vkdoom_m/src/g_shared/a_bridge.cpp

#include "actor.h"
#include "info.h"
#include "gi.h"
#include "m_random.h"

static FRandom pr_orbit ("Orbit");


// Custom bridge --------------------------------------------------------
/*
	args[0]: Bridge radius, in mapunits
	args[1]: Bridge height, in mapunits
	args[2]: Amount of bridge balls (if 0: Doom bridge)
	args[3]: Rotation speed of bridge balls, in byte angle per seconds, sorta:
		Since an arg is only a byte, it can only go from 0 to 255, while ZDoom's
		BAM go from 0 to 65535. Plus, it needs to be able to go either way. So,
		up to 128, it goes counterclockwise; 129-255 is clockwise, substracting
		256 from it to get the angle. A few example values:
		  0: Hexen default
	     11:  15° / seconds
		 21:  30° / seconds
		 32:  45° / seconds
		 64:  90° / seconds
		128: 180° / seconds
		192: -90° / seconds
		223: -45° / seconds
		233: -30° / seconds
		244: -15° / seconds
		This value only matters if args[2] is not zero.
	args[4]: Rotation radius of bridge balls, in bridge radius %.
		If 0, use Hexen default: ORBIT_RADIUS, regardless of bridge radius.
		This value only matters if args[2] is not zero.
*/

class ACustomBridge : public AActor
{
	DECLARE_CLASS (ACustomBridge, AActor)
public:
	void BeginPlay ();
	void Destroy() override;
};

IMPLEMENT_CLASS(ACustomBridge, false, false)

void ACustomBridge::BeginPlay ()
{
	if (args[2]) // Hexen bridge if there are balls
	{
		SetState(SeeState);
		radius = args[0] ? args[0] : 32;
		Height = args[1] ? args[1] : 2;
	}
	else // No balls? Then a Doom bridge.
	{
		radius = args[0] ? args[0] : 36;
		Height = args[1] ? args[1] : 4;
		RenderStyle = STYLE_Normal;
	}
}

void ACustomBridge::Destroy()
{
	// Hexen originally just set a flag to make the bridge balls remove themselves in A_BridgeOrbit.
	// But this is not safe with custom bridge balls that do not necessarily call that function.
	// So the best course of action is to look for all bridge balls here and destroy them ourselves.
	
	TThinkerIterator<AActor> it;
	AActor *thing;
	
	while ((thing = it.Next()))
	{
		if (thing->target == this)
		{
			thing->Destroy();
		}
	}
	Super::Destroy();
}

// Action functions for the non-Doom bridge --------------------------------

#define ORBIT_RADIUS	15

// New bridge stuff
//	Parent
//		special1	true == removing from world
//
//	Child
//		target		pointer to center mobj
//		angle		angle of ball

static void BridgeOrbit(AActor *self)
{
	if (self->target == NULL)
	{ // Don't crash if somebody spawned this into the world
	  // independantly of a Bridge actor.
		return;
	}
	// Set default values
	// Every five tics, Hexen moved the ball 3/256th of a revolution.
	DAngle rotationspeed = 45. / 32 * 3 / 5;
	double rotationradius = ORBIT_RADIUS;
	// If the bridge is custom, set non-default values if any.

	// Set angular speed; 1--128: counterclockwise rotation ~=1--180°; 129--255: clockwise rotation ~= 180--1°
	if (self->target->args[3] > 128) rotationspeed = 45. / 32 * (self->target->args[3] - 256) / TICRATE;
	else if (self->target->args[3] > 0) rotationspeed = 45. / 32 * (self->target->args[3]) / TICRATE;
	// Set rotation radius
	if (self->target->args[4]) rotationradius = ((self->target->args[4] * self->target->radius) / 100);

	self->Angles.Yaw += rotationspeed;
	self->SetOrigin(self->target->Vec3Angle(rotationradius, self->Angles.Yaw, 0), true);
	self->floorz = self->target->floorz;
	self->ceilingz = self->target->ceilingz;
}

DEFINE_ACTION_FUNCTION(ABridgeBall, A_BridgeOrbit)
{
	PARAM_SELF_PROLOGUE(AActor);
	BridgeOrbit(self);
	return 0;
}


DEFINE_ACTION_FUNCTION(ACustomBridge, A_BridgeInit)
{
	PARAM_SELF_PROLOGUE(AActor);
	PARAM_CLASS_DEF(balltype, AActor);

	AActor *ball;

	if (balltype == NULL)
	{
		balltype = PClass::FindActor("BridgeBall");
	}

	DAngle startangle = pr_orbit() * (360./256.);

	// Spawn triad into world -- may be more than a triad now.
	int ballcount = self->args[2]==0 ? 3 : self->args[2];

	for (int i = 0; i < ballcount; i++)
	{
		ball = Spawn(balltype, self->Pos(), ALLOW_REPLACE);
		ball->Angles.Yaw = startangle + (45./32) * (256/ballcount) * i;
		ball->target = self;
		BridgeOrbit(ball);
	}
	return 0;
}


// Invisible bridge --------------------------------------------------------

class AInvisibleBridge : public AActor
{
	DECLARE_CLASS (AInvisibleBridge, AActor)
public:
	void BeginPlay ();
};

IMPLEMENT_CLASS(AInvisibleBridge, false, false)

void AInvisibleBridge::BeginPlay ()
{
	Super::BeginPlay ();
	if (args[0])
		radius = args[0];
	if (args[1])
		Height = args[1];
}