//================================================================================================================================================================
//================================================================================================================================================================
void OceanHeightfield::CreateHeightfield(D3DXVECTOR2* out_h0, float* out_omega)
{
int i, j;
D3DXVECTOR2 K, Kn;
D3DXVECTOR2 wind_dir;
D3DXVec2Normalize(&wind_dir, &ocean_params.wind_dir);
float a = ocean_params.wave_amplitude * 1e-7f; // It is too small. We must scale it for editing.
float v = ocean_params.wind_speed;
float dir_depend = ocean_params.wind_dependency;
int height_map_dim = ocean_params.displacement_map_dim;
float patch_length = ocean_params.patch_length;
// initialize random generator.
srand(0);
for (i = 0; i <= height_map_dim; i++)
{
// K is wave-vector, range [-|DX/W, |DX/W], [-|DY/H, |DY/H]
K.y = (-height_map_dim / 2.0f + i) * (2 * D3DX_PI / patch_length);
for (j = 0; j <= height_map_dim; j++)
{
K.x = (-height_map_dim / 2.0f + j) * (2 * D3DX_PI / patch_length);
float phil = (K.x == 0 && K.y == 0) ? 0 : sqrtf(Phillips(K, wind_dir, v, a, dir_depend));
out_h0[i * (height_map_dim + 4) + j].x = float(phil * GaussRandom() * HALF_SQRT_2);
out_h0[i * (height_map_dim + 4) + j].y = float(phil * GaussRandom() * HALF_SQRT_2);
// The angular frequency is following the dispersion relation:
// out_omega^2 = g*k
// The equation of Gerstner wave:
// x = x0 - K/k * A * sin(dot(K, x0) - sqrt(g * k) * t), x is a 2D vector.
// z = A * cos(dot(K, x0) - sqrt(g * k) * t)
// Gerstner wave shows that a point on a simple sinusoid wave is doing a uniform circular
// motion with the center (x0, y0, z0), radius A, and the circular plane is parallel to
// vector K.
out_omega[i * (height_map_dim + 4) + j] = sqrtf(GRAV_ACCEL * sqrtf(K.x * K.x + K.y * K.y));
}
}
}
//=============================================
int GaussianNoiseGenerator::Execute(void)
{
int is;
float *noise_sig_ptr;
float noise_sigma;
float rand_var;
float noise_sig_val;
//--------------------------------------------
noise_sigma = Noise_Sigma;
long seed = Seed;
//---------------------------------------------
noise_sig_ptr = GET_OUTPUT_PTR(Noise_Sig);
//-------------------------------------------------
// main loop
for(is=0; is<Proc_Block_Size; is++)
{
// generate gaussian RV
GaussRandom(&seed, &rand_var);
noise_sig_val = noise_sigma * rand_var;
*noise_sig_ptr++ = noise_sig_val;
}// end of main loop
// put back variables that have changed
Seed = seed;
//----------------------------------------------
return(_MES_AOK);
};
