// TRANGLE.cpp : 定义控制台应用程序的入口点。
//

#include "stdafx.h"
#include<GL\glut.h>
#include<math.h>
#define PI 3.14
GLfloat Range=100.0f ;
bool DEPTH_TEST=false;
bool CULL_FACE=false;
bool OUTLINE_BACK=false;
static GLfloat xRot=0.0f;
static GLfloat yRot=0.0f;
bool STOP_DEPTHTEST=false;
void Init()
{glClearColor(0.0f,0.0f,0.0f,1.0f);glFrontFace(GL_CW);//单调着色
    glShadeModel(GL_FLAT);
}
void ChangeSize(int w,int h)
{if (h==0){h=1;}glViewport(0,0,w,h);glMatrixMode(GL_PROJECTION);glLoadIdentity();if (w<=h){glOrtho(-Range,Range,-Range*h/w,Range*h/w,-Range,Range);}else{glOrtho(-Range*w/h,Range*w/h,-Range,Range,-Range,Range);}glMatrixMode(GL_MODELVIEW);glLoadIdentity();}
void MyMenu(int value)
{switch (value){case 1:DEPTH_TEST=!DEPTH_TEST;break;case 2:CULL_FACE=!CULL_FACE;break;case 3:OUTLINE_BACK=!OUTLINE_BACK;break;case 4:STOP_DEPTHTEST=true;default:break;}
}
void MyspecialKey(int key,int x,int y)
{if (key==GLUT_KEY_LEFT){yRot-=5.0f;}if (key==GLUT_KEY_RIGHT){yRot+=5.0f;}if (key==GLUT_KEY_UP){xRot-=5.0f;}if (key==GLUT_KEY_DOWN){xRot+=5.0f;}if (xRot>355.0f){xRot=0.0f;}if (xRot<=-5.0f){xRot=355.0f;}if (yRot>355.0f){yRot=0.0f;}if (yRot<=-5.0f){yRot=355.0f;}glutPostRedisplay();
}
void Mydisplay()
{GLint color=1;GLfloat angle=0.0f;GLfloat x,y;glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);if (DEPTH_TEST){glEnable(GL_DEPTH_TEST);}else{glDisable(GL_DEPTH_TEST);}if (CULL_FACE){glEnable(GL_CULL_FACE);glCullFace(GL_BACK);}else{glDisable(GL_CULL_FACE);}if (STOP_DEPTHTEST){glDisable(GL_DEPTH_TEST);}if (OUTLINE_BACK){glPolygonMode(GL_BACK,GL_LINE);}else{glPolygonMode(GL_BACK,GL_FILL);}glPushMatrix();glRotatef(xRot,1.0f,0.0f,0.0f);glRotatef(yRot,0.0f,1.0f,0.0f);glBegin(GL_TRIANGLE_FAN);glVertex3f(0.0f,0.0f,75.0f);for (angle = 0;angle<PI*2; angle+=(PI/8)){x=50.0f*cos(angle);y=50.0f*sin(angle);if ((color%2)==0){glColor3f(0.0f,1.0f,0.0f);}else{glColor3f(1.0f,0.0f,0.0f);}color++;glVertex3f(x,y,0.0f);}glEnd();glBegin(GL_TRIANGLE_FAN);glVertex3f(0.0f,0.0f,0.0f);for (angle = 0;angle<PI*2; angle+=(PI/8)){x=50.0f*cos(angle);y=50.0f*sin(angle);if ((color%2)==0){glColor3f(0.0f,1.0f,0.0f);}else{glColor3f(1.0f,0.0f,0.0f);}color++;glVertex3f(x,y,0.0f);}glEnd();glPopMatrix();glutSwapBuffers();}
int main(int argc,char ** argv)
{glutInit(&argc,argv);glutInitDisplayMode(GLUT_RGB|GLUT_DOUBLE|GLUT_DEPTH);glutInitWindowPosition(500,300);glutInitWindowSize(600,600);glutCreateWindow("Trangle");Init();glutDisplayFunc(Mydisplay);glutReshapeFunc(ChangeSize);glutCreateMenu(MyMenu);glutAddMenuEntry("Depth Test",1);glutAddMenuEntry("CullFace",2);glutAddMenuEntry("Outline Back",3);glutAddMenuEntry("STOP DEPTHTEST",4);glutAttachMenu(GLUT_RIGHT_BUTTON);glutSpecialFunc(MyspecialKey);glutMainLoop();}