terrain.py 文件源码

def generate_hills(width, height, nhills):
    '''
    @param width float, terrain width
    @param height float, terrain height
    @param nhills int, #hills to gen. #hills actually generted is sqrt(nhills)^2
    '''
    # setup coordinate grid
    xmin, xmax = -width/2.0, width/2.0
    ymin, ymax = -height/2.0, height/2.0
    x, y = np.mgrid[xmin:xmax:STEP, ymin:ymax:STEP]
    pos = np.empty(x.shape + (2,))
    pos[:, :, 0] = x; pos[:, :, 1] = y

    # generate hilltops
    xm, ym = np.mgrid[xmin:xmax:width/np.sqrt(nhills), ymin:ymax:height/np.sqrt(nhills)]
    mu = np.c_[xm.flat, ym.flat]
    sigma = float(width*height)/(nhills*8)
    for i in range(mu.shape[0]):
        mu[i] = multivariate_normal.rvs(mean=mu[i], cov=sigma)

    # generate hills
    sigma = sigma + sigma*np.random.rand(mu.shape[0])
    rvs = [ multivariate_normal(mu[i,:], cov=sigma[i]) for i in range(mu.shape[0]) ]
    hfield = np.max([ rv.pdf(pos) for rv in rvs ], axis=0)
    return x, y, hfield