我正在使用 DXUT 使用 DirectX9 创建图形应用程序。在我的应用程序中，我想实现延迟着色。这种照明方法要求我为场景中的每个灯光渲染一个模板体积（遮罩）。为了避免单独渲染卷，我想使用 DirectX 的实例化能力。使用顶点着色器 3.0 和像素着色器 3.0，我已经成功地绘制了任何给定模型的多个实例，但是，当我尝试绘制实例化模板卷时，似乎没有数据写入后缓冲区的深度模板表面。
我的延迟着色实现在伪代码中如下所示：
将所有场景几何体（Instanced Geometry Pass）绘制到后备缓冲区：
- 启用 Z( D3DRS_ZENABLE, TRUE )
- 启用 ZWrites( D3DRS_ZWRITEENABLE, TRUE )
- 禁用模板（D3DRS_STENCILENABLE，FALSE）
- 设置剔除模式（D3DRS_CULLMODE，D3DCULL_CCW）
- 禁用 ColorWrites( D3DRS_COLORWRITEENABLE, 0 )
- 禁用 Alphablending（D3DRS_ALPHABLEENDENABLE，FALSE）
- 渲染场景
获取指向后台缓冲区的指针：
- IDirect3DDevice9::GetRenderTarget(0, pBackbufferSurface)
设置 3 个渲染目标（COLOR(0)、NORMAL(1)、POSITION(2)）：
- IDirect3DDevice9::SetRenderTarget(0 -> 2, 颜色 -> 位置)
将所有场景几何图形绘制到 3 个渲染目标：
- 启用 ColorWrites（D3DRS_COLORWRITEENABLE、CW_RED、CW_GREEN、CW_BLUE、CW_ALPHA）
- 渲染场景
将后台缓冲区重置为设备 RenderTarget 0：
- IDirect3DDevice9::SetRenderTarget(0, pBackbufferSurface)
将效果纹理（ SrcColor ）设置为 COLOR 渲染目标
- ID3DXEffect::SetTexture("g_TextureSrcColor", pRTColor)
渲染全屏四边形并从 COLOR 渲染目标采样（绘制场景）
使用实例化技术模板所有场景灯（这里是实际代码）：
// set the instance buffer vertex declaration
hr = pd3dDevice->SetVertexDeclaration( CContentManager::GetInstanceBufferVertexDeclaration() );
if( FAILED( hr ) )
{
DebugStringDX( ClassName, "Failed to IDirect3DDevice9::SetVertexDeclaration( instances )at RenderScene()", __LINE__, hr );
return hr;
}
// render instances of each light( sphere and cone )
for( UINT i = 0; i < 2; ++i )
{
// point to base model
CXModel *pXBase = ( CXModel* )pCM->GetAppObject( i );
if( !pXBase )
{
DebugStringDX( ClassName,
"Failed to retrieve the base light model at index( " + ToString( i ) + " ) at Render()",
__LINE__,
E_POINTER );
continue;
}
// if the model has no instances
// there is no reason to try and draw
UINT ucInstances = pXBase->GetNumInstances();
if( ucInstances < 1 )
continue;
// Set up the geometry data stream
hr = pd3dDevice->SetStreamSourceFreq( 0,
( D3DSTREAMSOURCE_INDEXEDDATA | ucInstances ) );
if( FAILED( hr ) )
{
DebugStringDX( ClassName, "Failed to IDirect3DDevice9::SetStreamSourceFreq( source )( index - " + ToString( i ) + " ) at RenderScene()", __LINE__, hr );
continue;
}
// Set up the instance data stream
IDirect3DVertexBuffer9 *pVBInstances = pXBase->GetInstanceBuffer();
hr = pd3dDevice->SetStreamSource( 1, pVBInstances, 0,
sizeof( CXModel::sInstanceEntry ) );
if( FAILED( hr ) )
{
DebugStringDX( ClassName, "Failed to IDirect3DDevice9::SetStreamSource( instances )( index - " + ToString( i ) + " ) at RenderScene()", __LINE__, hr );
continue;
}
hr = pd3dDevice->SetStreamSourceFreq( 1,
( D3DSTREAMSOURCE_INSTANCEDATA | 1ul ) );
if( FAILED( hr ) )
{
DebugStringDX( ClassName, "Failed to IDirect3DDevice9::SetStreamSourceFreq( instances )( index - " + ToString( i ) + " ) at Render()", __LINE__, hr );
continue;
}
// get light model frame root
pFrame = pXBase->GetFrameRoot();
if( !pFrame )
{
DebugStringDX( ClassName, "Failed to CXModel::GetFrameRoot( Light Model ) at Render()", __LINE__, hr );
continue;
}
//------------------------------------------------------------------------------------------------------------
// Stencil Volume Mask Pass
//------------------------------------------------------------------------------------------------------------
dev.SetRenderState( D3DRS_ZENABLE, TRUE );
dev.SetRenderState( D3DRS_ZWRITEENABLE, FALSE );
dev.SetRenderState( D3DRS_STENCILENABLE, TRUE );
dev.SetRenderState( D3DRS_STENCILFUNC, D3DCMP_ALWAYS );
dev.SetRenderState( D3DRS_STENCILFAIL, D3DSTENCILOP_KEEP );
dev.SetRenderState( D3DRS_STENCILZFAIL, D3DSTENCILOP_INCR );
dev.SetRenderState( D3DRS_STENCILPASS, D3DSTENCILOP_KEEP );
dev.SetRenderState( D3DRS_STENCILWRITEMASK, 0xffffffff );
dev.SetRenderState( D3DRS_CULLMODE, D3DCULL_NONE );
dev.SetRenderState( D3DRS_COLORWRITEENABLE, 0 );
hr = BeginPass( CFXDeferred::STENCIL );
if( FAILED( hr ) )
{
DebugStringDX( ClassName, "Failed to BeginPass( StencilVolumeMask ) at Render()", __LINE__, hr );
continue;
}
// draw the light model
hr = DrawStaticModel( pd3dDevice, pFrame, &mWorld, pmView, pmProjection, true, bRenderStrips );
if( FAILED( hr ) )
{
DebugStringDX( ClassName, "Failed to DrawStaticModel( Light Model ) at Render()", __LINE__, hr );
continue;
}
hr = pE->EndPass();
if( FAILED( hr ) )
{
DebugStringDX( ClassName, "Failed to ID3DXEffect::EndPass() at Render()", __LINE__, hr );
continue;
}
//------------------------------------------------------------------------------------------------------------
// Diffuse Light Pass
//------------------------------------------------------------------------------------------------------------
dev.SetRenderState( D3DRS_ALPHABLENDENABLE, TRUE );
dev.SetRenderState( D3DRS_SRCBLEND, D3DBLEND_ONE );
dev.SetRenderState( D3DRS_DESTBLEND, D3DBLEND_ONE );
dev.SetRenderState( D3DRS_ZENABLE, FALSE );
dev.SetRenderState( D3DRS_CULLMODE, D3DCULL_CW );
dev.SetRenderState( D3DRS_COLORWRITEENABLE,
D3DCOLORWRITEENABLE_RED | D3DCOLORWRITEENABLE_GREEN | D3DCOLORWRITEENABLE_BLUE | D3DCOLORWRITEENABLE_ALPHA );
dev.SetRenderState( D3DRS_STENCILENABLE, TRUE );
dev.SetRenderState( D3DRS_STENCILFUNC, D3DCMP_EQUAL );
dev.SetRenderState( D3DRS_STENCILMASK, 0x1 );
dev.SetRenderState( D3DRS_STENCILPASS, D3DSTENCILOP_ZERO );
dev.SetRenderState( D3DRS_STENCILREF, 0x1 );
dev.SetRenderState( D3DRS_STENCILZFAIL, D3DSTENCILOP_KEEP );
dev.SetRenderState( D3DRS_STENCILFAIL, D3DSTENCILOP_ZERO );
hr = BeginPass( CFXDeferred::DIFFUSELIGHTSTENCIL );
if( FAILED( hr ) )
{
DebugStringDX( ClassName, "Failed to BeginPass( DiffuseSpecularLightStencilPass ) at Render()", __LINE__, hr );
continue;
}
// draw light model
hr = DrawStaticModel( pd3dDevice, pFrame, &mWorld, pmView, pmProjection, true, bRenderStrips );
if( FAILED( hr ) )
{
DebugStringDX( ClassName, "Failed to DrawStaticModel( Light Model ) at Render()", __LINE__, hr );
continue;
}
hr = pE->EndPass();
if( FAILED( hr ) )
{
DebugStringDX( ClassName, "Failed to ID3DXEffect::EndPass() at Render()", __LINE__, hr );
continue;
}
}
这是实例缓冲区顶点声明：
// create instance vertex declaration
D3DVERTEXELEMENT9 pElements[] = {
{ 0, 0, D3DDECLTYPE_FLOAT3, D3DDECLMETHOD_DEFAULT, D3DDECLUSAGE_POSITION, 0 },
{ 0, 12, D3DDECLTYPE_FLOAT3, D3DDECLMETHOD_DEFAULT, D3DDECLUSAGE_NORMAL, 0 },
{ 0, 24, D3DDECLTYPE_FLOAT2, D3DDECLMETHOD_DEFAULT, D3DDECLUSAGE_TEXCOORD, 0 },
{ 1, 0, D3DDECLTYPE_FLOAT4, D3DDECLMETHOD_DEFAULT, D3DDECLUSAGE_TEXCOORD, 1 },
{ 1, 16, D3DDECLTYPE_FLOAT4, D3DDECLMETHOD_DEFAULT, D3DDECLUSAGE_TEXCOORD, 2 },
{ 1, 32, D3DDECLTYPE_FLOAT4, D3DDECLMETHOD_DEFAULT, D3DDECLUSAGE_TEXCOORD, 3 },
{ 1, 48, D3DDECLTYPE_FLOAT4, D3DDECLMETHOD_DEFAULT, D3DDECLUSAGE_TEXCOORD, 4 },
{ 1, 64, D3DDECLTYPE_FLOAT2, D3DDECLMETHOD_DEFAULT, D3DDECLUSAGE_TEXCOORD, 5 },
D3DDECL_END()
};
此方法无需实例化即可正常工作...实例化是否会阻止深度模板写入？当我使用 PIX 进行调试时，它表明“像素未通过模板测试”。这是在渲染之前清除后台缓冲区的调用：
pd3dDevice->Clear( 0, NULL, D3DCLEAR_TARGET | D3DCLEAR_ZBUFFER | D3DCLEAR_STENCIL, D3DCOLOR_ARGB( 0, 0, 0, 0 ), 1.0f, 0 ) );
在创建设备期间，我修改设置以使用 AutoDepthStencilFormat D3DFMT_D24S8，如下所示：
// check for D3DFMT_D24S8 AutoDepthStencilFormat
// if present set the AutoDepthStencilFormat to D3DFMT_D24S8
if( DXUTGetD3D9Enumeration()->GetPossibleDepthStencilFormatList()->Contains( D3DFMT_D24S8 ) )
{
pDeviceSettings->d3d9.pp.AutoDepthStencilFormat = D3DFMT_D24S8;
}
如果我将 IDirect3DDevice9::Clear() 的模板参数（最后一个参数）更改为 1。模板卷通过了模板测试...这是因为我设置模板操作以将模板值增加 1，如果像素为体积掩码与后缓冲区上的像素相交，并且在该事件中，承认光的像素颜色。这表明存在以下两个问题之一：
- 在“实例化几何通道”期间绘制场景（对象）时......后缓冲区不存储绘制对象时的深度（因此模板测试具有“0”值用于比较或
- 绘制模板卷（灯）时，后缓冲区不存储绘制卷的深度......
这是由于我的实例化方法吗？是因为着色器版本（vs3、ps3）还是 DX 版本？