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1
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2 // written in the D programming language
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3
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4 module samples.Simple;
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5
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6 import chipmunkd.chipmunk;
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7
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8 import samples.ChipmunkDemo;
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9
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10 static cpSpace *space;
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11
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12 // Init is called by the demo code to set up the demo.
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13 static cpSpace *
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14 init()
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15 {
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16 // Create a space, a space is a simulation world. It simulates the motions of rigid bodies,
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17 // handles collisions between them, and simulates the joints between them.
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18 space = cpSpaceNew();
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19
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20 // Lets set some parameters of the space:
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21 // More iterations make the simulation more accurate but slower
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22 space.iterations = 10;
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23 // These parameters tune the efficiency of the collision detection.
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24 // For more info: http://code.google.com/p/chipmunk-physics/wiki/cpSpace
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25 cpSpaceResizeStaticHash(space, 30.0f, 1000);
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26 cpSpaceResizeActiveHash(space, 30.0f, 1000);
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27 // Give it some gravity
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28 space.gravity = cpv(0, -100);
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29
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30 // Create A ground segment along the bottom of the screen
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31 // By attaching it to &space.staticBody instead of a body, we make it a static shape.
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32 cpShape *ground = cpSegmentShapeNew(&space.staticBody, cpv(-320,-240), cpv(320,-240), 0.0f);
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33 // Set some parameters of the shape.
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34 // For more info: http://code.google.com/p/chipmunk-physics/wiki/cpShape
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35 ground.e = 1.0f; ground.u = 1.0f;
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36 ground.layers = NOT_GRABABLE_MASK; // Used by the Demo mouse grabbing code
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37 // Add the shape to the space as a static shape
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38 // If a shape never changes position, add it as static so Chipmunk knows it only needs to
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39 // calculate collision information for it once when it is added.
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40 // Do not change the postion of a static shape after adding it.
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41 cpSpaceAddShape(space, ground);
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42
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43 // Add a moving circle object.
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44 cpFloat radius = 15.0f;
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45 cpFloat mass = 10.0f;
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46 // This time we need to give a mass and moment of inertia when creating the circle.
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47 cpBody *ballBody = cpBodyNew(mass, cpMomentForCircle(mass, 0.0f, radius, cpvzero));
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48 // Set some parameters of the body:
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49 // For more info: http://code.google.com/p/chipmunk-physics/wiki/cpBody
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50 ballBody.p = cpv(0, -100 + radius+50);
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51 ballBody.v = cpv(0, -20);
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52 // Add the body to the space so it will be simulated and move around.
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53 cpSpaceAddBody(space, ballBody);
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54
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55
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56 // Add a circle shape for the ball.
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57 // Shapes are always defined relative to the center of gravity of the body they are attached to.
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58 // When the body moves or rotates, the shape will move with it.
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59 // Additionally, all of the cpSpaceAdd*() functions return the thing they added so you can create and add in one go.
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60 cpShape *ballShape = cpSpaceAddShape(space, cpCircleShapeNew(ballBody, radius, cpvzero));
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61 ballShape.e = 0.0f; ballShape.u = 0.9f;
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62
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63 return space;
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64 }
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65
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66 // Update is called by the demo code each frame.
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67 static void
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68 update(int ticks)
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69 {
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70 // Chipmunk allows you to use a different timestep each frame, but it works much better when you use a fixed timestep.
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71 // An excellent article on why fixed timesteps for game logic can be found here: http://gafferongames.com/game-physics/fix-your-timestep/
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72 cpSpaceStep(space, 1.0f/60.0f);
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73 }
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74
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75 // destroy is called by the demo code to free all the memory we've allocated
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76 static void
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77 destroy()
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78 {
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79 cpSpaceFreeChildren(space);
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80 cpSpaceFree(space);
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81 }
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82
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83 chipmunkDemo Simple = {
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84 "Simple",
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85 null,
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86 &init,
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87 &update,
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88 &destroy,
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89 };
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