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cozzie

DX11 My First Constant Buffer, What's Wrong?

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Hi all,

I've starting moving from effects11 to managing things myself, also getting rid of the deprecated effects11 library.

First stop: constant buffers.

 

Here's what I'm trying to do:

- create constant buffers for the shader constants in my effect file

- replace the calls to SetMatrix, SetFloat etc. by updating the constant buffer and setting it to the device context

 

As far as I know this should be possible. If not, let me know :)

Basically this is sort of hybrid usage of managing things yourself and using effects11, but for me it's a first step.

Effects11 in the underlying code also calls PSSetConstantBuffer, VSSetConstantBuffer etc., I believe.

 

Here's my attempt for creating, updating and setting the constant buffer.

I get no compiler errors or warning during runtime, I just don't see the effect of the 'should be' update constant buffer.

When I just set the DirLights and EyePosW value through the effects library, the render is fine.

Any thoughts?

// the effect file
cbuffer cbPerFrame : register (b0)
{
	DirectionalLight gDirLights[3];
	float3 gEyePosW;
};

// buffer struct
struct CB_PER_FRAME
{
  DirectionalLight DirLights[3]; // 3x64 bytes
  DirectX::XMFLOAT3 EyePosW; // 12 bytes
  float padA; // 4 bytes
};

// creating the buffer
	CB_PER_FRAME cBufferPerFrame;
	cBufferPerFrame.DirLights[0] = mDirLights[0];
	cBufferPerFrame.DirLights[1] = mDirLights[1];
	cBufferPerFrame.DirLights[2] = mDirLights[2];
	cBufferPerFrame.EyePosW = mEyePosW;
	
	D3D11_BUFFER_DESC cBufferDesc;
	cBufferDesc.ByteWidth = sizeof(CB_PER_FRAME);
	cBufferDesc.Usage = D3D11_USAGE_DYNAMIC;
	cBufferDesc.BindFlags = D3D11_BIND_CONSTANT_BUFFER;
	cBufferDesc.CPUAccessFlags = D3D11_CPU_ACCESS_WRITE;
	cBufferDesc.MiscFlags = 0;
	cBufferDesc.StructureByteStride = 0;

	D3D11_SUBRESOURCE_DATA initData;
	initData.pSysMem = &cBufferPerFrame;
	initData.SysMemPitch = 0;
	initData.SysMemSlicePitch = 0;

	// create the buffer
	mCBuffer = NULL;
	HR(md3dDevice->CreateBuffer(&cBufferDesc, &initData, &mCBuffer));

// updating and setting the buffer
	// CONSTANT BUFFER: UPDATE (PER FRAME)
	D3D11_MAPPED_SUBRESOURCE mappedResource;
	md3dImmediateContext->Map(mCBuffer, 0, D3D11_MAP_WRITE_DISCARD, 0, &mappedResource);

	CB_PER_FRAME* dataPtr = (CB_PER_FRAME*)mappedResource.pData;

	dataPtr->DirLights[0] = mDirLights[0];
	dataPtr->DirLights[1] = mDirLights[1];
	dataPtr->DirLights[2] = mDirLights[2];
	dataPtr->EyePosW = mEyePosW;
	
	md3dImmediateContext->Unmap(mCBuffer, 0);
	md3dImmediateContext->PSSetConstantBuffers(0, 1, &mCBuffer);

// and 'the old way'
//	ID3DX11EffectVectorVariable	*mHEyePosW;
//	ID3DX11EffectVariable		*mHDirLights;

//	void SetEyePosW(const DirectX::XMFLOAT3& v)			{ mHEyePosW->SetRawValue(&v, 0, sizeof(DirectX::XMFLOAT3)); }
//	void SetDirLights(const DirectionalLight* lights)	{ mHDirLights->SetRawValue(lights, 0, 3*sizeof(DirectionalLight)); }

	// per frame constants
//	CD3d11Effects::mBasicFX->SetDirLights(mDirLights);		// CB PER FRAME
//	CD3d11Effects::mBasicFX->SetEyePosW(mEyePosW);			// CB PER FRAME

Edited by cozzie

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Problem solved, I was setting the CB's too early, the effects11 lib was overwriting them

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