version 0.3

[zeRace] / car.c

diff --git a/car.c b/car.c
new file mode 100644 (file)
index 0000000..e769567
--- /dev/null
+++ b/car.c
@@ -0,0 +1,84 @@
+#include "car.h"
+
+#define COEFF 1
+
+void move_car(struct _car *car,int keys,SDL_Surface *fun)
+{
+  int c,r,g,b;
+  
+  /* reset flags */
+  car->lapflag=0;
+  car->crashflag=0;
+  
+  /* get the pixel color under the center of car in the function map */
+  c=getpixel(fun,car->x,car->y);
+  /* red layer (checkpoints) */
+  r=(c    )&0xff;
+  /* green layer (road quality) */
+  g=(c>>8 )&0xff;
+  /* blue layer (unused) */
+  b=(c>>16)&0xff;
+
+  if (keys & 8) /* up */
+    car->speed+=0.01*2*COEFF;
+  if (keys & 4) /* down */
+    car->speed-=0.01*COEFF;
+  if (keys & 2) /* left */
+  {
+    if (car->speed<0)
+      car->angle+=0.01*(255-b)/255*COEFF;
+    else
+      car->angle-=0.01*(255-b)/255*COEFF;
+  }
+  if (keys & 1) /* right */
+  {
+    if (car->speed<0)
+      car->angle-=0.01*(255-b)/255*COEFF;
+    else
+      car->angle+=0.01*(255-b)/255*COEFF;
+  }
+  
+  /* limit angle between 0 and 2*pi */
+  if (car->angle<0) car->angle+=2*M_PI;
+  if (car->angle>2*M_PI) car->angle-=2*M_PI;
+  
+  /* update the speed depending on the road quality */
+  car->speed-=car->speed*(255-g)/1000;
+ 
+  /* if it is a wall we move back to the last position */
+  if (g==0)
+  {
+    car->x=car->ox;
+    car->y=car->oy;
+    car->crashflag=1;
+  }
+  
+  /* save the old position and compute the new one */
+  car->ox=car->x;
+  car->oy=car->y;
+  car->speed*=0.995;
+  car->x-=cos(car->angle)*car->speed;
+  car->y-=sin(car->angle)*car->speed;
+  
+  /* collision with the border of the screen */
+  if (car->x<car->w/2 || car->x>fun->w-car->w/2 || car->y<car->h/2 || car->y>fun->h-car->h/2)
+  {
+    car->x=car->ox;
+    car->y=car->oy;
+    car->speed=0;
+    car->crashflag=1;
+  }
+  
+  /* if we are on the next checkpoint, validate it (no missing allowed) */
+  if (r/8==car->lastcheck+1) car->lastcheck++;
+  /* if we validate all and start over, we complete a turn */
+  if (r/8==0 && car->lastcheck==31)
+  {
+    /* reset turn variables */
+    car->lastcheck=0;
+    car->lap++;
+    car->lapflag=1;
+  }
+  
+  return;
+}