プログラマ専用SNS ミクプラ

コード:

#include <DxLib.h>
#include <math.h>

#define OFFS_X 320
#define OFFS_Y 240

//  1/100の精度でランダムな数を得る
double GetRandomD( double max ){
	return (double)GetRand( max * 100 ) /100.0;
}

//ｘとyの値を持つ構造体
struct Vector{
	double x,y;
};

//円
struct Circle{
	Vector Position;
	double radius;
};

//敵
struct Enemy{
	 Circle c;
	 Vector Speed;
};


//円同士のあたり判定
bool CollisionDetection( Circle& lhs, Circle& rhs);


//円を表示
void ShowCircle(Circle& c, int color, int flag);

//目標地点までの移動量を計算
void CalculateMove( Circle& target, Enemy& enemy, double time);

//敵を移動させる
void MoveEnemy( Enemy& e );

int WINAPI WinMain( HINSTANCE hInstance, HINSTANCE hPrevInstance,LPSTR lpCmdLine, int nCmdShow ){
    ChangeWindowMode(TRUE);//ウィンドウモード
    if(DxLib_Init() == -1 || SetDrawScreen( DX_SCREEN_BACK )!=0) return -1;//初期化と裏画面化
	
	//移動するエリア
	Circle area;
	area.Position.x = 0;
	area.Position.y = 0;
	area.radius		= 150;

	//移動先の目標
	Circle target;
	target.Position.x = 30;
	target.Position.y = 30;
	target.radius	  = 5;

	//敵
	Enemy enemy;
	enemy.c.Position.x = -50;
	enemy.c.Position.y = -50;
	enemy.c.radius	  = 5;

	//敵の速度を計算
	CalculateMove( target, enemy, 3 );

	//待機時間
	double time = -1.0;

    while(ProcessMessage()==0 && ClearDrawScreen()==0){
		
		//目標に到達していれば、目標地点と速度を更新して、待機時間も設定
		if( CollisionDetection( enemy.c, target ) ){
			
			double d = GetRandomD( 150.0 );
			double rad = GetRandomD( TWO_PHI );

			CollisionDetection( enemy.c, target );
			target.Position.x = d*cos(rad);
			target.Position.y = d*sin(rad);

			CalculateMove( target, enemy, GetRandomD( 2.0 ) + 2.0 );
			time = GetRandomD( 2.0 ) + 0.5;
		
		}else if( time < 0.0 ){
			//待機時間がないときは移動
			MoveEnemy( enemy );
		
		}else{
			//待機時間中は待機
			time -= 1.0 / 60.0;
		}

		//描写
		ShowCircle( enemy.c , 0x00ff00, 1 );
		ShowCircle( area , 0xffffff, 0 );
		ShowCircle( target , 0xff0000, 1 );
		

        ScreenFlip();
    }
 
    DxLib_End();
    return 0;
}

bool CollisionDetection( Circle& lhs, Circle& rhs){
	double dx = lhs.Position.x - rhs.Position.x;
	double dy = lhs.Position.y - rhs.Position.y;
	double r = lhs.radius + rhs.radius;

	return r*r > dx*dx + dy*dy;
}

void ShowCircle(Circle& c, int color, int flag = 1 ){
	DrawCircle( c.Position.x + OFFS_X, c.Position.y + OFFS_Y, c.radius, color, flag );
}

void CalculateMove( Circle& target, Enemy& enemy, double time){
	double dx = target.Position.x - enemy.c.Position.x;
	double dy = target.Position.y - enemy.c.Position.y;

	time *= 60.0;

	enemy.Speed.x = dx / time;
	enemy.Speed.y = dy / time;

}

void MoveEnemy( Enemy& e ){
	e.c.Position.x += e.Speed.x;
	e.c.Position.y += e.Speed.y;
}