for when it's gaining on its target. A tell for when you're starting to lose too much speed!
			if (R_PointToDist2(0, 0, actor->momx, actor->momy) > (actor->tracer->player ? (16*actor->tracer->player->speed)/15
				: (16*R_PointToDist2(0, 0, actor->tracer->momx, actor->tracer->momy))/15) // Going faster than the target
				&& xyspeed > K_GetKartSpeed(actor->tracer->player, false)/4) // Don't display speedup lines at pitifully low speeds
			{
				mobj_t *fast = P_SpawnMobj(actor->x + (P_RandomRange(-24,24) * actor->scale),
					actor->y + (P_RandomRange(-24,24) * actor->scale),
					actor->z + (actor->height/2) + (P_RandomRange(-24,24) * actor->scale),
					MT_FASTLINE);
				fast->angle = R_PointToAngle2(0, 0, actor->momx, actor->momy);
				//fast->momx = (3*actor->momx)/4;
				//fast->momy = (3*actor->momy)/4;
				//fast->momz = (3*actor->momz)/4;
				fast->color = SKINCOLOR_RED;
				fast->colorized = true;
				K_MatchGenericExtraFlags(fast, actor);
			}

			return;
		}
		else // Target's gone, return to SEEKING
		{
			P_SetTarget(&actor->tracer, NULL);
			actor->extravalue1 = 2; // WAIT...
			actor->extravalue2 = 52; // Slightly over the respawn timer length
			return;
		}
	}
	else if (actor->extravalue1 == 2) // MODE: WAIT...
	{
		actor->momx = actor->momy = actor->momz = 0; // Stoooop

		// don't hurt players that have nothing to do with this:
		actor->flags |= MF_NOCLIPTHING;

		if (actor->lastlook != -1
			&& playeringame[actor->lastlook]
			&& !players[actor->lastlook].spectator
			&& !players[actor->lastlook].exiting)
		{
			spbplace = players[actor->lastlook].kartstuff[k_position];
			if (actor->extravalue2-- <= 0 && players[actor->lastlook].mo)
			{
				P_SetTarget(&actor->tracer, players[actor->lastlook].mo);
				actor->extravalue1 = 1; // TARGET ACQUIRED
				actor->extravalue2 = 7*TICRATE;
				actor->cvmem = wspeed;
			}
		}
		else
		{
			actor->extravalue1 = 0; // SEEKING
			actor->extravalue2 = 0;
			spbplace = -1;
		}
	}
	else // MODE: SEEKING
	{
		actor->lastlook = -1; // Just make sure this is reset

		if (!player || !player->mo || player->mo->health <= 0 || player->kartstuff[k_respawn])
		{
			// No one there? Completely STOP.
			actor->momx = actor->momy = actor->momz = 0;
			if (!player)
				spbplace = -1;
			return;
		}

		// Found someone, now get close enough to initiate the slaughter...

		// don't hurt players that have nothing to do with this:
		actor->flags |= MF_NOCLIPTHING;

		P_SetTarget(&actor->tracer, player->mo);
		spbplace = bestrank;

		dist = P_AproxDistance(P_AproxDistance(actor->x-actor->tracer->x, actor->y-actor->tracer->y), actor->z-actor->tracer->z);

		hang = R_PointToAngle2(actor->x, actor->y, actor->tracer->x, actor->tracer->y);
		vang = R_PointToAngle2(0, actor->z, dist, actor->tracer->z);

		{
			// Smoothly rotate horz angle
			angle_t input = hang - actor->angle;
			boolean invert = (input > ANGLE_180);
			if (invert)
				input = InvAngle(input);

			// Slow down when turning; it looks better and makes U-turns not unfair
			xyspeed = FixedMul(wspeed, max(0, (((180<<FRACBITS) - AngleFixed(input)) / 90) - FRACUNIT));

			input = FixedAngle(AngleFixed(input)/4);
			if (invert)
				input = InvAngle(input);

			actor->angle += input;

			// Smoothly rotate vert angle
			input = vang - actor->movedir;
			invert = (input > ANGLE_180);
			if (invert)
				input = InvAngle(input);

			// Slow down when turning; might as well do it for momz, since we do it above too
			zspeed = FixedMul(wspeed, max(0, (((180<<FRACBITS) - AngleFixed(input)) / 90) - FRACUNIT));

			input = FixedAngle(AngleFixed(input)/4);
			if (invert)
				input = InvAngle(input);

			actor->movedir += input;
		}

		actor->momx = FixedMul(FixedMul(xyspeed, FINECOSINE(actor->angle>>ANGLETOFINESHIFT)), FINECOSINE(actor->movedir>>ANGLETOFINESHIFT));
		actor->momy = FixedMul(FixedMul(xyspeed, FINESINE(actor->angle>>ANGLETOFINESHIFT)), FINECOSINE(actor->movedir>>ANGLETOFINESHIFT));
		actor->momz = FixedMul(zspeed, FINESINE(actor->movedir>>ANGLETOFINESHIFT));

		if (dist <= (3072*actor->tracer->scale)) // Close enough to target?
		{
			S_StartSound(actor, actor->info->attacksound); // Siren sound; might not need this anymore, but I'm keeping it for now just for debugging.
			actor->extravalue1 = 1; // TARGET ACQUIRED
			actor->extravalue2 = 7*TICRATE;
			actor->cvmem = wspeed;
		}
	}

	return;
}
	SRB2Kart Actions	[view]
A_BallhogExplode • A_FlameParticle • A_FZBoomFlash • A_FZBoomSmoke • A_ItemPop • A_JawzChase • A_JawzExplode • A_LightningFollowPlayer • A_MayonakaArrow • A_MementosTPParticles • A_MineExplode • A_RandomShadowFrame • A_ReaperThinker • A_RoamingShadowThinker • A_SPBChase
SRB2Kart/Actions/A SPBChase

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