// particle_fountain.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include<stdlib.h>
#include <stdio.h>
#include<Windows.h>
#include <time.h>
#include <GL\glut.h>
#include<GL\GLU.h>

#define MAX_PARTICLES 100 //max number of particles
#define MAX_BOUNCE_COUNT 3 //number of times a particle should bounce 
#define MAX_PARTICLE_AGE 90

//Colours
float R = 0.8f;
float G = 0.2f;
float B = 0.0f;
float cR = 0.001f;
float cG = 0.002f;
float cB = 0.003f;
float Size = 0.01f; //size for points
GLuint txParticle;
GLuint txPlane;


struct PARTICLE {
	float X,Y,Z; // Current position
	float sX,sY,sZ; // Current Speed/Movement
	float tX,tY,tZ; // Target Speed/Movement
	float R,B,G; // Particle Colour
	bool Active; // Is particle Active
	int Age; // Age of the particle
	int MaxAge; // Maximum Age before particle dies
	int BounceCount;
} Particles[MAX_PARTICLES];

void Init_Particles();
void Activate_Particles();
void Adjust_Particles();
void Render_Particles();
bool LoadBitmapTexture(char * FileName, GLuint &texid);
void timer(int extra);
void Load_Plane();
void DrawGLscene();
void Reshape(GLsizei w, GLsizei h);

int main(int argc, char** argv){
	 glutInit(&argc,argv);
    glutInitDisplayMode( GLUT_RGBA| GLUT_DOUBLE );
    glutInitWindowSize( 640, 480 );    
    glutCreateWindow("Particle fountain");

	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	glFrustum(-1.0, 1.0, -1.0, 1.0, 1.0, 10.0);
	glMatrixMode(GL_MODELVIEW);
	glLoadIdentity();
	glTranslatef(0.0, -0.9, -3.0); 

	Load_Plane();
    Init_Particles();
	glutDisplayFunc(DrawGLscene);
    glutTimerFunc(0, timer, 0);
    glutMainLoop();

}

void timer(int extra)
{
    glutPostRedisplay();
    glutTimerFunc(16, timer, 0);
}

void Load_Plane(){
	glEnable(GL_BLEND);
	glBlendFunc(GL_ONE_MINUS_SRC_ALPHA, GL_SRC_ALPHA);
	glColor4f(0.0f, 0.2f, 0.2f, 0.5f);
	glEnable(GL_TEXTURE_2D);
	glBindTexture(GL_TEXTURE_2D, txPlane);
	glBegin(GL_QUADS);
		glNormal3f(0.0f, 1.0f, 0.0f);
		glTexCoord2f(0.0f, 0.0f);
		glVertex3f(-10.0f, 0.0f, 10.0f);
		glTexCoord2f(1.0f, 0.0f);
		glVertex3f( 10.0f, 0.0f, 10.0f);
		glTexCoord2f(1.0f, 1.0f);
		glVertex3f( 10.0f, 0.0f, -10.0f);
		glTexCoord2f(0.0f, 1.0f);
		glVertex3f(-10.0f, 0.0f, -10.0f);
	glEnd();
}
void DrawGLscene(){
	
	glPushMatrix();
	glScalef(1.0f, -1.0f, 1.0f);
	Render_Particles();
	glPopMatrix();
	Render_Particles();

}


void Init_Particles(){
	LoadBitmapTexture("./Particle.bmp", txParticle);
	LoadBitmapTexture("./Plain.bmp",txPlane);
	
	int p;
	srand((int)time(NULL));
	for(p=0; p<MAX_PARTICLES; p++){
		Particles[p].Active = FALSE;
		Particles[p].tX = 0.0f;
		Particles[p].tY = -0.1f;
		Particles[p].tZ = 0.0f;
	}
}

void Activate_Particles(){
	int p;
	for(p=0; p<MAX_PARTICLES; p++){
		if(!Particles[p].Active){
			// Start the particle at 0,0,0 origin
			Particles[p].X = 0.0f;
			Particles[p].Y = 0.0f;
			Particles[p].Z = 0.0f;
			// The following lines set a random speed value
			Particles[p].sX = (((float)((rand() % 100) + 1)) /
				1000.0f) - 0.05f;
			Particles[p].sY = (((float)((rand() % 100) + 50)) /
				500.0f);
			Particles[p].sZ = (((float)((rand() % 100) + 1)) /
				1000.0f) - 0.05f;
			// We also activate the particle
			Particles[p].Active = true;
			// Set it's Age to zero
			Particles[p].Age = 0;
			// We also assign a max age to the particles
			Particles[p].MaxAge = MAX_PARTICLE_AGE;
			// We Also reset the bouncecount to zero
			Particles[p].BounceCount = 0;

			//Adding the colours
			Particles[p].R = R;
			Particles[p].G = G;
			Particles[p].B = B;
			R+=cR;
			G+=cG;
			B+=cB;
			if(R>1.0f){R=1.0f; cR=-cR;}
			if(R<0.0f){R=0.0f; cR=-cR;}
			if(G>1.0f){G=1.0f; cG=-cG;}
			if(G<0.0f){G=0.0f; cG=-cG;}
			if(B>1.0f){B=1.0f; cB=-cB;}
			if(B<0.0f){B=0.0f; cB=-cB;}
			return;
		}
}
}

void Adjust_Particles(){
	int p;
	for(p=0; p<MAX_PARTICLES; p++){
		// We move the speed towards the target speed by 1/20 (5%)
		Particles[p].sX+= (Particles[p].tX - Particles[p].sX) / 20.0f;
		Particles[p].sY+= (Particles[p].tY - Particles[p].sY) / 20.0f;
		Particles[p].sZ+= (Particles[p].tZ - Particles[p].sZ) / 20.0f;
		// Then we adjust the position of
		// the particle by the new speed
		Particles[p].X+= Particles[p].sX;
		Particles[p].Y+= Particles[p].sY;
		Particles[p].Z+= Particles[p].sZ;
		// Now for the bounce code.
		if(Particles[p].Y < 0.0f){
			Particles[p].Y = 0.0f;
			Particles[p].sY = -Particles[p].sY;
			Particles[p].BounceCount++;
			if(Particles[p].BounceCount > MAX_BOUNCE_COUNT){
				Particles[p].Active = FALSE;
			}
		}
		// And finally the age check
		Particles[p].Age++;
		if(Particles[p].Age > Particles[p].MaxAge){
			Particles[p].Active = FALSE;
		}
	}

}

void Render_Particles(){
	Activate_Particles();
    Adjust_Particles();

    glClear( GL_COLOR_BUFFER_BIT );

	int p;
	// Enable textures and bind our particle texture
	glEnable(GL_TEXTURE_2D);
	glBindTexture(GL_TEXTURE_2D, txParticle);
	// Disable Depth testing.
	glDisable(GL_DEPTH_TEST);
	// Enable blending
	glEnable(GL_BLEND);
	glBlendFunc(GL_SRC_COLOR,GL_ONE);
	for(p=0; p<MAX_PARTICLES; p++){
		if(Particles[p].Active){
			glColor4f(Particles[p].R,
				Particles[p].G,
				Particles[p].B, 1.0f);
			glPushMatrix();
			glTranslatef(Particles[p].X,
				Particles[p].Y,
				Particles[p].Z);
			glBegin(GL_QUADS);
			glNormal3f(0.0f, 0.0f, 1.0f);
			glTexCoord2f(0.0f, 0.0f);
			glVertex3f(-Size, -Size, 0.0f);
			glTexCoord2f(1.0f, 0.0f);
			glVertex3f(Size, -Size, 0.0f);
			glTexCoord2f(1.0f, 1.0f);
			glVertex3f(Size, Size, 0.0f);
			glTexCoord2f(0.0f, 1.0f);
			glVertex3f(-Size, Size, 0.0f);
			glEnd();
			glPopMatrix();
   
	
		}
	}
	 glEnable(GL_DEPTH_TEST);
	 glutSwapBuffers();
}

bool LoadBitmapTexture(char * FileName, GLuint &texid){
	HBITMAP hBMP; // Handle Of The Bitmap
	BITMAP BMP; // Bitmap Structure
	glGenTextures(1, &texid); // Create The Texture
	hBMP=(HBITMAP)LoadImage(GetModuleHandle(NULL),
		FileName,
		IMAGE_BITMAP, 0, 0,
		LR_CREATEDIBSECTION | LR_LOADFROMFILE
		);

	if (!hBMP) // Does The Bitmap Exist?
		return FALSE; // If Not Return False
	GetObject(hBMP, sizeof(BMP), &BMP); // Get The Object
	// hBMP: Handle To Graphics Object
	// sizeof(BMP): Size Of Buffer For Object Information
	// &BMP: Buffer For Object Information
	glPixelStorei(GL_UNPACK_ALIGNMENT, 4);
	// Pixel Storage Mode (Word Alignment / 4 Bytes)
	// Typical Texture Generation Using Data From The Bitmap
	glBindTexture(GL_TEXTURE_2D, texid);// Bind To The Texture ID
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER,
		GL_LINEAR); // Linear Min Filter
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER,
		GL_LINEAR); // Linear Mag Filter
	glTexImage2D(GL_TEXTURE_2D, 0, 3, BMP.bmWidth, BMP.bmHeight,
		0, GL_BGR_EXT, GL_UNSIGNED_BYTE, BMP.bmBits);
	DeleteObject(hBMP); // Delete The Object
	return TRUE; // Loading Was Successful
}