opengl粒子系统实现.doc

OpenGL进阶(六)-粒子系统/qp120291570/article/details/8373896一、提要 有一款例子特效软件叫做particle illution，在影视后期和游戏制作领域都可以用到，相信很多人都接触过，今天我们用SDL+OpenGL来实现例子效果。确保你搞定了物理模拟的代码！ 代码下载二、原理简介 所谓的例子系统，就是同时控制一大堆类似的对象，这些对象可能是形体，可能是图片，有着不同的特征（寿命，速度，位置）。有了之前的基础，我们可以很轻易地搞定今天的东西。三、代码清单首先是粒子的头文件，我直接写成结构体了，里面有一些基本的属性。cppview plaincopy1. /*2. Copyright:2012,ustcAllrightsreserved.3. contact:4. Filename:particle.h5. Description:Particalinopengl.6. Author:SilangQuan7. Version:1.08. Date:2012.12.209. */10. #ifndefPARTICLE_H11. #definePARTICLE_H12. #includevector3d.h13. typedefstruct14. 15. floatr;16. floatg;17. floatb;18. floatalpha;19. Color;20. 21. typedefstruct22. 23. Vector3Dposition;24. Vector3Dvelocity;25. Vector3Dacceleration;26. Colorcolor;27. floatage;28. floatlife;29. floatsize;30. Particle;31. 32. #endif/PARTICLE_Hcppview plaincopy1. /*2. Copyright:2012,ustcAllrightsreserved.3. contact:4. Filename:particle.h5. Description:Particalinopengl.6. Author:SilangQuan7. Version:1.08. Date:2012.12.209. */10. #ifndefPARTICLE_H11. #definePARTICLE_H12. #includevector3d.h13. typedefstruct14. 15. floatr;16. floatg;17. floatb;18. floatalpha;19. Color;20. 21. typedefstruct22. 23. Vector3Dposition;24. Vector3Dvelocity;25. Vector3Dacceleration;26. Colorcolor;27. floatage;28. floatlife;29. floatsize;30. Particle;31. 32. #endif/PARTICLE_H我们用球体来模拟例子，所以size表示的就是球体的半径。接下来是粒子系统类（类名拼写错了*-*）cppview plaincopy1. /*2. Copyright:2012,ustcAllrightsreserved.3. contact:4. Filename:particalsystem.h5. Description:Particalinopengl.6. Author:SilangQuan7. Version:1.08. Date:2012.12.209. */10. 11. #ifndefPARTICALSYSTEM_H12. #definePARTICALSYSTEM_H13. #include14. #include15. #include16. #include17. #include18. #include19. #include20. #includeparticle.h21. #definePI3.141592622. usingnamespacestd;23. classParticalSystem24. 25. public:26. ParticalSystem();27. ParticalSystem(int_count,float_gravity)ptlCount=_count;gravity=_gravity;28. voidinit();29. voidsimulate(floatdt);30. voidaging(floatdt);31. voidapplyGravity();32. voidkinematics(floatdt);33. voidrender();34. virtualParticalSystem();35. protected:36. private:37. intptlCount;38. floatgravity;39. GLUquadricObj*mySphere;40. vectorparticles;41. ;42. 43. #endif/PARTICALSYSTEM_Hcppview plaincopy1. /*2. Copyright:2012,ustcAllrightsreserved.3. contact:4. Filename:particalsystem.h5. Description:Particalinopengl.6. Author:SilangQuan7. Version:1.08. Date:2012.12.209. */10. 11. #ifndefPARTICALSYSTEM_H12. #definePARTICALSYSTEM_H13. #include14. #include15. #include16. #include17. #include18. #include19. #include20. #includeparticle.h21. #definePI3.141592622. usingnamespacestd;23. classParticalSystem24. 25. public:26. ParticalSystem();27. ParticalSystem(int_count,float_gravity)ptlCount=_count;gravity=_gravity;28. voidinit();29. voidsimulate(floatdt);30. voidaging(floatdt);31. voidapplyGravity();32. voidkinematics(floatdt);33. voidrender();34. virtualParticalSystem();35. protected:36. private:37. intptlCount;38. floatgravity;39. GLUquadricObj*mySphere;40. vectorparticles;41. ;42. 43. #endif/PARTICALSYSTEM_H解释一下几个重要函数：init：做一些例子系统的初始化工作；aging：计算粒子的年龄；applyGravity：向粒子施加重力；kinematics：这个单词的意思是运动学，所以就是负责管理粒子的加速，位移；simulate：例子模拟的总负责函数；render：渲染粒子；然后来看函数是怎么实现的：cppview plaincopy1. /*2. Copyright:2012,ustcAllrightsreserved.3. contact:4. Filename:particalsystem.Cpp5. Description:Particalinopengl.6. Author:SilangQuan7. Version:1.08. Date:2012.12.229. */10. 11. #includeparticalsystem.h12. 13. ParticalSystem:ParticalSystem()14. 15. /ctor16. 17. 18. ParticalSystem:ParticalSystem()19. 20. /dtor21. 22. 23. voidParticalSystem:init()24. 25. inti;26. srand(unsigned(time(0);27. Colorcolors3=0,0,1,1,1,0,1,1;28. for(i=0;iptlCount;i+)29. 30. /theta=(rand()%361)/360.0*2*PI;31. Particletmp=Vector3D(0,0,0),Vector3D(rand()%50)-26.0f),(rand()%50)-26.0f),(rand()%50)-26.0f),Vector3D(0,0,0),colorsrand()%2,0.0f,0.5+0.05*(rand()%10),0.3f;32. particles.push_back(tmp);33. 34. mySphere=gluNewQuadric();35. 36. voidParticalSystem:simulate(floatdt)37. 38. aging(dt);39. applyGravity();40. kinematics(dt);41. 42. voidParticalSystem:aging(floatdt)43. 44. for(vector:iteratoriter=particles.begin();iter!=particles.end();iter+)45. 46. iter-age+=dt;47. if(iter-ageiter-life)48. 49. iter-position=Vector3D(0,0,0);50. iter-age=0.0;51. iter-velocity=Vector3D(rand()%30)-15.0f),(rand()%30)-11.0f),(rand()%30)-15.0f);52. 53. 54. 55. voidParticalSystem:applyGravity()56. 57. for(vector:iteratoriter=particles.begin();iter!=particles.end();iter+)58. iter-acceleration=Vector3D(0,gravity,0);59. 60. 61. voidParticalSystem:kinematics(floatdt)62. 63. for(vector:iteratoriter=particles.begin();iter!=particles.end();iter+)64. 65. iter-position=iter-position+iter-velocity*dt;66. iter-velocity=iter-velocity+iter-acceleration*dt;67. 68. 69. voidParticalSystem:render()70. 71. 72. for(vector:iteratoriter=particles.begin();iter!=particles.end();iter+)73. 74. floatalpha=1-iter-age/iter-life;/calculatethealphavalueaccordingtotheageofparticle.75. Vector3Dtmp=iter-position;76. glColor4f(iter-color.r,iter-color.g,iter-color.b,alpha);77. glPushMatrix();78. glTranslatef(tmp.x,tmp.y,tmp.z);79. gluSphere(mySphere,iter-size,32,16);80. glPopMatrix();81. 82. 83. cppview plaincopy1. /*2. Copyright:2012,ustcAllrightsreserved.3. contact:4. Filename:particalsystem.Cpp5. Description:Particalinopengl.6. Author:SilangQuan7. Version:1.08. Date:2012.12.229. */10. 11. #includeparticalsystem.h12. 13. ParticalSystem:ParticalSystem()14. 15. /ctor16. 17. 18. ParticalSystem:ParticalSystem()19. 20. /dtor21. 22. 23. voidParticalSystem:init()24. 25. inti;26. srand(unsigned(time(0);27. Colorcolors3=0,0,1,1,1,0,1,1;28. for(i=0;iptlCount;i+)29. 30. /theta=(rand()%361)/360.0*2*PI;31. Particletmp=Vector3D(0,0,0),Vector3D(rand()%50)-26.0f),(rand()%50)-26.0f),(rand()%50)-26.0f),Vector3D(0,0,0),colorsrand()%2,0.0f,0.5+0.05*(rand()%10),0.3f;32. particles.push_back(tmp);33. 34. mySphere=gluNewQuadric();35. 36. voidParticalSystem:simulate(floatdt)37. 38. aging(dt);39. applyGravity();40. kinematics(dt);41. 42. voidParticalSystem:aging(floatdt)43. 44. for(vector:iteratoriter=particles.begin();iter!=particles.end();iter+)45. 46. iter-age+=dt;47. if(iter-ageiter-life)48. 49. iter-position=Vector3D(0,0,0);50. iter-age=0.0;51. iter-velocity=Vector3D(rand()%30)-15.0f),(rand()%30)-11.0f),(rand()%30)-15.0f);52. 53. 54. 55. voidParticalSystem:applyGravity()56. 57. for(vector:iteratoriter=particles.begin();iter!=particles.end();iter+)58. iter-acceleration=Vector3D(0,gravity,0);59. 60. 61. voidParticalSystem:kinematics(floatdt)62. 63. for(vector:iteratoriter=particles.begin();iter!=particles.end();iter+)64. 65. iter-position=iter-position+iter-velocity*dt;66. iter-velocity=iter-velocity+iter-acceleration*dt;67. 68. 69. voidParticalSystem:render()70. 71. 72. for(vector:iteratoriter=particles.begin();iter!=particles.end();iter+)73. 74. floatalpha=1-iter-age/iter-life;/calculatethealphavalueaccordingtotheageofparticle.75. Vector3Dtmp=iter-position;76. glColor4f(iter-color.r,iter-color.g,iter-color.b,alpha);77. glPushMatrix();78. glTranslatef(tmp.x,tmp.y,tmp.z);79. gluSphere(mySphere,iter-size,32,16);80. glPopMatrix();81. 82. 83. 实现还是比较简单的，下面渲染看一下.首先要在initGL函数中添加两句话：cppview plaincopy1. glEnable(GL_BLEND);2. glBlendFunc(GL_SRC_ALPHA,GL_ONE_MINUS_SRC_ALPHA);cppview plaincopy1. glEnable(GL_BLEND);2. glBlendFunc(GL_SRC_ALPHA,GL_ONE_MINUS_SRC_ALPHA);这样透明度才会有效。接着初始化一个例子系统，并对例子进行初始化：cppview plaincopy1. ParticalSystemps;cppview plaincopy1. ParticalSystemps;plainview plaincopy1. intmain(intargc,char*argv)2. 3. /Colordepthinbitsofourwindow.4. intflags=SDL_OPENGL|SDL_RESIZABLE;5. /SettheSDL6. initSDL(SCREEN_WIDTH,SCREEN_HEIGHT,SCREEN_BPP,flags);7. /SettheOpenGL8. initGL(SCREEN_WIDTH,SCREEN_HEIGHT);9. ps=ParticalSystem(100,-15.0);10. ps.init();11. /mainloop12. while(true)13. 14. /*Processincomingevents.*/15. handleEvents();16. ps.simulate(0.01);17. /*Drawthescreen.*/18. renderGL();19. 20. return0;21. plainview plaincopy1. intmain(intargc,char*argv)2. 3. /Colordepthinbitsofourwindow.4. intflags=SDL_OPENGL|SDL_RESIZABLE;5. /SettheSDL6. initSDL(SCREEN_WIDTH,SCREEN_HEIGHT,SCREEN_BPP,flags);7. /SettheOpenGL8. initGL(SCREEN_WIDTH,SCREEN_HEIGHT);9. ps=ParticalSystem(100,-15.0);10. ps.init();11. /mainloop12. while(true)13. 14. /*Processincomingevents.*/15. handleEvents();16. ps.simulate(0.01);17. /*Drawthescreen.*/18. renderGL();19. 20. return0;21. 然后是渲染函数：cppview plaincopy1. voidrenderGL()2. 3. /Clearthecoloranddepthbuffers.4. glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);5. /Wedontwanttomodifytheprojectionmatrix.*/6. glMatrixMode(GL_MODELVIEW);7. glLoadIdentity();8. /Movedownthez-axis.9. glTranslatef(0.0f,0.0f,-35.0f);10. ps.render();11. SDL_GL_SwapBuffers();12. cppview plaincopy1. voidrenderGL()2. 3. /Clearthecoloranddepthbuffers.4. glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);5. /Wedontwanttomodifytheprojectionmatrix.*/6. glMatrixMode(GL_MODELVIEW);7. glLoadIdentity();8. /Movedownthez-axis.9. glTranslatef(0.0f,0.0f,-35.0f);10. ps.render();11. SDL_GL_SwapBuffers();12. 跑一下：效果还是不错的下面我们来实现一些更棒的效果！四、动态模糊和碰撞检测动态模糊的实现比较简单，主循环不再每次把整个画面清空，而是每帧画一个半透明的黑色长方形，就可以模拟动态模糊(motion blur)的效果。将之前的cppview plaincopy1. /Clearthecoloranddepthbuffers.2. glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);cppview plaincopy1. /Clearthecoloranddepthbuffers.2. glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);改成cppview plaincopy1. /Clearthedepthbuffers.2. glClear(GL_DEPTH_BUFFER_BIT);cppview plaincopy1. /Clearthedepthbuffers.2. glClear(GL_DEPTH_BUFFER_BIT);然后在例子系统的render函数中添加画矩形的代码：cppview plaincopy1. voidParticalSystem:render()2. 3. 4. for(vector:iteratoriter=particles.begin();iter!=particles.end();iter+)5. 6. floatalpha=1-iter-age/iter-life;7. Vector3Dtmp=iter-position;8. glColor4f(iter-color.r,iter-color.g,iter-color.b,alpha);9. /glColor4f(1.0f,1.0f,1.0f,0.1);10. glPushMatrix();11. glTranslatef(tmp.x,tmp.y,tmp.z);12. gluSphere(mySphere,iter-size,32,16);13. glPopMatrix();14. 15. 16. /Motionblue17. glColor4f(0.0f,0.0f,0.0f,0.1);18. glBegin(GL_QUADS);19. glVertex3f(-20.0f,-20.0f,20.0f);20. glVertex3f(20.0f,-20.0f,20.0f);21. glVertex3f(20.0f,20.0f,20.0f);22. glVertex3f(-20.0f,20.0f,20.0f);23. glEnd();24. 25. cppview plaincopy1. voidParticalSystem:render()2. 3. 4. for(vector:iteratoriter=particles.begin();iter!=particles.end();iter+)5. 6. floatalpha=1-iter-age/iter-life;7. Vector3Dtmp=iter-position;8. glColor4f(iter-color.r,iter-color.g,iter-color.b,alpha);9. /glColor4f(1.0f,1.0f,1.0f,0.1);10. glPushMatrix();11. glTranslatef(tmp.x,tmp.y,tmp.z);12. gluSphere(mySphere,iter-size,32,16);13. glPopMatrix();14. 15. 16. /Motionblue17. glColor4f(0.0f,0.0f,0.0f,0.1);18. glBegin(GL_QUADS);19. glVertex3f(-20.0f,-20.0f,20.0f);20. glVertex3f(20.0f,-20.0f,20.0f);21. glVertex3f(20.0f,20.0f,20.0f);22. glVertex3f(-20.0f,20.0f,20.0f);23. glEnd();24. 25. 渲染一下：效果还不错！碰撞检测之前也实现过，在粒子系统里面加检测函数就Ok了.cppview plaincopy1. voidParticalSystem:checkBump(floatx1,floatx2,floaty1,floaty2)2. 3. for(vector:iteratoriter=particles.begin();iter!=particles.end();iter+)4. 5. if(iter-position.x-iter-sizeposition.x+iter-sizex2)iter-velocity.x=-iter-velocity.x;6. if(iter-position.y-iter-sizeposition.y+iter-sizey2)iter-velocity.y=-iter-velocity.y;7. 8. cppview plaincopy1. voidParticalSystem:checkBump(floatx1,floatx2,floaty1,floaty2)2. 3. for(vector:iteratoriter=particles.begin();iter!=particles.end();iter+)4. 5. if(iter-position.x-iter-sizeposition.x+iter-sizex2)iter-velocity.x=-iter-velocity.x;6. if(iter-position.y-iter-sizeposition.y+iter-sizey2)iter-velocity.y=-iter-velocity.y;7. 8