CODE:

#pragma once

//----------------------------------------------------------------------------//
//	定数
//----------------------------------------------------------------------------//
#define SCREEN_X (600)
#define SCREEN_Y (400)
#define SCREEN_DEFAULT_POS_X (300)
#define SCREEN_DEFAULT_POS_Y (100)
#define CIRCLE_MAX (3)

//----------------------------------------------------------------------------//
//	型定義
//----------------------------------------------------------------------------//
typedef enum {
    GREEN,
    BLUE,
    RED,
    YELLOW,
    AQUABLUE,
    MAGENTA,
    WHITE,
} E_color;

typedef struct {
    double pos_x, pos_y;
    int radius;
    double angle, speed;
    E_color color;
} circle_t;

CODE:

#pragma comment(lib,"user32.lib")
#pragma comment(lib,"gdi32.lib")

#include "wingxa.h"
#include "define.h"
#define _USE_MATH_DEFINES
#include 
#include 

//----------------------------------------------------------------------------//
//	プロトタイプ
//----------------------------------------------------------------------------//
void BlendDraw(circle_t *cir);
bool HitCheck(int,int,circle_t *cir,circle_t *cir2);
void CircleDraw(circle_t *cir);
void CircleMove(circle_t *cir);


//----------------------------------------------------------------------------//
//	メイン
//----------------------------------------------------------------------------//
void main(void)
{
    // 位置x, 位置y, 半径, 角度, 速度, 色
    circle_t circle[3] = 
    {
        -0.5*100, 100*(1-sqrt(3.0)/4), 100, 90, 10, GREEN,
        0.5*100, 100*(1-sqrt(3.0)/4), 100, 180, 15, BLUE,
        0, 100*(1+sqrt(3.0)/4), 100, 270, 5, RED
    };

    gwinsize(SCREEN_X,SCREEN_Y); // 画面のサイズを指定
    ginit(2);
    gsetorg(SCREEN_DEFAULT_POS_X,SCREEN_DEFAULT_POS_Y);  // スクリーン内の原点座標を指定

    while(!keypress()){
        CircleDraw(circle);
        BlendDraw(circle);
        CircleMove(circle);
        swapbuffers();
    }

}


/**
* 加法混色描画処理
* @param *cir 円データ
*/
void BlendDraw(circle_t *cir)
{
    int ix, iy; 
    // 画面サイズ/スクリーン原点に合わせる(ix、iy)
    for (iy=-SCREEN_DEFAULT_POS_Y; iypos_x)*(px-cir->pos_x) + (py-cir->pos_y)*(py-cir->pos_y) - (cir->radius*cir->radius) pos_x)*(px-cir2->pos_x) + (py-cir2->pos_y)*(py-cir2->pos_y) - (cir2->radius*cir2->radius) color){
        case RED:
            gcolor(255,0,0);
            break;
        case GREEN:
            gcolor(0,255,0);
            break;
        case BLUE:
            gcolor(0,0,255);
            break;
        }
        gcirc((cir+num)->pos_x, (cir+num)->pos_y, (cir+num)->radius);
    }
}


/**
* 円の移動処理
* @param *cir 円データ
*/
void CircleMove(circle_t *cir)
{
    int num;
    for(num=0; numpos_x += cos((cir+num)->angle) * (cir+num)->speed;
        (cir+num)->pos_y += sin((cir+num)->angle) * (cir+num)->speed;

        // 壁判定
        if ( (cir+num)->pos_x > SCREEN_X-SCREEN_DEFAULT_POS_X - ((cir+num)->speed+(cir+num)->radius) ) (cir+num)->angle = (rand()%180+90)  * (M_PI/180);// 右画面判定
        if ( (cir+num)->pos_x speed+(cir+num)->radius)         ) (cir+num)->angle = (rand()%180+270) * (M_PI/180);// 左画面判定
        if ( (cir+num)->pos_y > SCREEN_Y-SCREEN_DEFAULT_POS_Y-((cir+num)->speed+(cir+num)->radius)   ) (cir+num)->angle = (rand()%180+180) * (M_PI/180);// 上画面判定
        if ( (cir+num)->pos_y speed+(cir+num)->radius)         ) (cir+num)->angle = rand()%180       * (M_PI/180);// 下画面判定
    }

}