用openGL做一个时钟动画

#include<stdlib.h>
#include<glut.h>
#include<gl\GLU.h>
#include<gl\GL.h>
#include<math.h>
#include<stdio.h>
#include<windows.h>

float tite = 0.0f;
const float PI = 3.14159f;
const int W_width = 500;
const int W_height = 500;
float xc, yc, R, n;
float ss, mm, hh;
const int S_width = glutGet(GLUT_SCREEN_WIDTH);
const int S_height = glutGet(GLUT_SCREEN_HEIGHT);

//system
void init();
void draw();
void reShape(int ww, int hh);

//colck
void drawCircle();
void myIdle();
void drawline();
void TimerFunc(int value);
void arith_foot();
void drawshortLine();
void TimerFunc(int value);

void init(){
	glClear(GL_COLOR_BUFFER_BIT);
	glClearColor(1.0f, 0.5f, 0.8f, 1.0);
	//colck
	SYSTEMTIME Timetite;
	GetLocalTime(&Timetite);
	xc = 0.0f, yc = 0.0f, R = 100.0f, n = 20.0f, ss = Timetite.wSecond, mm = Timetite.wMinute, hh = Timetite.wHour;
}
int main(int agrs, char **args) {
	glutInit(&agrs, args);
	init();
	glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB);
	glutInitWindowSize(W_width, W_height);
	glutInitWindowPosition((S_width - W_width) / 2, (S_height - W_width) / 2);
	glutCreateWindow("openGL");
	//设置视景体窗口

	glClearColor(0.6f, 0.4f, 0.3f, 1.0f); //清除窗口颜色的代码
	glutDisplayFunc(draw);
	glutReshapeFunc(reShape);
	glutMainLoop();
	return 0;
}

void draw(void) {
	glClear(GL_COLOR_BUFFER_BIT);
	glColor3f(1.0f, 0.0f, 0.0f);
	drawCircle();
	arith_foot();
	drawshortLine();
	//TimerFunc(10);
	glutTimerFunc(1000, TimerFunc, 10);
	//drawline();
	glutSwapBuffers();
	//shapes
}
void reShape(int ww, int hh) {
	glViewport(0, 0, ww, hh);
	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	if (hh == 0) hh = 1;
	if (ww >= hh) {
		gluOrtho2D(-500, 500 * (float)ww / hh, -500, 500);
	}
	else
	{
		gluOrtho2D(-500, 500, -500, 500 * (float)hh / ww);
	}
	glMatrixMode(GL_MODELVIEW);
}
//利用基本图元的绘制来实现简单动画的功能(时钟)
//draw circle
void drawCircle() {
	glBegin(GL_LINE_LOOP);
	for (int i = 0; i < n; i++) {
		glVertex2d(xc + R * cos(i * 2 * PI / n), yc + R * sin(i * 2 * PI / n));
	}
	glEnd();
}//画出时钟圆
//直线测试
void drawline() {
	glBegin(GL_LINES);
	glVertex2d(xc, yc);
	glVertex2d(R*cos(tite), R*sin(tite));
	glEnd();
}
//闲置函数
void myIdle(void) {
	tite += 0.002f;
	if (tite >= 2 * PI) {
		tite = 0.0f;
	}
	glutPostRedisplay();
}
void TimerFunc(int value) {//更新时分秒的值
	int carry1 = 0;
	ss += 1;
	if (ss >= 60) {
		ss = 0;
		carry1 = 1;
	}
	mm += carry1;
	int carry2 = 0;
	if (mm >= 60) {
		carry2 = 1;
		mm = 0;
	}
	hh += carry2;
	if (hh == 24) hh = 0;
	glutPostRedisplay();//(回调函数)返回draw方法根据ss,mm,hh更新xs,xm,xh的刻度值
}
//draw hh,ss,mm lines（绘制时针与分针的刻度线）
void drawshortLine(){
	int lines = 60;
	for (int i = 0; i < lines;i++){
		if (i % 5 == 0){//时针
			glLineWidth(5);
			glColor3f(0.0, 1.0, 0.0);
			glBegin(GL_LINES);
			glVertex2f(xc + (R-10)*sin(2*PI*i/lines),yc+(R-10)*cos(2*PI*i/lines));
			glVertex2f(xc + R*sin(2 * PI*i / lines), yc + R*cos(2 * PI*i / lines));
			glEnd();
		}
		else{
			glLineWidth(2);
			glColor3f(0.0,0.0,1.0);
			glBegin(GL_LINES);
			glVertex2f(xc+(R-5)*sin(2*PI*i/lines),yc+(R-5)*cos(2*PI*i/lines));
			glVertex2f(xc + R*sin(2 * PI*i / lines), yc + R*cos(2 * PI*i / lines));
			glEnd();
		}
	}	
}
//arith foot colck（每一次调用draw方法的时候都会根据此时不同的ss,mm,hh重新计算时分秒指针的值）
void arith_foot(){
	float xs = 0.0f, ys=0.0f, xm=0.0f, ym=0.0f, xh=0.0f, yh=0.0f;
	glLineWidth(1);
	xs = xc + (R-10)*sin(ss*2*PI/60);//根据比值法计算出秒针与y轴之间的角度来计算x终点位置与y终点位置
	ys = yc + (R - 10)*cos(ss * 2 * PI / 60);
	glColor3f(1.0f,0.0f,0.0f);
	glBegin(GL_LINES);
	glVertex2f(xc,yc);
	glVertex2f(xs,ys);
	glEnd();

	glLineWidth(3); 
	xm = xm + (R - 25)*sin((mm + ss / 60) * 2 * PI / 60);//秒针与分针都是60份
	ym = ym + (R - 25)*cos((mm + ss / 60) * 2 * PI / 60);
	glColor3f(0.0f, 1.0f, 0.0f);
	glBegin(GL_LINES);
	glVertex2f(xc,yc);
	glVertex2f(xm,ym);
	glEnd();
	
	glLineWidth(5);
	xh = xh + (R - 45)*sin((hh + (mm + ss / 60) / 60) * 2 * PI / 12);//每一次走的角度分为12份
	yh = yh + (R - 45)*cos((hh + (mm + ss / 60) / 60) * 2 * PI / 12);
	glColor3f(0.0f,0.0f,1.0f);
	glBegin(GL_LINES);
	glVertex2f(xc,yc);
	glVertex2f(xh,yh);
	glEnd();
}
//draw a lots of shapes
void Shapes(){
	//draw points
	glPointSize(10);
	glBegin(GL_POINT);
	//glVertex2d();
	//glVertex2d();
	//glVertex2d();
	glEnd();
}

 

来源：CSDN

作者：一剑孤寂

链接：https://blog.csdn.net/Icecoldless/article/details/80023346