Cube  Diff

// physics.cpp: no physics books were hurt nor consulted in the construction of
// this code. All physics computations and constants were invented on the fly
// and simply tweaked until they "felt right", and have no basis in reality.
// Collision detection is simplistic but very robust (uses discrete steps at
// fixed fps).

#include "cube.h"

#import "DynamicEntity.h"
#import "MapModelInfo.h"

// collide with player or monster
bool
plcollide(
    DynamicEntity *d, DynamicEntity *o, float &headspace, float &hi, float &lo)
{
	if (o.state != CS_ALIVE)
		return true;
	const float r = o.radius + d.radius;
	if (fabs(o.o.x - d.o.x) < r && fabs(o.o.y - d.o.y) < r) {
		if (d.o.z - d.eyeheight < o.o.z - o.eyeheight) {
			if (o.o.z - o.eyeheight < hi)
				hi = o.o.z - o.eyeheight - 1;
		} else if (o.o.z + o.aboveeye > lo)
			lo = o.o.z + o.aboveeye + 1;

		if (fabs(o.o.z - d.o.z) < o.aboveeye + d.eyeheight)
			return false;
		if (d.monsterstate)
			return false; // hack
		headspace = d.o.z - o.o.z - o.aboveeye - d.eyeheight;
		if (headspace < 0)
			headspace = 10;
	}
	return true;
}

bool

		bs = 1 << mip;
		return cornertest(mip, x, y, dx, dy, bx, by, bs);
	}
	return stest;
}

void
mmcollide(DynamicEntity *d, float &hi, float &lo) // collide with a mapmodel
{
	loopv(ents)
	{
		entity &e = ents[i];
		if (e.type != MAPMODEL)
			continue;
		MapModelInfo *mmi = getmminfo(e.attr2);
		if (mmi == nil || !mmi.h)
			continue;
		const float r = mmi.rad + d.radius;
		if (fabs(e.x - d.o.x) < r && fabs(e.y - d.o.y) < r) {
			float mmz =
			    (float)(S(e.x, e.y)->floor + mmi.zoff + e.attr3);
			if (d.o.z - d.eyeheight < mmz) {
				if (mmz < hi)
					hi = mmz;
			} else if (mmz + mmi.h > lo)
				lo = mmz + mmi.h;
		}
	}
}

// all collision happens here
// spawn is a dirty side effect used in spawning
// drop & rise are supplied by the physics below to indicate gravity/push for
// current mini-timestep

bool
collide(DynamicEntity *d, bool spawn, float drop, float rise)
{
	// figure out integer cube rectangle this entity covers in map
	const float fx1 = d.o.x - d.radius;


	const float fy1 = d.o.y - d.radius;
	const float fx2 = d.o.x + d.radius;
	const float fy2 = d.o.y + d.radius;
	const int x1 = fast_f2nat(fx1);
	const int y1 = fast_f2nat(fy1);
	const int x2 = fast_f2nat(fx2);
	const int y2 = fast_f2nat(fy2);
	float hi = 127, lo = -128;
	// big monsters are afraid of heights, unless angry :)
	float minfloor = (d.monsterstate && !spawn && d.health > 100)
	    ? d.o.z - d.eyeheight - 4.5f
	    : -1000.0f;


	for (int x = x1; x <= x2; x++)
		for (int y = y1; y <= y2; y++) {

			// collide with map
			if (OUTBORD(x, y))
				return false;
			sqr *s = S(x, y);
			float ceil = s->ceil;
			float floor = s->floor;
			switch (s->type) {
			case SOLID:

				hi = ceil;
			if (floor > lo)
				lo = floor;
			if (floor < minfloor)
				return false;
		}

	if (hi - lo < d.eyeheight + d.aboveeye)
		return false;

	float headspace = 10;
	for (id player in players) {

		if (player == [OFNull null] || player == d)

			continue;
		if (!plcollide(d, player, headspace, hi, lo))
			return false;
	}
	if (d != player1)
		if (!plcollide(d, player1, headspace, hi, lo))
			return false;

	// this loop can be a performance bottleneck with many monster on a slow
	// cpu, should replace with a blockmap but seems mostly fast enough
	for (DynamicEntity *monster in getmonsters())
		if (!vreject(d.o, monster.o, 7.0f) && d != monster &&
		    !plcollide(d, monster, headspace, hi, lo))
			return false;
	headspace -= 0.01f;

	mmcollide(d, hi, lo); // collide with map models

	if (spawn) {
		// just drop to floor (sideeffect)
		d.o = OFMakeVector3D(d.o.x, d.o.y, lo + d.eyeheight);
		d.onfloor = true;
	} else {
		const float space = d.o.z - d.eyeheight - lo;
		if (space < 0) {
			if (space > -0.01)
				// stick on step
				d.o = OFMakeVector3D(
				    d.o.x, d.o.y, lo + d.eyeheight);
			else if (space > -1.26f)
				// rise thru stair
				d.o =
				    OFMakeVector3D(d.o.x, d.o.y, d.o.z + rise);
			else
				return false;
		} else
			// gravity
			d.o = OFMakeVector3D(d.o.x, d.o.y,
			    d.o.z - min(min(drop, space), headspace));


		const float space2 = hi - (d.o.z + d.aboveeye);
		if (space2 < 0) {
			if (space2 < -0.1)
				return false; // hack alert!
			// glue to ceiling
			d.o = OFMakeVector3D(d.o.x, d.o.y, hi - d.aboveeye);
			// cancel out jumping velocity
			d.vel = OFMakeVector3D(d.vel.x, d.vel.y, 0);
		}

		d.onfloor = d.o.z - d.eyeheight - lo < 0.001f;
	}
	return true;
}

float
rad(float x)
{

}

// main physics routine, moves a player/monster for a curtime step
// moveres indicated the physics precision (which is lower for monsters and
// multiplayer prediction) local is false for multiplayer prediction

void
moveplayer(DynamicEntity *pl, int moveres, bool local, int curtime)
{
	const bool water = hdr.waterlevel > pl.o.z - 0.5f;
	const bool floating = (editmode && local) || pl.state == CS_EDITING;

	OFVector3D d; // vector of direction we ideally want to move in

	d.x = (float)(pl.move * cos(rad(pl.yaw - 90)));
	d.y = (float)(pl.move * sin(rad(pl.yaw - 90)));
	d.z = 0;

	if (floating || water) {
		d.x *= (float)cos(rad(pl.pitch));
		d.y *= (float)cos(rad(pl.pitch));
		d.z = (float)(pl.move * sin(rad(pl.pitch)));
	}

	d.x += (float)(pl.strafe * cos(rad(pl.yaw - 180)));
	d.y += (float)(pl.strafe * sin(rad(pl.yaw - 180)));


	const float speed = curtime / (water ? 2000.0f : 1000.0f) * pl.maxspeed;
	const float friction =
	    water ? 20.0f : (pl.onfloor || floating ? 6.0f : 30.0f);

	const float fpsfric = friction / curtime * 20.0f;

	// slowly apply friction and direction to
	// velocity, gives a smooth movement
	vmul(pl.vel, fpsfric - 1);
	vadd(pl.vel, d);
	vdiv(pl.vel, fpsfric);
	d = pl.vel;
	vmul(d, speed); // d is now frametime based velocity vector

	pl.blocked = false;
	pl.moving = true;

	if (floating) {

		// just apply velocity
		vadd(pl.o, d);
		if (pl.jumpnext) {
			pl.jumpnext = false;
			pl.vel = OFMakeVector3D(pl.vel.x, pl.vel.y, 2);
		}
	} else {
		// apply velocity with collision

		if (pl.onfloor || water) {
			if (pl.jumpnext) {
				pl.jumpnext = false;
				// physics impulse upwards
				pl.vel =
				    OFMakeVector3D(pl.vel.x, pl.vel.y, 1.7);
				// dampen velocity change even harder, gives
				// correct water feel
				if (water)
					pl.vel = OFMakeVector3D(pl.vel.x / 8,
					    pl.vel.y / 8, pl.vel.z);

				if (local)
					playsoundc(S_JUMP);
				else if (pl.monsterstate) {
					OFVector3D loc = pl.o;
					playsound(S_JUMP, &loc);
				}
			} else if (pl.timeinair > 800) {
				// if we land after long time must have been a
				// high jump, make thud sound
				if (local)
					playsoundc(S_LAND);
				else if (pl.monsterstate) {
					OFVector3D loc = pl.o;
					playsound(S_LAND, &loc);
				}
			}
			pl.timeinair = 0;
		} else
			pl.timeinair += curtime;


		const float gravity = 20;
		const float f = 1.0f / moveres;
		// incorrect, but works fine
		float dropf = ((gravity - 1) + pl.timeinair / 15.0f);
		// float slowly down in water
		if (water) {
			dropf = 5;
			pl.timeinair = 0;
		}

		// at high fps, gravity kicks in too fast
		const float drop = dropf * curtime / gravity / 100 / moveres;
		// extra smoothness when lifting up stairs
		const float rise = speed / moveres / 1.2f;

		loopi(moveres) // discrete steps collision detection & sliding
		{
			// try move forward
			pl.o = OFMakeVector3D(pl.o.x + f * d.x,
			    pl.o.y + f * d.y, pl.o.z + f * d.z);

			if (collide(pl, false, drop, rise))
				continue;
			// player stuck, try slide along y axis
			pl.blocked = true;
			pl.o = OFMakeVector3D(pl.o.x - f * d.x, pl.o.y, pl.o.z);
			if (collide(pl, false, drop, rise)) {
				d.x = 0;
				continue;
			}

			// still stuck, try x axis
			pl.o = OFMakeVector3D(
			    pl.o.x + f * d.x, pl.o.y - f * d.y, pl.o.z);
			if (collide(pl, false, drop, rise)) {
				d.y = 0;
				continue;
			}

			// try just dropping down
			pl.moving = false;
			pl.o = OFMakeVector3D(pl.o.x - f * d.x, pl.o.y, pl.o.z);

			if (collide(pl, false, drop, rise)) {
				d.y = d.x = 0;
				continue;
			}
			pl.o = OFMakeVector3D(pl.o.x, pl.o.y, pl.o.z - f * d.z);
			break;
		}
	}

	// detect wether player is outside map, used for skipping zbuffer clear
	// mostly

	if (pl.o.x < 0 || pl.o.x >= ssize || pl.o.y < 0 || pl.o.y > ssize)
		pl.outsidemap = true;
	else {
		sqr *s = S((int)pl.o.x, (int)pl.o.y);
		pl.outsidemap = SOLID(s) ||
		    pl.o.z < s->floor - (s->type == FHF ? s->vdelta / 4 : 0) ||
		    pl.o.z > s->ceil + (s->type == CHF ? s->vdelta / 4 : 0);
	}

	// automatically apply smooth roll when strafing

	if (pl.strafe == 0)
		pl.roll = pl.roll / (1 + (float)sqrt((float)curtime) / 25);
	else {
		pl.roll += pl.strafe * curtime / -30.0f;
		if (pl.roll > maxroll)
			pl.roll = (float)maxroll;
		if (pl.roll < -maxroll)
			pl.roll = (float)-maxroll;
	}

	// play sounds on water transitions

	if (!pl.inwater && water) {
		OFVector3D loc = pl.o;
		playsound(S_SPLASH2, &loc);
		pl.vel = OFMakeVector3D(pl.vel.x, pl.vel.y, 0);
	} else if (pl.inwater && !water) {
		OFVector3D loc = pl.o;
		playsound(S_SPLASH1, &loc);
	}
	pl.inwater = water;
}

void
moveplayer(DynamicEntity *pl, int moveres, bool local)
{
	loopi(physicsrepeat) moveplayer(pl, moveres, local,
	    i ? curtime / physicsrepeat
	      : curtime - curtime / physicsrepeat * (physicsrepeat - 1));
}