Gravity modes and Newtonian gravity for fireworks

Resolves issue #59

includes/powder.h

@@ -804,6 +804,8 @@ void detach(int i);
 
 void part_change_type(int i, int x, int y, int t);
 
+void get_gravity_field(int x, int y, float particleGrav, float newtonGrav, float *pGravX, float *pGravY);
+
 int InCurrentBrush(int i, int j, int rx, int ry);
 
 int get_brush_flags();

src/elementdata.c

@@ -100,7 +100,7 @@ part_type ptypes[PT_NUM] =
 	{"GLOW",	PIXPACK(0x445464),	0.3f,	0.02f * CFDS,	0.98f,	0.80f,	0.0f,	0.15f,	0.00f,	0.000f	* CFDS,	2,	0,		0,	0,	2,	1,	1,	40,		SC_LIQUID,		R_TEMP+20.0f+273.15f,	44,		"Glow, Glows under pressure", ST_LIQUID, TYPE_LIQUID|PROP_LIFE_DEC, &update_GLOW, &graphics_GLOW},
 	{"BRCK",	PIXPACK(0x808080),	0.0f,	0.00f * CFDS,	0.90f,	0.00f,	0.0f,	0.0f,	0.00f,	0.000f	* CFDS,	0,	0,		0,	0,	1,	1,	1,	100,	SC_SOLIDS,		R_TEMP+0.0f	+273.15f,	251,	"Brick, breakable building material.", ST_SOLID, TYPE_SOLID|PROP_HOT_GLOW, NULL, NULL},
 	{"CFLM",	PIXPACK(0x8080FF),	0.9f,	0.04f * CFDS,	0.97f,	0.20f,	0.0f,	-0.1f,	0.00f,	0.0005f	* CFDS,	1,	0,		0,	0,	1,	1,	1,	2,		SC_EXPLOSIVE,	0.0f,					88,		"Sub-zero flame.", ST_LIQUID, TYPE_GAS|PROP_LIFE_DEC|PROP_LIFE_KILL, NULL, &graphics_HFLM},
-	{"FIRW",	PIXPACK(0xFFA040),	0.7f,	0.02f * CFDS,	0.96f,	0.80f,	-0.99f,	0.1f,	0.00f,	0.000f	* CFDS,	1,	0,		0,	0,	30,	1,	1,	55,		SC_EXPLOSIVE,	R_TEMP+0.0f	+273.15f,	70,		"Fireworks!", ST_SOLID, TYPE_PART|PROP_LIFE_DEC, &update_FIRW, &graphics_FIRW},
+	{"FIRW",	PIXPACK(0xFFA040),	0.4f,	0.02f * CFDS,	0.96f,	0.95f,	-0.5f,	0.1f,	0.00f,	0.000f	* CFDS,	1,	0,		0,	0,	30,	1,	1,	55,		SC_EXPLOSIVE,	R_TEMP+0.0f	+273.15f,	70,		"Fireworks!", ST_SOLID, TYPE_PART|PROP_LIFE_DEC, &update_FIRW, &graphics_FIRW},
 	{"FUSE",	PIXPACK(0x0A5706),	0.0f,   0.00f * CFDS,   0.90f,  0.00f,  0.0f,   0.0f,   0.0f,   0.0f	* CFDS, 0,	0,		0,	0,	20,	1,	1,	100,	SC_SOLIDS,		R_TEMP+0.0f	+273.15f,	200,	"Solid. Burns slowly. Ignites at somewhat high temperatures and electricity.", ST_SOLID, TYPE_SOLID, &update_FUSE, NULL},
 	{"FSEP",	PIXPACK(0x63AD5F),	0.7f,	0.02f * CFDS,	0.96f,	0.80f,	0.0f,	0.1f,	0.00f,	0.000f	* CFDS,	1,	0,		0,	0,	30,	1,	1,	70,		SC_POWDERS,		R_TEMP+0.0f	+273.15f,	70,		"Fuse Powder. See FUSE.", ST_SOLID, TYPE_PART, &update_FSEP, NULL},
 	{"AMTR",	PIXPACK(0x808080),	0.7f,   0.02f * CFDS,   0.96f,  0.80f,  0.00f,  0.10f,  1.00f,  0.0000f * CFDS, 0,	0,		0,	0,	0,	1,	1,	100,	SC_NUCLEAR,	 	R_TEMP+0.0f +273.15f,	70,		"Anti-Matter, Destroys a majority of particles", ST_NONE, TYPE_PART, &update_AMTR, NULL}, //Maybe TYPE_ENERGY?

src/elements/firw.c

@@ -29,8 +29,19 @@ int update_FIRW(UPDATE_FUNC_ARGS) {
 					rt = parts[r>>8].type;
 					if (rt==PT_FIRE||rt==PT_PLSM||rt==PT_THDR)
 					{
+						float gx, gy, multiplier;
+						get_gravity_field(x, y, ptypes[PT_FIRW].gravity, 1.0f, &gx, &gy);
+						if (gx*gx+gy*gy < 0.001f)
+						{
+							float angle = (rand()%6284)*0.001f;//(in radians, between 0 and 2*pi)
+							gx += sinf(angle)*ptypes[PT_FIRW].gravity*0.5f;
+							gy += cosf(angle)*ptypes[PT_FIRW].gravity*0.5f;
+						}
 						parts[i].tmp = 1;
-						parts[i].life = rand()%40+60;
+						parts[i].life = rand()%10+20;
+						multiplier = (parts[i].life+20)*0.2f/sqrtf(gx*gx+gy*gy);
+						parts[i].vx -= gx*multiplier;
+						parts[i].vy -= gy*multiplier;
 					}
 				}
 	}
@@ -38,8 +49,7 @@ int update_FIRW(UPDATE_FUNC_ARGS) {
 		if (parts[i].life<=0) {
 			parts[i].tmp=2;
 		} else {
-			// TODO: different gravity modes + Newtonian gravity
+			parts[i].flags &= ~FLAG_STAGNANT;
-			parts[i].vy = -parts[i].life*0.04f - 0.1f;
 		}
 	}
 	else if (parts[i].tmp>=2) {
@@ -54,8 +64,8 @@ int update_FIRW(UPDATE_FUNC_ARGS) {
 			{
 				magnitude = ((rand()%60)+40)*0.05f;
 				angle = (rand()%6284)*0.001f;//(in radians, between 0 and 2*pi)
-				parts[np].vx = parts[i].vx + cosf(angle)*magnitude;
+				parts[np].vx = parts[i].vx*0.5f + cosf(angle)*magnitude;
-				parts[np].vy = parts[i].vy + sinf(angle)*magnitude - 2.5f;
+				parts[np].vy = parts[i].vy*0.5f + sinf(angle)*magnitude;
 				parts[np].ctype = col;
 				parts[np].tmp = 1;
 				parts[np].life = rand()%40+70;

src/elements/fwrk.c

@@ -17,22 +17,42 @@
 
 int update_FWRK(UPDATE_FUNC_ARGS) {
 	int r, rx, ry, np;
-	if ((parts[i].temp>400&&(9+parts[i].temp/40)>rand()%100000&&parts[i].life==0&&!pmap[y-1][x])||parts[i].ctype==PT_DUST)
+	if (parts[i].life==0 && ((parts[i].temp>400&&(9+parts[i].temp/40)>rand()%100000&&surround_space)||parts[i].ctype==PT_DUST))
 	{
-		np = create_part(-1, x , y-1 , PT_FWRK);
+		float gx, gy, multiplier, gmax;
-		if (np!=-1)
+		int randTmp;
+		get_gravity_field(x, y, ptypes[PT_FWRK].gravity, 1.0f, &gx, &gy);
+		if (gx*gx+gy*gy < 0.001f)
 		{
-			parts[np].vy = rand()%8-22;
+			float angle = (rand()%6284)*0.001f;//(in radians, between 0 and 2*pi)
-			parts[np].vx = rand()%20-rand()%20;
+			gx += sinf(angle)*ptypes[PT_FWRK].gravity*0.5f;
-			parts[np].life=rand()%15+25;
+			gy += cosf(angle)*ptypes[PT_FWRK].gravity*0.5f;
-			parts[np].dcolour = parts[i].dcolour;
+		}
-			kill_part(i);
+		gmax = fmaxf(fabsf(gx), fabsf(gy));
-			return 1;
+		if (eval_move(PT_FWRK, (int)(x-(gx/gmax)+0.5f), (int)(y-(gy/gmax)+0.5f), NULL))
+		{
+			multiplier = 15.0f/sqrtf(gx*gx+gy*gy);
+
+			//Some variation in speed parallel to gravity direction
+			randTmp = (rand()%200)-100;
+			gx += gx*randTmp*0.002f;
+			gy += gy*randTmp*0.002f;
+			//and a bit more variation in speed perpendicular to gravity direction
+			randTmp = (rand()%200)-100;
+			gx += -gy*randTmp*0.005f;
+			gy += gx*randTmp*0.005f;
+
+			parts[i].life=rand()%10+18;
+			parts[i].ctype=0;
+			parts[i].vx -= gx*multiplier;
+			parts[i].vy -= gy*multiplier;
+			parts[i].dcolour = parts[i].dcolour;
+			return 0;
 		}
 	}
 	if (parts[i].life>=45)
 		parts[i].life=0;
-	if ((parts[i].life<3&&parts[i].life>0)||(parts[i].vy>6&&parts[i].life>0))
+	if (parts[i].life<3&&parts[i].life>0)
 	{
 		int r = (rand()%245+11);
 		int g = (rand()%245+11);
@@ -47,8 +67,8 @@ int update_FWRK(UPDATE_FUNC_ARGS) {
 			{
 				magnitude = ((rand()%60)+40)*0.05f;
 				angle = (rand()%6284)*0.001f;//(in radians, between 0 and 2*pi)
-				parts[np].vx = parts[i].vx + cosf(angle)*magnitude;
+				parts[np].vx = parts[i].vx*0.5f + cosf(angle)*magnitude;
-				parts[np].vy = parts[i].vy + sinf(angle)*magnitude - 2.5f;
+				parts[np].vy = parts[i].vy*0.5f + sinf(angle)*magnitude;
 				parts[np].ctype = col;
 				parts[np].tmp = 1;
 				parts[np].life = rand()%40+70;

src/powder.c

@@ -56,6 +56,28 @@ int pmap_count[YRES][XRES];
 unsigned cb_pmap[YRES][XRES];
 unsigned photons[YRES][XRES];
 
+void get_gravity_field(int x, int y, float particleGrav, float newtonGrav, float *pGravX, float *pGravY)
+{
+	*pGravX = newtonGrav*gravx[(y/CELL)*(XRES/CELL)+(x/CELL)];
+	*pGravY = newtonGrav*gravy[(y/CELL)*(XRES/CELL)+(x/CELL)];
+	switch (gravityMode)
+	{
+		default:
+		case 0: //normal, vertical gravity
+			*pGravY += particleGrav;
+			break;
+		case 1: //no gravity
+			break;
+		case 2: //radial gravity
+			if (x-XCNTR != 0 || y-YCNTR != 0)
+			{
+				float pGravMult = particleGrav/sqrtf((x-XCNTR)*(x-XCNTR) + (y-YCNTR)*(y-YCNTR));
+				*pGravX -= pGravMult * (float)(x - XCNTR);
+				*pGravY -= pGravMult * (float)(y - YCNTR);
+			}
+	}
+}
+
 static int pn_junction_sprk(int x, int y, int pt)
 {
 	unsigned r = pmap[y][x];