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# How do I create more than one constant buffer ?

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### #1Danisflying  Members   -  Reputation: 100

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Posted 25 March 2012 - 06:46 PM

The reason why I want to create a second constant buffer is to render a second cube, Is there another way to create a duplicate of a cube .

### #2Asesh  Members   -  Reputation: 270

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Posted 25 March 2012 - 07:55 PM

solution: instancing

### #3Hornsj3  Members   -  Reputation: 195

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Posted 25 March 2012 - 08:00 PM

I believe there are more than one constant buffer register. If you want 2 distinct constant buffers you can create an array of constant buffers and pass that to your shader SetConstantBuffers(...) function.

### #4Danisflying  Members   -  Reputation: 100

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Posted 25 March 2012 - 08:15 PM

How would I create that register ?

### #5Bacterius  Crossbones+   -  Reputation: 12838

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Posted 26 March 2012 - 12:54 AM

How are you creating your first constant buffer? That said you don't normally create a new constant buffer just to store a cube. Constant buffers are for stuff like camera position, world/view/projection matrices, shader parameters, etc... vertex and mesh data usually goes within the vertex declarations.

“If I understand the standard right it is legal and safe to do this but the resulting value could be anything.”

### #6kauna  Crossbones+   -  Reputation: 2918

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Posted 26 March 2012 - 01:12 AM

You create a second constant buffer in the same way as you create the first constant buffer.

Also, you may reuse a single constant buffer for different drawing calls. ie. fill constant buffer for the first cube, draw, re-fill the same constant buffer for the second cube (like with different world matrix and color etc), draw the second cube and so on.

Cheers!

### #7Danisflying  Members   -  Reputation: 100

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Posted 26 March 2012 - 07:59 AM

I understand creating the second constant buffer, It how do I run both constant buffers at the same time using VSSetConstantBuffers function

### #8TiagoCosta  Crossbones+   -  Reputation: 3435

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Posted 26 March 2012 - 09:22 AM

I understand creating the second constant buffer, It how do I run both constant buffers at the same time using VSSetConstantBuffers function

Assuming you're using DirectX 11, you can declare two constant buffers in HLSL like this:

cbuffer cbuffer0 : register(b0)
{
//..
}

cbuffer cbuffer1 : register(b1)
{
//...
}


Then use:

ID3D11Buffer** ppCBuffers = {pCBuffer0, pCBuffer1};

VSSetConstantBuffers(0, 2, ppCBuffers);


### #9Hornsj3  Members   -  Reputation: 195

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Posted 26 March 2012 - 09:50 AM

Assuming you're using DirectX 11, you can declare two constant buffers in HLSL like this:

Oh... I always assume 11

### #10Danisflying  Members   -  Reputation: 100

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Posted 26 March 2012 - 09:58 AM

I'm getting an error when it comes to CreateVertexShader function

### #11kauna  Crossbones+   -  Reputation: 2918

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Posted 29 March 2012 - 01:00 AM

I'm getting an error when it comes to CreateVertexShader function

Which error do you get?

I am not following exactly what you are trying to accomplish since all the techniques to draw any object multiple times have been presented and you don't give a clue which option you are following. Read my previous post. It is the simplest way to draw the same cube as many times as you wish and you'll only need a single constant buffer for it.

Best regards!

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