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。