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c++matrixdirectxdirectx-11direct3d11

Why does XMMatrixLookAtLH result in a debug error?

I am developing a DirectX 11 game in C++ and I am trying to create a view matrix but when I do I am getting the following debug error:

Assertion failed!

Program: ...ate-Direct3D11\Build\Debug\Template-Direct3D11.exe
File: C:\Program Files (x86)\Windows Kits...\DirectX...rix.inl
Line: 1971

Expression: !XMVector3Equal(EyeDirection, XMVectorZero())

For information on how your program can cause an assertion
failure, see the Visual C++ documentation on asserts

(Press Retry to debug the application - JIT must be enabled)'Template-Direct3D11.exe' (Win32): Loaded 'C:\Windows\SysWOW64\TextShaping.dll'. 
Template-Direct3D11.exe has triggered a breakpoint.

Here is the code:

DirectX::XMVECTOR eyePos = DirectX::XMVectorSet(0.f, 0.f, -2.f, 0.f);
DirectX::XMVECTOR lookAtPos = DirectX::XMVectorSet(0.f, 0.f, -2.f, 0.f);
DirectX::XMVECTOR upVector = DirectX::XMVectorSet(0.f, 1.f, 0.f, 0.f);
DirectX::XMMATRIX view = DirectX::XMMatrixLookAtLH(eyePos, lookAtPos, upVector); //Debug Error

I cannot find any information online about this because it seems that everyone has a different error than me.

Can anyone help?

Solution

  • The eyPos and the lookAtPos you are setting are the same value... The result is a 0-length unit vector for direction.

    DirectX::XMVectorSet is not the best way to initialize a constant vector. Read the DirectXMath Programmer's Guide particularly the Getting Started guide.