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I am working on a level editor and I would like to render my viewports (ranging from one to four) at different sizes. However, while thinking of an efficient way to do this I have ran into a wall. From what I can determine the best way to do this wold be

Set D3DContext's D3D11_VIEWPORT to be the size of the "Render View Port One"'s size
Render the first viewport

Set D3DContext's D3D11_VIEWPORT to be the size of the "Render View Port Two"'s size
Render the second viewport

Set D3DContext's D3D11_VIEWPORT to be the size of the "Render View Port Three"'s size
Render the third viewport

Set D3DContext's D3D11_VIEWPORT to be the size of the "Render View Port Fours"'s size
Render the fourth viewport

This seems rather inefficient though. Does anyone have any better suggestions?

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[quote name='RDragon1' timestamp='1306730887' post='4817377']
Why does this sound inefficient to you?
[/quote]

It seems inefficient due to having to change the viewport over and over.

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In D3D11 you can have multiple viewports (and render targets) bound simultaneously, and in a geometry shader you can replicate your triangle to each viewport using SV_ViewportArrayIndex and SV_RenderTargetArrayIndex. However this typically only ends up saving you CPU time, and not GPU tiime. So I would not bother implementing that unless CPU performance becomes an issue.

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I would say 'no' to the original question - it doesn't sound inefficient to me. There really is no way to get around it, and I am sure that a change to the view port is not that big of a deal. Building on the technique that Matt mentioned, you could use an array of viewports, and then have multiple copies of your geometry which each have the corresponding viewport index specified as a vertex attribute.

That would eliminate the need to reset your view ports, but honestly that would be a colossal waste of memory. After you spend some time on the API, you will see that those four calls will be the least of your problems :)

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