1 /*
2 * Copyright (c) 2006-2009 Erin Catto http://www.box2d.org
3 *
4 * This software is provided 'as-is', without any express or implied
5 * warranty.  In no event will the authors be held liable for any damages
6 * arising from the use of this software.
7 * Permission is granted to anyone to use this software for any purpose,
8 * including commercial applications, and to alter it and redistribute it
9 * freely, subject to the following restrictions:
10 * 1. The origin of this software must not be misrepresented; you must not
11 * claim that you wrote the original software. If you use this software
12 * in a product, an acknowledgment in the product documentation would be
13 * appreciated but is not required.
14 * 2. Altered source versions must be plainly marked as such, and must not be
15 * misrepresented as being the original software.
16 * 3. This notice may not be removed or altered from any source distribution.
17 */
18 
19 #ifndef TILES_H
20 #define TILES_H
21 
22 /// This stress tests the dynamic tree broad-phase. This also shows that tile
23 /// based collision is _not_ smooth due to Box2D not knowing about adjacency.
24 class Tiles : public Test
25 {
26 public:
27     enum
28     {
29         e_count = 20
30     };
31 
Tiles()32     Tiles()
33     {
34         m_fixtureCount = 0;
35         b2Timer timer;
36 
37         {
38             float32 a = 0.5f;
39             b2BodyDef bd;
40             bd.position.y = -a;
41             b2Body* ground = m_world->CreateBody(&bd);
42 
43 #if 1
44             int32 N = 200;
45             int32 M = 10;
46             b2Vec2 position;
47             position.y = 0.0f;
48             for (int32 j = 0; j < M; ++j)
49             {
50                 position.x = -N * a;
51                 for (int32 i = 0; i < N; ++i)
52                 {
53                     b2PolygonShape shape;
54                     shape.SetAsBox(a, a, position, 0.0f);
55                     ground->CreateFixture(&shape, 0.0f);
56                     ++m_fixtureCount;
57                     position.x += 2.0f * a;
58                 }
59                 position.y -= 2.0f * a;
60             }
61 #else
62             int32 N = 200;
63             int32 M = 10;
64             b2Vec2 position;
65             position.x = -N * a;
66             for (int32 i = 0; i < N; ++i)
67             {
68                 position.y = 0.0f;
69                 for (int32 j = 0; j < M; ++j)
70                 {
71                     b2PolygonShape shape;
72                     shape.SetAsBox(a, a, position, 0.0f);
73                     ground->CreateFixture(&shape, 0.0f);
74                     position.y -= 2.0f * a;
75                 }
76                 position.x += 2.0f * a;
77             }
78 #endif
79         }
80 
81         {
82             float32 a = 0.5f;
83             b2PolygonShape shape;
84             shape.SetAsBox(a, a);
85 
86             b2Vec2 x(-7.0f, 0.75f);
87             b2Vec2 y;
88             b2Vec2 deltaX(0.5625f, 1.25f);
89             b2Vec2 deltaY(1.125f, 0.0f);
90 
91             for (int32 i = 0; i < e_count; ++i)
92             {
93                 y = x;
94 
95                 for (int32 j = i; j < e_count; ++j)
96                 {
97                     b2BodyDef bd;
98                     bd.type = b2_dynamicBody;
99                     bd.position = y;
100 
101                     //if (i == 0 && j == 0)
102                     //{
103                     //  bd.allowSleep = false;
104                     //}
105                     //else
106                     //{
107                     //  bd.allowSleep = true;
108                     //}
109 
110                     b2Body* body = m_world->CreateBody(&bd);
111                     body->CreateFixture(&shape, 5.0f);
112                     ++m_fixtureCount;
113                     y += deltaY;
114                 }
115 
116                 x += deltaX;
117             }
118         }
119 
120         m_createTime = timer.GetMilliseconds();
121     }
122 
Step(Settings * settings)123     void Step(Settings* settings)
124     {
125         const b2ContactManager& cm = m_world->GetContactManager();
126         int32 height = cm.m_broadPhase.GetTreeHeight();
127         int32 leafCount = cm.m_broadPhase.GetProxyCount();
128         int32 minimumNodeCount = 2 * leafCount - 1;
129         float32 minimumHeight = ceilf(logf(float32(minimumNodeCount)) / logf(2.0f));
130         m_debugDraw.DrawString(5, m_textLine, "dynamic tree height = %d, min = %d", height, int32(minimumHeight));
131         m_textLine += 15;
132 
133         Test::Step(settings);
134 
135         m_debugDraw.DrawString(5, m_textLine, "create time = %6.2f ms, fixture count = %d",
136             m_createTime, m_fixtureCount);
137         m_textLine += 15;
138 
139         //b2DynamicTree* tree = &m_world->m_contactManager.m_broadPhase.m_tree;
140 
141         //if (m_stepCount == 400)
142         //{
143         //  tree->RebuildBottomUp();
144         //}
145     }
146 
Create()147     static Test* Create()
148     {
149         return new Tiles;
150     }
151 
152     int32 m_fixtureCount;
153     float32 m_createTime;
154 };
155 
156 #endif
157