#include <graphics.h>
#include <conio.h>
#include <math.h>


// 定义全局变量
int	rosesize = 500;
int	h = -250;


// 定义结构体
struct DOT
{
	double x;
	double y;
	double z;
	double r;	// 红色
	double g;	// 绿色
	// b(蓝色) 通过 r 计算
};


// 计算点
bool calc(double a, double b, double c, DOT &d)
{
	double j, n, o, w, z;

	if(c > 60)				// 花柄
	{
		d.x = sin(a * 7) * (13 + 5 / (0.2 + pow(b * 4, 4))) - sin(b) * 50;
		d.y = b * rosesize + 50;
		d.z = 625 + cos(a * 7) * (13 + 5 / (0.2 + pow(b * 4, 4))) + b * 400;
		d.r = a * 1 - b / 2;
		d.g = a;
		return true;
	}
	
	double A = a * 2 - 1;
	double B = b * 2 - 1;
	if(A * A + B * B < 1)
	{
		if(c > 37)			// 叶
		{
			j = (int(c) & 1);
			n = j ? 6 : 4;
			o = 0.5 / (a + 0.01) + cos(b * 125) * 3 - a * 300;
			w = b * h;
			
			d.x = o * cos(n) + w * sin(n) + j * 610 - 390;
			d.y = o * sin(n) - w * cos(n) + 550 - j * 350;
			d.z = 1180 + cos(B + A) * 99 - j * 300;
			d.r = 0.4 - a * 0.1 + pow(1 - B * B, -h * 6) * 0.15 - a * b * 0.4 + cos(a + b) / 5 + pow(cos((o * (a + 1) + (B > 0 ? w : -w)) / 25), 30) * 0.1 * (1 - B * B);
			d.g = o / 1000 + 0.7 - o * w * 0.000003;
			return true;
		}
		if(c > 32)			// 花萼
		{
			c = c * 1.16 - 0.15;
			o = a * 45 - 20;
			w = b * b * h;
			z = o * sin(c) + w * cos(c) + 620;

			d.x = o * cos(c) - w * sin(c);
			d.y = 28 + cos(B * 0.5) * 99 - b * b * b * 60 - z / 2 - h;
			d.z = z;
			d.r = (b * b * 0.3 + pow((1 - (A * A)), 7) * 0.15 + 0.3) * b;
			d.g = b * 0.7;
			return true;
		}
		
		// 花
		o = A * (2 - b) * (80 - c * 2);
		w = 99 - cos(A) * 120 - cos(b) * (-h - c * 4.9) + cos(pow(1 - b, 7)) * 50 + c * 2;
		z = o * sin(c) + w * cos(c) + 700;
		
		d.x = o * cos(c) - w * sin(c);
		d.y = B * 99 - cos(pow(b, 7)) * 50 - c / 3 - z / 1.35 + 450;
		d.z = z;
		d.r = (1 - b / 1.2) * 0.9 + a * 0.1;
		d.g = pow((1 - b), 20) / 4 + 0.05;
		return true;
	}

	return false;
}


// 主函数
void main()
{
	// 定义变量
	short	*zBuffer;
	int		x, y, z, zBufferIndex;
	DOT		dot;

	// 初始化
	initgraph(640, 480);				// 创建绘图窗口
	setbkcolor(WHITE);					// 设置背景色为白色
	cleardevice();						// 清屏

	// 初始化 z-buffer
	zBuffer = new short[rosesize * rosesize];
	memset(zBuffer, 0, sizeof(short) * rosesize * rosesize);

	for(int j = 0; j < 2000 && !_kbhit(); j++)	// 按任意键退出
	{
		for(int i = 0; i < 10000; i++)			// 减少是否有按键的判断
			if(calc(double(rand()) / RAND_MAX, double(rand()) / RAND_MAX, rand() % 46 / 0.74, dot))
			{
				z = int(dot.z + 0.5);
				x = int(dot.x * rosesize / z - h + 0.5);
				y = int(dot.y * rosesize / z - h + 0.5);
				if (y >= rosesize) continue;

				zBufferIndex = y * rosesize + x;

				if(!zBuffer[zBufferIndex] || zBuffer[zBufferIndex] > z)
				{
					zBuffer[zBufferIndex] = z;

					// 画点
					int r = ~int((dot.r * h));				if (r < 0) r = 0;	if (r > 255) r = 255;
					int g = ~int((dot.g * h));				if (g < 0) g = 0;	if (g > 255) g = 255;
					int b = ~int((dot.r * dot.r * -80));	if (b < 0) b = 0;	if (b > 255) b = 255;
					putpixel(x + 50, y - 20, RGB(r, g, b));
				}
			}

		Sleep(1);
	}

	// 退出
	delete []zBuffer;
	_getch();
	closegraph();
}