C / C++ / MFC

// Vertex buffer description
wrl::ComPtr<ID3D11Buffer> _vertexBuf;
D3D11_BUFFER_DESC _vbd = {};
_vbd.BindFlags = D3D11_BIND_VERTEX_BUFFER;
_vbd.Usage = D3D11_USAGE_DEFAULT;
_vbd.CPUAccessFlags = 0u;
_vbd.MiscFlags = 0u;
_vbd.ByteWidth = sizeof(_vertices);
_vbd.StructureByteStride = sizeof(Vertex);

D3D11_SUBRESOURCE_DATA _vsd = {};
_vsd.pSysMem = _vertices;

// Create vertex buffer
GFX_THROW_INFO(_hr,
    mp_device->CreateBuffer(&_vbd, &_vsd, &_vertexBuf)
);

// Bind vertex buffer to pipeline
const UINT _stride = sizeof(Vertex);
const UINT _offset = 0u;
GFX_THROW_INFO_ONLY(_v,
    mp_context->IASetVertexBuffers(
        0u,
        1u,
        _vertexBuf.GetAddressOf(),
        &_stride,
        &_offset
    )
);


// Index buffer description
wrl::ComPtr<ID3D11Buffer> _indexBuf;
D3D11_BUFFER_DESC _ibd = {};
_ibd.BindFlags = D3D11_BIND_INDEX_BUFFER;
_ibd.Usage = D3D11_USAGE_DEFAULT;
_ibd.CPUAccessFlags = 0u;
_ibd.MiscFlags = 0u;
_ibd.ByteWidth = sizeof(_indices);
_ibd.StructureByteStride = sizeof(unsigned short);

D3D11_SUBRESOURCE_DATA _isd = {};
_isd.pSysMem = _indices;

// Create index buffer
GFX_THROW_INFO(_hr,
    mp_device->CreateBuffer(&_ibd, &_isd, &_indexBuf)
);

// Bind index buffer to pipeline
GFX_THROW_INFO_ONLY(_v,
    mp_context->IASetIndexBuffer(
        _indexBuf.Get(),
        DXGI_FORMAT_R16_UINT,
        0u
    )
);

if (m_indexCount == 0) {
    // temporary, just a build of vectors from local arrays
    std::vector<Vertex> _verts;
    for (int _i = 0; _i < 8; _i += 1)
        _verts.push_back(_vertices[_i]);
    std::vector<unsigned short> _inds;
    for (int _i = 0; _i < 36; _i += 1)
        _inds.push_back(_indices[_i]);


    m_indexCount = _inds.size();
    m_ibufIndex = AddBind(std::make_unique<IndexBuffer>(*this, _inds));
    m_vbufIndex = AddBind(std::make_unique<VertexBuffer>(*this, _verts));

} else {
    ((IndexBuffer*)(m_binds[m_ibufIndex].get()))->Bind(*this);
    ((VertexBuffer*)(m_binds[m_vbufIndex].get()))->Bind(*this);
}

#include <cmath>
#include <iostream>
using namespace std;

int main()
{
  const size_t N = 18;
  const double delta = M_PI/N;

  for ( double phi = 0; phi < 2*M_PI; phi += delta)
  {
    double s = sin(phi);
    double a = asin(s);
    cout << "phi = " << phi << ", sin(phi) = " << s << ", asin(sin(phi)) = " << a << "\n";
  }
  cout << endl;
}

phi = 0, sin(phi) = 0, asin(sin(phi)) = 0
phi = 0.174533, sin(phi) = 0.173648, asin(sin(phi)) = 0.174533
phi = 0.349066, sin(phi) = 0.34202, asin(sin(phi)) = 0.349066
phi = 0.523599, sin(phi) = 0.5, asin(sin(phi)) = 0.523599
phi = 0.698132, sin(phi) = 0.642788, asin(sin(phi)) = 0.698132
phi = 0.872665, sin(phi) = 0.766044, asin(sin(phi)) = 0.872665
phi = 1.0472, sin(phi) = 0.866025, asin(sin(phi)) = 1.0472
phi = 1.22173, sin(phi) = 0.939693, asin(sin(phi)) = 1.22173
phi = 1.39626, sin(phi) = 0.984808, asin(sin(phi)) = 1.39626
phi = 1.5708, sin(phi) = 1, asin(sin(phi)) = 1.5708
phi = 1.74533, sin(phi) = 0.984808, asin(sin(phi)) = 1.39626
phi = 1.91986, sin(phi) = 0.939693, asin(sin(phi)) = 1.22173
phi = 2.0944, sin(phi) = 0.866025, asin(sin(phi)) = 1.0472
phi = 2.26893, sin(phi) = 0.766044, asin(sin(phi)) = 0.872665
phi = 2.44346, sin(phi) = 0.642788, asin(sin(phi)) = 0.698132
phi = 2.61799, sin(phi) = 0.5, asin(sin(phi)) = 0.523599
phi = 2.79253, sin(phi) = 0.34202, asin(sin(phi)) = 0.349066
phi = 2.96706, sin(phi) = 0.173648, asin(sin(phi)) = 0.174533
phi = 3.14159, sin(phi) = 1.45473e-15, asin(sin(phi)) = 1.45473e-15
phi = 3.31613, sin(phi) = -0.173648, asin(sin(phi)) = -0.174533
phi = 3.49066, sin(phi) = -0.34202, asin(sin(phi)) = -0.349066
phi = 3.66519, sin(phi) = -0.5, asin(sin(phi)) = -0.523599
phi = 3.83972, sin(phi) = -0.642788, asin(sin(phi)) = -0.698132
phi = 4.01426, sin(phi) = -0.766044, asin(sin(phi)) = -0.872665
phi = 4.18879, sin(phi) = -0.866025, asin(sin(phi)) = -1.0472
phi = 4.36332, sin(phi) = -0.939693, asin(sin(phi)) = -1.22173
phi = 4.53786, sin(phi) = -0.984808, asin(sin(phi)) = -1.39626
phi = 4.71239, sin(phi) = -1, asin(sin(phi)) = -1.5708
phi = 4.88692, sin(phi) = -0.984808, asin(sin(phi)) = -1.39626
phi = 5.06145, sin(phi) = -0.939693, asin(sin(phi)) = -1.22173
phi = 5.23599, sin(phi) = -0.866025, asin(sin(phi)) = -1.0472
phi = 5.41052, sin(phi) = -0.766044, asin(sin(phi)) = -0.872665
phi = 5.58505, sin(phi) = -0.642788, asin(sin(phi)) = -0.698132
phi = 5.75959, sin(phi) = -0.5, asin(sin(phi)) = -0.523599
phi = 5.93412, sin(phi) = -0.34202, asin(sin(phi)) = -0.349066
phi = 6.10865, sin(phi) = -0.173648, asin(sin(phi)) = -0.174533
phi = 6.28319, sin(phi) = -4.68582e-15, asin(sin(phi)) = -4.68582e-15

#include <cmath>
#include <iostream>
using namespace std;

int main()
{
  double angle = asin( 40/80.6225 );
  cout << "angle " << angle << " (" << (angle * 180 / M_PI) << " degrees)" << endl;
}

angle 0.519147 (29.7449 degrees)

Quote:

That is you get the first quadrant angle correnspondig to the sin value passed as argument.

Gopi Nath wrote:

What may be the issue?