Added ability to attach tow rope to disabled craft.

makefile

@@ -30,7 +30,7 @@ OBJS += load.o lookup.o
 OBJS += main.o mission.o missionInfo.o
 OBJS += objectives.o options.o
 OBJS += player.o
-OBJS += radar.o
+OBJS += radar.o rope.o
 OBJS += save.o sound.o starfield.o starSystems.o stats.o
 OBJS += testMission.o textures.o text.o title.o transition.o triggers.o
 OBJS += util.o

src/battle/entities.c

@@ -92,6 +92,8 @@ void doEntities(void)
 					break;
 			}
 			
+			doRope(e);
+			
 			restrictToGrid(e);
 			
 			e->x += e->dx;
@@ -228,6 +230,8 @@ void drawEntities(void)
 		}
 		
 		drawTargetRects(e);
+		
+		drawRope(e);
 	}
 }
 

src/battle/entities.h

@@ -29,6 +29,8 @@ extern void doFighter(void);
 extern void addToGrid(Entity *e);
 extern void removeFromGrid(Entity *e);
 extern Entity **getAllEntsWithin(int x, int y, int w, int h, Entity *ignore);
+extern void doRope(Entity *e);
+extern void drawRope(Entity *e);
 
 extern App app;
 extern Battle battle;

src/battle/extractionPoint.c

@@ -22,6 +22,7 @@ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 
 static void think(void);
 static void handleFleeingEntities(void);
+static void cutTowRope(Entity *e);
 
 Entity *spawnExtractionPoint(void)
 {
@@ -63,6 +64,21 @@ static void handleFleeingEntities(void)
 		if (e->health > 0 && e->flags & EF_FLEEING && getDistance(e->x, e->y, self->x, self->y) <= 64)
 		{
 			e->alive = ALIVE_ESCAPED;
+			
+			cutTowRope(e);
+		}
+	}
+}
+
+static void cutTowRope(Entity *attachment)
+{
+	Entity *e;
+	
+	for (e = battle.entityHead.next ; e != NULL ; e = e->next)
+	{
+		if (e->towing == attachment)
+		{
+			e->towing = NULL;
 		}
 	}
 }

src/battle/extractionPoint.h

@@ -27,6 +27,7 @@ extern SDL_Texture *getTexture(char *filename);
 extern Entity *spawnEntity(void);
 extern Entity **getAllEntsWithin(int x, int y, int w, int h, Entity *ignore);
 extern int getDistance(int x1, int y1, int x2, int y2);
+extern void destroyRope(Entity *owner);
 
 extern Battle battle;
 extern Entity *self;

src/battle/fighters.c

@@ -27,6 +27,7 @@ static void spinDie(void);
 static void straightDie(void);
 static void randomizeDart(Entity *dart);
 static void randomizeDartGuns(Entity *dart);
+static void attachRope(void);
 
 Entity *spawnFighter(char *name, int x, int y, int side)
 {
@@ -174,6 +175,8 @@ void doFighter(void)
 			separate();
 		}
 		
+		attachRope();
+		
 		self->reload = MAX(self->reload - 1, 0);
 		self->shieldRecharge = MAX(self->shieldRecharge - 1, 0);
 		self->armourHit = MAX(self->armourHit - 25, 0);
@@ -207,7 +210,7 @@ void doFighter(void)
 				battle.missionTarget = NULL;
 			}
 		}
-		else if (self->systemPower <= 0)
+		else if (self->systemPower <= 0 || (self->flags & EF_DISABLED))
 		{
 			self->dx *= 0.99;
 			self->dy *= 0.99;
@@ -332,6 +335,30 @@ static void separate(void)
 	}
 }
 
+static void attachRope(void)
+{
+	int i, distance;
+	Entity *e, **candidates;
+	
+	if ((self->flags & EF_HAS_ROPE) && self->towing == NULL)
+	{
+		candidates = getAllEntsWithin(self->x, self->y, self->w, self->h, self);
+	
+		for (i = 0, e = candidates[i] ; e != NULL ; e = candidates[++i])
+		{
+			if ((e->flags & EF_DISABLED) && e->alive == ALIVE_ALIVE)
+			{
+				distance = getDistance(e->x, e->y, self->x, self->y);
+				
+				if (distance > 0 && distance <= 32)
+				{
+					self->towing = e;
+				}
+			}
+		}
+	}
+}
+
 void drawFighter(Entity *e)
 {
 	SDL_Texture *shieldHitTexture = getTexture("gfx/battle/shieldHit.png");

src/battle/fighters.h

@@ -42,6 +42,7 @@ extern void checkTrigger(char *name, int type);
 extern Entity **getAllEntsWithin(int x, int y, int w, int h, Entity *ignore);
 extern Entity *spawnEntity(void);
 extern void adjustObjectiveTargetValue(char *name, int type, int amount);
+extern void addRope(Entity *src, Entity *dest);
 
 extern App app;
 extern Battle battle;

src/battle/rope.c

@@ -0,0 +1,57 @@
+/*
+Copyright (C) 2015 Parallel Realities
+
+This program is free software; you can redistribute it and/or
+modify it under the terms of the GNU General Public License
+as published by the Free Software Foundation; either version 2
+of the License, or (at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+
+See the GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program; if not, write to the Free Software
+Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+
+*/
+
+#include "rope.h"
+
+void doRope(Entity *owner)
+{
+	float dx, dy, angle, force;
+	int distance;
+	
+	if (owner->towing)
+	{
+		distance = getDistance(owner->towing->x, owner->towing->y, owner->x, owner->y);
+		
+		if (distance > ROPE_DISTANCE)
+		{
+			angle = getAngle(owner->x, owner->y, owner->towing->x, owner->towing->y);
+				
+			dx = sin(TO_RAIDANS(angle));
+			dy = -cos(TO_RAIDANS(angle));
+			force = (distance - ROPE_DISTANCE) * 0.02;
+			
+			owner->towing->dx -= (dx * force);
+			owner->towing->dy -= (dy * force);
+		}
+		
+		owner->towing->dx *= 0.985;
+		owner->towing->dy *= 0.985;
+	}
+}
+
+void drawRope(Entity *owner)
+{
+	if (owner->towing)
+	{
+		SDL_SetRenderDrawColor(app.renderer, 200, 200, 200, SDL_ALPHA_OPAQUE);
+	
+		SDL_RenderDrawLine(app.renderer, owner->x - battle.camera.x, owner->y - battle.camera.y, owner->towing->x - battle.camera.x, owner->towing->y - battle.camera.y);
+	}
+}

src/battle/rope.h

@@ -0,0 +1,32 @@
+/*
+Copyright (C) 2015 Parallel Realities
+
+This program is free software; you can redistribute it and/or
+modify it under the terms of the GNU General Public License
+as published by the Free Software Foundation; either version 2
+of the License, or (at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+
+See the GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program; if not, write to the Free Software
+Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+
+*/
+
+#include "SDL2/SDL.h"
+
+#include "../defs.h"
+#include "../structs.h"
+
+#define ROPE_DISTANCE	128
+
+extern float getAngle(int x1, int y1, int x2, int y2);
+extern int getDistance(int x1, int y1, int x2, int y2);
+
+extern App app;
+extern Battle battle;

src/structs.h

@@ -109,6 +109,7 @@ struct Entity {
 	Weapon missiles;
 	long flags;
 	SDL_Point targetLocation;
+	Entity *towing;
 	Entity *target;
 	void (*action)(void);
 	void (*defaultAction)(void);