深度探索DxFramework 4-1
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第4章 初始锋芒 剖析DemoA
4.1 Demo实现的功能点和整体架构
4.1.1 实现的功能点
4.1.2 Demo的整体架构
4.2 Demo实例类的定义和初始化
1class C_DemoA : public C_GameState
2{
3public:
4 C_DemoA();
5 virtual ~C_DemoA();
6 virtual void Input();
7 virtual void Update();
8 virtual void Render2D();
9private:
10 C_Sprite* p_Background; //背景图片
11 C_Sprite* p_Box; //用来演示的小方盒
12
13 // 各种dxfrramework支持的图片格式
14 C_Sprite* p_Bmp8; //8位bmp格式
15 C_Sprite* p_Bmp24; //24位bmp格式
16 C_Sprite* p_Png8; //8位png格式
17 C_Sprite* p_Png24; //24位png格式
18 C_Sprite* p_Png32; //32位png格式
19 DVECTOR2 translation; // box的屏幕坐标
20 int alpha; // box的透明度
21 static const int VELOCITY; // box的移动速度，为常量
22 static const int ANIMATION_SPEED; // box的动画变化速度，为常量
23};
24
25C_DemoA::C_DemoA()
26{
27 alpha = 255;
28 p_Background = new C_Sprite(_T("demoa_background.png"));
29 p_Box = new C_Sprite(_T("box-3-2-2.png"));
30 translation = DVECTOR2(400,300) - p_Box->GetCenter();
31
32 //载入DxFramework所能支持的不同格式的图片，创建精灵
33 p_Bmp8 = new C_Sprite(_T("bitmap8.bmp"));
34 p_Bmp24 = new C_Sprite(_T("bitmap24.bmp"));
35 p_Png8 = new C_Sprite(_T("png8.png"));
36 p_Png24 = new C_Sprite(_T("png24.png"));
37 p_Png32 = new C_Sprite(_T("png32.png"));
38 gp_Timer->Reset(); //把计时器清零，准备用来对小方盒产生动画效果
39
40 //因为使用了背景图片，所以不必每帧都清空颜色缓冲区和z缓冲区
41 gp_View->SetClear(false);
42}
4.3 对外设输入的响应
1void C_DemoA::Input()
2{
3 // 按ESC键退出demo，返回主菜单
4 if (gp_Controller->GetKeyState(DIK_ESCAPE)== BUTTON_PRESSED){
5 gp_Model->ChangeState(MENU);
6 }
7
8 // 按F2，F3键切换到demo B，demo C
9 if (gp_Controller->GetKeyState(DIK_F2)== BUTTON_PRESSED){
10 gp_Model->ChangeState(DEMOB);
11 }
12 if (gp_Controller->GetKeyState(DIK_F3)== BUTTON_PRESSED){
13 gp_Model->ChangeState(DEMOC);
14 }
15
16 //按上下左右箭头键，向上，向下，向左，向右移动小方盒
17 double increment = VELOCITY * gp_Timer->GetElapsed();
18 if (gp_Controller->GetKeyState(DIK_UP) == BUTTON_DOWN)
19 translation.y -= increment;
20 if (gp_Controller->GetKeyState(DIK_DOWN) == BUTTON_DOWN)
21 translation.y += increment;
22 if (gp_Controller->GetKeyState(DIK_LEFT) == BUTTON_DOWN)
23 translation.x -= increment;
24 if (gp_Controller->GetKeyState(DIK_RIGHT) == BUTTON_DOWN)
25 translation.x += increment;
26}
4.4 更新各属性状态
1void C_DemoA::Update()
2{
3 //把当前时刻除以动画显示速度，得到余数
4 double tempTime = gp_Timer->TimeMod(ANIMATION_SPEED);
5
6 // 如果等于0，表示到了切换帧的时间了。把当前显示的动画帧切换到其他动画帧去
7 if(tempTime == 0){
8 p_Box->Animate();
9 alpha = 0;
10 }else{
11 // 如果不等于0的话，就用余数除以动画显示速度，乘以圆周率，做正弦操作
12 // 使得alpha值产生周期性重复变化的效果
13 alpha = (int)(255 * sin(D3DX_PI * tempTime/ANIMATION_SPEED));
14 }
15
16 // 对小方盒的坐标做检查，放置小方盒超出屏幕范围
17 if (translation.x < 0)
18 translation.x = 0;
19 if (translation.x > (C_View::SCREEN_WIDTH-p_Box->GetWidth()))
20 translation.x = C_View::SCREEN_WIDTH-p_Box->GetWidth();
21 if (translation.y < 0)
22 translation.y = 0;
23 if (translation.y > (C_View::SCREEN_HEIGHT-p_Box->GetHeight())
24 translation.y = C_View::SCREEN_HEIGHT-p_Box->GetHeight();
25}
4.5 渲染
1void C_DemoA::Render2D() {
2
3 //渲染背景
4 p_Background->Render2D();
5
6 p_Box->Render2D( translation, DVECTOR2(0,0), 0, DVECTOR2(1,1),
7 D3DCOLOR_ARGB(alpha,255,255,255));
8 //渲染不同格式的图形
9 p_Bmp8->Render2D(DVECTOR2(459,461));
10 p_Bmp24->Render2D(DVECTOR2(523,461));
11 p_Png8->Render2D(DVECTOR2(587,461));
12 p_Png24->Render2D(DVECTOR2(651,461));
13 p_Png32->Render2D(DVECTOR2(715,461));
14 // 显示当前的alpha值
15 gp_Model->GetFont()->Render2D(_T("Alpha Value = ")+
16 toTString(alpha),DVECTOR2(5,350), BLACK);
17}
