/*
	模擬瀑布的粒子系統

*/
#include?
#include?
#include?
#include?

//?variables?to?keep?track?of?the?current?rotation?on?each?axis
GLfloat?camPitch?=?0.0?camYaw?=?1.0?camRadius?=?12.0;
int?mxmy;?//?used?to?calculate?mouse?displacement
int?mdown;?//?is?a?button?down?
int?buttonDown;?//?if?so?which?button?

char?*outfile?=?“windowDump.raw“;

typedef?GLfloat?point3[3];

GLfloat?t=0.0;????????//?parameter?for?the?family?of?functions

#define?HOWMANY?1000000
#define?ToUpdate?100

int?WIDTH?=?500;
int?HEIGHT?=?500;
static??GLubyte?bufImage[500][500][3];

float?particles[HOWMANY][7];

GLfloat?white[]?=?{1.0?1.0?1.0?1.0};
GLfloat?yellow[]=?{1.0?1.0?0.0?1.0};
GLfloat?mat_shininess[]={?30.0?};

//?function?prototypes?follow
GLfloat?XX（?int?）;
GLfloat?ZZ（?int?）;
void?myinit（?void?）;
float?tweak（float）;
void?particlesInit（int）;
void?update（int）;
void?drawParticle（int）;
void?waterfall（void）;
//void?surface（?void?）;
void?display（?void?）;
void?reshape（?int?int?）;
void?keyboard（unsigned?char?int?int?）;
void?animate（?void?）;

void?saveWindow（char?*?int?int）;

//?initialize?OpenGL?and?all?necessary?global?variables
void?myinit（void）
{
????????int?i;
		
		GLfloat?light_pos0[]={??0.0?10.0?10.0??1.0?};?//?first?light?over?z-axis
????????GLfloat?light_col0[]={??1.0??0.0??0.0??1.0?};?//?and?red
????????GLfloat?amb_color0[]={??0.3??0.0??0.0??1.0?};?//?even?ambiently
????????
????????GLfloat?light_pos1[]={??5.0?10.0?-7.26?1.0?};?//?second?light?back/right
????????GLfloat?light_col1[]={??0.0??1.0??0.0??1.0?};?//?and?green
????????GLfloat?amb_color1[]={??0.0??0.3??0.0??1.0?};?//?even?ambiently
????????
????????GLfloat?light_pos2[]={?-5.0?10.0?-7.26?1.0?};?//?third?light?back/left
????????GLfloat?light_col2[]={??0.0??0.0??1.0??1.0?};?//?and?blue
????????GLfloat?amb_color2[]={??0.0??0.0??0.3??1.0?};?//?even?ambiently
????????
//??????set?up?overall?light?data
????????GLfloat?mat_specular[]??={?0.8?0.8?0.8?1.0?};

????????glClearColor（?0.0?0.0?1.0?0.0?）;
????????glShadeModel（GL_SMOOTH）;?//?use?gourand?shading
????????glMaterialfv（GL_FRONT_AND_BACK?GL_SPECULAR?mat_specular?）;
????????
????????glLightfv（GL_LIGHT0?GL_POSITION?light_pos0?）;?//?light?0
????????glLightfv（GL_LIGHT0?GL_AMBIENT?amb_color0?）;
????????glLightfv（GL_LIGHT0?GL_SPECULAR?light_col0?）;
????????glLightfv（GL_LIGHT0?GL_DIFFUSE?light_col0?）;
????????
????????glLightfv（GL_LIGHT1?GL_POSITION?light_pos1?）;?//?light?1
????????glLightfv（GL_LIGHT1?GL_AMBIENT?amb_color1?）;
????????glLightfv（GL_LIGHT1?GL_SPECULAR?light_col1?）;
????????glLightfv（GL_LIGHT1?GL_DIFFUSE?light_col1?）;
????????
????????glLightfv（GL_LIGHT2?GL_POSITION?light_pos2?）;?//?light?2
????????glLightfv（GL_LIGHT2?GL_AMBIENT?amb_color2?）;
????????glLightfv（GL_LIGHT2?GL_SPECULAR?light_col2?）;
????????glLightfv（GL_LIGHT2?GL_DIFFUSE?light_col2?）;
????????
????????glLig