src/main.cpp

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3 #include <string.h>
   4 #include <unistd.h>
   5
   6 #include "jelly/JellyPhysics.h"
   7 #include "videolib/videolib.h"
   8
   9
  10 ////////////////////////////////////////////////////////////////////////////////
  11 static float scale_x = 30.0f;
  12 static float scale_y = 22.0f;
  13 static float center_x = -12.0f;
  14 static float center_y = -20.0f;
  15
  16
  17 static inline int x2s (float x) { return (x-center_x)*scale_x; }
  18 static inline int y2s (float y) { return SCR_WIDTH-(y-center_y)*scale_y; }
  19
  20 static inline float s2x (int x) { return ((float)x/scale_x)+center_x; }
  21 static inline float s2y (int y) { return ((float)(SCR_WIDTH-y)/scale_y)+center_y; }
  22
  23
  24 static void dll (float x0, float y0, float x1, float y1, Uint32 clr) {
  25   x0 = x2s(x0);
  26   y0 = y2s(y0);
  27   x1 = x2s(x1);
  28   y1 = y2s(y1);
  29   draw_line(x0, y0, x1, y1, clr);
  30 }
  31
  32
  33 ////////////////////////////////////////////////////////////////////////////////
  34 using namespace JellyPhysics;
  35
  36
  37 ////////////////////////////////////////////////////////////////////////////////
  38 // simple inherited classes, to add gravity force
  39 class FallingBody : public SpringBody {
  40 public:
  41   FallingBody (
  42     World *w, ClosedShape &s, float massPerPoint,
  43     float edgeSpringK, float edgeSpringDamp,
  44     const Vector2 &pos, float angle, const Vector2 &scale
  45   ) : SpringBody(w, s, massPerPoint, edgeSpringK, edgeSpringDamp, pos, angle, scale, false) {}
  46
  47   FallingBody (
  48     World *w, const ClosedShape &shape, float massPerPoint,
  49     float shapeSpringK, float shapeSpringDamp,
  50     float edgeSpringK, float edgeSpringDamp,
  51     const Vector2 &pos, float angleinRadians,
  52     const Vector2 &scale, bool kinematic=false
  53   ) : SpringBody(w, shape, massPerPoint, shapeSpringK, shapeSpringDamp, edgeSpringK, edgeSpringDamp, pos, angleinRadians, scale, kinematic) {}
  54
  55   virtual void accumulateExternalForces () {
  56     // gravity!
  57     for (unsigned int i = 0; i < mPointMasses.size(); ++i) mPointMasses[i].Force += Vector2(0.0f, -9.8f*mPointMasses[i].mass());
  58   }
  59 };
  60
  61
  62 class FallingPressureBody : public PressureBody {
  63 public:
  64   FallingPressureBody (
  65     World *w, const ClosedShape &s, float mpp,
  66     float gasPressure, float shapeK, float shapeD,
  67     float edgeK, float edgeD,
  68     const Vector2 &pos, float angleInRadians, const Vector2 &scale,
  69     bool kinematic) : PressureBody(w, s, mpp, gasPressure, shapeK, shapeD, edgeK, edgeD, pos, angleInRadians, scale, kinematic) {}
  70
  71   virtual void accumulateExternalForces () {
  72     // gravity!
  73     for (unsigned int i = 0; i < mPointMasses.size(); ++i) mPointMasses[i].Force += Vector2(0.0f, -9.8f*mPointMasses[i].mass());
  74   }
  75 };
  76
  77
  78 ////////////////////////////////////////////////////////////////////////////////
  79 static World *mWorld;
  80
  81
  82 static void createI (float x, float y) {
  83   // this is a complex body, in the shape of a capital "I", and connected with many internal springs.
  84   ClosedShape shape;
  85   shape.begin();
  86   shape.addVertex(Vector2(-1.5f,  2.0f));
  87   shape.addVertex(Vector2(-0.5f,  2.0f));
  88   shape.addVertex(Vector2( 0.5f,  2.0f));
  89   shape.addVertex(Vector2( 1.5f,  2.0f));
  90   shape.addVertex(Vector2( 1.5f,  1.0f));
  91   shape.addVertex(Vector2( 0.5f,  1.0f));
  92   shape.addVertex(Vector2( 0.5f, -1.0f));
  93   shape.addVertex(Vector2( 1.5f, -1.0f));
  94   shape.addVertex(Vector2( 1.5f, -2.0f));
  95   shape.addVertex(Vector2( 0.5f, -2.0f));
  96   shape.addVertex(Vector2(-0.5f, -2.0f));
  97   shape.addVertex(Vector2(-1.5f, -2.0f));
  98   shape.addVertex(Vector2(-1.5f, -1.0f));
  99   shape.addVertex(Vector2(-0.5f, -1.0f));
 100   shape.addVertex(Vector2(-0.5f,  1.0f));
 101   shape.addVertex(Vector2(-1.5f,  1.0f));
 102   shape.finish();
 103
 104   FallingBody *body = new FallingBody(mWorld, shape, 1.0f, 150.0f, 5.0f, 300.0f, 15.0f, Vector2(x, y), 0.0f, Vector2::One);
 105   body->addInternalSpring(0, 14, 300.0f, 10.0f);
 106   body->addInternalSpring(1, 14, 300.0f, 10.0f);
 107   body->addInternalSpring(1, 15, 300.0f, 10.0f);
 108   body->addInternalSpring(1, 5, 300.0f, 10.0f);
 109   body->addInternalSpring(2, 14, 300.0f, 10.0f);
 110   body->addInternalSpring(2, 5, 300.0f, 10.0f);
 111   body->addInternalSpring(1, 5, 300.0f, 10.0f);
 112   body->addInternalSpring(14, 5, 300.0f, 10.0f);
 113   body->addInternalSpring(2, 4, 300.0f, 10.0f);
 114   body->addInternalSpring(3, 5, 300.0f, 10.0f);
 115   body->addInternalSpring(14, 6, 300.0f, 10.0f);
 116   body->addInternalSpring(5, 13, 300.0f, 10.0f);
 117   body->addInternalSpring(13, 6, 300.0f, 10.0f);
 118   body->addInternalSpring(12, 10, 300.0f, 10.0f);
 119   body->addInternalSpring(13, 11, 300.0f, 10.0f);
 120   body->addInternalSpring(13, 10, 300.0f, 10.0f);
 121   body->addInternalSpring(13, 9, 300.0f, 10.0f);
 122   body->addInternalSpring(6, 10, 300.0f, 10.0f);
 123   body->addInternalSpring(6, 9, 300.0f, 10.0f);
 124   body->addInternalSpring(6, 8, 300.0f, 10.0f);
 125   body->addInternalSpring(7, 9, 300.0f, 10.0f);
 126 }
 127
 128
 129 static void createBall (float x, float y) {
 130   // pressure body: similar to a SpringBody, but with internal pressurized gas to help maintain shape
 131   ClosedShape ball;
 132   ball.begin();
 133   for (int i = 0; i < 360; i += 20) {
 134     ball.addVertex(Vector2(cosf(VectorTools::degToRad((float)-i)), sinf(VectorTools::degToRad((float)-i))));
 135   }
 136   ball.finish();
 137   new FallingPressureBody(mWorld, ball, 1.0f, 40.0f, 10.0f, 1.0f, 300.0f, 20.0f, Vector2(x, y), 0, Vector2::One, false);
 138 }
 139
 140
 141 static void initialize (void) {
 142   // create physics world
 143   mWorld = new World();
 144   // static ground object
 145   // all Closed Shape objects are assumed to be a list of lines going from point to point, with the last point
 146   // connecting back to the first point to close the shape. this is a simple rectangle to represent the ground for this demo.
 147   // ClosedShape objects are automatically "centered" when you call finish(), and that center becomes the center when
 148   // setting the position of the object.
 149   ClosedShape groundShape;
 150   groundShape.begin();
 151   groundShape.addVertex(Vector2(-10.0f, -2.0f));
 152   groundShape.addVertex(Vector2(-10.0f,  2.0f));
 153   groundShape.addVertex(Vector2( 10.0f,  2.0f));
 154   groundShape.addVertex(Vector2( 10.0f, -2.0f));
 155   groundShape.finish();
 156   // make the body
 157   // creating the body. since this is a static body, we can use the base class Body.
 158   // setting the mass per point to 0.0f or INFINITY makes it immobile / static.
 159   new Body(mWorld, groundShape, INFINITY, Vector2(0.0f, -5.0f), 0.0f, Vector2::One, false);
 160 }
 161
 162
 163 ////////////////////////////////////////////////////////////////////////////////
 164 static void update (int elapsed_ms) {
 165   sdl_frame_changed = 1;
 166   // UPDATE the physics!
 167   for (int i = 0; i < 3; ++i) mWorld->update(1/200.0f);
 168 }
 169
 170
 171 ////////////////////////////////////////////////////////////////////////////////
 172 static void process_mousedown (SDL_MouseButtonEvent *ev) {
 173   if (ev->button == SDL_BUTTON_LEFT) {
 174     float x = s2x(ev->x);
 175     float y = s2y(ev->y);
 176     //fprintf(stderr, "x=%.15g; y=%.15g\n", x, y);
 177     ClosedShape shape;
 178     shape.begin();
 179     shape.addVertex(Vector2(-1.0f,  0.0f));
 180     shape.addVertex(Vector2( 0.0f,  1.0f));
 181     shape.addVertex(Vector2( 1.0f,  0.0f));
 182     shape.addVertex(Vector2( 0.0f, -1.0f));
 183     shape.finish();
 184
 185     FallingBody *body = new FallingBody(mWorld, shape, 1.0f, 300.0f, 10.0f, Vector2(x, y), VectorTools::degToRad((float)rand()/RAND_MAX*360.0f), Vector2::One);
 186     body->addInternalSpring(0, 2, 400.0f, 12.0f);
 187     body->addInternalSpring(1, 3, 400.0f, 12.0f);
 188     return;
 189   }
 190
 191   if (ev->button == SDL_BUTTON_RIGHT) {
 192     float x = s2x(ev->x);
 193     float y = s2y(ev->y);
 194     createI(x, y);
 195     return;
 196   }
 197
 198   if (ev->button == SDL_BUTTON_MIDDLE) {
 199     float x = s2x(ev->x);
 200     float y = s2y(ev->y);
 201     createBall(x, y);
 202     return;
 203   }
 204 }
 205
 206
 207 static void rebuild (void) {
 208   memset(sdl_vscr, 0, SCR_WIDTH*SCR_HEIGHT*sizeof(sdl_vscr[0]));
 209   for (int f = 0; f < mWorld->bodyCount(); ++f) {
 210     Body *b = mWorld->getBody(f);
 211     const ClosedShape &shp = b->getBaseShape();
 212     Vector2List vrt = shp.transformVertices(b->getDerivedPosition(), b->getDerivedAngle(), b->getScale());
 213     unsigned int pn = vrt.size()-1;
 214     for (unsigned int vn = 0; vn < vrt.size(); pn = vn++) {
 215       //fprintf(stderr, "vn=%u; x=%d; y=%d\n", vn, x2s(vrt[vn].X), y2s(vrt[vn].Y));
 216       dll(vrt[pn].X, vrt[pn].Y, vrt[vn].X, vrt[vn].Y, rgb2col(255, 255, 255));
 217     }
 218   }
 219   //
 220   {
 221     static char buf[128];
 222     snprintf(buf, sizeof(buf), "body count: %d", mWorld->bodyCount());
 223     //draw_str_pr(1, 1, "Meow!WO-OIl!", rgb2col(255, 255, 0), rgba2col(0, 0, 200, 200));
 224     draw_str(1, 1, buf, rgb2col(255, 255, 0), mWorld->bodyCount());
 225   }
 226 }
 227
 228
 229
 230 ////////////////////////////////////////////////////////////////////////////////
 231 static void process_keydown (SDL_KeyboardEvent *ev) {
 232   if (ev->keysym.sym == SDLK_RETURN && (ev->keysym.mod&KMOD_ALT)) { switch_fullscreen(); return; }
 233   if (ev->keysym.sym == SDLK_ESCAPE) { post_quit_message(); return; }
 234   if (ev->keysym.sym == SDLK_SPACE) {
 235     /* clear world */
 236     while (mWorld->bodyCount() > 1) delete mWorld->getBody(mWorld->bodyCount()-1);
 237   }
 238 }
 239
 240
 241 ////////////////////////////////////////////////////////////////////////////////
 242 int main (int argc, char *argv[]) {
 243   sdl_mag2x = 0;
 244   videolib_args(&argc, argv);
 245   if (videolib_init("JellyPhysics Demo 00") < 0) {
 246     fprintf(stderr, "FATAL: can't initialize SDL!\n");
 247     exit(1);
 248   }
 249   vl_fps = 60;
 250   vl_rebuild = rebuild;
 251   vl_update = update;
 252   vl_process_keydown = process_keydown;
 253   vl_process_mousedown = process_mousedown;
 254   initialize();
 255   vl_main_loop();
 256   return 0;
 257 }