（转）SkyBox

稍微讲下天空盒

天空盒的顶点

struct SkyBoxVertex
{
SkyBoxVertex();
SkyBoxVertex(float x, float y, float z, float u, float v);
SkyBoxVertex(const D3DXVECTOR3& p, const D3DXVECTOR2& uv);

D3DXVECTOR3 m_pos;
D3DXVECTOR2 m_tex0;
};
#define D3DFVF_SKYBOX (D3DFVF_XYZ | D3DFVF_TEX1 )

SkyBoxVertex::SkyBoxVertex()
: m_pos(0.0f, 0.0f, 0.0f), m_tex0(0.0f, 0.0f)
{
}

SkyBoxVertex::SkyBoxVertex(float x, float y, float z, float u, float v)
: m_pos(x, y, z), m_tex0(u, v)
{
}

SkyBoxVertex::SkyBoxVertex(const D3DXVECTOR3& p, const D3DXVECTOR2& uv)
: m_pos(p), m_tex0(uv)
{
}

天空盒类

class CSkyBox
{
private:


LPDIRECT3DDEVICE9            m_pD3DDevice;

LPDIRECT3DVERTEXBUFFER9     m_pVB;//顶点缓存

LPDIRECT3DINDEXBUFFER9      m_pIB;//索引缓存

LPDIRECT3DTEXTURE9          m_pTextrue[6];//六面纹理


public:

CSkyBox(LPDIRECT3DDEVICE9 g_pD3DDevice);

~CSkyBox(void);

HRESULT InitSkyBox(int scale);

void    Render(D3DXVECTOR3 CamPos);

bool    SetTexture( const char *TextureFile, int flag );
};

CSkyBox::CSkyBox(LPDIRECT3DDEVICE9 g_pD3DDevice)
{
m_pD3DDevice = g_pD3DDevice;
m_pVB        = NULL;
m_pIB        = NULL;
memset(m_pTextrue,NULL,sizeof(m_pTextrue));

}

CSkyBox::~CSkyBox(void)
{
}
HRESULT CSkyBox::InitSkyBox(int scale)
{

if( FAILED( m_pD3DDevice->CreateVertexBuffer( 24*sizeof(SkyBoxVertex),
                                         D3DUSAGE_WRITEONLY,
                 0,
              D3DPOOL_MANAGED,
              &m_pVB, 0)))
{
   return E_FAIL;
}

SkyBoxVertex* v = 0;
m_pVB->Lock(0, 0, (void**)&v, 0);

// positive x
v[0] = SkyBoxVertex( 1.0f*scale, -1.0f*scale, 1.0f*scale, 0.0f, 1.0f);
v[1] = SkyBoxVertex( 1.0f*scale, 1.0f*scale, 1.0f*scale, 0.0f, 0.0f);
v[2] = SkyBoxVertex( 1.0f*scale, 1.0f*scale, -1.0f*scale, 1.0f, 0.0f);
v[3] = SkyBoxVertex( 1.0f*scale, -1.0f*scale, -1.0f*scale, 1.0f, 1.0f);

// negative x
v[4] = SkyBoxVertex(-1.0f*scale, -1.0f*scale, -1.0f*scale, 0.0f, 1.0f);
v[5] = SkyBoxVertex(-1.0f*scale, 1.0f*scale, -1.0f*scale, 0.0f, 0.0f);
v[6] = SkyBoxVertex(-1.0f*scale, 1.0f*scale, 1.0f*scale, 1.0f, 0.0f);
v[7] = SkyBoxVertex(-1.0f*scale, -1.0f*scale, 1.0f*scale, 1.0f, 1.0f);

// positive y
v[8] = SkyBoxVertex(-1.0f*scale, 1.0f*scale, 1.0f*scale, 0.0f, 1.0f);
v[9] = SkyBoxVertex(-1.0f*scale, 1.0f*scale, -1.0f*scale, 0.0f, 0.0f);
v[10] = SkyBoxVertex( 1.0f*scale, 1.0f*scale, -1.0f*scale, 1.0f, 0.0f);
v[11] = SkyBoxVertex( 1.0f*scale, 1.0f*scale, 1.0f*scale, 1.0f, 1.0f);

// negative y
v[12] = SkyBoxVertex(-1.0f*scale, -1.0f*scale, -1.0f*scale, 0.0f, 1.0f);
v[13] = SkyBoxVertex(-1.0f*scale, -1.0f*scale, 1.0f*scale, 0.0f, 0.0f);
v[14] = SkyBoxVertex( 1.0f*scale, -1.0f*scale, 1.0f*scale, 1.0f, 0.0f);
v[15] = SkyBoxVertex( 1.0f*scale, -1.0f*scale, -1.0f*scale, 1.0f, 1.0f);

// positive z
v[16] = SkyBoxVertex(-1.0f*scale, -1.0f*scale, 1.0f*scale, 0.0f, 1.0f);
v[17] = SkyBoxVertex(-1.0f*scale, 1.0f*scale, 1.0f*scale, 0.0f, 0.0f);
v[18] = SkyBoxVertex( 1.0f*scale, 1.0f*scale, 1.0f*scale, 1.0f, 0.0f);
v[19] = SkyBoxVertex( 1.0f*scale, -1.0f*scale, 1.0f*scale, 1.0f, 1.0f);

// negative z
v[20] = SkyBoxVertex( 1.0f*scale, -1.0f*scale, -1.0f*scale, 0.0f, 1.0f);
v[21] = SkyBoxVertex( 1.0f*scale, 1.0f*scale, -1.0f*scale, 0.0f, 0.0f);
v[22] = SkyBoxVertex(-1.0f*scale, 1.0f*scale, -1.0f*scale, 1.0f, 0.0f);
v[23] = SkyBoxVertex(-1.0f*scale, -1.0f*scale, -1.0f*scale, 1.0f, 1.0f);

m_pVB->Unlock();


if( FAILED(m_pD3DDevice->CreateIndexBuffer( 36*sizeof(WORD),
             D3DUSAGE_WRITEONLY,
             D3DFMT_INDEX16,
             D3DPOOL_MANAGED,
             &m_pIB, 0)))
{
   return E_FAIL;
}

WORD* g_Indices = 0;
m_pIB->Lock(0, 0, (void**)&g_Indices, 0);

// positive x
g_Indices[0] = 0; g_Indices[1] = 1; g_Indices[2] = 2;
g_Indices[3] = 0; g_Indices[4] = 2; g_Indices[5] = 3;

// negative x
g_Indices[6] = 4; g_Indices[7] = 5; g_Indices[8] = 6;
g_Indices[9] = 4; g_Indices[10] = 6; g_Indices[11] = 7;

// positive y
g_Indices[12] = 8; g_Indices[13] = 9; g_Indices[14] = 10;
g_Indices[15] = 8; g_Indices[16] = 10; g_Indices[17] = 11;

// negative y
g_Indices[18] = 12; g_Indices[19] = 13; g_Indices[20] = 14;
g_Indices[21] = 12; g_Indices[22] = 14; g_Indices[23] = 15;

// positive z
g_Indices[24] = 16; g_Indices[25] = 17; g_Indices[26] = 18;
g_Indices[27] = 16; g_Indices[28] = 18; g_Indices[29] = 19;

// negative z
g_Indices[30] = 20; g_Indices[31] = 21; g_Indices[32] = 22;
g_Indices[33] = 20; g_Indices[34] = 22; g_Indices[35] = 23;

m_pIB->Unlock();

return S_OK;
}
bool CSkyBox::SetTexture(const char *TextureFile, int flag)
{
if(FAILED(D3DXCreateTextureFromFile(m_pD3DDevice,TextureFile
                                   ,&m_pTextrue[flag])))
{
   return false;
}
else
{
   return true;
}
}
void CSkyBox::Render(D3DXVECTOR3 CamPos)
{

m_pD3DDevice->SetRenderState(D3DRS_LIGHTING,false);//关闭灯光

//防止z-buffer写入，主要是使天空盒看起来有无限远的结果
// m_pD3DDevice->SetRenderState(D3DRS_ZWRITEENABLE,false);
// m_pD3DDevice->SetRenderState(D3DRS_ZENABLE, false);

//利用夹取纹理寻址的方式来实现天空盒的无缝连接
// m_pD3DDevice->SetSamplerState(0, D3DSAMP_ADDRESSU, D3DTADDRESS_CLAMP);
// m_pD3DDevice->SetSamplerState(0, D3DSAMP_ADDRESSV, D3DTADDRESS_CLAMP);

//天空盒和摄影机一块运动
D3DXMATRIX world;
D3DXMatrixTranslation(&world,CamPos.x, CamPos.y, CamPos.z);
m_pD3DDevice->SetTransform(D3DTS_WORLD,&world);


m_pD3DDevice->SetStreamSource(0, m_pVB, 0, sizeof(SkyBoxVertex));
m_pD3DDevice->SetFVF(D3DFVF_SKYBOX);
m_pD3DDevice->SetIndices(m_pIB);

for(int i = 0; i < 6; ++i)
{
   m_pD3DDevice->SetTexture(0, m_pTextrue[i]);
   m_pD3DDevice->DrawIndexedPrimitive(D3DPT_TRIANGLELIST,
                                  0,   // 将要绘制的索引缓冲区的起始地址
                                  i*4, //　索引数组中最小的索引值
                                  4,   // 要绘制的索引数组中的顶点数量
                                  i*6, // 从索引数组中的第几个元素开始绘制图元
                                  2); // 绘制的图元数量
}

//恢复成默认的属性
    m_pD3DDevice->SetRenderState(D3DRS_LIGHTING, true);
m_pD3DDevice->SetRenderState(D3DRS_ZWRITEENABLE, true);
m_pD3DDevice->SetRenderState(D3DRS_ZENABLE, true);
m_pD3DDevice->SetSamplerState(0, D3DSAMP_ADDRESSU, D3DTADDRESS_WRAP);
m_pD3DDevice->SetSamplerState(0, D3DSAMP_ADDRESSV, D3DTADDRESS_WRAP);


}