ShadowMap.cpp

#include "ShadowMap.h"


ShadowMap::ShadowMap(ID3D11Device* device, UINT width, UINT height):mWidth(width),mHeight(height),mDepthMapSRV(0),mDepthMapDSV(0)
{
	mViewport.TopLeftX = 0.0f;
	mViewport.TopLeftY = 0.0f;
	mViewport.Width = static_cast<float>(width);
	mViewport.Height = static_cast<float>(height);
	mViewport.MinDepth = 0.0f;
	mViewport.MaxDepth = 1.0f;

	//使用无类型的格式，因为DSV将用DXGI_FORMAT_D24_UNORM_S8_UINT修改数据，SRV将用DXGI_FORMAT_R24_UNORM_X8_TYPELESS修改位
	D3D11_TEXTURE2D_DESC texDesc;
	texDesc.Width = mWidth;
	texDesc.Height = mHeight;
	texDesc.MipLevels = 1;
	texDesc.ArraySize = 1;
	texDesc.Format = DXGI_FORMAT_R24G8_TYPELESS;
	texDesc.SampleDesc.Count = 1;
	texDesc.SampleDesc.Quality = 0;
	texDesc.Usage = D3D11_USAGE_DEFAULT;
	texDesc.BindFlags = D3D11_BIND_DEPTH_STENCIL | D3D11_BIND_SHADER_RESOURCE;
	texDesc.CPUAccessFlags = 0;
	texDesc.MiscFlags = 0;

	ID3D11Texture2D* depthMap = 0;
	HR(device->CreateTexture2D(&texDesc,0,&depthMap));

	D3D11_DEPTH_STENCIL_VIEW_DESC dsvDesc;
	dsvDesc.Flags = 0;
	dsvDesc.Format = DXGI_FORMAT_D24_UNORM_S8_UINT;
	dsvDesc.ViewDimension = D3D11_DSV_DIMENSION_TEXTURE2D;
	dsvDesc.Texture2D.MipSlice = 0;
	HR(device->CreateDepthStencilView(depthMap,&dsvDesc,&mDepthMapDSV));

	D3D11_SHADER_RESOURCE_VIEW_DESC srvDesc;
	srvDesc.Format = DXGI_FORMAT_R24_UNORM_X8_TYPELESS;
	srvDesc.ViewDimension = D3D11_SRV_DIMENSION_TEXTURE2D;
	srvDesc.Texture2D.MipLevels = texDesc.MipLevels;
	srvDesc.Texture2D.MostDetailedMip = 0;
	HR(device->CreateShaderResourceView(depthMap,&srvDesc,&mDepthMapSRV));

	ReleaseCOM(depthMap);
}



ShadowMap::~ShadowMap(void)
{
	ReleaseCOM(mDepthMapSRV);
	ReleaseCOM(mDepthMapDSV);

}

ID3D11ShaderResourceView* ShadowMap::DeptchMapSRV()
{
	return mDepthMapSRV;
}

void ShadowMap::BindDsvAndSetNullRenderTarget(ID3D11DeviceContext* dc)
{
	dc->RSSetViewports(1,&mViewport);

	//设置render target 为null，因为我们只会绘制到depth buffer中。设置null renderTarget会禁掉颜色写入。
	ID3D11RenderTargetView* renderTargets[1] = {0};
	dc->OMSetRenderTargets(1,renderTargets,mDepthMapDSV);

	dc->ClearDepthStencilView(mDepthMapDSV,D3D11_CLEAR_DEPTH,1.0f,0);
}