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can a mipmap texture be bound to render target

Started by chenpan Jul 11, 2011 at 8:50 AM 7 replies 10k views

Original Post

Jul 11, 2011 at 8:50 AM

Hey,
I want to create a mipmap texture manually.
Such that texel (i, j) of level n stores the minimum of texels (2i, 2j), (2i+1, 2j), (2i, 2j+1), (2i+1, 2j+1) in level n-1.
Now I have level 0 of the mipmap texture.
I want to fill texels data to the other levels using shader.
Just like render to texture. I want to render to a level of a mipmap texture.
Can I bind a level of a mipmap texture to the render target? How to do it?
Thank you in advance!

Adam_42

Jul 11, 2011 at 10:00 AM

Which API are you using?

Under D3D9 I think you'd need to create one render target per mip level which you can then render to with an appropriate shader using the higher mip level as a source texture, and then you'd copy from those into the mip levels of a separate texture using StretchRect().

Why do you want do do this?

chenpan

Jul 11, 2011 at 12:34 PM

I'm using D3D10.
I'm implementing a paper.

Which API are you using?

Under D3D9 I think you'd need to create one render target per mip level which you can then render to with an appropriate shader using the higher mip level as a source texture, and then you'd copy from those into the mip levels of a separate texture using StretchRect().

Why do you want do do this?

pcmaster

Jul 11, 2011 at 12:42 PM

You can generate each mip-map manually using a shader or whatever. But you'll probably have to create a temporary render-target of the selected mip-map's resolution, render the mip-map into it (using a shader) and then copy this tmp render-target texture into the sub-resource of your final texture (ID3D11DeviceContext::CopySubresourceRegion() + D3D11CalcSubresource(mipLevel, 0, numMipLevels), the same for DX10). The final texture has to be created first, with all the mip-map levels and they will be "replaced" this way.

mind in a box

Jul 11, 2011 at 12:56 PM

I did that before when implementing some ScreenSpaceDisplacementMapping-Paper.

Here's one little helper struct which should gibe you the information you need:

struct PostFX_SSDM_Mip_RTV_SRV
 {
 ~PostFX_SSDM_Mip_RTV_SRV()
 {
 if(SRV)SRV->Release();
 if(RTV)RTV->Release();
 }
 
 PostFX_SSDM_Mip_RTV_SRV()
 {
 SRV=NULL;
 RTV=NULL;
 }
 
 HRESULT Create(ID3D11Resource* Res, DXGI_FORMAT fmt, int Level)
 {
 HRESULT hr=S_OK;
 
 //Create a render target view
 D3D11_RENDER_TARGET_VIEW_DESC DescRT;
 DescRT.Format = fmt;
 DescRT.ViewDimension = D3D11_RTV_DIMENSION_TEXTURE2D;
 DescRT.Texture2D.MipSlice = Level;
 LE(DXUTGetD3D11Device()->CreateRenderTargetView(Res,&DescRT,&RTV));
 
 // Get the mip level and create the SRV
 ID3D11Resource* MipRes;
 RTV->GetResource(&MipRes);
 
 // Create the resource view
 D3D11_SHADER_RESOURCE_VIEW_DESC DescRV;
 DescRV.Format = fmt;
 DescRV.ViewDimension = D3D11_SRV_DIMENSION_TEXTURE2D;
 DescRV.Texture2D.MipLevels = 1;
 DescRV.Texture2D.MostDetailedMip = Level;
 
 LE(DXUTGetD3D11Device()->CreateShaderResourceView(MipRes , &DescRV, &SRV ));
 
 MipRes->Release();
 
 return hr;
 }
 
 ID3D11ShaderResourceView* SRV;
 ID3D11RenderTargetView* RTV;
 };

It has been a while since I wrote that code, but it should work. Just replace all 11s with 10s.

chenpan

Jul 11, 2011 at 1:10 PM

uh, it works. I just think it's inconvenient. So I'm wondering if D3D10 support setting a level of a mipmap texture as render target. That will be very convenient.

You can generate each mip-map manually using a shader or whatever. But you'll probably have to create a temporary render-target of the selected mip-map's resolution, render the mip-map into it (using a shader) and then copy this tmp render-target texture into the sub-resource of your final texture (ID3D11DeviceContext::CopySubresourceRegion() + D3D11CalcSubresource(mipLevel, 0, numMipLevels), the same for DX10). The final texture has to be created first, with all the mip-map levels and they will be "replaced" this way.

mind in a box

Jul 11, 2011 at 1:33 PM

uh, it works. I just think it's inconvenient. So I'm wondering if D3D10 support setting a level of a mipmap texture as render target. That will be very convenient.[/quote]

Well, I just told you how to create that rendertargetview...

chenpan

Jul 11, 2011 at 2:03 PM

Thank you very much. Your code snippet helps a lot.

I did that before when implementing some ScreenSpaceDisplacementMapping-Paper.

Here's one little helper struct which should gibe you the information you need:
struct PostFX_SSDM_Mip_RTV_SRV { ~PostFX_SSDM_Mip_RTV_SRV() { if(SRV)SRV->Release(); if(RTV)RTV->Release(); } PostFX_SSDM_Mip_RTV_SRV() { SRV=NULL; RTV=NULL; } HRESULT Create(ID3D11Resource* Res, DXGI_FORMAT fmt, int Level) { HRESULT hr=S_OK; //Create a render target view D3D11_RENDER_TARGET_VIEW_DESC DescRT; DescRT.Format = fmt; DescRT.ViewDimension = D3D11_RTV_DIMENSION_TEXTURE2D; DescRT.Texture2D.MipSlice = Level; LE(DXUTGetD3D11Device()->CreateRenderTargetView(Res,&DescRT,&RTV)); // Get the mip level and create the SRV ID3D11Resource* MipRes; RTV->GetResource(&MipRes); // Create the resource view D3D11_SHADER_RESOURCE_VIEW_DESC DescRV; DescRV.Format = fmt; DescRV.ViewDimension = D3D11_SRV_DIMENSION_TEXTURE2D; DescRV.Texture2D.MipLevels = 1; DescRV.Texture2D.MostDetailedMip = Level; LE(DXUTGetD3D11Device()->CreateShaderResourceView(MipRes , &DescRV, &SRV )); MipRes->Release(); return hr; } ID3D11ShaderResourceView* SRV; ID3D11RenderTargetView* RTV; };

It has been a while since I wrote that code, but it should work. Just replace all 11s with 10s.

chenpan

Jul 19, 2011 at 2:19 AM

What should I do other than creating the rendertargetview? Reset the viewport? Or anything else? Thank you ~

uh, it works. I just think it's inconvenient. So I'm wondering if D3D10 support setting a level of a mipmap texture as render target. That will be very convenient.

Well, I just told you how to create that rendertargetview...
[/quote]

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