多媒体技术实验报告

1、1q实验 粒子系统讲授时数：0.5学时。一、 实验类型研究创新型实验 二、 实验目的 通过本实验让学生熟练掌握三维图形程序编写，掌握粒子系统的设计与实现，加深对粒子系统的认识。 本实验要实现一个基于粒子系统的烟花效果模拟。粒子系统包括：粒子初始化、粒子状态控制、粒子的绘制。 实现本系统实现之后，学生可以在此基础上进行扩展，例如模拟喷泉效果。喷泉效果的实现包括：粒子颜色保持蓝色，粒子运动受到重力作用。三、 实验要求 三维图形绘制工程配置和环境设置。 粒子系统设计，实现粒子系统的数据结构和管理的设计模式。 各个粒子位置、颜色计算。 粒子的绘制。 提交程序使用手册（可简单到为一个readme文件）。

2、四、 实验内容利用opengl实现一个粒子系统，模拟烟花效果。五、 开设方式小组实验。六、 学时数8学时。七、 参考资料1 vc+编程指南，2 nehe opengl框架程序3 opengl sdk下载/八、 实验后记电 子 科 技 大 学实 验 报 告学生姓名： 学 号： 指导教师：实验地点： 实验时间：一、实验室名称：计算机学院软件实验室二、实验项目名称：粒子系统三、实验学时：8学时四、实验原理粒子系统在计算机动画中被广泛用于模拟爆炸、喷泉、流星等效果。在本实验中，粒子系统被用来模拟不断喷射的烟花。实现粒子系统包括：（1）粒子初始化。（2）粒子运动和

3、颜色模拟。（3）粒子生命周期模拟。粒子的初始化给所有的粒子的位置、速度、生命和衰减周期赋值；运动和颜色模拟是计算粒子的速度、位置在每一时间步长之后变化的值；粒子的生命周期模拟是在粒子生命完结之后重新初始化该粒子。为了实现这样的效果，粒子应该具有以下属性：（1）boolactive;粒子的活动状态，为true时，才模拟粒子。（2）floatlife;粒子的生命值，在模拟过程中不断减少，如果为0就重新初始化粒子。（3）floatfade;粒子的生命值减少的速度。（4）floatr;粒子颜色r分量。（5）floatg;粒子颜色g分量。（6）floatb;粒子颜色b分量。（7）floatx;粒子位置x

4、分量。（8）floaty;粒子位置y分量。（9）floatz;粒子位置z分量。（10）floatxi;粒子速度x分量。（11）floatyi;粒子速度y分量。（12）floatzi;粒子速度z分量。（13）floatxg;粒子加速度x分量。（14）floatyg;粒子加速度x分量。（15）floatzg;粒子加速度x分量。在具体的模拟过程中，需要创建一个数组叫particle数组存max_particles个元素。也就是说我们创建1000(max_particles)个粒子,存储空间为每个粒子提供相应的信息。使用光滑的阴影,清除背景为黑色,关闭深度测试,绑定并映射纹理。启用映射位图后我们选择粒

5、子纹理。唯一的改变就是禁用深度测试和初始化粒子。并且创建一个循环loop.这个环将会更新每一个粒子。每次循环时首先检查粒子是否活跃。如果不活跃,则不被更新。在这个程序中,它们始终活跃。五、实验目的本实验要实现粒子系统。粒子系统包括以下模块：粒子初始化；位置、速度、颜色实时计算；生命周期控制。基本系统实现之后，可以在此基础上扩展为喷泉效果。实现喷泉效果需要一下几个模块：（1）粒子水平方向的随机初速度。（2）粒子运动模拟。（3）位置低于地面，重新初始化。六、实验内容利用opengl实现一个粒子系统。七、实验器材（设备、元器件）1. 操作系统：windows xp2. 开发工具：vc2005，ope

6、ngl库3. 普通pc即可八、实验步骤(1) 创建工程启动vc+2005，选择菜单中的“文件”-“新建”-“项目”。在弹出的对话框中，左边的“项目类型”框中，选择“visual c+”，在右边框中，选择“win32项目”。在对话框下边，选择工程文件存放目录及输入名称，如particle，单击“确定”。在“win32应用程序向导”中单击“下一步”，在“应用程序类型”中选择“windows应用程序”；在“附加选项”中选择“空项目”。点击“完成”。(2) 设置此工程所需的opengl库选择菜单中的“项目”-“属性”。在弹出的“particle属性页”对话框中，展开“链接器”选择“输入”。选择右边框中

7、的“附加依赖项”，单击最右端的“”小按钮，弹出“附加依赖项”对话框，输入“opengl32.lib glut.lib glaux.lib glu32.lib”（注意，输入双引号中的内容，各个库用空格分开；否则会出现链接错误。如果编译时提示找不到以上的lib文件，把“链接器-常规-附加库目录”选择为opengl sdk所在目录，或者从opengl sdk中把这几个lib文件放到microsoft visual studio 8vclib）。“配置属性-常规-字符集”设置为“未设置”。“c/c+-预编译头-创建/使用预编译头”设置为“不使用预编译头”。单击“确定”结束。项目属性设置完成。(3) 在

8、工程项目中添加源文件在“解决方案资源管理器”中，选中particle项目下的“源文件”筛选器。右键点击后选择“添加”，然后选择新建项。在“添加新项”的窗口中选择“c+文件（.cpp）”模板，并命名为main.cpp。(4) 录入源程序程序使用到了资源文件“particle.bmp”作为粒子的贴图，该文件如下：图1 particle.bmp将该文件保存在工程目录“particledata”目录下。将源程序写入到工程中。新建好main.cpp文件后，将代码写入该文件。参考源代码如下：main.cpp#include / header file for windows#include / heade

9、r file for standard input/output#include / header file for the opengl32 library#include / header file for the glu32 library#include / header file for the glaux library#definemax_particles1000/ number of particles to createhdchdc=null;/ private gdi device contexthglrchrc=null;/ permanent rendering co

10、ntexthwndhwnd=null;/ holds our window handlehinstancehinstance;/ holds the instance of the applicationboolkeys256;/ array used for the keyboard routineboolactive=true;/ window active flag set to true by defaultboolfullscreen=true;/ fullscreen flag set to fullscreen mode by defaultboolrainbow=true;/

11、rainbow mode?boolsp;/ spacebar pressed?boolrp;/ enter key pressed?floatslowdown=2.0f;/ slow down particlesfloatxspeed;/ base x speed (to allow keyboard direction of tail)floatyspeed;/ base y speed (to allow keyboard direction of tail)floatzoom=-40.0f;/ used to zoom outgluintloop;/ misc loop variable

12、gluintcol;/ current color selectiongluintdelay;/ rainbow effect delaygluinttexture1;/ storage for our particle texturetypedef struct/ create a structure for particleboolactive;/ active (yes/no)floatlife;/ particle lifefloatfade;/ fade speedfloatr;/ red valuefloatg;/ green valuefloatb;/ blue valueflo

13、atx;/ x positionfloaty;/ y positionfloatz;/ z positionfloatxi;/ x directionfloatyi;/ y directionfloatzi;/ z directionfloatxg;/ x gravityfloatyg;/ y gravityfloatzg;/ z gravityparticles;/ particles structureparticles particlemax_particles;/ particle array (room for particle info)static glfloat colors1

14、23=/ rainbow of colors1.0f,0.5f,0.5f,1.0f,0.75f,0.5f,1.0f,1.0f,0.5f,0.75f,1.0f,0.5f,0.5f,1.0f,0.5f,0.5f,1.0f,0.75f,0.5f,1.0f,1.0f,0.5f,0.75f,1.0f,0.5f,0.5f,1.0f,0.75f,0.5f,1.0f,1.0f,0.5f,1.0f,1.0f,0.5f,0.75f;lresultcallback wndproc(hwnd, uint, wparam, lparam);/ declaration for wndprocaux_rgbimagerec

15、 *loadbmp(char *filename)/ loads a bitmap image file *file=null;/ file handle if (!filename)/ make sure a filename was given return null;/ if not return null file=fopen(filename,r);/ check to see if the file exists if (file)/ does the file exist? fclose(file);/ close the handlereturn auxdibimageload

16、(filename);/ load the bitmap and return a pointer return null;/ if load failed return nullint loadgltextures()/ load bitmap and convert to a texture int status=false;/ status indicator aux_rgbimagerec *textureimage1;/ create storage space for the textures memset(textureimage,0,sizeof(void *)*1);/ se

17、t the pointer to null if (textureimage0=loadbmp(data/particle.bmp)/ load particle texture status=true;/ set the status to trueglgentextures(1, &texture0);/ create one textureglbindtexture(gl_texture_2d, texture0);gltexparameteri(gl_texture_2d,gl_texture_mag_filter,gl_linear);gltexparameteri(gl_textu

18、re_2d,gl_texture_min_filter,gl_linear);glteximage2d(gl_texture_2d, 0, 3, textureimage0-sizex, textureimage0-sizey, 0, gl_rgb, gl_unsigned_byte, textureimage0-data); if (textureimage0)/ if texture existsif (textureimage0-data)/ if texture image existsfree(textureimage0-data);/ free the texture image

19、memoryfree(textureimage0);/ free the image structure return status;/ return the statusglvoid resizeglscene(glsizei width, glsizei height)/ resize and initialize the gl windowif (height=0)/ prevent a divide by zero byheight=1;/ making height equal oneglviewport(0,0,width,height);/ reset the current v

20、iewportglmatrixmode(gl_projection);/ select the projection matrixglloadidentity();/ reset the projection matrix/ calculate the aspect ratio of the windowgluperspective(45.0f,(glfloat)width/(glfloat)height,0.1f,200.0f);glmatrixmode(gl_modelview);/ select the modelview matrixglloadidentity();/ reset t

21、he modelview matrixint initgl(glvoid)/ all setup for opengl goes hereif (!loadgltextures()/ jump to texture loading routinereturn false;/ if texture didnt load return falseglshademodel(gl_smooth);/ enable smooth shadingglclearcolor(0.0f,0.0f,0.0f,0.0f);/ black backgroundglcleardepth(1.0f);/ depth bu

22、ffer setupgldisable(gl_depth_test);/ disable depth testingglenable(gl_blend);/ enable blendingglblendfunc(gl_src_alpha,gl_one);/ type of blending to performglhint(gl_perspective_correction_hint,gl_nicest);/ really nice perspective calculationsglhint(gl_point_smooth_hint,gl_nicest);/ really nice poin

23、t smoothingglenable(gl_texture_2d);/ enable texture mappingglbindtexture(gl_texture_2d,texture0);/ select our texturefor (loop=0;loopmax_particles;loop+)/ initials all the texturesparticleloop.active=true;/ make all the particles activeparticleloop.life=1.0f;/ give all the particles full lifeparticl

24、eloop.fade=float(rand()%100)/1000.0f+0.003f;/ random fade speedparticleloop.r=colorsloop*(12/max_particles)0;/ select red rainbow colorparticleloop.g=colorsloop*(12/max_particles)1;/ select red rainbow colorparticleloop.b=colorsloop*(12/max_particles)2;/ select red rainbow colorparticleloop.xi=float

25、(rand()%50)-26.0f)*10.0f;/ random speed on x axisparticleloop.yi=float(rand()%50)-25.0f)*10.0f;/ random speed on y axisparticleloop.zi=float(rand()%50)-25.0f)*10.0f;/ random speed on z axisparticleloop.xg=0.0f;/ set horizontal pull to zeroparticleloop.yg=-0.8f;/ set vertical pull downwardparticleloo

26、p.zg=0.0f;/ set pull on z axis to zeroreturn true;/ initialization went okint drawglscene(glvoid)/ heres where we do all the drawingglclear(gl_color_buffer_bit | gl_depth_buffer_bit);/ clear screen and depth bufferglloadidentity();/ reset the modelview matrixfor (loop=0;loopmax_particles;loop+)/ loo

27、p through all the particlesif (particleloop.active)/ if the particle is activefloat x=particleloop.x;/ grab our particle x positionfloat y=particleloop.y;/ grab our particle y positionfloat z=particleloop.z+zoom;/ particle z pos + zoom/ draw the particle using our rgb values, fade the particle based

28、 on its lifeglcolor4f(particleloop.r,particleloop.g,particleloop.b,particleloop.life);glbegin(gl_triangle_strip);/ build quad from a triangle strip gltexcoord2d(1,1); glvertex3f(x+0.5f,y+0.5f,z); / top rightgltexcoord2d(0,1); glvertex3f(x-0.5f,y+0.5f,z); / top leftgltexcoord2d(1,0); glvertex3f(x+0.5

29、f,y-0.5f,z); / bottom rightgltexcoord2d(0,0); glvertex3f(x-0.5f,y-0.5f,z); / bottom leftglend();/ done building triangle stripparticleloop.x+=particleloop.xi/(slowdown*1000);/ move on the x axis by x speedparticleloop.y+=particleloop.yi/(slowdown*1000);/ move on the y axis by y speedparticleloop.z+=

30、particleloop.zi/(slowdown*1000);/ move on the z axis by z speedparticleloop.xi+=particleloop.xg;/ take pull on x axis into accountparticleloop.yi+=particleloop.yg;/ take pull on y axis into accountparticleloop.zi+=particleloop.zg;/ take pull on z axis into accountparticleloop.life-=particleloop.fade

31、;/ reduce particles life by fadeif (particleloop.life0.0f)/ if particle is burned outparticleloop.life=1.0f;/ give it new lifeparticleloop.fade=float(rand()%100)/1000.0f+0.003f;/ random fade valueparticleloop.x=0.0f;/ center on x axisparticleloop.y=0.0f;/ center on y axisparticleloop.z=0.0f;/ center

32、 on z axisparticleloop.xi=xspeed+float(rand()%60)-32.0f);/ x axis speed and directionparticleloop.yi=yspeed+float(rand()%60)-30.0f);/ y axis speed and directionparticleloop.zi=float(rand()%60)-30.0f);/ z axis speed and directionparticleloop.r=colorscol0;/ select red from color tableparticleloop.g=co

33、lorscol1;/ select green from color tableparticleloop.b=colorscol2;/ select blue from color table/ if number pad 8 and y gravity is less than 1.5 increase pull upwardsif (keysvk_numpad8 & (particleloop.yg-1.5f) particleloop.yg-=0.01f;/ if number pad 6 and x gravity is less than 1.5 increase pull righ

34、tif (keysvk_numpad6 & (particleloop.xg-1.5f) particleloop.xg-=0.01f;if (keysvk_tab)/ tab key causes a burstparticleloop.x=0.0f;/ center on x axisparticleloop.y=0.0f;/ center on y axisparticleloop.z=0.0f;/ center on z axisparticleloop.xi=float(rand()%50)-26.0f)*10.0f;/ random speed on x axisparticlel

35、oop.yi=float(rand()%50)-25.0f)*10.0f;/ random speed on y axisparticleloop.zi=float(rand()%50)-25.0f)*10.0f;/ random speed on z axis return true;/ everything went okglvoid killglwindow(glvoid)/ properly kill the windowif (fullscreen)/ are we in fullscreen mode?changedisplaysettings(null,0);/ if so sw

36、itch back to the desktopshowcursor(true);/ show mouse pointerif (hrc)/ do we have a rendering context?if (!wglmakecurrent(null,null)/ are we able to release the dc and rc contexts?messagebox(null,release of dc and rc failed.,shutdown error,mb_ok | mb_iconinformation);if (!wgldeletecontext(hrc)/ are

37、we able to delete the rc?messagebox(null,release rendering context failed.,shutdown error,mb_ok | mb_iconinformation);hrc=null;/ set rc to nullif (hdc & !releasedc(hwnd,hdc)/ are we able to release the dcmessagebox(null,release device context failed.,shutdown error,mb_ok | mb_iconinformation);hdc=nu

38、ll;/ set dc to nullif (hwnd & !destroywindow(hwnd)/ are we able to destroy the window?messagebox(null,could not release hwnd.,shutdown error,mb_ok | mb_iconinformation);hwnd=null;/ set hwnd to nullif (!unregisterclass(opengl,hinstance)/ are we able to unregister classmessagebox(null,could not unregi

39、ster class.,shutdown error,mb_ok | mb_iconinformation);hinstance=null;/ set hinstance to null/*this code creates our opengl window. parameters are:* *title- title to appear at the top of the window* *width- width of the gl window or fullscreen mode* *height- height of the gl window or fullscreen mod

40、e* *bits- number of bits to use for color (8/16/24/32)* *fullscreenflag- use fullscreen mode (true) or windowed mode (false)*/ bool createglwindow(char* title, int width, int height, int bits, bool fullscreenflag)gluintpixelformat;/ holds the results after searching for a matchwndclasswc;/ windows c

41、lass structuredworddwexstyle;/ window extended styledworddwstyle;/ window stylerectwindowrect;/ grabs rectangle upper left / lower right valueswindowrect.left=(long)0;/ set left value to 0windowrect.right=(long)width;/ set right value to requested widthwindowrect.top=(long)0;/ set top value to 0wind

42、owrect.bottom=(long)height;/ set bottom value to requested heightfullscreen=fullscreenflag;/ set the global fullscreen flaghinstance= getmodulehandle(null);/ grab an instance for our windowwc.style= cs_hredraw | cs_vredraw | cs_owndc;/ redraw on size, and own dc for window.wc.lpfnwndproc= (wndproc)

43、wndproc;/ wndproc handles messageswc.cbclsextra= 0;/ no extra window datawc.cbwndextra= 0;/ no extra window datawc.hinstance= hinstance;/ set the instancewc.hicon= loadicon(null, idi_winlogo);/ load the default iconwc.hcursor= loadcursor(null, idc_arrow);/ load the arrow pointerwc.hbrbackground= nul

44、l;/ no background required for glwc.lpszmenuname= null;/ we dont want a menuwc.lpszclassname= opengl;/ set the class nameif (!registerclass(&wc)/ attempt to register the window classmessagebox(null,failed to register the window class.,error,mb_ok|mb_iconexclamation);return false;/ return falseif (fu

45、llscreen)/ attempt fullscreen mode?devmode dmscreensettings;/ device modememset(&dmscreensettings,0,sizeof(dmscreensettings);/ makes sure memorys cleareddmscreensettings.dmsize=sizeof(dmscreensettings);/ size of the devmode structuredmscreensettings.dmpelswidth= width;/ selected screen widthdmscreen

46、settings.dmpelsheight= height;/ selected screen heightdmscreensettings.dmbitsperpel= bits;/ selected bits per pixeldmscreensettings.dmfields=dm_bitsperpel|dm_pelswidth|dm_pelsheight;/ try to set selected mode and get results. note: cds_fullscreen gets rid of start bar.if (changedisplaysettings(&dmsc

47、reensettings,cds_fullscreen)!=disp_change_successful)/ if the mode fails, offer two options. quit or use windowed mode.if (messagebox(null,the requested fullscreen mode is not supported bynyour video card. use windowed mode instead?,nehe gl,mb_yesno|mb_iconexclamation)=idyes)fullscreen=false;/ windowed mode selected. fullscreen = falseelse/ pop up a message box letting user know the program is closing.messa