第9章课后习题参考答案

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1、第九章 习题参考答案1基于Turbo C环境进行动画编程可以采用哪些方法？（1）全局画擦画：cleardevice( )（2）局部画擦画：getimage( ) putimage( )（3）页切换：setactivepage( ) setvisualpage( )（4）延时: delay( )（5）函数式（6）图形变换2简要说说你对OpenGL及OGRE的认识？（1）GL是美国SGI公司为图形工作站开发的一种功能强大的三维图形机制，经过长期发展，在跨平台移植的过程中，由GL扩充形成了OpenGL，目前，它已经成为高性能图形和交互式视景处理的工业标准。有了OpenGL的帮助，编程者可以轻松地进行

2、三维动画的程序设计。OpenGL提供的相关库有：1）OpenGL核心库（GL）2）OpenGL实用库（GLU）3）OpenGL辅助库（GLAUX）4）OpenGL工具库（GLUT）5）OpenGL对窗口系统的扩展（WGL，等等）对于各个库，函数功能可分为两大类：渲染功能，提供图形绘制所需的各种功能函数；窗口管理功能，管理窗口系统的所有相关功能，如键盘鼠标的响应，各种窗口事件等等。（2）OGRE（Object-oriented Graphics Rendering Engine，面向对象的图形渲染引擎）是国际上知名的开源图形渲染引擎。OGRE是用C+开发的面向对象且使用灵活的3D引擎，它的目的是

3、让编程者能更容易开发基于3D的动画或游戏等应用程序。引擎中的类库对更底层的系统库（如OpenGL或Direct3D）的全部使用细节进行了简化封装和抽象，同时提供基于现实世界的对象接口以及其它非常有用的工具类。因此，利用OGRE引擎来进行动画编程可以提高开发的效率，并且一般情况下要比基于OpenGL的动画编程还简单些。3基于Turbo C环境编写模拟自由落体的动画。#include#include#define g 10main()int x=320,y,t; int gdriver=DETECT,gmode; initgraph(&gdriver,&gmode,); cleardevice()

4、; setcolor(15); do for(t=0;t10;t+) y=0.5*g*t*t; circle(x,y,20);delay(50000); cleardevice(); for(t=0;t10;t+) y=405-(90*t-0.5*g*t*t); circle(x,y,20);delay(50000); cleardevice(); while(!kbhit(); closegraph();4编写基于OpenGL图形库的Visual C+程序，内容为旋转一茶壶的三维动画。#include #include #include static float rot = 0.0f;voi

5、d init(void) glClearColor(0.0, 0.0, 0.0, 0.0); glShadeModel(GL_SMOOTH); glEnable(GL_DEPTH_TEST);void display(void)glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);glLoadIdentity();gluLookAt(0.0f, 1.5f, 5.0f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f);glBegin(GL_QUADS);glColor3f(1.0f, 0.0f, 0.0f);glNormal

6、3f( 0.0f, 1.0f, 0.0f);glVertex3f(-2.5f, -0.75f, 2.5f);glVertex3f(2.5f, -0.75f, 2.5f);glVertex3f(2.5f, -0.75f, -2.5f);glVertex3f(-2.5f, -0.75f, -2.5f);glEnd();glRotatef(rot, 0.0f, 1.0f, 0.0f);glColor3f(1.0f, 1.0f, 1.0f);glutSolidTeapot(1.0f);rot += 0.1f;glutSwapBuffers();void reshape (int width, int

7、height)glViewport(0, 0, width, height); glMatrixMode(GL_PROJECTION);glLoadIdentity();gluPerspective(45.0f, (GLfloat)width/(GLfloat)height, 0.1f, 100.0f);glMatrixMode(GL_MODELVIEW);glLoadIdentity();void keyboard(unsigned char key, int x, int y)switch (key)case 27:exit(0);break;case p:break;default:br

8、eak; int main(int argc, char* argv)glutInit(&argc, argv);glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);glutInitWindowSize(640, 480); glutInitWindowPosition(100, 100);glutCreateWindow(Rotate);init();glutDisplayFunc(display); glutReshapeFunc(reshape);glutKeyboardFunc(keyboard);glutIdleFunc(

9、display);glutMainLoop();return 0;5编写基于OGRE引擎的Visual C+程序，内容为一9行9列的机器人阵列。#include #include #include ExampleApplication.hclass SelectionRectangle : public ManualObjectpublic: SelectionRectangle(const String &name) : ManualObject(name) setRenderQueueGroup(RENDER_QUEUE_OVERLAY); setUseIdentityProjection

10、(true); setUseIdentityView(true); setQueryFlags(0); void setCorners(float left, float top, float right, float bottom) left = left * 2 - 1; right = right * 2 - 1; top = 1 - top * 2; bottom = 1 - bottom * 2; clear(); begin(, RenderOperation:OT_LINE_STRIP); position(left, top, -1); position(right, top,

11、 -1); position(right, bottom, -1); position(left, bottom, -1); position(left, top, -1); end(); AxisAlignedBox box; box.setInfinite(); setBoundingBox(box); void setCorners(const Vector2 &topLeft, const Vector2 &bottomRight) setCorners(topLeft.x, topLeft.y, bottomRight.x, bottomRight.y); ;class DemoLi

12、stener : public ExampleFrameListener, public OIS:MouseListenerpublic: DemoListener(RenderWindow* win, Camera* cam, SceneManager *sceneManager) : ExampleFrameListener(win, cam, false, true), mSceneMgr(sceneManager), mSelecting(false) mRect = new SelectionRectangle(Selection SelectionRectangle); mScen

13、eMgr-getRootSceneNode()-createChildSceneNode()-attachObject(mRect); mVolQuery = mSceneMgr-createPlaneBoundedVolumeQuery(PlaneBoundedVolumeList(); mMouse-setEventCallback(this); / DemoListener DemoListener() mSceneMgr-destroyQuery(mVolQuery); delete mRect; bool mouseMoved(const OIS:MouseEvent &arg) C

14、EGUI:System:getSingleton().injectMouseMove(arg.state.X.rel, arg.state.Y.rel); if (mSelecting) CEGUI:MouseCursor *mouse = CEGUI:MouseCursor:getSingletonPtr(); mStop.x = mouse-getPosition().d_x / (float)arg.state.width; mStop.y = mouse-getPosition().d_y / (float)arg.state.height; mRect-setCorners(mSta

15、rt, mStop); return true; bool mousePressed(const OIS:MouseEvent &arg, OIS:MouseButtonID id) if (id = OIS:MB_Left) CEGUI:MouseCursor *mouse = CEGUI:MouseCursor:getSingletonPtr(); mStart.x = mouse-getPosition().d_x / (float)arg.state.width; mStart.y = mouse-getPosition().d_y / (float)arg.state.height;

16、 mStop = mStart; mSelecting = true; mRect-clear(); mRect-setVisible(true); return true; bool mouseReleased(const OIS:MouseEvent &arg, OIS:MouseButtonID id) if (id = OIS:MB_Left) performSelection(mStart, mStop); mSelecting = false; mRect-setVisible(false); return true; void performSelection(const Vec

17、tor2 &first, const Vector2 &second) float left = first.x, right = second.x, top = first.y, bottom = second.y; if (left right) swap(left, right); if (top bottom) swap(top, bottom); if (right - left) * (bottom - top) getCameraToViewportRay(left, top); Ray topRight = mCamera-getCameraToViewportRay(righ

18、t, top); Ray bottomLeft = mCamera-getCameraToViewportRay(left, bottom); Ray bottomRight = mCamera-getCameraToViewportRay(right, bottom); PlaneBoundedVolume vol; vol.planes.push_back(Plane(topLeft.getPoint(3), topRight.getPoint(3), bottomRight.getPoint(3); vol.planes.push_back(Plane(topLeft.getOrigin

19、(), topLeft.getPoint(100), topRight.getPoint(100); vol.planes.push_back(Plane(topLeft.getOrigin(), bottomLeft.getPoint(100), topLeft.getPoint(100); vol.planes.push_back(Plane(bottomLeft.getOrigin(), bottomRight.getPoint(100), bottomLeft.getPoint(100); vol.planes.push_back(Plane(topRight.getOrigin(),

20、 topRight.getPoint(100), bottomRight.getPoint(100); PlaneBoundedVolumeList volList; volList.push_back(vol); mVolQuery-setVolumes(volList); SceneQueryResult result = mVolQuery-execute(); deselectObjects(); SceneQueryResultMovableList:iterator itr; for (itr = result.movables.begin(); itr != result.mov

21、ables.end(); +itr) selectObject(*itr); void deselectObjects() std:list:iterator itr; for (itr = mSelected.begin(); itr != mSelected.end(); +itr) (*itr)-getParentSceneNode()-showBoundingBox(false); void selectObject(MovableObject *obj) obj-getParentSceneNode()-showBoundingBox(true); mSelected.push_ba

22、ck(obj); private: Vector2 mStart, mStop; SceneManager *mSceneMgr; PlaneBoundedVolumeListSceneQuery *mVolQuery; std:list mSelected; SelectionRectangle *mRect; bool mSelecting; static void swap(float &x, float &y) float tmp = x; x = y; y = tmp; ;class DemoApplication : public ExampleApplicationpublic:

23、 DemoApplication() : mRenderer(0), mSystem(0) DemoApplication() if (mSystem) delete mSystem; if (mRenderer) delete mRenderer; protected: CEGUI:OgreCEGUIRenderer *mRenderer; CEGUI:System *mSystem; void createScene(void) mRenderer = new CEGUI:OgreCEGUIRenderer(mWindow, Ogre:RENDER_QUEUE_OVERLAY, false

24、, 3000, mSceneMgr); mSystem = new CEGUI:System(mRenderer); CEGUI:SchemeManager:getSingleton().loadScheme(CEGUI:utf8*)TaharezLookSkin.scheme); CEGUI:MouseCursor:getSingleton().setImage(CEGUI:utf8*)TaharezLook, (CEGUI:utf8*)MouseArrow); mCamera-setPosition(-60, 100, -60); mCamera-lookAt(60, 0, 60); mS

25、ceneMgr-setAmbientLight(ColourValue:White); for (int i = 0; i 9; +i) for (int j = 0; j createEntity(Robot + StringConverter:toString(i + j * 10), robot.mesh); SceneNode *node = mSceneMgr-getRootSceneNode()-createChildSceneNode(Vector3(i * 15, 0, j * 15); node-attachObject(ent); node-setScale(0.2, 0.

26、2, 0.2); void createFrameListener(void) mFrameListener = new DemoListener(mWindow, mCamera, mSceneMgr); mFrameListener-showDebugOverlay(true); mRoot-addFrameListener(mFrameListener); ;#if OGRE_PLATFORM = OGRE_PLATFORM_WIN32#define WIN32_LEAN_AND_MEAN#include windows.hINT WINAPI WinMain(HINSTANCE hIn

27、st, HINSTANCE, LPSTR strCmdLine, INT)#elseint main(int argc, char *argv)#endif / Create application object DemoApplication app; try app.go(); catch(Exception& e) #if OGRE_PLATFORM = OGRE_PLATFORM_WIN32 MessageBoxA(NULL, e.getFullDescription().c_str(), An exception has occurred!, MB_OK | MB_ICONERROR

28、 | MB_TASKMODAL);#else fprintf(stderr, An exception has occurred: %sn, e.getFullDescription().c_str();#endif return 0;6利用3D Max软件制作模拟神州飞船返回地面的三维动画。（略）7简述基于编程实现的动画与基于软件制作的动画的异同点。编程实现方式：灵活，可以随心所欲进行动画创作，但要求较高，需要大量编程；软件制作方式：方便，可以快速生成动画，但受限于所采用软件的功能强弱，仅需少量脚本；事实上，很难说哪一种方式更好，主要看需求，若软件制作方式能够完成的，且采购正版软件的费用在用

29、户的承受范围之内，那不妨采用软件制作方式，而当软件制作方式不能实现所需要的功能和效果时，那就必须进行手工编程了。通常大些的动画作品往往采用两者结合的方式来开发。8编程实现卫星1、卫星2以及地球三个球体在空间中的运动旋转三维动画，环境不限。/*三个球体在空间中的运动旋转三维动画 */#include #include #include #include #include #include #include #include #include #include #define ESC 27 #define F 80 /*此数表示通常情况下操作者离电脑的距离（80厘米）*/ #define HIGH

30、T 480 /*屏幕纵向分辩率 */ #define WIDE 640 /*屏幕横向分辨率 */ #define PAI 3.1415926 /*圆周率*/ #define TIME 0.2 /*转动间隔时间（每0.2秒转动5度）*/ typedef struct float x; float y; _2D ; /*二维坐标点*/ typedef struct float x; float y; float z; _3D; /*三维坐标点*/ typedef struct int anglex; int angley; int anglez; Axle; /*轴向量（angle x,y,z分别

31、表示向量与x,y,z轴的夹角）*/ typedef struct /*纬度圈由赤道加上南北半球的各四个纬度圈共9个纬度圈组成，经度等分成10个圈*/ /*所以用 二维数组g910来记录经纬度交点*/ _3D *g910; /* temp910用来记录g910各点从三维变换到二维时的坐标 */ _2D *temp910; _3D *center; /*自转中心坐标，即球心坐标*/ _3D *round_center; /*公转中心坐标*/ float r; /*球体半径*/ Globe; /*球体*/ float Observe_Mat44,World_Mat44; /*观察坐标矩阵 与世界坐标

32、矩阵 */ float Sin360,Cos360; /*存放三角函数值的两个数组，可以减少大量的浮点运算，以提高效率*/ size_t Size2D,Size3D,Sizeaxle,Sizeglobe;/*各结构体的尺寸*/ _3D *Observe; /*观察者所在的位置坐标 */ Globe *Moon1,*Moon2,*Earth; /*卫星1，卫星2，地球 三个球体 */ int Zangle=5; /*转动角速度*/ /*建立三角函数表*/ void create_table() int i; for(i=0;ix=160; Observe-y=0; Observe-z=0; /*

33、把单位矩阵赋值给目标矩阵*/ void to_EMat(float mat44) int i,j; for(i=0;i4;i+) for(j=0;j4;j+) matij=0; for(i=0;ix=point2-x; point1-y=point2-y; point1-z=point2-z; /*把二维坐标点1的值赋给点2*/ void _2D_cpy(_2D *point1,_2D *point2) point1-x=point2-x; point1-y=point2-y; /*初始化各结构体的尺寸*/ void init_size() Size2D=sizeof(_2D); Size3D

34、=sizeof(_3D); Sizeaxle=sizeof(Axle); Sizeglobe=sizeof(Globe); /*初始化观察坐标矩阵与世界坐标矩阵（设定为单位矩阵）*/ void init_Mat() int i,j; for(i=0;i4;i+) for(j=0;j4;j+) Observe_Matij=0; World_Matij=0; for(i=0;i4;i+) Observe_Matii=1; World_Matii=1; /*矩阵1乘矩阵2得到矩阵3*/ void mat_mult(float mat144,float mat244,float mat344) int

35、 i,j; for(i=0; i4; i+) for(j=0; j4; j+) mat3ij=mat1i0*mat20j+mat1i1*mat21j+mat1i2*mat22j+mat1i3*mat23j; /*复制矩阵2到矩阵1*/ void mat_cpy(float mat144,float mat244) int i,j; for(i=0;i=3;i+) for(j=0;jx,2)+pow(Observe-y,2),0.5); _3Dr=pow(pow(Observe-x,2)+pow(Observe-y,2)+pow(Observe-z,2),0.5); Observe_Mat00=

36、Observe-y/_2Dr*-1; Observe_Mat01=Observe-x*Observe-z/_2Dr/_3Dr*-1; Observe_Mat02=Observe-x/_3Dr*-1; Observe_Mat10=Observe-x/_2Dr; Observe_Mat11=Observe-y*Observe-z/_2Dr/_3Dr*-1; Observe_Mat12=Observe-y/_3Dr*-1; Observe_Mat21=_2Dr/_3Dr; Observe_Mat22=Observe-z/_3Dr*-1; Observe_Mat32=_3Dr; Observe_Mat

37、33=1; /*三维坐标点对指定矩阵变换以得到新的三维坐标*/ void _3D_mult_mat(_3D *Source,float mat44) _3D *temp; temp=(_3D *)malloc(Size3D); temp-x=Source-x*mat00+Source-y*mat10+Source-z*mat20+mat30; temp-y=Source-x*mat01+Source-y*mat11+Source-z*mat21+mat31; temp-z=Source-x*mat02+Source-y*mat12+Source-z*mat22+mat32; _3D_cpy(S

38、ource,temp); /*把三维坐标点从世界坐标变换成观察坐标*/ void world_to_ob(_3D *point1,_3D *point2) point2-x=point1-x*Observe_Mat00+point1-y*Observe_Mat10+ point1-z*Observe_Mat20+Observe_Mat30; point2-y=point1-x*Observe_Mat01+point1-y*Observe_Mat11+ point1-z*Observe_Mat21+Observe_Mat31; point2-z=point1-x*Observe_Mat02+po

39、int1-y*Observe_Mat12+ point1-z*Observe_Mat22+Observe_Mat32; /*把三维坐标投影为二维坐标*/ void _3Dto_2D(_3D *_3Dpoint,_2D *_2Dpoint) _2Dpoint-x=WIDE/2+F*_3Dpoint-x/_3Dpoint-z; _2Dpoint-y=HIGHT/2-F*_3Dpoint-y/_3Dpoint-z; /*球体绕z轴转动后的坐标变换*/ void z_round(Globe *globe,int angle) float z44; int i,j; to_EMat(z); z00=Co

40、sget_angle(angle); z01=Singet_angle(angle); z10=-z01; z11=z00; for(i=0;i9;i+) for(j=0;jgij,z); /*球体绕y轴转动后的坐标变换*/ void y_round(Globe *globe,int angle) float y44; int i,j; to_EMat(y); y00=Cosget_angle(angle); y20=Singet_angle(angle); y02=-y20; y22=y00; for(i=0;i9;i+) for(j=0;jgij,y); /*球体绕x轴转动后的坐标变换*/

41、 void x_round(Globe *globe,int angle) float x44; int i,j; to_EMat(x); x11=Cosget_angle(angle); x12=Singet_angle(angle); x21=-x12; x22=x11; for(i=0;i9;i+) for(j=0;jgij,x); /*初始化图形模式*/ void init_gph() int gd=DETECT,gm; initgraph(&gd,&gm,); setfillstyle(SOLID_FILL,BLACK); bar(0,0,640,480); /*开辟一个用来存放球体

42、数据的空间，并返回头地址*/ Globe *create_globe() Globe *p; int i,j; p=(Globe *)malloc(Sizeglobe); for(i=0;i9;i+) for(j=0;jgij=(_3D *)malloc(Size3D); p-tempij=(_2D *)malloc(Size2D); p-center=(_3D *)malloc(Size3D); p-round_center=(_3D *)malloc(Size3D); return p; /*把一个角化为0-360的角，要求是它的三角函数值不变*/ int get_angle(int an

43、gle) angle%=360; if(anglex=x0; p-y=y0; p-z=z0; return p; /*给一个轴向量赋值*/ Axle *get_axle(int qx,int qy,int qz) Axle *p; p=(Axle *)malloc(Sizeaxle); p-anglex=qx; p-angley=qy; p-anglez=qz; return p; /*从世界坐标原点平移球体到指定点（球体初始化时用）*/ void place_globe(Globe *globe) float tempf44; int i,j; to_EMat(tempf); tempf30

44、=(globe-center)-x; tempf31=(globe-center)-y; tempf32=(globe-center)-z; for(i=0;i9;i+) for(j=0;jgij,tempf); /*球体初始化*/ void init_globe(Globe *globe,float r,_3D *thecenter,_3D *rnd_center) int i,j; globe-r=r; for(i=-4;i=4;i+) for(j=0;jgi+4j)-x=r*Cosget_angle(i*18)*Cosget_angle(j*36); (globe-gi+4j)-y=r*

45、Cosget_angle(i*18)*Singet_angle(j*36); (globe-gi+4j)-z=r*Singet_angle(i*18); _3D_cpy(globe-center,thecenter); _3D_cpy(globe-round_center,rnd_center); place_globe(globe); /*把球体上的点从世界坐标变成观察坐标，然后再把观察坐标投影为二维坐标*/ void Wglobe_to_2D(Globe *globe) int i,j; _3D *point; for(i=0;i9;i+) for(j=0;jgij,point); _3D

46、to_2D(point,globe-tempij); /*用指定颜色绘制球体*/ void draw_globe(Globe *g,int color) int i,j,n; Wglobe_to_2D(g); setcolor(color); for(i=0;i9;i+) for(j=0;jtempij)-x,(g-tempij)-y,(g-tempin)-x,(g-tempin)-y); for(j=0;j10;j+) for(i=0;itempij)-x,(g-tempij)-y,(g-tempnj)-x,(g-tempnj)-y); /*初始化*/ void init_start() i

47、nt i; _3D *p1,*p2,*p3,*p4; init_gph(); setcolor(RED); circle(320,240,200); init_size(); create_table(); init_observe(); init_Mat(); create_obMat(); Moon1=create_globe(); Moon2=create_globe(); Earth=create_globe(); p1=get_3Dpoint(0,100,0); p2=get_3Dpoint(0,-100,0); p3=get_3Dpoint(0,0,0); p4=get_3Dpoi

48、nt(0,0,0); init_globe(Moon1,20,p1,p4); init_globe(Moon2,20,p2,p4); init_globe(Earth,50,p3,p4); draw_globe(Earth,BLUE); draw_globe(Moon1,DARKGRAY); draw_globe(Moon2,CYAN); /*各球体随时间变化而在各自轨道上运行的动画（按任意键退出）*/ void roll() clock_t start,end; int angle=0; start=clock(); while(!kbhit() end=clock(); if(end-start)/CLK_TCKTIME) draw_globe(Moon1,BLACK); draw_globe(Moon2,BLACK); draw_globe(Earth,BLACK); z_round(Moon1,Zangle); x_round(Moon2,Z