HGE教程翻译（7）

Tutorial 07 – 成千上万的野兔

 

这篇教程示范HGE渲染多种混合模式。

 

创建精灵

我们跳过所有的技术细节直接来到动作。首先创建并初始化一对精灵，用于"game objects"和背景。注意背景精灵是如何从小的64x64图块创建并在底部上色。

 

HTEXTURE tex, bgtex;

hgeSprite *spr, *bgspr;

tex=hge->Texture_Load("zazaka.png");

spr=new hgeSprite(tex,0,0,64,64);

spr->SetHotSpot(32,32);

bgtex=hge->Texture_Load("bg2.png");

bgspr=new hgeSprite(bgtex,0,0,800,600);

bgspr->SetBlendMode(BLEND_COLORADD | BLEND_ALPHABLEND);

bgspr->SetColor(0xFF000000,0);

bgspr->SetColor(0xFF000000,1);

bgspr->SetColor(0xFF000040,2);

bgspr->SetColor(0xFF000040,3);

 

初始化游戏对象数组

现在我们创建数组，保存"game objects"的属性并用任意值填充。

 

#define MAX_OBJECTS 2000

struct sprObject

{

  float x,y;

  float dx,dy;

  float scale,rot;

  float dscale,drot;

  DWORD color;

};

sprObject*  pObjects;

int         nObjects;

pObjects=new sprObject[MAX_OBJECTS];

nObjects=1000;

for(i=0; i<MAX_OBJECTS; i++)

{

  pObjects[i].x=hge->Random_Float(0,SCREEN_WIDTH);

  pObjects[i].y=hge->Random_Float(0,SCREEN_HEIGHT);

  pObjects[i].dx=hge->Random_Float(-200,200);

  pObjects[i].dy=hge->Random_Float(-200,200);

  pObjects[i].scale=hge->Random_Float(0.5f,2.0f);

  pObjects[i].dscale=hge->Random_Float(-1.0f,1.0f);

  pObjects[i].rot=hge->Random_Float(0,M_PI*2);

  pObjects[i].drot=hge->Random_Float(-1.0f,1.0f);

}

 

改变混合模式

SetBlend函数使用一个0到4的int变量来调整游戏对象数组的混合模式。

 

void SetBlend(int blend)

{

  static int sprBlend[5]=

  {

    BLEND_COLORMUL | BLEND_ALPHABLEND | BLEND_NOZWRITE,

    BLEND_COLORADD | BLEND_ALPHABLEND | BLEND_NOZWRITE,

    BLEND_COLORMUL | BLEND_ALPHABLEND | BLEND_NOZWRITE,

    BLEND_COLORMUL | BLEND_ALPHAADD   | BLEND_NOZWRITE,

    BLEND_COLORMUL | BLEND_ALPHABLEND | BLEND_NOZWRITE

  };

  static DWORD sprColors[5][5]=

  {

    {0xFFFFFFFF, 0xFFFFE080, 0xFF80A0FF, 0xFFA0FF80, 0xFFFF80A0},

    {0xFF000000, 0xFF303000, 0xFF000060, 0xFF006000, 0xFF600000},

    {0x80FFFFFF, 0x80FFE080, 0x8080A0FF, 0x80A0FF80, 0x80FF80A0},

    {0x80FFFFFF, 0x80FFE080, 0x8080A0FF, 0x80A0FF80, 0x80FF80A0},

    {0x40202020, 0x40302010, 0x40102030, 0x40203010, 0x40102030}

  };

  if(blend>4) blend=0;

  nBlend=blend;

  spr->SetBlendMode(sprBlend[blend]);

  for(int i=0;i<MAX_OBJECTS;i++)

    { pObjects[i].color=sprColors[blend][hge->Random_Int(0,4)]; }

}

 

更新屏幕

 

在FrameFunc中我们遍历游戏对象数组并计算它们的新位置。

 

  for(i=0; i<nObjects; i++)

  {

    pObjects[i].x+=pObjects[i].dx*dt;

    if(pObjects[i].x>SCREEN_WIDTH || pObjects[i].x<0)

      { pObjects[i].dx=-pObjects[i].dx; }

    pObjects[i].y+=pObjects[i].dy*dt;

    if(pObjects[i].y>SCREEN_HEIGHT || pObjects[i].y<0)

      { pObjects[i].dy=-pObjects[i].dy; }

    pObjects[i].scale+=pObjects[i].dscale*dt;

    if(pObjects[i].scale>2 || pObjects[i].scale<0.5)

      { pObjects[i].dscale=-pObjects[i].dscale; }

    pObjects[i].rot+=pObjects[i].drot*dt;

  }

渲染屏幕

在RenderFunc中我们遍历游戏对象数组并渲染它们。

 

  hge->Gfx_BeginScene();

  bgspr->Render(0,0);

  for(i=0; i<nObjects; i++)

  {

    spr->SetColor(pObjects[i].color); 

    spr->RenderEx(pObjects[i].x, pObjects[i].y,

                  pObjects[i].rot, pObjects[i].scale);

  }

  hge->Gfx_EndScene();

 

使用UP 和 DOWN键调整精灵的数量，空格键改变混合模式，ESC退出。