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OpenGL What's D3D equivalent to OpenGL tessellation?

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I am new D3D programming and surprised to find that there is no tessellation in D3D 9/10. Maybe Microsoft give it another terminology. So what's D3D equivalent to OpenGL tessellation? I also search the term "tessellation" in this forum but find no results.

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Here is an overview of Direct3D11 tesselation: [url="http://msdn.microsoft.com/en-us/library/windows/desktop/ff476340(v=vs.85).aspx"]http://msdn.microsof...p/ff476340.aspx[/url]

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Actually DX9 level hardware supported tesselation as well in the form of N patches, [url="http://msdn.microsoft.com/en-us/library/windows/desktop/bb206188(v=vs.85).aspx"]http://msdn.microsof...8(v=vs.85).aspx[/url]

Don't confuse this with the DX11 shader based tesselation however.

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Are the N-patches computed and processed on CPU, not on GPU, right? Like GLU library tesselation functions for OpenGL.

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[quote name='Martins Mozeiko' timestamp='1334605214' post='4931832']
Are the N-patches computed and processed on CPU, not on GPU, right? Like GLU library tesselation functions for OpenGL.
[/quote]
Depends on the GPU some DX9 hardware had this in hardware but it was never a really popular feature so not every card supports it, current level hardware no longer supports this(HD6970, HD4850). Look at the devcaps2 structure to see if your hardware supports this feature.Flags to look at
This is from a HD4850:
[code]
D3DDEVCAPS2_DMAPNPATCH NO
D3DDEVCAPS2_ADAPTIVETESSRTPATCH NO
D3DDEVCAPS2_ADAPTIVETESSNPATCH NO
D3DDEVCAPS2_PRESAMPLEDDMAPNPATCH YES
[/code]

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[quote name='Ingenu' timestamp='1334598190' post='4931795']
It's a D3D11 feature.
[/quote]
Thanks, does this D3D11 feature work on D3D9/10 hardware?

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[quote name='NightCreature83' timestamp='1334609270' post='4931871']
[quote name='Martins Mozeiko' timestamp='1334605214' post='4931832']
Are the N-patches computed and processed on CPU, not on GPU, right? Like GLU library tesselation functions for OpenGL.
[/quote]
Depends on the GPU some DX9 hardware had this in hardware but it was never a really popular feature so not every card supports it, current level hardware no longer supports this(HD6970, HD4850). Look at the devcaps2 structure to see if your hardware supports this feature.Flags to look at
This is from a HD4850:
[code]
D3DDEVCAPS2_DMAPNPATCH NO
D3DDEVCAPS2_ADAPTIVETESSRTPATCH NO
D3DDEVCAPS2_ADAPTIVETESSNPATCH NO
D3DDEVCAPS2_PRESAMPLEDDMAPNPATCH YES
[/code]
[/quote]
It's hard to believe such a widely-used feature on OpenGL is not popular on D3D. So you mean N-patches is obsolete.

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[quote name='leonard2012' timestamp='1334623655' post='4931968']
It's hard to believe such a widely-used feature on OpenGL is not popular on D3D. So you mean N-patches is obsolete.
[/quote]

The tesselation offered by GLU is done in software and isn't a part of OpenGL itself, the comparable functionality in D3D is probably:
http://msdn.microsoft.com/en-us/library/windows/desktop/bb174094%28v=vs.85%29.aspx from the D3DX library.

For proper hardware tesselation in both APIs you need D3D11/OpenGL 4 tesselation shaders. (or lower OpenGL versions if the GL_ARB_tesselation_shader extension is available)

There is also an ATI extension GL_ATI_pn_triangles that does the n-patch tesselation on some radeon cards (some will do it in software and IIRC it was supported by some nvidia drivers aswell (software only) and a GL_AMD_vertex_shader_tesselator that provides hardware tesslation similar to that used on the xbox360, (The 2nd one has no equivalent in D3D and AFAIK was never supported by any vendor other than AMD.

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[quote name='SimonForsman' timestamp='1334626437' post='4931983']
[quote name='leonard2012' timestamp='1334623655' post='4931968']
It's hard to believe such a widely-used feature on OpenGL is not popular on D3D. So you mean N-patches is obsolete.
[/quote]

The tesselation offered by GLU is done in software and isn't a part of OpenGL itself, the comparable functionality in D3D is probably:
[url="http://msdn.microsoft.com/en-us/library/windows/desktop/bb174094%28v=vs.85%29.aspx"]http://msdn.microsof...4(v=vs.85).aspx[/url] from the D3DX library.

For proper hardware tesselation in both APIs you need D3D11/OpenGL 4 tesselation shaders. (or lower OpenGL versions if the GL_ARB_tesselation_shader extension is available)

There is also an ATI extension GL_ATI_pn_triangles that does the n-patch tesselation on some radeon cards (some will do it in software and IIRC it was supported by some nvidia drivers aswell (software only) and a GL_AMD_vertex_shader_tesselator that provides hardware tesslation similar to that used on the xbox360, (The 2nd one has no equivalent in D3D and AFAIK was never supported by any vendor other than AMD.
[/quote]
Thank you for your further help.
Though GLU is not part of GL, these two libraries are often regarded as one by many developers. Software tessellation is OK as long as this feature is provided. When I refer to OpenGL tessellation, I mean the group of OpenGL 1.2 functions like gluNewTess, gluTessBeginPolygon, gluTessBeginContour and so on. Did you mean the ID3DXPatchMesh::Tessellate method is equivalent to these OpenGL functions and implemented in software?

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[quote name='leonard2012' timestamp='1334628147' post='4931988']
[quote name='SimonForsman' timestamp='1334626437' post='4931983']
[quote name='leonard2012' timestamp='1334623655' post='4931968']
It's hard to believe such a widely-used feature on OpenGL is not popular on D3D. So you mean N-patches is obsolete.
[/quote]

The tesselation offered by GLU is done in software and isn't a part of OpenGL itself, the comparable functionality in D3D is probably:
[url="http://msdn.microsoft.com/en-us/library/windows/desktop/bb174094%28v=vs.85%29.aspx"]http://msdn.microsof...4(v=vs.85).aspx[/url] from the D3DX library.

For proper hardware tesselation in both APIs you need D3D11/OpenGL 4 tesselation shaders. (or lower OpenGL versions if the GL_ARB_tesselation_shader extension is available)

There is also an ATI extension GL_ATI_pn_triangles that does the n-patch tesselation on some radeon cards (some will do it in software and IIRC it was supported by some nvidia drivers aswell (software only) and a GL_AMD_vertex_shader_tesselator that provides hardware tesslation similar to that used on the xbox360, (The 2nd one has no equivalent in D3D and AFAIK was never supported by any vendor other than AMD.
[/quote]
Thank you for your further help.
Though GLU is not part of GL, these two libraries are often regarded as one by many developers. Software tessellation is OK as long as this feature is provided. When I refer to OpenGL tessellation, I mean the group of OpenGL 1.2 functions like gluNewTess, gluTessBeginPolygon, gluTessBeginContour and so on. Did you mean the ID3DXPatchMesh::Tessellate method is equivalent to these OpenGL functions and implemented in software?
[/quote]

Its doing something similar atleast (Allthough the D3DX tesselators seems to operate on meshes while the GLU one works on polygons), D3DX is a utility library just like GLU so it is also software only.

You can use GLU along with Direct3D aswell if you want. (or D3DX with OpenGL)

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[quote name='leonard2012' timestamp='1334628147' post='4931988']
Though GLU is not part of GL, these two libraries are often regarded as one by many developers. Software tessellation is OK as long as this feature is provided. When I refer to OpenGL tessellation, I mean the group of OpenGL 1.2 functions like gluNewTess, gluTessBeginPolygon, gluTessBeginContour and so on. Did you mean the ID3DXPatchMesh::Tessellate method is equivalent to these OpenGL functions and implemented in software?
[/quote]GLU is [b]not[/b] part of OpenGL, it's a utility library designed to be used with OpenGL. It's also ancient and hardly every used these days.
Case in point: you can also use "GLU tessellation" ([i]not "GL tessellation"[/i]) with Direct3D because it's just a software utility library.

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@ SimonForsman and Hodgman, thanks for the help.
I prefer to go the D3D-only route, as OpenGL may not be supported on Windows 8 on ARM.

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[quote name='leonard2012' timestamp='1334673284' post='4932142']
@ SimonForsman and Hodgman, thanks for the help.
I prefer to go the D3D-only route, as OpenGL may not be supported on Windows 8 on ARM.
[/quote]

That shouldn't be a problem if you statically link to GLU; like they said, GLU is not part of OpenGL so whether or not OpenGL is present isn't relevant (unless you're using certain functions that depend on an OpenGL context being active).

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I experiment with GLU tessellation method to solve my polygon tessellation issue this week and find it is a viable solution. However, when I apply this method to render a world map, I find quite a few triangles (though less than 10% of total triangles) are not filled. A pronouned error locates at east Asia where a long streak-shaped triangle is not filled. There are also some small ones at the north of Canada.
I also render the map in wireframe mode to inspect the correctness of GLU tessellation result and do not find anything errorous.
My implementation is inspired by Moya's code at [url="http://vterrain.org/Implementation/Libs/glu_tesselation.c"]http://vterrain.org/...u_tesselation.c[/url]. The idea is to gather the tesselated triangles in the callback function for [size=4]GLU_TESS_VERTEX and determine the primitive type in the callback function for GLU_TESS_BEGIN. Could someone kindly give me some hint as to why a small fraction of triangles are not filled.[/size]

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