util_weather.cpp

/*
* Copyright (c) 2010 Jice
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#include <math.h>
#include "main.hpp"

#define OCTAVES 7.0f
#define SCALE 2.0f
#define MAX_WIND_SPEED 4.0f
#define LIGHTNING_LEVEL 0.4f
#define LIGHTNING_RADIUS 500
#define LIGHTNING_LIFE 2.0f
#define LIGHTNING_INTENSITY_SPEED 20.0f
#define LIGHTNING_MIN_PROB 7.0f
#define LIGHTNING_MAX_PROB 1.0f
#define RAIN_MIN_PROB 4000
#define RAIN_MED_PROB 400
#define RAIN_MAX_PROB 10

void Weather::init(int width, int height) {
	map = new TCODHeightMap(width+2,height+2);
	// TODO : would be better with a 3d noise and slowly varying z
	// but you can notice the difference only when time is accelerated
	map->addFbm(&noise2d,SCALE,SCALE,0.0f,0.0f,OCTAVES,0.5f,0.5f);
	dx=dy=noisex=noisey=20000.0f;
	indicatorDelta=0.0f;
	changeFactor=1.0f;
	update(0.1f);
}

void Weather::move(int dx, int dy) {
	this->dx+=dx;
	this->dy+=dy;
}

const char *Weather::getWeather() {
	if (indicator > 0.9f ) return "The sky is completely clear.";
	else if ( indicator > 0.7f ) return "The sky is clear.";
	else if ( indicator > 0.6f ) return "It's cloudy.";
	else if ( indicator > 0.5f ) return "You feel a breeze.";
	else if ( indicator > 0.4f ) return "It's drizzling.";
	else if ( indicator > 0.3f ) return "It's raining.";
	else if ( indicator > 0.2f ) return "You get caught in a storm.";
	else return "The storm is raging"; 	
}

void Weather::update(float elapsed) {
	static float localElapsed=0.0f;
	localElapsed+=elapsed;
	float perlinx=changeFactor*localElapsed / 100.0f;
	indicator=(1.0f+noise1d.get(&perlinx, TCOD_NOISE_SIMPLEX))*0.5f + indicatorDelta;
	indicator=CLAMP(0.0f,1.0f,indicator);
	float windspeed=1.0f-indicator;
	perlinx*=2.0f;
	float windDir = (2.0f*3.1415926f*0.5f)*(1.0f+noise1d.get(&perlinx, TCOD_NOISE_SIMPLEX));
	dx += MAX_WIND_SPEED * windspeed * cosf(windDir)*elapsed;
	dy += 0.5f * MAX_WIND_SPEED * windspeed * sinf(windDir) *elapsed;
	if ( indicator < LIGHTNING_LEVEL ) {
		float storm=(LIGHTNING_LEVEL-indicator)/LIGHTNING_LEVEL; // storm power 0-1
		float lp = LIGHTNING_MIN_PROB + (int)((LIGHTNING_MAX_PROB-LIGHTNING_MIN_PROB) *storm); // nb of lightning per second
		int fps=TCODSystem::getFps();
		if( fps > 0 ) {
			int ilp=(int)(lp * fps);
			if (TCODRandom::getInstance()->getInt(0,ilp)==0) {
				// new lightning
				lightning_t l;
				l.posx = TCODRandom::getInstance()->getInt(0,map->w);
				l.posy = TCODRandom::getInstance()->getInt(0,map->h);
				l.life = TCODRandom::getInstance()->getFloat(0.1f,LIGHTNING_LIFE);
				l.radius=TCODRandom::getInstance()->getInt(LIGHTNING_RADIUS,LIGHTNING_RADIUS*2);
				l.noisex=TCODRandom::getInstance()->getFloat(0.0f,1000.0f);
				l.intensity=0.0f;
				lightnings.push(l);
			}
		}
	} 

	int bx=0,by=0;
	while ( dx >= 1.0f ) {
		dx-= 1.0f;
		noisex+=1.0f;
		bx++;
	}
	while ( dx <= -1.0f ) {
		dx+= 1.0f;
		noisex-=1.0f;
		bx--;
	}
	while ( dy >= 1.0f ) {
		dy-= 1.0f;
		noisey+=1.0f;
		by++;
	} 
	while ( dy <= -1.0f ) {
		dy+= 1.0f;
		noisey-=1.0f;
		by--;
	}
	// update lightnings
	for (lightning_t *l=lightnings.begin(); l!= lightnings.end(); l++) {
		l->life-= elapsed;
		l->noisex+=elapsed*LIGHTNING_INTENSITY_SPEED;
		if (l->life<= 0) {
			l=lightnings.remove(l);
		} else {
			l->intensity=0.5f*noise1d.get(&l->noisex, TCOD_NOISE_SIMPLEX)+1.0f;
			l->posx-=bx;
			l->posy-=by;
		}
	}
		
	if ( bx || by ) {
		// recompute the whole map
		// TODO : should recompute only missing rows/columns
		// the world generator demo has that, but only for 
		// horizontal move. Here clouds move in any direction
		map->clear();
		map->addFbm(&noise2d,SCALE,SCALE,noisex,noisey,OCTAVES,0.5f,0.5f);
	}
}

float Weather::getCloud(int x, int y) {
	// cloud layer
	// 1.0 : no cloud
	// 0 : dark cloud. This way you can easily render ground with color * cloud coef
	float cdx=dx,cdy=dy;
	if ( dx >= 0 ) x++;
	else cdx=dx+1.0f;
	if ( dy >= 0 ) y++;
	else cdy=dy+1.0f;
	float val = map->getInterpolatedValue(x+cdx,y+cdy); // between 0 and 1
	val += 2*indicator-0.5f;
	val = CLAMP(0.2f,1.0f,val);
	return val;
}

float Weather::getLightning(int x, int y) {
	if (indicator >= 0.3f) return 0.0f;
	if ( dx >= 0 ) x++;
	if ( dy >= 0 ) y++;
	float res=0.0f;
	float cloud=map->getValue(x,y);
	cloud = 1.0f - cloud; // inverted cloud. 0 = sky, 1=dark cloud
	cloud -= 0.6f; // no lightning under 0.6f. cloud is now 0 - 0.4
	if ( cloud <= 0.0f ) return 0.0f;
	cloud = cloud / 0.4f; // now back to 0-1 range (but only for really cloudy zones) 
	for (lightning_t *l=lightnings.begin(); l!= lightnings.end(); l++) {
		int dx=l->posx-x;
		int dy=l->posy-y;
		int dist=dx*dx+dy*dy;
		if ( dist < l->radius) {
			res+= l->intensity * (float)(l->radius-dist)/l->radius;
		} 
	}
	float ret= cloud * res;
	return CLAMP(0.0f,1.0f,ret);
}

bool Weather::hasRainDrop() {
	if ( indicator >= 0.5f ) return false;
	int prob;
	if ( indicator >= 0.3f ) {
		prob = (int)(RAIN_MIN_PROB+(RAIN_MED_PROB-RAIN_MIN_PROB)*(0.5f-indicator)*5);
	} else {
		prob = (int)(RAIN_MED_PROB+(RAIN_MAX_PROB-RAIN_MED_PROB)*(0.3f-indicator)*3.33f);
	}
	int rp=TCODRandom::getInstance()->getInt(0,prob);
	return rp==0;
}

void Weather::calculateAmbient(float timeInSeconds) {
	// calculate ambient light
	static TCODColor night(0,0,128);
	static TCODColor dawn(196,0,0);
	static TCODColor dawn2(220,200,64);
	static TCODColor day(255,255,195);
	float coef=0.0f;
	float hour = timeInSeconds / 3600.0f;
	// TODO : should use a color gradient map for that..
	if ( hour > 21.0f || hour < 6.0f ) {
		ambientColor=night; // night
		coef=0.0;
	} else if ( hour < 7.0f ) {
		// between 6am and 7am
		coef = (hour - 6.0f); 
		ambientColor = TCODColor::lerp(night,dawn,coef);
		coef /= 3.0f;
	} else if ( hour < 8.0f ) {
		// between 7am and 8am
		coef = (hour - 7.0f); 
		ambientColor = TCODColor::lerp(dawn,dawn2,coef);
		coef = 0.33333f + coef/3.0f;
	} else if ( hour < 9.0f ) {
		// between 8am and 9am
		coef = (hour - 8.0f); 
		ambientColor = TCODColor::lerp(dawn2,day,coef);
		coef = 0.66666f + coef/3.0f;
	} else if ( hour < 18.0f ) {
		// between 9am and 6pm
		ambientColor = day;
		coef=1.0f;
	} else if ( hour < 19.0f ) {
		// between 6pm and 7pm
		coef = (hour - 18.0f); 
		ambientColor = TCODColor::lerp(day,dawn2,coef);
		coef = 0.66666f + (1.0f-coef)/3.0f;
	} else if ( hour < 20.0f ) {
		// between 7pm and 8pm
		coef = (hour - 19.0f); 
		ambientColor = TCODColor::lerp(dawn2,dawn,coef);
		coef = 0.33333f + (1.0f-coef)/3.0f;
	} else if ( hour < 21.0f ) {
		// between 8pm and 9pm
		coef = (hour - 20.0f); 
		ambientColor = TCODColor::lerp(dawn,night,coef);
		coef = (1.0f-coef)/3.0f;
	}
}