OpenGL的显示列表

我们用glNewList()命令来开始构造显示列表。第二个参数GL_COMPILE告诉OpenGL我们想预先在内存中构造这个列表，这样每次画的时候就不必重新计算怎么构造物体了。GL_COMPILE类似于编程。在你写程序的时候，把它装载到编译器里，你每次运行程序都需要重新编译。而如果他已经编译成了.exe文件，那么每次你只需要点击那个.exe文件就可以运行它了，不需要编译。当OpenGL编译过显示列表后，就不需要再每次显示的时候重新编译它了。这就是为什么用显示列表可以加快速度。<?xml:namespace prefix = o />

你可以在glNewList()和glEngList()中间加上任何你想加上的代码。可以设置颜色，贴图等等。唯一不能加进去的代码就是会改变显示列表的代码。显示列表一旦建立，你就不能改变它。

比如你想加上glColor3ub(rand()%255,rand()%255,rand()%255)，使得每一次画物体时都会有不同的颜色。但因为显示列表只会建立一次，所以每次画物体的时候颜色都不会改变。物体将会保持第一次建立显示列表时的颜色。 如果你想改变显示列表的颜色，你只有在调用显示列表之前改变颜色。

成员变量区：
intm_GLPixelIndex;
HGLRCm_hGLContext;//绘制环境

GLfloatxrot;//绕x轴旋转量
GLfloatyrot;//绕y轴旋转量

GLfloatxspeed;//X旋转速度
GLfloatyspeed;//Y旋转速度

GLfloatz;//深入屏幕的距离

GLuintfilter;
GLuinttexture[1];
GLfloatLightAmbient[4];//环境光参数
GLfloatLightDiffuse[4];//漫射光参数
GLfloatLightPosition[4];//光源位置

GLbooleanbLighting;//是否启用光照
boollPressed;
boolfPressed;


GLuintbox;//保存盒子的显示列表
GLuinttop;//保存盒子顶部的显示列表
GLuintxloop;//X轴循环变量
GLuintyloop;//Y轴循环变量


staticGLfloatboxcol[5][3];

staticGLfloattopcol[5][3];

成员函数区：

BOOLCOpenGLDemoView::PreTranslateMessage(MSG*pMsg)
{
//TODO:Addyourspecializedcodehereand/orcallthebaseclass
if(pMsg->message==WM_KEYDOWN)
{
SendMessage(pMsg->message,pMsg->wParam,pMsg->lParam);
returntrue;
}
else
{
returnCView::PreTranslateMessage(pMsg);
}
}

voidCOpenGLDemoView::OnKeyDown(UINTnChar,UINTnRepCnt,UINTnFlags)
{
//TODO:Addyourmessagehandlercodehereand/orcalldefault
switch(nChar)
{
caseVK_LEFT:
{//左键
yspeed-=0.02f;
break;
}
caseVK_RIGHT:
{//右键
yspeed+=0.02f;
break;
}
caseVK_NEXT:
{//Page_Down键按下
z+=0.2f;
break;
}
caseVK_PRIOR:
{//Page_Up键按下
z-=0.2f;
break;
}
caseVK_UP:
{//Page_Up键按下
xspeed-=0.02f;
break;
}
caseVK_DOWN:
{//Page_Up键按下
xspeed+=0.02f;
break;
}
case'F':
{
fPressed=TRUE;
break;
}
case'L':
{
lPressed=TRUE;
break;
}

default:
break;
}

CView::OnKeyDown(nChar,nRepCnt,nFlags);
}

voidCOpenGLDemoView::OnKeyUp(UINTnChar,UINTnRepCnt,UINTnFlags)
{
//TODO:Addyourmessagehandlercodehereand/orcalldefault
switch(nChar)
{
case'F':
{
if(fPressed==TRUE)
{
filter=(filter+1)%3;
}
fPressed=FALSE;
break;
}
case'L':
{
if(lPressed==TRUE)
{//防止长时间按着'L'键而导致光照持续变化
bLighting=!bLighting;
if(bLighting)
{
glEnable(GL_LIGHTING);
}
else
{
glDisable(GL_LIGHTING);
}
}
lPressed=FALSE;
break;
}
default:
break;
}

CView::OnKeyUp(nChar,nRepCnt,nFlags);
}


GLvoidCOpenGLDemoView::BuildLists()
{
box=glGenLists(2);//Generate2DifferentLists
glNewList(box,GL_COMPILE);//StartWithTheBoxList
glBegin(GL_QUADS);
//BottomFace
glNormal3f(0.0f,-1.0f,0.0f);
glTexCoord2f(1.0f,1.0f);glVertex3f(-1.0f,-1.0f,-1.0f);
glTexCoord2f(0.0f,1.0f);glVertex3f(1.0f,-1.0f,-1.0f);
glTexCoord2f(0.0f,0.0f);glVertex3f(1.0f,-1.0f,1.0f);
glTexCoord2f(1.0f,0.0f);glVertex3f(-1.0f,-1.0f,1.0f);
//FrontFace
glNormal3f(0.0f,0.0f,1.0f);
glTexCoord2f(0.0f,0.0f);glVertex3f(-1.0f,-1.0f,1.0f);
glTexCoord2f(1.0f,0.0f);glVertex3f(1.0f,-1.0f,1.0f);
glTexCoord2f(1.0f,1.0f);glVertex3f(1.0f,1.0f,1.0f);
glTexCoord2f(0.0f,1.0f);glVertex3f(-1.0f,1.0f,1.0f);
//BackFace
glNormal3f(0.0f,0.0f,-1.0f);
glTexCoord2f(1.0f,0.0f);glVertex3f(-1.0f,-1.0f,-1.0f);
glTexCoord2f(1.0f,1.0f);glVertex3f(-1.0f,1.0f,-1.0f);
glTexCoord2f(0.0f,1.0f);glVertex3f(1.0f,1.0f,-1.0f);
glTexCoord2f(0.0f,0.0f);glVertex3f(1.0f,-1.0f,-1.0f);
//Rightface
glNormal3f(1.0f,0.0f,0.0f);
glTexCoord2f(1.0f,0.0f);glVertex3f(1.0f,-1.0f,-1.0f);
glTexCoord2f(1.0f,1.0f);glVertex3f(1.0f,1.0f,-1.0f);
glTexCoord2f(0.0f,1.0f);glVertex3f(1.0f,1.0f,1.0f);
glTexCoord2f(0.0f,0.0f);glVertex3f(1.0f,-1.0f,1.0f);
//LeftFace
glNormal3f(-1.0f,0.0f,0.0f);
glTexCoord2f(0.0f,0.0f);glVertex3f(-1.0f,-1.0f,-1.0f);
glTexCoord2f(1.0f,0.0f);glVertex3f(-1.0f,-1.0f,1.0f);
glTexCoord2f(1.0f,1.0f);glVertex3f(-1.0f,1.0f,1.0f);
glTexCoord2f(0.0f,1.0f);glVertex3f(-1.0f,1.0f,-1.0f);
glEnd();
glEndList();
top=box+1;//StorageFor"Top"Is"Box"PlusOne
glNewList(top,GL_COMPILE);//NowThe"Top"DisplayList
glBegin(GL_QUADS);
//TopFace
glNormal3f(0.0f,1.0f,0.0f);
glTexCoord2f(0.0f,1.0f);glVertex3f(-1.0f,1.0f,-1.0f);
glTexCoord2f(0.0f,0.0f);glVertex3f(-1.0f,1.0f,1.0f);
glTexCoord2f(1.0f,0.0f);glVertex3f(1.0f,1.0f,1.0f);
glTexCoord2f(1.0f,1.0f);glVertex3f(1.0f,1.0f,-1.0f);
glEnd();
glEndList();
}

intCOpenGLDemoView::DrawGLScene()
{//Here'sWhereWeDoAllTheDrawing

glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);//ClearScreenAndDepthBuffer

glPushAttrib(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT|GL_CURRENT_BIT);
glPushMatrix();

glBindTexture(GL_TEXTURE_2D,texture[this->filter]);//绑定到选定的纹理上
for(yloop=1;yloop<6;yloop++)
{
for(xloop=0;xloop<yloop;xloop++)
{
glLoadIdentity();//ResetTheView
glTranslatef(1.4f+(float(xloop)*2.8f)-(float(yloop)*1.4f),((6.0f-float(yloop))*2.4f)-7.0f,z);
glRotatef(45.0f-(2.0f*yloop)+xrot,1.0f,0.0f,0.0f);
glRotatef(45.0f+yrot,0.0f,1.0f,0.0f);
glColor3fv(boxcol[yloop-1]);
glCallList(box);
glColor3fv(topcol[yloop-1]);
glCallList(top);
}
}
xrot+=this->xspeed;
yrot+=this->yspeed;
returnTRUE;//EverythingWentOK
}

BOOLCOpenGLDemoView::InitGL(GLvoid)//AllSetupForOpenGLGoesHere
{
if(!LoadGLTextures())//JumpToTextureLoadingRoutine(NEW)
{
returnFALSE;//IfTextureDidn'tLoadReturnFALSE
}
this->BuildLists();
glEnable(GL_TEXTURE_2D);//EnableTextureMapping(NEW)

glLightfv(GL_LIGHT1,GL_AMBIENT,LightAmbient);//设置环境光
glLightfv(GL_LIGHT1,GL_DIFFUSE,LightDiffuse);//设置漫射光
glLightfv(GL_LIGHT1,GL_POSITION,LightPosition);//设置光源位置
glEnable(GL_LIGHT1);//启用一号光源

glShadeModel(GL_SMOOTH);//EnableSmoothShading
COLORREFcolor=::GetSysColor(COLOR_3DFACE);
glClearColor((float)GetRValue(color)/255.0f,
(float)GetGValue(color)/255.0f,
(float)GetBValue(color)/255.0f,
1.0);

glClearDepth(1.0f);//DepthBufferSetup
glEnable(GL_DEPTH_TEST);//EnablesDepthTesting
glDepthFunc(GL_LEQUAL);//TheTypeOfDepthTestingToDo
glHint(GL_PERSPECTIVE_CORRECTION_HINT,GL_NICEST);//ReallyNicePerspectiveCalculations

returnTRUE;//InitializationWentOK
}

效果如图所示：