samples.TheoJansen source code

1 
2 // written in the D programming language
3 
4 module samples.TheoJansen;
5 
6 import dchip.all;
7 
8 import samples.ChipmunkDemo;
9 
10 import gameApp;
11 
12 import std.math;
13 
14 enum M_PI = PI;
15 enum M_PI_2 = PI*0.5f;
16 
17 static cpSpace *space;
18 
19 static cpConstraint *motor;
20 
21 static void
22 update(int ticks)
23 {
24     cpFloat coef = (2.0f + arrowDirection.y)/3.0f;
25     cpFloat rate = arrowDirection.x*10.0f*coef;
26     cpSimpleMotorSetRate(motor, rate);
27     motor.maxForce = (rate) ? 100000.0f : 0.0f;
28 
29     enum int steps = 3;
30     enum cpFloat dt = 1.0f/60.0f/cast(cpFloat)steps;
31 
32     for(int i=0; i<steps; i++){
33         cpSpaceStep(space, dt);
34     }
35 }
36 
37 static cpFloat seg_radius = 3.0f;
38 
39 static void
40 make_leg(cpFloat side, cpFloat offset, cpBody *chassis, cpBody *crank, cpVect anchor)
41 {
42     cpVect a, b;
43     cpShape *shape;
44 
45     cpFloat leg_mass = 1.0f;
46 
47     // make leg
48     a = cpvzero, b = cpv(0.0f, side);
49     cpBody *upper_leg = cpBodyNew(leg_mass, cpMomentForSegment(leg_mass, a, b));
50     upper_leg.p = cpv(offset, 0.0f);
51     cpSpaceAddBody(space, upper_leg);
52     cpSpaceAddShape(space, cpSegmentShapeNew(upper_leg, a, b, seg_radius));
53     cpSpaceAddConstraint(space, cpPivotJointNew2(chassis, upper_leg, cpv(offset, 0.0f), cpvzero));
54 
55     // lower leg
56     a = cpvzero, b = cpv(0.0f, -1.0f*side);
57     cpBody *lower_leg = cpBodyNew(leg_mass, cpMomentForSegment(leg_mass, a, b));
58     lower_leg.p = cpv(offset, -side);
59     cpSpaceAddBody(space, lower_leg);
60     shape = cpSegmentShapeNew(lower_leg, a, b, seg_radius);
61     shape.group = 1;
62     cpSpaceAddShape(space, shape);
63     shape = cpCircleShapeNew(lower_leg, seg_radius*2.0f, b);
64     shape.group = 1;
65     shape.e = 0.0f; shape.u = 1.0f;
66     cpSpaceAddShape(space, shape);
67     cpSpaceAddConstraint(space, cpPinJointNew(chassis, lower_leg, cpv(offset, 0.0f), cpvzero));
68 
69     cpSpaceAddConstraint(space, cpGearJointNew(upper_leg, lower_leg, 0.0f, 1.0f));
70 
71     cpConstraint *constraint;
72     cpFloat diag = cpfsqrt(side*side + offset*offset);
73 
74     constraint = cpPinJointNew(crank, upper_leg, anchor, cpv(0.0f, side));
75     cpPinJointSetDist(constraint, diag);
76     cpSpaceAddConstraint(space, constraint);
77     constraint = cpPinJointNew(crank, lower_leg, anchor, cpvzero);
78     cpPinJointSetDist(constraint, diag);
79     cpSpaceAddConstraint(space, constraint);
80 }
81 
82 static cpSpace *
83 init()
84 {
85     space = cpSpaceNew();
86 
87     cpResetShapeIdCounter();
88 
89     space = cpSpaceNew();
90     space.iterations = 20;
91     space.gravity = cpv(0,-500);
92 
93     cpBody *staticBody = space.staticBody;
94     cpShape *shape;
95     cpVect a, b;
96 
97     // Create segments around the edge of the screen.
98     shape = cpSegmentShapeNew(staticBody, cpv(-320,-240), cpv(-320,240), 0.0f);
99     shape.e = 1.0f; shape.u = 1.0f;
100     shape.layers = NOT_GRABABLE_MASK;
101     cpSpaceAddShape(space, shape);
102 
103     shape = cpSegmentShapeNew(staticBody, cpv(320,-240), cpv(320,240), 0.0f);
104     shape.e = 1.0f; shape.u = 1.0f;
105     shape.layers = NOT_GRABABLE_MASK;
106     cpSpaceAddShape(space, shape);
107 
108     shape = cpSegmentShapeNew(staticBody, cpv(-320,-240), cpv(320,-240), 0.0f);
109     shape.e = 1.0f; shape.u = 1.0f;
110     shape.layers = NOT_GRABABLE_MASK;
111     cpSpaceAddShape(space, shape);
112 
113     cpFloat offset = 30.0f;
114 
115     // make chassis
116     cpFloat chassis_mass = 2.0f;
117     a = cpv(-offset, 0.0f), b = cpv(offset, 0.0f);
118     cpBody *chassis = cpBodyNew(chassis_mass, cpMomentForSegment(chassis_mass, a, b));
119     cpSpaceAddBody(space, chassis);
120     shape = cpSegmentShapeNew(chassis, a, b, seg_radius);
121     shape.group = 1;
122     cpSpaceAddShape(space, shape);
123 
124     // make crank
125     cpFloat crank_mass = 1.0f;
126     cpFloat crank_radius = 13.0f;
127     cpBody *crank = cpBodyNew(crank_mass, cpMomentForCircle(crank_mass, crank_radius, 0.0f, cpvzero));
128     cpSpaceAddBody(space, crank);
129     shape = cpCircleShapeNew(crank, crank_radius, cpvzero);
130     shape.group = 1;
131     cpSpaceAddShape(space, shape);
132     cpSpaceAddConstraint(space, cpPivotJointNew2(chassis, crank, cpvzero, cpvzero));
133 
134     cpFloat side = 30.0f;
135 
136     int num_legs = 2;
137     for(int i=0; i<num_legs; i++){
138         make_leg(side,  offset, chassis, crank, cpvmult(cpvforangle(cast(cpFloat)(2*i+0)/cast(cpFloat)num_legs*M_PI), crank_radius));
139         make_leg(side, -offset, chassis, crank, cpvmult(cpvforangle(cast(cpFloat)(2*i+1)/cast(cpFloat)num_legs*M_PI), crank_radius));
140     }
141 
142     motor = cpSimpleMotorNew(chassis, crank, 6.0f);
143     cpSpaceAddConstraint(space, motor);
144 
145     return space;
146 }
147 
148 static void
149 destroy()
150 {
151     ChipmunkDemoFreeSpaceChildren(space);
152     cpSpaceFree(space);
153 }
154 
155 chipmunkDemo TheoJansen = {
156     "Theo Jansen Machine",
157     null,
158     &init,
159     &update,
160     &destroy,
161 };