Glut下提供了一些現成的繪製立體的API,如glutWireSphere繪製球,glutWireCone繪製椎體,glutWireCube繪製立體,glutWireTorus繪製甜圈,glutWireTeapot繪製茶壺,glutWireOctahedron繪製八面體。
Demo程序利用這些API繪製相應的立體,單擊鼠標右鍵在彈出的菜單裏可以選擇需要繪製的立體以及是wire還是solid填充的,按鍵盤的UP、DOWN、LEFT、RIGHT按鍵可以旋轉座標系。由於Glut提供的多面體API默認半徑是1.0f的,我使用glScalef對其進行了放大。示例效果如下:
源代碼:
- // GlutDemo.cpp : 定義控制檯應用程序的入口點。
- //
- #include "stdafx.h"
- #include <gl/glut.h>
- #include <math.h>
- //圓周率宏
- #define GL_PI 3.1415f
- //獲取屏幕的寬度
- GLint SCREEN_WIDTH=0;
- GLint SCREEN_HEIGHT=0;
- //設置程序的窗口大小
- GLint windowWidth=400;
- GLint windowHeight=300;
- //繞x軸旋轉角度
- GLfloat xRotAngle=0.0f;
- //繞y軸旋轉角度
- GLfloat yRotAngle=0.0f;
- //受支持的點大小範圍
- GLfloat sizes[2];
- //受支持的點大小增量
- GLfloat step;
- enum MODELS{
- SPHERE=0,
- CONE,
- CUBE,
- TORUS,
- DODECAHEDRON,
- TEAPOT,
- OCTAHEDRON,
- TETRAHEDRON,
- ICOSAHEDRON
- };
- GLint iModel=SPHERE;
- GLboolean bWire=GL_TRUE;
- //菜單回調函數
- void processMenu(int value){
- switch(value){
- case 1:
- iModel=SPHERE;
- break;
- case 2:
- iModel=CONE;
- break;
- case 3:
- iModel=CUBE;
- break;
- case 4:
- iModel=TORUS;
- break;
- case 5:
- iModel=DODECAHEDRON;
- break;
- case 6:
- iModel=TEAPOT;
- break;
- case 7:
- iModel=OCTAHEDRON;
- break;
- case 8:
- iModel=TETRAHEDRON;
- break;
- case 9:
- iModel=ICOSAHEDRON;
- break;
- case 10:
- bWire=GL_TRUE;
- break;
- case 11:
- bWire=GL_FALSE;
- break;
- default:
- break;
- }
- //重新繪製
- glutPostRedisplay();
- }
- //顯示回調函數
- void renderScreen(void){
- //將窗口顏色清理爲黑色
- glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
- //將模板緩衝區值全部清理爲1
- glClearStencil(1);
- //使能模板緩衝區
- glEnable(GL_STENCIL_TEST);
- //把整個窗口清理爲當前清理顏色:黑色。清除深度緩衝區、模板緩衝區
- glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT|GL_STENCIL_BUFFER_BIT);
- //將當前Matrix狀態入棧
- glPushMatrix();
- //座標系繞x軸旋轉xRotAngle
- glRotatef(xRotAngle,1.0f,0.0f,0.0f);
- //座標系繞y軸旋轉yRotAngle
- glRotatef(yRotAngle,0.0f,1.0f,0.0f);
- //進行平滑處理
- glEnable(GL_POINT_SMOOTH);
- glHint(GL_POINT_SMOOTH,GL_NICEST);
- glEnable(GL_LINE_SMOOTH);
- glHint(GL_LINE_SMOOTH,GL_NICEST);
- glEnable(GL_POLYGON_SMOOTH);
- glHint(GL_POLYGON_SMOOTH,GL_NICEST);
- //白色繪製座標系
- glColor3f(1.0f,1.0f,1.0f);
- glBegin(GL_LINES);
- glVertex3f(-9.0f,0.0f,0.0f);
- glVertex3f(9.0f,0.0f,0.0f);
- glVertex3f(0.0f,-9.0f,0.0f);
- glVertex3f(0.0f,9.0f,0.0f);
- glVertex3f(0.0f,0.0f,-9.0f);
- glVertex3f(0.0f,0.0f,9.0f);
- glEnd();
- glPushMatrix();
- glTranslatef(9.0f,0.0f,0.0f);
- glRotatef(90.0f,0.0f,1.0f,0.0f);
- glutSolidCone(0.3,0.6,10,10);
- glPopMatrix();
- glPushMatrix();
- glTranslatef(0.0f,9.0f,0.0f);
- glRotatef(-90.0f,1.0f,0.0f,0.0f);
- glutSolidCone(0.3,0.6,10,10);
- glPopMatrix();
- glPushMatrix();
- glTranslatef(0.0f,0.0f,9.0f);
- glRotatef(90.0f,0.0f,0.0f,1.0f);
- glutSolidCone(0.3,0.6,10,10);
- glPopMatrix();
- //設置繪畫顏色爲金色
- glColor3f(0.0f,1.0f,0.0f);
- switch(iModel){
- //球
- case SPHERE:
- if(bWire){
- glutWireSphere(8.0f,20,20);
- }
- else{
- glutSolidSphere(8.0f,20,20);
- }
- break;
- //錐體
- case CONE:
- if(bWire){
- glutWireCone(4.0f,8.0f,20,20);
- }
- else{
- glutSolidCone(4.0f,8.0f,20,20);
- }
- break;
- //立體
- case CUBE:
- if(bWire){
- glutWireCube(8.0f);
- }
- else{
- glutSolidCube(8.0f);
- }
- break;
- //甜圈
- case TORUS:
- if(bWire){
- glutWireTorus(3.0f,6.0f,20,20);
- }
- else{
- glutSolidTorus(3.0f,6.0f,20,20);
- }
- break;
- //十六面體,默認半徑1.0
- case DODECAHEDRON:
- glScalef(6.0f,6.0f,6.0f);//x,y,z軸均放大6倍
- if(bWire){
- glutWireDodecahedron();
- }
- else{
- glutSolidDodecahedron();
- }
- break;
- //茶壺
- case TEAPOT:
- if(bWire){
- glutWireTeapot(8.0f);
- }
- else{
- glutSolidTeapot(8.0f);
- }
- break;
- //八面體,默認半徑1.0
- case OCTAHEDRON:
- glScalef(6.0f,6.0f,6.0f);//x,y,z軸均放大6倍
- if(bWire){
- glutWireOctahedron();
- }
- else{
- glutSolidOctahedron();
- }
- break;
- //四面體,默認半徑1.0
- case TETRAHEDRON:
- glScalef(6.0f,6.0f,6.0f);//x,y,z軸均放大6倍
- if(bWire){
- glutWireTetrahedron();
- }
- else{
- glutSolidTetrahedron();
- }
- break;
- //二十面體,默認半徑1.0
- case ICOSAHEDRON:
- glScalef(6.0f,6.0f,6.0f);//x,y,z軸均放大6倍
- if(bWire){
- glutWireIcosahedron();
- }
- else{
- glutSolidIcosahedron();
- }
- break;
- default:
- break;
- }
- //恢復壓入棧的Matrix
- glPopMatrix();
- //交換兩個緩衝區的指針
- glutSwapBuffers();
- }
- //設置Redering State
- void setupRederingState(void){
- //設置清理顏色爲黑色
- glClearColor(0.0f,0.0,0.0,1.0f);
- //設置繪畫顏色爲綠色
- glColor3f(1.0f,1.0f,0.0f);
- //使能深度測試
- glEnable(GL_DEPTH_TEST);
- //獲取受支持的點大小範圍
- glGetFloatv(GL_POINT_SIZE_RANGE,sizes);
- //獲取受支持的點大小增量
- glGetFloatv(GL_POINT_SIZE_GRANULARITY,&step);
- printf("point size range:%f-%f\n",sizes[0],sizes[1]);
- printf("point step:%f\n",step);
- }
- //窗口大小變化回調函數
- void changSize(GLint w,GLint h){
- //橫寬比率
- GLfloat ratio;
- //設置座標系爲x(-100.0f,100.0f)、y(-100.0f,100.0f)、z(-100.0f,100.0f)
- GLfloat coordinatesize=10.0f;
- //窗口寬高爲零直接返回
- if((w==0)||(h==0))
- return;
- //設置視口和窗口大小一致
- glViewport(0,0,w,h);
- //對投影矩陣應用隨後的矩陣操作
- glMatrixMode(GL_PROJECTION);
- //重置當前指定的矩陣爲單位矩陣
- glLoadIdentity();
- ratio=(GLfloat)w/(GLfloat)h;
- //正交投影
- if(w<h)
- glOrtho(-coordinatesize,coordinatesize,-coordinatesize/ratio,coordinatesize/ratio,-coordinatesize,coordinatesize);
- else
- glOrtho(-coordinatesize*ratio,coordinatesize*ratio,-coordinatesize,coordinatesize,-coordinatesize,coordinatesize);
- //對模型視圖矩陣堆棧應用隨後的矩陣操作
- glMatrixMode(GL_MODELVIEW);
- //重置當前指定的矩陣爲單位矩陣
- glLoadIdentity();
- }
- //按鍵輸入處理回調函數
- void specialKey(int key,int x,int y){
- if(key==GLUT_KEY_UP){
- xRotAngle-=5.0f;
- }
- else if(key==GLUT_KEY_DOWN){
- xRotAngle+=5.0f;
- }
- else if(key==GLUT_KEY_LEFT){
- yRotAngle-=5.0f;
- }
- else if(key==GLUT_KEY_RIGHT){
- yRotAngle+=5.0f;
- }
- //重新繪製
- glutPostRedisplay();
- }
- int main(int argc, char* argv[])
- {
- int nModelMenu;
- int nWireMenu;
- int nMainMenu;
- //初始化glut
- glutInit(&argc,argv);
- //使用雙緩衝區、深度緩衝區、模板緩衝區
- glutInitDisplayMode(GLUT_DOUBLE|GLUT_RGBA|GLUT_DEPTH|GLUT_STENCIL);
- //獲取系統的寬像素
- SCREEN_WIDTH=glutGet(GLUT_SCREEN_WIDTH);
- //獲取系統的高像素
- SCREEN_HEIGHT=glutGet(GLUT_SCREEN_HEIGHT);
- //創建窗口,窗口名字爲OpenGL Glut Demo
- glutCreateWindow("OpenGL Glut Demo");
- //設置窗口大小
- glutReshapeWindow(windowWidth,windowHeight);
- //窗口居中顯示
- glutPositionWindow((SCREEN_WIDTH-windowWidth)/2,(SCREEN_HEIGHT-windowHeight)/2);
- //創建二級菜單
- nModelMenu=glutCreateMenu(processMenu);
- glutAddMenuEntry("Sphere",1);
- glutAddMenuEntry("Cone",2);
- glutAddMenuEntry("Cube",3);
- glutAddMenuEntry("Torus",4);
- glutAddMenuEntry("Dodecahedron",5);
- glutAddMenuEntry("Teapot",6);
- glutAddMenuEntry("Octahedron",7);
- glutAddMenuEntry("Tetrahedron",8);
- glutAddMenuEntry("Icosahedron",9);
- nWireMenu=glutCreateMenu(processMenu);
- glutAddMenuEntry("Wire",10);
- glutAddMenuEntry("Solid",11);
- nMainMenu=glutCreateMenu(processMenu);
- glutAddSubMenu("Model",nModelMenu);
- glutAddSubMenu("WireOrSolid",nWireMenu);
- //將菜單榜定到鼠標右鍵上
- glutAttachMenu(GLUT_RIGHT_BUTTON);
- //窗口大小變化時的處理函數
- glutReshapeFunc(changSize);
- //設置顯示回調函數
- glutDisplayFunc(renderScreen);
- //設置按鍵輸入處理回調函數
- glutSpecialFunc(specialKey);
- //設置全局渲染參數
- setupRederingState();
- glutMainLoop();
- return 0;
- }