Bullet(Cocos2dx)之优化PhysicsDraw3D

分类： cocos2d-x 物理引擎 2015-01-06 20:01 168人阅读 评论(0) 收藏 举报

cocos2dx bullet 物理引擎

为了测试bullet物体的大小，匆匆写完的PhysicsDraw3D的效率低的要命，这也是为什么cocos2dx弃用了DrawPrimitives,而去使用DrawNode

DrawPrimitives每次绘制都去调用glDrawElements,假如每帧绘制10000条线段，那么就要调用10000次glDrawElements，可见效率之低。

而DrawNode采取的是批处理的方式，当drawLine的时候不是立即绘制，而是将线段的信息添加到数组里，当draw时统一调用gl的绘制函数

10000/1可不是一个小数目啊。

下图使用DrawPrimitives方法

加入40个Sphere帧率就掉到40，70的帧率更是惨不忍睹

下图使用DrawNode方法

为了解决这个问题就要参照DrawNode实现一个简单的DrawNode3D

不管三七二十一，将DrawNode的头文件代码copy，删去一些不需要的，

1.修改V2F_C4B_T2F为V3F_C4B_T2F

2.修改Vec2为Vec3，要绘制3D

3.保留drawPoint,drawPoints,drawLine，其他的绘制函数不要

[cpp] view plain copy

1. #ifndef__DRAW_NODE_3D_H__
2. #define__DRAW_NODE_3D_H__
4. #include"cocos2d.h"
5. USING_NS_CC;
7. classDrawNode3D:publicNode
8. {
9. public:
10. staticDrawNode3D*create();
12. voiddrawPoint(constVec3&point,constfloatpointSize,constColor4F&color);
14. voiddrawPoints(constVec3*position,unsignedintnumberOfPoints,constColor4F&color);
16. voiddrawLine(constVec3&origin,constVec3&destination,constColor4F&color);
17. //Overrides
18. virtualvoiddraw(Renderer*renderer,constMat4&transform,uint32_tflags)override;
20. voidclear();
22. constBlendFunc&getBlendFunc()const;
24. voidsetBlendFunc(constBlendFunc&blendFunc);
26. voidonDraw(constMat4&transform,uint32_tflags);
27. voidonDrawGLLine(constMat4&transform,uint32_tflags);
28. voidonDrawGLPoint(constMat4&transform,uint32_tflags);
30. CC_CONSTRUCTOR_ACCESS:
31. DrawNode3D();
32. virtual~DrawNode3D();
33. virtualboolinit();
35. protected:
36. voidensureCapacity(intcount);
37. voidensureCapacityGLPoint(intcount);
38. voidensureCapacityGLLine(intcount);
40. GLuint_vao;
41. GLuint_vbo;
42. GLuint_vaoGLPoint;
43. GLuint_vboGLPoint;
44. GLuint_vaoGLLine;
45. GLuint_vboGLLine;
47. int_bufferCapacity;
48. GLsizei_bufferCount;
49. V3F_C4B_T2F*_buffer;
51. int_bufferCapacityGLPoint;
52. GLsizei_bufferCountGLPoint;
53. V3F_C4B_T2F*_bufferGLPoint;
54. Color4F_pointColor;
55. int_pointSize;
57. int_bufferCapacityGLLine;
58. GLsizei_bufferCountGLLine;
59. V3F_C4B_T2F*_bufferGLLine;
61. BlendFunc_blendFunc;
62. CustomCommand_customCommand;
63. CustomCommand_customCommandGLPoint;
64. CustomCommand_customCommandGLLine;
66. bool_dirty;
67. bool_dirtyGLPoint;
68. bool_dirtyGLLine;
70. private:
71. CC_DISALLOW_COPY_AND_ASSIGN(DrawNode3D);
72. };
74. #endif

对于DrawNode.cpp按照上面所说同样修改

要记住

[cpp] view plain copy

1. glVertexAttribPointer(GLProgram::VERTEX_ATTRIB_POSITION,3,GL_FLOAT,GL_FALSE,sizeof(V3F_C4B_T2F),(GLvoid*)offsetof(V3F_C4B_T2F,vertices));
2. 要将GLProgram::VERTEX_ATTRIB_POSITION,2改为GLProgram::VERTEX_ATTRIB_POSITION,3

因为顶点有三个元素，.cpp代码过多，请在文章最后下载源码，要注意的是绘制时开启深度测试

修改PhysicsDraw3D

删除成员变量,添加DrawNode3D*_drawNode,由于DrawNode3D继承自Node所以创建时要将其添加到父节点上，

修改create，init为如下

staticPhysicsDraw3D*createWithLayer(Node*layer);

boolinitWithLayer(Node*layer);

同时添加

voidclearDraw();

我们知道DrawNode如果不执行clear，那么就不会清空上一帧的绘制数据

具体修改如下：

[cpp] view plain copy

1. PhysicsDraw3D*PhysicsDraw3D::createWithLayer(Node*layer)
2. {
3. autodraw=newPhysicsDraw3D;
4. if(draw&&draw->initWithLayer(layer))
5. {
6. returndraw;
7. }
9. returnnullptr;
10. }
11. boolPhysicsDraw3D::initWithLayer(Node*layer)
12. {
13. _drawNode=DrawNode3D::create();
14. layer->addChild(_drawNode);
15. _debugDrawMode=btIDebugDraw::DBG_MAX_DEBUG_DRAW_MODE;
16. returntrue;
17. }
19. voidPhysicsDraw3D::clearDraw()
20. {
21. _drawNode->clear();
22. }

销毁时也要将_drawNode从Parent中移除

[cpp] view plain copy

1. voidPhysicsDraw3D::destroy()
2. {
3. _drawNode->removeFromParent();
4. deletethis;
5. }
7. drawLine也就简化了
8. voidPhysicsDraw3D::drawLine(constbtVector3&from,constbtVector3&to,constbtVector3&color)
9. {
10. Vec3vertices[2]={
11. Vec3(from.x(),from.y(),from.z()),
12. Vec3(to.x(),to.y(),to.z())
13. };
15. _color.r=color.x();
16. _color.g=color.y();
17. _color.b=color.z();
18. _color.a=1.f;
20. _drawNode->drawLine(vertices[0],vertices[1],_color);
21. }

PhysicsWorld3D创建的静态函数添加

[cpp] view plain copy

1. staticPhysicsWorld3D*createWithDebug(Node*layer,constbtVector3&gravity=btVector3(0,-10,0));

为的就是创建调试绘制

[cpp] view plain copy

1. boolPhysicsWorld3D::initWorldWithDebug(Node*layer,constbtVector3&gravity)
2. {
3. if(!this->initWorld(gravity))
4. {
5. returnfalse;
6. }
8. _debugDraw=PhysicsDraw3D::createWithLayer(layer);
9. _world->setDebugDrawer(_debugDraw);
11. returntrue;
12. }

同时删除initWorld对_debugDraw的创建，每次绘制时需要判断是否为debug

[cpp] view plain copy

1. voidPhysicsWorld3D::debugDraw()
2. {
3. if(_debugDraw)
4. {
5. _debugDraw->clearDraw();
6. _world->debugDrawWorld();
7. }
8. }

完整源码

csdn

github