渲染目标视图ID3D11RenderTargetView

D3D11在使用某个渲染对象渲染之前，需要先用背景纯色清空渲染目标

    md3dImmediateContext->ClearRenderTargetView(mRenderTargetView, reinterpret_cast<const float*>(&(Colors::Blue)));

在OBS中

void render_main_texture(struct obs_core_video *video)
{
...
    //设置自定义当前的渲染对象
    gs_set_render_target(video->render_texture, NULL);

    //调用ClearRenderTargetView对video->render_texture进行背景纯色清空渲染目标
    gs_clear(GS_CLEAR_COLOR, &clear_color, 1.0f, 0);
...
}

只不，在OBS中对render_texture因为支持立方体，故可能会有6个渲染纹理。

struct gs_texture_2d : gs_texture {
...
    ComPtr<ID3D11RenderTargetView> renderTarget[6];
    ComPtr<ID3D11RenderTargetView> renderTargetLinear[6];//非DXGI_FORMAT_UNKNOWN格式时创建
...

ID3D11RenderTargetView的创建可详见void gs_texture_2d::InitRenderTargets()

void gs_texture_2d::InitRenderTargets()
{
    if (type == GS_TEXTURE_2D)
    {
        D3D11_RENDER_TARGET_VIEW_DESC rtv;
        rtv.Format = dxgiFormatView;
        rtv.ViewDimension = D3D11_RTV_DIMENSION_TEXTURE2D;
        rtv.Texture2D.MipSlice = 0;

        hr = device->device->CreateRenderTargetView(texture, &rtv, renderTarget[0].Assign());
        ..//错误判断
        if (dxgiFormatView == dxgiFormatViewLinear)
        {
            renderTargetLinear[0] = renderTarget[0];
        } 
        else
        {
            rtv.Format = dxgiFormatViewLinear;
            hr = device->device->CreateRenderTargetView(texture, &rtv,renderTargetLinear[0].Assign());
    }
    else
    {
        D3D11_RENDER_TARGET_VIEW_DESC rtv;
        rtv.Format = dxgiFormatView;
        rtv.ViewDimension = D3D11_RTV_DIMENSION_TEXTURE2DARRAY;
        rtv.Texture2DArray.MipSlice = 0;
        rtv.Texture2DArray.ArraySize = 1;

        for (UINT i = 0; i < 6; i++) 
        {
            rtv.Texture2DArray.FirstArraySlice = i;
            hr = device->device->CreateRenderTargetView(texture, &rtv, renderTarget[i].Assign());
            ..//错误判断
            if (dxgiFormatView == dxgiFormatViewLinear) 
            {
                renderTargetLinear[i] = renderTarget[i];
            } 
            else
            {
                rtv.Format = dxgiFormatViewLinear;
                hr = device->device->CreateRenderTargetView(texture, &rtv,renderTargetLinear[i].Assign());
            }
        }
    }
}