📄 csdn_文档中心_alpha 闪烁效果.htm
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color_mode = rand() % NumColorModes;
}
//0..5 0==无变化，1==饱和色，2==宝石色，3==柔和色， // 4==亮色，5==暗色和冷色，<BR>但不适用于大多数情况，
color_modifier_age--;
if (color_modifier_age == 0) {
color_modifier_age = min_color_modifier_age + (int)(rnd()*
(max_color_modifier_age - min_color_modifier_age));
color_modifier_mode = rand() % NumColorModifierModes;
}
//更新闪烁效果
for (i=0; i<nCurNumSparkles; i++) {
sparkle[i].cur_age--;
if (sparkle[i].cur_age == 0) {
sparkle[i] = RandomSparkle();
}
sparkle[i].scale *= sparkle[i].delta_scale;
}
} // UpdateSparkles() 结束
</PRE>
<P><B><FONT face=arial>DrawSparkles</B></FONT>
对粒子系统定位代码中使用的前面方向进行计算。该值被用来生成每个粒子各顶点的偏移量。图 5 对此进行了说明。</P><IMG
alt=粒子定位示意图 border=0 height=300
src="CSDN_文档中心_Alpha 闪烁效果.files/directx0900-5.gif" width=300>
<P><B>图 5. 粒子定位</B></P>
<P>为了提高效率，闪烁效果按绘制的纹理进行排序。索引列表及 <B><FONT
face=arial>DrawIndexedPrimitive</B></FONT> 用来绘制粒子系统的四边形。</P><PRE class=clsCode>BOOL DrawSparkles(LPDIRECT3DDEVICE7 lpDev, D3DVECTOR from, D3DVECTOR at)
{
D3DVECTOR view_dir, position, dx, dy;
UINT i;
view_dir = Normalize(at - from);
dx = CrossProduct(view_dir, D3DVECTOR(0.0f, 1.0f, 0.0f));
dy = CrossProduct(view_dir, dx);
dx = CrossProduct(view_dir, dy);
// 绘制闪烁效果
// 为提高效率，我们要将所有使用相同纹理的闪烁效果
// 批量处理并只进行一次 DrawPrim 调用
int flags[NumTextures];
for (int tex=0; tex<NumTextures; tex++) {
flags[tex] = 0;
}
// 计算出正在使用哪些纹理
for (i=0; i<nCurNumSparkles; i++) {
flags[sparkle[i].texture]++;
}
// 对于每种使用的纹理，批量处理闪烁效果并进行绘制
for (tex=0; tex<NumTextures; tex++) {
if (flags[tex] == 0)
continue;
// 设置正确的材质/纹理组合
lpDev->SetTexture(0,g_ptexSparkleTextures[tex]);
//建造用于批处理的四边形
int num = 0;
for (i=0; i<nCurNumSparkles; i++) {
if (sparkle[i].texture != tex)
continue;
D3DVECTOR sx = dx * sparkle[i].scale;
D3DVECTOR sy = dy * sparkle[i].scale;
float color_scale = (float)sparkle[i].cur_age /
sparkle[i].age;
D3DVECTOR cur_color = sparkle[i].color * color_scale;
D3DCOLOR color = D3DRGB(cur_color[0], cur_color[1],
cur_color[2]);
position = sparkle[i].position;
s_mesh[num*4+0] = D3DLVERTEX(position+sx+sy, color, 0,
1.0f, 1.0f);
s_mesh[num*4+1] = D3DLVERTEX(position-sx+sy, color, 0,
0.0f, 1.0f);
s_mesh[num*4+2] = D3DLVERTEX(position-sx-sy, color, 0,
0.0f, 0.0f);
s_mesh[num*4+3] = D3DLVERTEX(position+sx-sy, color, 0,
1.0f, 0.0f);
num++;
}
// 已完成批处理的创建，现在进行着色
if (lpDev->DrawIndexedPrimitive(D3DPT_TRIANGLELIST,
D3DFVF_LVERTEX, (LPVOID)s_mesh,
4*flags[tex], s_indices,
6*flags[tex], 0) != D3D_OK)
return FALSE;
}
return TRUE;
} // DrawSparkles() 结束
</PRE>
<P>图 6 和图 7 显示了由 alpha 混色粒子系统产生的图像的附加屏幕快照。</P><IMG alt=屏幕保护程序的屏幕快照
border=0 height=338
src="CSDN_文档中心_Alpha 闪烁效果.files/directx0900-6.jpg" width=450>
<P><B>图 6. <FONT face=arial>MSDNSparkles</FONT> 屏幕快照 2</B></P><IMG
alt=屏幕保护程序的屏幕快照 border=0 height=338
src="CSDN_文档中心_Alpha 闪烁效果.files/directx0900-7.jpg" width=450>
<P><B>图 7. <FONT face=arial>MSDNSparkles</FONT> 屏幕快照 3</B></P>
<P><B><FONT class=105v><FONT face=arial><FONT size=3>MSDNSparkles
的内部构件</FONT></B></FONT><FONT size=3> </FONT></FONT>
<P>让我们继续探讨过载应用程序函数的实现过程。我在下面重新列出了函数的原型，这样您就不必回卷到本文开始的地方。我将对 Direct3D
屏幕保护程序框架允许覆盖的每个过载函数进行考查。</P><PRE class=clsCode>//--------------------------------------------------------------------------
// 外部函数原型
//--------------------------------------------------------------------------
HRESULT App_ConfirmDevice( DDCAPS*, D3DDEVICEDESC* );
HRESULT App_OneTimeSceneInit();
VOID App_DeleteDeviceObjects( HWND, LPDIRECT3DDEVICE7 );
HRESULT App_InitDeviceObjects( HWND, LPDIRECT3DDEVICE7 );
HRESULT App_FrameMove( LPDIRECT3DDEVICE7, FLOAT );
HRESULT App_Render( LPDIRECT3DDEVICE7 );
HRESULT App_RestoreSurfaces();
HRESULT App_FinalCleanup();
</PRE>
<P><B><FONT face=arial>ConfirmDevice</FONT> </B>
<P>MSDNSparkles <B><FONT face=arial>App_ConfirmDevice</B></FONT>
函数验证设备是否能够进行 ONE:ONE alpha 混色。这是 alpha 最简单的形式 —
并且，根据我的经验，所有的显卡都可以执行这种 alpha 混色。下面是 MSDNSparkles 实现 <B><FONT
face=arial>App_ConfirmDevice</B></FONT> 的过程。</P><PRE class=clsCode>HRESULT App_ConfirmDevice( DDCAPS* pddDriverCaps,
D3DDEVICEDESC7* pd3dDeviceDesc )
{
// 获取 triangle caps（硬件或软件），并检验 alpha 混色
LPD3DPRIMCAPS pdpc = &pd3dDeviceDesc->dpcTriCaps;
if( 0 == ( pdpc->dwSrcBlendCaps & pdpc->dwDestBlendCaps & D3DBLEND_ONE ) )
return E_FAIL;
return S_OK;
}
</PRE>
<P><B><FONT face=arial>OneTimeSceneInit</FONT> </B>
<P><B><FONT face=arial>App_OneTimeSceneInit</FONT></B>
函数首先给随机数生成器播种，并设置背景颜色和初始化纹理列表。然后，它使用纹理列表创建 MSDNSparkles 使用的纹理。最后，调用
<B><FONT face=arial>InitSparkles</B></FONT> 对粒子系统进行初始化。</P><PRE class=clsCode>HRESULT App_OneTimeSceneInit()
{
// 给随机数生成器播种
srand(time(0));
//初始化背景颜色
bckColor = D3DRGB(0,0,0);
//装载纹理数据
memcpy(g_szSparkleTextures[0],"dx5.bmp",sizeof("dx5.bmp"));
memcpy(g_szSparkleTextures[1],"dx7.bmp",sizeof("dx7.bmp"));
memcpy(g_szSparkleTextures[2],"flare1.bmp",sizeof("flare1.bmp"));
memcpy(g_szSparkleTextures[3],"flare2.bmp",sizeof("flare2.bmp"));
memcpy(g_szSparkleTextures[4],"flare3.bmp",sizeof("flare3.bmp"));
memcpy(g_szSparkleTextures[5],"flare4.bmp",sizeof("flare5.bmp"));
memcpy(g_szSparkleTextures[6],"flare5.bmp",sizeof("flare5.bmp"));
memcpy(g_szSparkleTextures[7],"flare6.bmp",sizeof("flare6.bmp"));
memcpy(g_szSparkleTextures[8],"flare7.bmp",sizeof("flare7.bmp"));
memcpy(g_szSparkleTextures[9],"flare8.bmp",sizeof("flare8.bmp"));
memcpy(g_szSparkleTextures[10],"shine1.bmp",sizeof("flare1.bmp"));
memcpy(g_szSparkleTextures[11],"shine2.bmp",sizeof("flare2.bmp"));
memcpy(g_szSparkleTextures[12],"shine3.bmp",sizeof("flare3.bmp"));
memcpy(g_szSparkleTextures[13],"shine4.bmp",sizeof("flare5.bmp"));
memcpy(g_szSparkleTextures[14],"shine5.bmp",sizeof("flare5.bmp"));
memcpy(g_szSparkleTextures[15],"shine6.bmp",sizeof("flare6.bmp"));
for ( int i = 0; i < NumTextures; i++)
D3DTextr_CreateTextureFromFile( (char *)g_szSparkleTextures[i] );
InitSparkles();
return S_OK;
}
</PRE>
<P><B><FONT face=arial>InitDeviceObjects</FONT> </B>
<P><B><FONT face=arial>App_InitDeviceObjects</B> 函数使用 helper 函数
<B><FONT face=arial>SetTextureState</B>、<B>SetRenderState</B> 和
<B>SetViewState</B></FONT>。这些函数分别对纹理列表、应用程序所使用的着色状态和查看系统进行设置。请注意，已启用了alpha
混色，混色状态将为加色而设置成 ONE:ONE。</P><PRE class=clsCode>void SetTextureState(LPDIRECT3DDEVICE7 pd3dDevice )
{
// 设置纹理状态
D3DTextr_RestoreAllTextures( pd3dDevice );
// 装载纹理表面
for( int i=0; i<NumTextures; i++ )
g_ptexSparkleTextures[i] = D3DTextr_GetSurface( (char *)
g_szSparkleTextures[i]);
}
void SetRenderState(LPDIRECT3DDEVICE7 pd3dDevice )
{
// alpha 混色状态
pd3dDevice->SetRenderState(D3DRENDERSTATE_ALPHABLENDENABLE, TRUE);
pd3dDevice->SetRenderState(D3DRENDERSTATE_SRCBLEND, srcBlend);
pd3dDevice->SetRenderState(D3DRENDERSTATE_DESTBLEND, dstBlend);
// 过滤器状态
pd3dDevice->SetTextureStageState(0,D3DTSS_MINFILTER, D3DFILTER_LINEAR);
pd3dDevice->SetTextureStageState(0,D3DTSS_MAGFILTER, D3DFILTER_LINEAR);
pd3dDevice->SetTextureStageState(0,D3DTSS_MIPFILTER, D3DFILTER_LINEAR);
// 设置非纹理着色状态
pd3dDevice->SetRenderState(D3DRENDERSTATE_DITHERENABLE, FALSE);
pd3dDevice->SetRenderState(D3DRENDERSTATE_SPECULARENABLE, FALSE);
pd3dDevice->SetRenderState(D3DRENDERSTATE_ZWRITEENABLE, FALSE);
pd3dDevice->SetRenderState(D3DRENDERSTATE_ZENABLE, FALSE);
pd3dDevice->SetRenderState(D3DRENDERSTATE_CULLMODE, D3DCULL_NONE);
// 注：在 DX7 中，要关闭顶点照明，需要将 D3DRENDERSTATE_LIGHTING 设置为 FALSE
// （并改用 D3DLVERTEX 中的颜色）
pd3dDevice->SetRenderState( D3DRENDERSTATE_LIGHTING, FALSE );
}
void SetViewState(LPDIRECT3DDEVICE7 pd3dDevice )
{
// 获取宽高比
pd3dDevice->GetViewport(&vp);
FLOAT fAspect = ((FLOAT)vp.dwHeight) / vp.dwWidth;
// 设置变换矩阵
D3DUtil_SetProjectionMatrix( proj,
g_PI/4,//1.0f;
fAspect,
1.0f, MAX_DIST );
pd3dDevice->SetTransform( D3DTRANSFORMSTATE_PROJECTION, &proj);
D3DUtil_SetViewMatrix( view, from, at, up );
pd3dDevice->SetTransform( D3DTRANSFORMSTATE_VIEW, &view);
D3DUtil_SetIdentityMatrix( world );
pd3dDevice->SetTransform( D3DTRANSFORMSTATE_WORLD, &world);
}
HRESULT App_InitDeviceObjects( HWND hWnd, LPDIRECT3DDEVICE7 pd3dDevice )
{
// 检查参数
if( NULL==pd3dDevice )
return E_INVALIDARG;
// 设置纹理状态
SetTextureState( pd3dDevice );
// 设置着色状态
SetRenderState( pd3dDevice );
// 设置查看系统
SetViewState( pd3dDevice );
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