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PODirect3D WVP Stretching issue
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copied!<p>I've been working on my own 3D Engine using Direct3D. This went pretty good, until I ran into an issue with the World View and Projection Matrices. I'am using code from previous projects that I worked, but doesn't in the project. So I decided to use the Direct3D functions D3DXMatrixLookAtLH and D3DXMatrixPerspectiveFovLH.</p> <p>This gives a working matrices, but if by rotating or translating the camera I move geometry close to the edge of the screen, it stretches that entire object in the horizontal axis, now i'm not sure if this is correct or not.</p> <p>Cube in the middle of the screen looks normal: <img src="https://i.stack.imgur.com/38d4T.png" alt="Normal Cube"></p> <p>But if I move it to the side it starts to stretch: <img src="https://i.stack.imgur.com/7nfSN.png" alt="Stretched cube"></p> <p>This is the View matrix that I get in such a case:</p> <pre><code>-0.81964797 -0.017183444 -0.57260966 0.00000000 0.00000000 0.99954993 -0.029995499 0.00000000 0.57286739 -0.024585750 -0.81927919 0.00000000 -1.1457349 0.049171507 1.6385586 1.0000000 </code></pre> <p>I also noticed that between the WVP matrix in the application and the matrix the shader receives it gets transposed. ( I use memcpy to get it in the CBuffer, so that shouldn't be the problem) This is not a major issue, I just transpose it before it gets send, but I would like to know if this is common.</p> <p>this is my shader:</p> <pre><code>cbuffer WVP :cb0 { float4x4 WVP; }; struct VOut { float4 position : SV_POSITION; float4 color : COLOR; }; VOut VShader(float3 position : POSITION, float4 color : COLOR) { VOut output; output.position = mul( float4(position, 1.0f), WVP); output.color = color; return output; } float4 PShader(float4 position : SV_POSITION, float4 color : COLOR) : SV_TARGET { return color; } </code></pre> <p>This is the code in that happens every frame to update the View matrix according to input:</p> <pre><code>// reset the vectors so the changes don't stack vcPos.Set(x, y, z); vcDir.Set(0.0f, 0.0f, -1.0f); // Rotate the dir vector Matrix3D m; m.Rota(Looky/100, 0.0f, Lookx/100); vcDir.RotateWith(m); // add the pos to the dir vector so it points to in a direction rather then a point in the world vcDir += vcPos; // Set and get the View matrix g_pDevice->SetViewMatrix(vcRight, vcUp, vcDir, vcPos ); g_pDevice->GetViewProjMatrix(&g_mView, NULL); // Multiply them g_mWVP = g_mWorld * g_mView * g_mProj; // Transpose them so the shader tranposes them back. Transpose(&g_mWVP); </code></pre> <p>And this is the behind the scenes part of it:</p> <p>View:</p> <pre><code>D3DXMatrixLookAtLH(&m_mView, &D3DXVECTOR3(vcPos.x, vcPos.y, vcPos.z), &D3DXVECTOR3(vcDir.x, vcDir.y, vcDir.z), &D3DXVECTOR3(vcUp.x, vcUp.y, vcUp.z)); // The .x/.y/.z has to do with some compatability stuff </code></pre> <p>Proj:</p> <pre><code>D3DXMatrixPerspectiveFovLH(&m_mProj, FOV, Aspect, m_fNear, m_fFar); // Straight forward D3DXMatrixPerspectiveFovLH(&m_mProj, 90.0, Aspect, 0.1f, 100.0f); // With values </code></pre> <p>Update2: Complete rewrite with new information</p> <p>Update3: I'm having problems with the View matrix and maybe the Projection. The World matrix works fine.</p> <p>Update4:</p> <p>After changing some more code, I now have something that seems to be working! The only Problem I have right now is the stretching to the side.</p>

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