计算机图形学 -- 基本图形函数练习

1. 基本

#include<glut.h>
#pragma comment(linker,"/subsystem:\"windows\" /entry:\"mainCRTStartup\"")

void mydisplay(void)
{
	//glClearColor ： 通过glClear使用红，绿，蓝以及AFA值来清除颜色缓冲区，并且缺省值全是0. 即（0，0，0，0）
	glClearColor(1.0,1.0,0.0,0.0);	//设置背景为绿色		
	glClear(GL_COLOR_BUFFER_BIT);
	
	//在左上角画一个黄色的矩形
	glColor3f(0.0f,1.0f,1.0f);
	glRectf(-0.9f,0.0f,0.0f,0.9f);//分别是左下角和右上角两点坐标

	//在右上角画一个花花的三角形
	glBegin(GL_TRIANGLES);
	glColor3f(1.0f,0.0f,0.0f);	glVertex2f(0.9f,0.0f);
	glColor3f(0.0f,1.0f,0.0f);	glVertex2f(0.5f,0.6f);
	glColor3f(0.0f,0.0f,1.0f);	glVertex2f(0.1f,0.0f);
	glEnd();

	//画两个点
	glPointSize(5);//表示点的像素
	glBegin(GL_POINTS);
	glColor3f(0.0f,0.0f,0.0f);	glVertex2f(0.05f,0.0f);
	glColor3f(1.0f,0.0f,0.0f);	glVertex2f(0.05f,-0.5f);
	glEnd();

	glFlush();
}

int main(int argc,char *argv[])
{
	glutInit(&argc,argv);
	glutInitDisplayMode(GLUT_RGB|GLUT_SINGLE);
	glutInitWindowPosition(300,100);
	glutInitWindowSize(500,500);
	glutCreateWindow("Basic Shape");
	glutDisplayFunc(&mydisplay);
	glutMainLoop();
	return 0;
}

2. 升级1

#include<glut.h>
#include<math.h>
#pragma comment(linker,"/subsystem:\"windows\" /entry:\"mainCRTStartup\"")
const GLfloat R = 0.8f;
const GLfloat PI = 3.1415926536f;
const int n = 600;

void basicshape2(void)
{
	int i;
	glClearColor(1.0,1.0,0.0,0.8);
	glClear(GL_COLOR_BUFFER_BIT);

/* ---------------------- ----------------------*/
	glLineWidth(3);
	glBegin(GL_POLYGON);	//以闭合折线方式画圆
	glColor3f(1.0f,0.0f,0.0f);
	for(i=0; i<n; ++i)
		glVertex2f(R*cos(2*PI/n*i), R*sin(2*PI/n*i));
	glEnd();

/* ---------------------- ----------------------*/
	glBegin(GL_LINE_LOOP);	//以闭合折线方式画五角星
	glColor3f(0.0f,1.0f,0.0f);

	GLfloat bx=R*cos(18*PI/180);
	GLfloat by=R*sin(18*PI/180);
	GLfloat cx=R*sin(36*PI/180);
	GLfloat cy=R*cos(36*PI/180);
	
	glVertex2f(-bx,by);
	glVertex2f(bx,by);
	glVertex2f(-cx,-cy);
	glVertex2f(0.0f,R);
	glVertex2f(cx,-cy);

	glEnd();

/* ---------------------- ----------------------*/
	glBegin(GL_POLYGON);	//以填充方式画菱形,多边形，五角星也是可以的啦~
	glVertex2f(-0.8f,0.95f);
	glVertex2f(-0.7f,0.85f);
	glVertex2f(-0.8f,0.75f);
	glVertex2f(-0.9f,0.85f);
	glEnd();

	glBegin(GL_POLYGON);	//对称一下
	glVertex2f(0.8f,0.95f);
	glVertex2f(0.7f,0.85f);
	glVertex2f(0.8f,0.75f);
	glVertex2f(0.9f,0.85f);
	glEnd();
	//这里有两个菱形，可以用GL_QUADS一次搞定，独立的~

/* ---------------------- ----------------------*/
	glColor3f(0.0f,0.0f,1.0f);
	glBegin(GL_TRIANGLES);	//两个三角形
	glVertex2f(-1.0f,-1.0f);
	glVertex2f(-0.95f,-0.7f);
	glVertex2f(-0.8f,-0.7f);
	glVertex2f(-1.0f,-1.0f);
	glVertex2f(-0.8f,-0.75f);
	glVertex2f(-0.8f,-0.95f);
	glEnd();

	glFlush();
}

int main(int argc,char *argv[])
{
	glutInit(&argc,argv);
	glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);
	glutInitWindowPosition(150,150);
	glutInitWindowSize(500,500);

	glutCreateWindow("Baisc Shape2");
	glutDisplayFunc(basicshape2);

	glutMainLoop();
	return 0;
}

3. 升级2

#include<GL/glut.h>
#include<math.h>
#pragma comment(linker,"/subsystem:\"windows\" /entry:\"mainCRTStartup\"")
const float R1 = 0.8f;
const float R2 = 0.4f;
const float PI = 3.1415926;
void myDisplay_1()
{
	glClearColor(1.0f,1.0f,1.0f,0.0f);
	glClear(GL_COLOR_BUFFER_BIT);
	

	//*****下面开始画矩形和三角形
	glColor3f(1.0f,0.0f,0.0f);
	glBegin(GL_POLYGON);
	glVertex2f(0.4f,0);
	glVertex2f(0,0.4f);
	glVertex2f(-0.4f,0);
	glVertex2f(0,-0.4f);
	glEnd();

	glBegin(GL_TRIANGLES);	//四个三角形
	glColor3f(1.0f,1.0f,0.0f);
	glVertex2f(0.4f,-0.4f);
	glVertex2f(0.8f,0);
	glVertex2f(0.4f,0.4f);
	
	glColor3f(0.0f,0.0f,1.0f);
	glVertex2f(0.4f,0.4f);
	glVertex2f(-0.4f,0.4f);
	glVertex2f(0,0.8f);

	glColor3f(1.0f,0.0f,1.0f);
	glVertex2f(-0.4f,0.4f);
	glVertex2f(-0.4f,-0.4f);
	glVertex2f(-0.8f,0);

	glColor3f(0.0f,1.0f,0.0f);
	glVertex2f(-0.4f,-0.4f);
	glVertex2f(0.4f,-0.4f);
	glVertex2f(0,-0.8f);

	glEnd();

	//******描边
	glColor3f(0.0f,0.0f,0.0f);
	glBegin(GL_LINE_LOOP);

	glVertex2f(0.4f,0);//矩形的边
	glVertex2f(0,0.4f);
	glVertex2f(-0.4f,0);
	glVertex2f(0,-0.4f);
	glEnd();

	glBegin(GL_LINE_LOOP);//三角形的边,可当作两个矩形
	glVertex2f(0.8f,0);
	glVertex2f(0.4f,-0.4f);
	glVertex2f(0,-0.8f);
	glVertex2f(-0.4f,-0.4f);
	glVertex2f(-0.8f,0);
	glVertex2f(-0.4f,0.4f);
	glVertex2f(0,0.8f);
	glVertex2f(0.4f,0.4f);
	glVertex2f(0.4f,-0.4f);
	glVertex2f(-0.4f,-0.4f);
	glVertex2f(-0.4f,0.4f);
	glVertex2f(0.4f,0.4f);
	glEnd();

	glFlush();
}

void myDisplay_2()
{
	glClearColor(1.0f,1.0f,1.0f,0.0f);
	glClear(GL_COLOR_BUFFER_BIT);
	
	for(int i=0;i<=270;i+=90){
		
		glColor3f(1.0f,0.0f,0.0f);
		glBegin(GL_POLYGON);
		glVertex2f(R1*cos(i*PI/180),R1*sin(i*PI/180));
		glVertex2f(R2*cos((i+25)*PI/180),R2*sin((i+25)*PI/180));
		glVertex2f(0,0);
		glVertex2f(R2*cos((i-25)*PI/180),R2*sin((i-25)*PI/180));
		glEnd();

		glColor3f(0.0f,0.0f,0.0f);
		glBegin(GL_LINE_LOOP);
		glVertex2f(R1*cos(i*PI/180),R1*sin(i*PI/180));
		glVertex2f(R2*cos((i+25)*PI/180),R2*sin((i+25)*PI/180));
		glVertex2f(0,0);
		glVertex2f(R2*cos((i-25)*PI/180),R2*sin((i-25)*PI/180));
		glEnd();	
	}
	
	for(i=45;i<=315;i+=90){
		
		glColor3f(0.0f,1.0f,0.0f);
		glBegin(GL_POLYGON);
		glVertex2f(R1*cos(i*PI/180),R1*sin(i*PI/180));
		glVertex2f(R2*cos((i+20)*PI/180),R2*sin((i+20)*PI/180));
		glVertex2f(0,0);
		glVertex2f(R2*cos((i-20)*PI/180),R2*sin((i-20)*PI/180));
		glEnd();
		
		glColor3f(0.0f,0.0f,0.0f);
		glBegin(GL_LINE_LOOP);
		glVertex2f(R1*cos(i*PI/180),R1*sin(i*PI/180));
		glVertex2f(R2*cos((i+20)*PI/180),R2*sin((i+20)*PI/180));
		glVertex2f(0,0);
		glVertex2f(R2*cos((i-20)*PI/180),R2*sin((i-20)*PI/180));
		glEnd();

	}
		
	glFlush();
}


int main(int argc,char * argv[])
{
	glutInit(&argc,argv);
	glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);
	glutInitWindowPosition(100,100);
	glutInitWindowSize(500,500);
	glutCreateWindow("sheng2_1");

	glutDisplayFunc(myDisplay_1);

	glutInitWindowPosition(700,100);
	glutInitWindowSize(500,500);
	glutCreateWindow("sheng2_2");
	glutDisplayFunc(myDisplay_2);

	glutMainLoop();
	return 0;
}