粒子集散开，均匀分布正方形内

//粒子集散开，均匀分布正方形内
#include <GL/glut.h>
#include <stdio.h>
#include <math.h>										// 数学函数头文件
#include <olectl.h>	


#define RADIUS  4
#define WIDTH_HEIGHT_RATIO 2


#define WINDOW_HEIGHT 500
#define WINDOW_WIDTH  WINDOW_HEIGHT * WIDTH_HEIGHT_RATIO


#define	MAX_PARTICLES  100           //定义粒子的数目，就目前的程序健壮性，请设为9


int x = RADIUS;
float r1 = 0.0,g1 = 1.0,b1 = 0.0;          //正方形颜色的设定，初始化


int flagStop = 0,m = 0;
//////////////////////////////////////////////////////////////////////
typedef struct
{
	float	r,g,b;										// 粒子的颜色
	float	x,y;										// 粒子位置
	float	xSpeed,ySpeed;								// 粒子的速度
	float   xAddspeed,yAddspeed;
} PARTICLES;


PARTICLES particle[MAX_PARTICLES];						// 粒子系统数组
// 粒子颜色数组
static GLfloat colors[12][3]=											
{
	{1.0f, 0.0f, 0.0f},  {0.0f, 1.0f, 0.0f}, {0.0f, 1.0f, 1.0f}, {1.0f, 1.0f, 0.0f},
	{1.0f, 0.0f, 1.0f},  {0.0f, 1.0f, 1.0f},{1.0f, 0.0f, 0.0f},  {0.0f, 1.0f, 0.0f}, 
	{0.0f, 0.0f, 1.0f}, {1.0f, 1.0f, 0.0f},{1.0f, 0.0f, 1.0f},  {0.0f, 1.0f, 1.0f}
};


static GLfloat speeds[12][2]=							//粒子的速度							
{
	{12.0f,13.0f},  {3.0f,2.0f}, {7.0f,9.0f}, {8.0f,13.0f},
	{14.0f,44.0f},  {39.0f,46.0f}, {33.0f,45.0f}, {32.0f,12.0f},
	{22.0f,12.0f}, {9.0f,21.0f}, {21.0f,9.0f}, {8.0f,21.0f}
};


/*
数组实现的
*/
static GLfloat setlocation[][2]=						//粒子进入 正方形后的 位置									
{
	{650.0f,150.0f},  {650.0f,250.0f}, {650.0f,350.0f}, 
	{750.0f,150.0f},  {750.0f,250.0f}, {750.0f,350.0f}, 
	{850.0f,150.0f},  {850.0f,250.0f}, {850.0f,350.0f},
};

void ParticleInit()
{
	int loop;
	for (loop = 0; loop < MAX_PARTICLES; ++loop)
	{
		particle[loop].r = colors[rand()%12][0];						// 粒子颜色的红色分量
		particle[loop].g = colors[rand()%12][1];						// 粒子颜色的绿色分量
		particle[loop].b = colors[rand()%12][2];						// 粒子颜色的蓝色分量
		particle[loop].xSpeed = speeds[rand()%12][0];					// 沿x轴的随机速度
		particle[loop].ySpeed = speeds[rand()%12][1];;					// 沿y轴的随机速度
	
		//particle[loop].zSpeed = (float)(rand()%150);					// 沿z轴的随机速度(0,150)	
	}
}


void Draw(int x ,int y)
{
	glPushMatrix();							//保存现在的位置
	glTranslatef(x,y,0);					//移动
	glScalef(RADIUS,RADIUS,0);				//放大  倍
	glutSolidSphere(1.5f, 10, 10);			//渲染一个球  
	glPopMatrix();							//恢复以前的保存
}




void DrawParticle(void)
{
	float x,y,r,g,b;
	int loop;
	
	for (loop=0; loop < MAX_PARTICLES; ++loop)						
	{
		x = particle[loop].x;				// 定义粒子坐标
		y = particle[loop].y;
	
		r = particle[loop].r;
		g =	particle[loop].g;
		b = particle[loop].b;


		glColor3f(r,g,b);
		Draw(x,y);
	}
}


void UpdatePosition()
{
	int loop;
	for(loop = 0;loop < MAX_PARTICLES;++loop)
	{
		particle[loop].x += particle[loop].xSpeed;
		if(particle[loop].x > 550 & particle[loop].x < 950 & particle[loop].y > 50 & particle[loop].y < 450)
		{
			m ++;
			if(m < 400)
			{
				particle[loop].x = setlocation[rand()%9][0];	//for寻环实现 闪烁抖动
				particle[loop].y = setlocation[rand()%9][1];
			}
			else
			{
				for(loop = 0;loop < MAX_PARTICLES;++loop)
				{
					particle[loop].x = setlocation[loop][0];
					particle[loop].y = setlocation[loop][1];
				}


			}
			//正方形的坐标点		
		}
		else
		{
		
			//控制 x 坐标
			if( particle[loop].x > WINDOW_WIDTH - RADIUS)
			{
				particle[loop].x = WINDOW_WIDTH - RADIUS;
				particle[loop].xSpeed = -particle[loop].xSpeed ;
			}
			else if(particle[loop].x < RADIUS)
			{
				x = RADIUS;
				particle[loop].xSpeed  = -particle[loop].xSpeed ;
			}


			//控制 y 坐标
			particle[loop].y += particle[loop].ySpeed;


			if(particle[loop].y > (WINDOW_HEIGHT - RADIUS))
			{
				particle[loop].y = WINDOW_HEIGHT - RADIUS;
				particle[loop].ySpeed = -particle[loop].ySpeed;
			}
			else if( particle[loop].y < RADIUS)  
			{
				particle[loop].y = RADIUS;
				particle[loop].ySpeed = -particle[loop].ySpeed;
			}
		}
	}
	
}




void myinit()
{
    glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	gluOrtho2D(0, WINDOW_WIDTH, 0, WINDOW_HEIGHT);
    glMatrixMode(GL_MODELVIEW);
    glClearColor (0.0, 0.0, 0.0, 1.0);   //背景颜色的设定（1,1,1）白色，（0,0,0）黑色
	ParticleInit();	
}


//////////////////////////////////////////////////////xin tian
void triangle (GLsizei mode)
{
	if(mode == 1)
		glPolygonMode(GL_FRONT_AND_BACK,GL_LINE);//多边形模式为线框
	else 
		glPolygonMode(GL_FRONT_AND_BACK,GL_FILL); //多边形模式为填充多边形
	//	glBegin(GL_TRIANGLES);//三角形 三个点画一个三角形，剩下的不足三个舍掉
	glBegin(GL_POLYGON);//
	glColor3f(r1,g1,b1);//设定当前颜色 为绿色
	glVertex2f(550.0, 450.0);
	glVertex2f(550.0, 50.0);
	glVertex2f(950.0, 50.0);
	glVertex2f(950.0, 450.0);
	glEnd();
}


/*============================================*/
void display(void)
{
 	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);							// 清除场景和深度缓存
	DrawParticle();
	glViewport(0, 0, 800, 400);//指定从0，0开始（相对于显示窗口的左下角的位置）长宽均为400的
	triangle(1);
	glutSwapBuffers();// 刷新GL命令队列	
}


void TimerFunc(int value)
{
	if(0 == flagStop)UpdatePosition();
	glutPostRedisplay();
    glutTimerFunc(50, TimerFunc, 1);
}


/*============================================*/
void mouse(int btn, int state, int x, int y)
{
	if(btn==GLUT_LEFT_BUTTON && state == GLUT_DOWN) 
	{
		flagStop ++;
		flagStop = flagStop % 2;
	}


	glutPostRedisplay();
}




/*============================================*/
void keys1(unsigned char key, int x, int y)         //按键控制粒子的速度变化
{
	
	if(key == 'x')                                // x    加速                                      
	{	
		for(int loop = 0;loop < MAX_PARTICLES;++loop)
		{
			particle[loop].xSpeed = 1.2 * particle[loop].xSpeed;			// 沿x轴的速度
			particle[loop].ySpeed = 1.2 * particle[loop].ySpeed;			// 沿y轴的速度
		}


	}		
	else if(key == 'c')                         // c      减速		
	{
		for(int loop = 0;loop < MAX_PARTICLES;++loop)
		{
			particle[loop].xSpeed = 0.8 * particle[loop].xSpeed;			// 沿x轴的速度
			particle[loop].ySpeed = 0.8 * particle[loop].ySpeed;			// 沿y轴的速度
		}
	}
	else if(key == 'z')                        //z        速度还原
	{  
		for(int loop = 0;loop < MAX_PARTICLES;++loop)
		{
			particle[loop].xSpeed = speeds[rand()%12][0];			// 沿x轴的随机速度
			particle[loop].ySpeed = speeds[rand()%12][1];;			// 沿y轴的随机速度
		}
	}
	else if(key == 'v')
	{
		r1 = colors[rand()%12][0];						// 正方形颜色的红色分量
		g1 = colors[rand()%12][1];						// 正方形颜色的绿色分量
		b1 = colors[rand()%12][2];						// 正方形颜色的蓝色分量
	}
	else
	{
	
	}	
    glutPostRedisplay();
}

/*============================================*/
void myReshape(GLsizei w, GLsizei h)
{
	glViewport(0, 0, (GLsizei)(w), (GLsizei)(h));				// 重置当前视口大小
}

/*============================================*/
void main(int argc, char **argv)
{
	/* Standard GLUT initialization */
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH );	/* default, not needed */
    glutInitWindowSize(800, 800/WIDTH_HEIGHT_RATIO);					
    glutInitWindowPosition(0,0);								/* place window top left on display */
	glutCreateWindow("Ball Collision");							/* window title */


																/* callback functions */
    glutDisplayFunc(display);	
	glutMouseFunc(mouse);		
	glutKeyboardFunc(keys1);		
	glutReshapeFunc (myReshape);

	glutTimerFunc(500, TimerFunc, 1);							//指定定时器回调函数

	myinit();													/* set attributes */
	glutMainLoop();												/* enter event loop */	
}

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