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OpenGL Confuzed with Direct3D10 Shaders

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Hello there! :) I am a little confuzed with Direct3D 10 shaders. All the MS SDK Examples are using fx files and Techniques. I want a more "non easy/utility" way to do it.. so I am using functions like D3D10CompileShader(), CreateVertexShader() etc.. Now I can't find information about how I set the shader constants! for example .. i want to pass the view, world and projection matrices in the vertex shader. How i do that? ps: I dont have any previous Direct3D experience. (only OpenGL with ARB ASM programs) thanks for your time!

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Hey DumpAlien,

I haven't written any Direct X 10 stuff yet, just read a few articles and from my understanding you set constants using the new CB's (Constant Buffers). So for example:

Your objects constant buffer in HLSL could be.

cbuffer obj
float4x4 matWorld
float4 vPos

When you call D3D10CompileShader you can get back the constant table from the last parameter (LPD3DXCONSTANTTABLE * ppConstantTable). You can then access this information using the ID3DXConstantTable interface functions ie GetConstantByName, SetMatrixArray etc.

Hope thats some help and someone can give u a better answer

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Reflect the compiled shader so you can get the count and name of the CBs the shader is using. Save which name belongs to which index. Create CBs, fill them. Then set the CBs with XXSetConstantBuffers.

Yeah, it's not so straightforward, the documentation is very much lacking.

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Yes very true, my answer was a mix of direct x 9 and 10 lol..

Had another look at the SDK and the information is in there, look in the programming guide under resources and "Creating Buffer Resources".

ID3D10Buffer* g_pConstantBuffer10 = NULL;

D3DXMATRIX mWorldViewProj; //mWorldViewProj will probably be global to all shaders in a project.
//It's a good idea not to move it around between shaders.
D3DXVECTOR4 vSomeVectorThatMayBeNeededByASpecificShader;
float fSomeFloatThatMayBeNeededByASpecificShader;
float fTime; //fTime may also be global to all shaders in a project.
float fSomeFloatThatMayBeNeededByASpecificShader2;
float fSomeFloatThatMayBeNeededByASpecificShader3;

cbDesc.ByteWidth = sizeof( VS_CONSTANT_BUFFER );
cbDesc.Usage = D3D10_USAGE_DYNAMIC;
cbDesc.BindFlags = D3D10_BIND_CONSTANT_BUFFER;
cbDesc.CPUAccessFlags = D3D10_CPU_ACCESS_WRITE;
cbDesc.MiscFlags = 0;
hr = g_pd3dDevice->CreateBuffer( &cbDesc, NULL, &g_pConstantBuffer10 );
if( FAILED( hr ) )
return hr;

g_pd3dDevice->VSSetConstantBuffers( 0, 1, g_pConstantBuffer10 );

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Thanks for your replies guys!
I found some information from Humus framework (www.humus.ca)
Like you said me, he reflects the shaders to get the information and then
he access the variables using UpdateSubresource() function.
The code is a little confuzing for start but I will fight it:P

Thanks again guys!

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