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POmultiplication of matrices in vertex shader
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  1. POmultiplication of matrices in vertex shader
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    copied!<p>When I multiply matrices on CPU</p> <pre><code>D3DXMATRIX mb = mbb.matWorld * mbb.matView * mbb.matProj; D3D11_BUFFER_DESC bd; ZeroMemory(&amp;bd, sizeof(bd)); bd.Usage = D3D11_USAGE_DEFAULT; bd.ByteWidth = sizeof(D3DXMATRIX); bd.BindFlags = D3D11_BIND_CONSTANT_BUFFER; bd.CPUAccessFlags = 0; D3D11_SUBRESOURCE_DATA initData; ZeroMemory(&amp;initData, sizeof(initData)); initData.pSysMem = &amp;mb; //***************************************** cbuffer ConstantBuffer : register(cb0) { matrix mat; float4 vs(float4 pos : POSITION) : SV_POSITION { float4 ret = mul(pos, mat); return ret; } </code></pre> <p>It works great. But when I do it on GPU</p> <pre><code>struct Buffer { D3DXMATRIX mat[3]; }; Buffer b; // b[..] = .... D3D11_BUFFER_DESC bd; ZeroMemory(&amp;bd, sizeof(bd)); bd.Usage = D3D11_USAGE_DEFAULT; bd.ByteWidth = sizeof(D3DXMATRIX) * 3; bd.BindFlags = D3D11_BIND_CONSTANT_BUFFER; bd.CPUAccessFlags = 0; D3D11_SUBRESOURCE_DATA initData; ZeroMemory(&amp;initData, sizeof(initData)); initData.pSysMem = &amp;b; //***************************************** cbuffer ConstantBuffer : register(cb0) { matrix matWorld; matrix matView; matrix matProj; } float4 vs(float4 pos : POSITION) { float4 ret = mul(pos, matWorld); ret = mul(ret, matView); ret = mul(ret, matProj); return ret; } </code></pre> <p>Nothing is rendered on the screen. What's wrong?</p> <p>I've been debugging with PIX and it shows that in both versions post-vs vertices are the same.</p> <p>I noticed that it's caused by projection matrix. For my projection matrix I do:</p> <pre><code>D3DXMatrixPerspectiveFovLH(&amp;mbb.matProj, D3DX_PI / 2, (float) init_params.width / init_params.height, 0.01f, 100.0f) </code></pre> <p>FIXED</p> <p>I have to transpose matrices before passing them to vertex shader.</p>
 

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