creating a 3d plane using Frank Luna's technique
- by numerical25
I am creating a 3d plane that lays on the x and z axis. and has hills that extend on the y axis. bulk of the code looks like this
float PeaksAndValleys::getHeight(float x, float z)const
{
return 0.3f*( z*sinf(0.1f*x) + x*cosf(0.1f*z) );
}
void PeaksAndValleys::init(ID3D10Device* device, DWORD m, DWORD n, float dx)
{
md3dDevice = device;
mNumRows = m;
mNumCols = n;
mNumVertices = m*n;
mNumFaces = (m-1)*(n-1)*2;
// Create the geometry and fill the vertex buffer.
std::vector<Vertex> vertices(mNumVertices);
float halfWidth = (n-1)*dx*0.5f;
float halfDepth = (m-1)*dx*0.5f;
for(DWORD i = 0; i < m; ++i)
{
float z = halfDepth - i*dx;
for(DWORD j = 0; j < n; ++j)
{
float x = -halfWidth + j*dx;
// Graph of this function looks like a mountain range.
float y = getHeight(x,z);
vertices[i*n+j].pos = D3DXVECTOR3(x, y, z);
// Color the vertex based on its height.
if( y < -10.0f )
vertices[i*n+j].color = BEACH_SAND;
else if( y < 5.0f )
vertices[i*n+j].color = LIGHT_YELLOW_GREEN;
else if( y < 12.0f )
vertices[i*n+j].color = DARK_YELLOW_GREEN;
else if( y < 20.0f )
vertices[i*n+j].color = DARKBROWN;
else
vertices[i*n+j].color = WHITE;
}
}
D3D10_BUFFER_DESC vbd;
vbd.Usage = D3D10_USAGE_IMMUTABLE;
vbd.ByteWidth = sizeof(Vertex) * mNumVertices;
vbd.BindFlags = D3D10_BIND_VERTEX_BUFFER;
vbd.CPUAccessFlags = 0;
vbd.MiscFlags = 0;
D3D10_SUBRESOURCE_DATA vinitData;
vinitData.pSysMem = &vertices[0];
HR(md3dDevice->CreateBuffer(&vbd, &vinitData, &mVB));
// Create the index buffer. The index buffer is fixed, so we only
// need to create and set once.
std::vector<DWORD> indices(mNumFaces*3); // 3 indices per face
// Iterate over each quad and compute indices.
int k = 0;
for(DWORD i = 0; i < m-1; ++i)
{
for(DWORD j = 0; j < n-1; ++j)
{
indices[k] = i*n+j;
indices[k+1] = i*n+j+1;
indices[k+2] = (i+1)*n+j;
indices[k+3] = (i+1)*n+j;
indices[k+4] = i*n+j+1;
indices[k+5] = (i+1)*n+j+1;
k += 6; // next quad
}
}
D3D10_BUFFER_DESC ibd;
ibd.Usage = D3D10_USAGE_IMMUTABLE;
ibd.ByteWidth = sizeof(DWORD) * mNumFaces*3;
ibd.BindFlags = D3D10_BIND_INDEX_BUFFER;
ibd.CPUAccessFlags = 0;
ibd.MiscFlags = 0;
D3D10_SUBRESOURCE_DATA iinitData;
iinitData.pSysMem = &indices[0];
HR(md3dDevice->CreateBuffer(&ibd, &iinitData, &mIB));
}
My question pretains to the cosf and sinf. I am formiluar with trigonometry and I understand sin, cosine, and tangent. but I am not formiluar with cosf and sinf and what they do. From looking at this example. they have alot to do with finding a y value.
