DirectX11 广告牌未显示

Question

我正在尝试广告牌，但是当我使用"newWorld"时，广告牌没有显示，我已经测试了它是否是我绘制广告牌的方式，但它不是，因为当我更改为它自己的本地世界时，它出现在屏幕上。

    // Calculate the rotation that needs to be applied to the billboard model to face the current camera position using the arc tangent function.
XMFLOAT3 CarPos = XMFLOAT3(Billboards->GetPosition().x, Billboards->GetPosition().y, Billboards->GetPosition().z);
XMFLOAT3 CamPos = XMFLOAT3(fCam->GetEye().x, fCam->GetEye().y, fCam->GetEye().z);
float angle;
float BBrotation;
XMMATRIX newWorld = XMLoadFloat4x4(&Billboards->GetWorld());
angle = atan2(CarPos.x - CamPos.x, CarPos.z - CamPos.z) * (180 / XM_PI);
BBrotation = angle * 0.0174532925f; 
XMMatrixRotationY(BBrotation);
XMMatrixTranslation(CarPos.x, CarPos.y, CarPos.z);
XMMATRIX bbRotMatix = XMMatrixRotationY(BBrotation);
XMMATRIX bbCarPos = XMMatrixTranslation(CarPos.x, CarPos.y, CarPos.z);
newWorld = bbCarPos + bbRotMatix;
XMMATRIX bilworld = XMLoadFloat4x4(&Billboards->GetWorld());
cb.World = XMMatrixTranspose(newWorld);
_pImmediateContext->UpdateSubresource(_pConstantBuffer, 0, nullptr, &cb, 0, 0);
Billboards->Draw(_pd3dDevice, _pImmediateContext, _pTreeRV, _pSpecRV);
Billboards->SetTranslation(30.0f, 0.0f, 0.0f);
Billboards->SetRotation(-90.0f, 0.0f, 0.0);

Answer 1

Directx Tool Kit 中的 SimpleMath DirectXMath 包装器具有右手广告牌函数，您可能会发现作为参考很有用。

inline Matrix Matrix::CreateBillboard( const Vector3& object, const Vector3& cameraPosition, const Vector3& cameraUp, const Vector3* cameraForward )
{
    using namespace DirectX;
    XMVECTOR O = XMLoadFloat3( &object );
    XMVECTOR C = XMLoadFloat3( &cameraPosition );
    XMVECTOR Z = XMVectorSubtract( O, C );
    XMVECTOR N = XMVector3LengthSq( Z );
    if ( XMVector3Less( N, g_XMEpsilon ) )
    {
        if ( cameraForward )
        {
            XMVECTOR F = XMLoadFloat3( cameraForward );
            Z = XMVectorNegate( F );
        }
        else
            Z = g_XMNegIdentityR2;
    }
    else
    {
        Z = XMVector3Normalize( Z );
    }
    XMVECTOR up = XMLoadFloat3( &cameraUp );
    XMVECTOR X = XMVector3Cross( up, Z );
    X = XMVector3Normalize( X );
    XMVECTOR Y = XMVector3Cross( Z, X );
    XMMATRIX M;
    M.r[0] = X;
    M.r[1] = Y;
    M.r[2] = Z;
    M.r[3] = XMVectorSetW( O, 1.f );
    Matrix R;
    XMStoreFloat4x4( &R, M );
    return R;
}
inline Matrix Matrix::CreateConstrainedBillboard( const Vector3& object, const Vector3& cameraPosition, const Vector3& rotateAxis,
                                                  const Vector3* cameraForward, const Vector3* objectForward )
{
    using namespace DirectX;
    static const XMVECTORF32 s_minAngle = { 0.99825467075f, 0.99825467075f, 0.99825467075f, 0.99825467075f }; // 1.0 - XMConvertToRadians( 0.1f );
    XMVECTOR O = XMLoadFloat3( &object );
    XMVECTOR C = XMLoadFloat3( &cameraPosition );
    XMVECTOR faceDir = XMVectorSubtract( O, C );
    XMVECTOR N = XMVector3LengthSq( faceDir );
    if (XMVector3Less(N, g_XMEpsilon))
    {
        if (cameraForward)
        {
            XMVECTOR F = XMLoadFloat3( cameraForward );
            faceDir = XMVectorNegate( F );
        }
        else
            faceDir = g_XMNegIdentityR2;
    }
    else
    {
        faceDir = XMVector3Normalize( faceDir );
    }
    XMVECTOR Y = XMLoadFloat3( &rotateAxis );
    XMVECTOR X, Z;
    XMVECTOR dot = XMVectorAbs( XMVector3Dot( Y, faceDir ) );
    if ( XMVector3Greater( dot, s_minAngle ) )
    {
        if ( objectForward )
        {
            Z = XMLoadFloat3( objectForward );
            dot = XMVectorAbs( XMVector3Dot( Y, Z ) );
            if ( XMVector3Greater( dot, s_minAngle ) )
            {
                dot = XMVectorAbs( XMVector3Dot( Y, g_XMNegIdentityR2 ) );
                Z = ( XMVector3Greater( dot, s_minAngle ) ) ? g_XMIdentityR0 : g_XMNegIdentityR2;
            }
        }
        else
        {
            dot = XMVectorAbs( XMVector3Dot( Y, g_XMNegIdentityR2 ) );
            Z = ( XMVector3Greater( dot, s_minAngle ) ) ? g_XMIdentityR0 : g_XMNegIdentityR2;
        }
        X = XMVector3Cross( Y, Z );
        X = XMVector3Normalize( X );
        Z = XMVector3Cross( X, Y );
        Z = XMVector3Normalize( Z );
    }
    else
    {
        X = XMVector3Cross( Y, faceDir );
        X = XMVector3Normalize( X );
        Z = XMVector3Cross( X, Y );
        Z = XMVector3Normalize( Z );
    }
    XMMATRIX M;
    M.r[0] = X;
    M.r[1] = Y;
    M.r[2] = Z;
    M.r[3] = XMVectorSetW( O, 1.f );
    Matrix R;
    XMStoreFloat4x4( &R, M );
    return R;
}