Painter/flash_star

#include "PX_Firework.h"
%定义烟花的各类属性
typedef enum 
{
	PX_FIREWORK_STATE_RAISING,
	PX_FIREWORK_STATE_BLOOMING,
}PX_FIREWORK_STATE;
%构造结构体来表达目标的物理属性
typedef struct  
{
	px_point array[32];
	unsigned int delay;
	float size;
	float vx, vy;
	px_color clr;
}PX_Firework_paritcal;
%将物理结构和状态绑入一个对象
typedef struct  
{
	PX_Firework_paritcal particals[96];
	PX_FIREWORK_STATE state;
	unsigned int elapsed;
}PX_Firework;

%利用逐帧更新实现烟花动画
void PX_FireworkParticalUpdate(PX_Firework_paritcal* pdesc, unsigned int elapsed)
{
%烟花持续时间
	int i;
	unsigned int update_atom;
	if (elapsed>1000)
	{
		elapsed = 1000;
	}
	while (elapsed)
	{
		if (elapsed>10)
		{
			update_atom = 10;
			elapsed -= 10;
		}
		else
		{
			update_atom = elapsed;
			elapsed = 0;
		}
%运动轨迹
		pdesc->array[0].x += pdesc->vx * update_atom / 1000;
		pdesc->array[0].y += pdesc->vy * update_atom / 1000;

		pdesc->vx -= pdesc->vx * 0.9f * update_atom / 1000;
		pdesc->vy -= pdesc->vy * 0.9f * update_atom / 1000;

		pdesc->delay += update_atom;

%烟花并非一个球体，是一个球体的阵列。
		while (pdesc->delay > 20)
		{
			pdesc->delay -= 20;
			for (i = PX_COUNTOF(pdesc->array) - 1; i > 0; i--)
			{
				pdesc->array[i] = pdesc->array[i - 1];
			}
		}
	}
}
%变色效果
void PX_FireworkParticalRender(PX_Firework_paritcal* pdesc, px_surface * psurface, px_bool bb,unsigned int elapsed)
{
	int i;
	float scale;
	px_color color;

	for (i = PX_COUNTOF(pdesc->array) - 1; i >= 0; i--)
	{
		color = pdesc->clr;
		if (bb)
		{
			if (elapsed > 3000)
			{
				elapsed = 3000;
			}
			color._argb.a = (px_uchar)((3000 - elapsed) / 3000.f * 255);
			scale = (PX_COUNTOF(pdesc->array) - i) * (0.5f + elapsed / 2000.f) / PX_COUNTOF(pdesc->array);
		}
		else
		{
			scale = (PX_COUNTOF(pdesc->array) - i) *1.0f/ PX_COUNTOF(pdesc->array);
		}
		color._argb.a = (px_uchar)(color._argb.a*scale);
		PX_GeoDrawSolidCircle(psurface, (int)pdesc->array[i].x, (int)pdesc->array[i].y, (int)(pdesc->size * scale), color);
	}
}
%绽放的过程
void PX_FireworkRender(px_surface* psurface, PX_Object* pObject, unsigned int elapsed)
{
	PX_Firework* pdesc = PX_ObjectGetDesc(PX_Firework, pObject);
	pdesc->elapsed += elapsed;
	if (pdesc->state==PX_FIREWORK_STATE_RAISING)
	{
		PX_FireworkParticalUpdate(pdesc->particals, elapsed);
		PX_FireworkParticalRender(pdesc->particals, psurface,0,pdesc->elapsed);

		if (pdesc->elapsed>=1200)
		{
			int i;
			int j;
			px_color clr;
			pdesc->elapsed = 0;
			pdesc->state = PX_FIREWORK_STATE_BLOOMING;

			for (i = 0; i < PX_COUNTOF(pdesc->particals); i++)
			{
				for (j = 0; j < PX_COUNTOF(pdesc->particals->array); j++)
				{
					pdesc->particals[i].array[j].x = pdesc->particals[0].array[0].x;
					pdesc->particals[i].array[j].y = pdesc->particals[0].array[0].y;
				}
			}
			clr = PX_COLOR(255, 128 + (PX_rand() % 128), 128 + (PX_rand() % 128), 128 + (PX_rand() % 128));
			for (i=0;i<32;i++)
			{
				
				pdesc->particals[i].vx = 300 * PX_sin_angle(360 * i / 32.f);
				pdesc->particals[i].vy = 300 * PX_cos_angle(360 * i / 32.f);
				pdesc->particals[i].clr = clr;
				pdesc->particals[i].size = 8;
			}
%动态变色
			clr = PX_COLOR(255, 128 + (PX_rand() % 128), 128 + (PX_rand() % 128), 128 + (PX_rand() % 128));
			for (i = 32; i < 64; i++)
			{
				pdesc->particals[i].vx = 200 * PX_sin_angle(360 * (i - 32) / 32.f);
				pdesc->particals[i].vy = 200 * PX_cos_angle(360 * (i - 32) / 32.f);
				pdesc->particals[i].clr = clr;
				pdesc->particals[i].size = 6;
			}

			clr = PX_COLOR(255, 128 + (PX_rand() % 128), 128 + (PX_rand() % 128), 128 + (PX_rand() % 128));
			for (i = 64; i < 96; i++)
			{
				pdesc->particals[i].vx = 100 * PX_sin_angle(360 * (i - 64) / 32.f);
				pdesc->particals[i].vy = 100 * PX_cos_angle(360 * (i - 64) / 32.f);
				pdesc->particals[i].clr = clr;
				pdesc->particals[i].size = 3;
			}
		}

	}
	else if (pdesc->state == PX_FIREWORK_STATE_BLOOMING)
	{
		int i;
		for (i=0;i<PX_COUNTOF(pdesc->particals);i++)
		{
			PX_FireworkParticalUpdate(pdesc->particals+i, elapsed);
			PX_FireworkParticalRender(pdesc->particals+i, psurface,1, pdesc->elapsed);
		}
		if (pdesc->elapsed>3000)
		{
			PX_ObjectDelayDelete(pObject);
		}
	}
}

%创建烟花实体
PX_Object* PX_FireworkCreate(px_memorypool* mp, PX_Object* Parent, float x, float y)
{
	int i;
	PX_Firework desc;
	PX_memset(&desc, 0, sizeof(desc));
	desc.state = PX_FIREWORK_STATE_RAISING;
	desc.elapsed = 0;
	for (i=0;i<PX_COUNTOF(desc.particals[0].array);i++)
	{
		desc.particals[0].array[i].x = x;
		desc.particals[0].array[i].y = y;
	}
	desc.particals[0].vx = 0;
	desc.particals[0].vy = -400;
	desc.particals[0].size = 6;
	desc.particals[0].clr = PX_COLOR(255, 128 + (PX_rand() % 128), 128 + (PX_rand() % 128), 128 + (PX_rand() % 128));
%返回函数，生成烟花，程序结束
	return PX_ObjectCreateEx(mp, Parent, x, y, 0, 0, 0, 0, 0, 0, PX_FireworkRender, 0, &desc, sizeof(desc));
}