fixed motor timeout

draw.c

@@ -126,7 +126,7 @@ void draw_forces(SDL_Renderer *ren, Body *body) {
 
     Vect F;
     for (int i = 0; i < body->num_motors; i++) {
-        if (body->motors[i].TTL <= 0) {
+        if (body->motors[i].timeout < SDL_GetTicks()) {
             continue;
         }
         F.x += body->motors[i].x;

game.c

@@ -364,8 +364,8 @@ void set_motor_max_velocity(Body *thing, int motorID, double max) {
     thing->motors[motorID].max_velocity = max;
 }
 
-void set_motor_ttl(Body *thing, int motorID, double ttl) {
-    thing->motors[motorID].TTL = ttl;
+void set_motor_timeout(Body *thing, int motorID, uint32_t timeout) {
+    thing->motors[motorID].timeout = timeout;
 }
 
 void set_motor_newtons(Body *thing, int motorID, double x, double y) {
@@ -386,7 +386,7 @@ void add_motor(Body *thing, double x, double y) {
     motor.x = x;
     motor.y = y;
 
-    motor.TTL = INFINITY;
+    motor.timeout = -1;
     motor.max_velocity = 999899;
 
     motor.update_motor = default_motor_curve;
@@ -448,13 +448,15 @@ void advance_thing(Body * thing) {
         return;
     }
 
-    uint32_t time_delta = SDL_GetTicks() - thing->last_advance_time ;
+    uint32_t now = SDL_GetTicks();
+
+    uint32_t time_delta = now - thing->last_advance_time ;
     thing->last_advance_time = SDL_GetTicks(); // in milliseconds
     //time_delta = 17;
     
     // motors
     for (int i = 0; i < thing->num_motors; i++) {
-        if (thing->motors[i].TTL <= 0) {
+        if (thing->motors[i].timeout < now) {
             continue;
         }
 
@@ -469,10 +471,6 @@ void advance_thing(Body * thing) {
         double dirF = atan2(F.y, F.x);
         double dirV = atan2(V.y, V.x);
 
-        if (thing->motors[i].TTL != INFINITY) {
-            thing->motors[i].TTL--;
-        }
-
         double diff = dirV > dirF ? dirV - dirF: dirF - dirV;
 
         if (thing->motors[i].max_velocity > vect_mag(vel_in_dir)
@@ -625,8 +623,6 @@ void step(int interval) {
     const uint8_t * keyboard;
     keyboard = SDL_GetKeyboardState(NULL);
 
-    //set_motor_ms(&player.physics, 0 ,0);
-    //
     set_motor_newtons(player.physics, M_PLAYER_WALK, 0, 0);
 
     if (keyboard[SDL_SCANCODE_W]) {
@@ -643,9 +639,9 @@ void step(int interval) {
             && !keyboard[SDL_SCANCODE_A]
             && !keyboard[SDL_SCANCODE_S]
             && !keyboard[SDL_SCANCODE_D]) {
-        set_motor_ttl(player.physics, M_PLAYER_WALK, 90); 
+        set_motor_timeout(player.physics, M_PLAYER_WALK, SDL_GetTicks()+1000*2); 
     }
 
     advance_things();
-    logwrite(DEBUG, "Update Physics \n");
+    logwrite(DEBUG, "Updated Physics \n");
 }

game.h

@@ -28,8 +28,9 @@ typedef struct motorstruct {
                         // does not apply force if the velocity in the 
                         // direction of the motor vector is greater than
                         // max_velocity
-    int TTL; // motor dies after this expires.
-            // units are simulation tick
+    uint32_t timeout;// absolute time (in ms, from when the program starts) 
+                     // for when the motor stops. 
+                     // set to -1 for infinity
     void (*update_motor)(struct motorstruct *motor); // function pointer for generating 
                                         // the motor's output curve
 } Motor;