在matplotlib中分层构图和surface_plot
ahl*_*481 13 python plot matplotlib z-order contourf
我在分层和zorderpython中苦苦挣扎.我正在使用带有三个相关元素的matplotlib进行3D绘图:surface_plot一个行星的A ,一个surface_plot围绕该行星的环,以及一个contourf显示行星的阴影投射到环上的图像.
我希望图形能够精确地显示这种情况在现实生活中的样子,环绕着行星,阴影位于相应位置的环上.如果影子在给定POV的行星后面,我希望阴影被行星阻挡,反之亦然,如果阴影位于行星前面,对于给定的POV.
需要说明的是,这只是一个分层问题.我的行星,戒指和阴影都正确地绘制.但是,阴影永远不会显示在地球的前面.它就好像行星正在"阻挡"阴影,即使行星在层次方面应该位于阴影之下.
我已经尝试了我能想到的每一件事,zorder并重新排列调用各种绘图元素的顺序.环DO正确地显示在行星前面,但阴影不会.
我的实际代码很长.这里是相关部分:
绘图设置:
def setup_saturn_plot(ax3, elev, azim, drawz, drawxy,view):
ax3.set_aspect('equal','box')
ax3.view_init(elev=elev, azim=azim)
if(view=="top" or view == "Top" or view == "TOP"):
ax3.dist = 5.5
if(view=="star" or view == "Star" or view == "STAR"):
ax3.dist = 5.0 #4.5 is best value
proj3d.persp_transformation = orthographic_proj
# hide grid and background
ax3.w_xaxis.set_pane_color((1.0, 1.0, 1.0, 1.0))
ax3.w_yaxis.set_pane_color((1.0, 1.0, 1.0, 1.0))
ax3.w_zaxis.set_pane_color((1.0, 1.0, 1.0, 1.0))
ax3.grid(False)
# hide z axis in orthographic top view, xy axes in star view
if (drawz == False):
ax3.w_zaxis.line.set_lw(0.)
ax3.set_zticks([])
if (drawz == True):
ax3.set_zlabel('Z (1000 km)',fontsize=12)
if (drawxy == False):
ax3.w_xaxis.line.set_lw(0.)
ax3.set_xticks([])
ax3.w_yaxis.line.set_lw(0.)
ax3.set_yticks([])
if (drawxy == True):
ax3.set_xlabel('X (1000 km)',fontsize=12)
ax3.set_ylabel('Y (1000 km)',fontsize=12)
行星:
def draw_saturn(ax3, elev, azim):
# Saturn dimensions
radius = 60268. / 1000.
radius_pole = 54364. / 1000.
# draw Saturn
phi, theta = np.mgrid[0.0:np.pi:100j, 0.0:2.0*np.pi:100j]
x = radius*np.sin(phi)*np.cos(theta)
y = radius*np.sin(phi)*np.sin(theta)
z = radius_pole*np.cos(phi)
line3 = ax3.plot_surface(x, y, z, color="w", edgecolor='b', rstride = 8, cstride=5, shade=False, lw=0.25)
#line3 = ax3.plot_wireframe(x, y, z, color="w", edgecolor='b', rstride = 5, cstride=5, lw=0.25)
ax3.tick_params(labelsize=10)
戒指:
def draw_rings(ax3, elev, azim, draw_mode):
# Saturn dimensions
radius = 60268. / 1000.
# Saturn rings
dringmin = 1.110 * radius
dringmax = 1.236 * radius
cringmin = 1.239 * radius
titanringlet = 1.292 * radius
maxwellgap = 1.452 * radius
cringmax = 1.526 * radius
bringmin = 1.526 * radius
bringmax = 1.950 * radius
aringmin = 2.030 * radius
enckegap = 2.214 * radius
keelergap = 2.265 * radius
aringmax = 2.270 * radius
fringmin = 2.320 * radius
gringmin = 2.754 * radius
gringmax = 2.874 * radius
eringmin = 2.987 * radius
eringmax = 7.964 * radius
if (draw_mode == 'back'):
offset = -azim*np.pi/180. - 0.5*np.pi
if (draw_mode == 'front'):
offset = -azim*np.pi/180. + 0.5*np.pi
rad, theta = np.mgrid[dringmin:dringmax:4j, 0.0-offset:1.0*np.pi-offset:100j]
x = rad * np.cos(theta)
y = rad * np.sin(theta)
z = 0. * rad
line1 = ax3.plot_surface(x, y, z, color="w", edgecolor='b', rstride = 8, cstride=25, shade=False, lw=0.25,alpha=0.)
rad, theta = np.mgrid[cringmin:cringmax:4j, 0.0-offset:1.0*np.pi-offset:100j]
x = rad * np.cos(theta)
y = rad * np.sin(theta)
z = 0. * rad
line2 = ax3.plot_surface(x, y, z, color="w", edgecolor='b', rstride = 8, cstride=25, shade=False, lw=0.25,alpha=0.)
rad, theta = np.mgrid[bringmin:bringmax:4j, 0.0-offset:1.0*np.pi-offset:100j]
x = rad * np.cos(theta)
y = rad * np.sin(theta)
z = 0. * rad
line3 = ax3.plot_surface(x, y, z, color="w", edgecolor='b', rstride = 8, cstride=25, shade=False, lw=0.25,alpha=0.)
rad, theta = np.mgrid[aringmin:aringmax:4j, 0.0-offset:1.0*np.pi-offset:100j]
x = rad * np.cos(theta)
y = rad * np.sin(theta)
z = 0. * rad
line4 = ax3.plot_surface(x, y, z, color="w", edgecolor='b', rstride = 8, cstride=25, shade=False, lw=0.25,alpha=0.)
rad, theta = np.mgrid[fringmin:1.005*fringmin:2j, 0.0-offset:1.0*np.pi-offset:100j]
x = rad * np.cos(theta)
y = rad * np.sin(theta)
z = 0. * rad
line7 = ax3.plot_surface(x, y, z, color="w", edgecolor='b', rstride = 8, cstride=25, shade=False, lw=0.1,alpha=0.)
阴影:
def draw_shadowboundary(ax3, sundir):
#azimuthal angle between x direction and direction of sun
alpha = np.arctan2(sundir[1],sundir[0])
#adjustments to keep -pi/2 < alpha < pi/2
alphaadj = 0.*np.pi/180.
if (alpha<0.):
alpha += 2.*np.pi
if ((alpha >= np.pi/2.) & (alpha <= np.pi)):
alpha += np.pi
alphaadj = np.pi
if ((alpha > np.pi) & (alpha <= 3.*np.pi/2.)):
alpha -= np.pi
alphaadj = np.pi
if (alpha>3.*np.pi/2.):
alpha-=2*np.pi
#azimuthal angle between x direction and northern summer -- found using VIMS_2005_14_OMICET and VIMS_2017_053_ALPORI to define eq. of plane of Sun's annual path in chosen coordinate system: -0.193318*x + 0.1963755*y + 0.5471502*z = 0
beta = 44.5505*np.pi/180.
#Saturn's obliquity -- from NASA fact sheet
psi = 26.73*np.pi/180.
#Saturn's oblateness -- from NASA fact sheet
obl = 0.09796
#helpful definitions for optimization
cpsic = np.cos(psi*np.cos(alpha+beta))
spsic = np.sin(psi*np.cos(alpha+beta))
calpha = np.cos(alpha)
salpha = np.sin(alpha)
#Saturn's projected shorter planetary axis as seen by the sun & ring inner edge
req = 60268. / 1000.
b = req*sqrt((1.-obl)*(1.-obl)*cpsic*cpsic + spsic*spsic)
ringstart = 1.239 * req
ringend = 2.270 * req
#shadow boundary of Saturn's rings -- can approximate using a=inf and cancelling terms
a = 9.582*1.496*10.**5
shadowline = lambda x,y : (1/a)*sqrt((req*salpha*(-a+x*calpha*cpsic+y*salpha)*(y*calpha-x*cpsic*salpha)/sqrt((y*calpha-x*cpsic*salpha)**2 + (x*spsic)**2) + calpha*(a*cpsic*(x*calpha*cpsic+y*salpha) + b*x*(a-x*calpha*cpsic-y*salpha)*spsic*spsic/sqrt((y*calpha-x*cpsic*salpha)**2 + (x*spsic)**2)))**2 + (req*calpha*(a-x*calpha*cpsic-y*salpha)*(y*calpha-x*cpsic*salpha)/sqrt((y*calpha-x*cpsic*salpha)**2 + (x*spsic)**2) + salpha*(a*cpsic*(x*calpha*cpsic+y*salpha)+b*x*(a-x*calpha*cpsic-y*salpha)*spsic*spsic/sqrt((y*calpha-x*cpsic*salpha)**2 + (x*spsic)**2)))**2)
#azimuthal radius & antisolar angle for inequalities
radius = lambda x,y : np.sqrt(x**2+y**2)
anti = lambda x,y : abs(np.arctan2(y,x)-(alpha-alphaadj))
#properties of shadow
samples=1200
d = np.linspace(-3*req,3*req,samples)
x,y = np.meshgrid(d,d)
#z = ((radius(x,y)<=shadowline(x,y)) & (ringstart<=radius(x,y)) & (np.pi/2<=anti(x,y)) & (anti(x,y)<=3.*np.pi/2)).astype(int)
z = ((radius(x,y)<=shadowline(x,y)) & (ringstart<=radius(x,y)) & (radius(x,y)<=ringend) & (np.pi/2<=anti(x,y)) & (anti(x,y)<=3.*np.pi/2)).astype(int)
cmap = matplotlib.colors.ListedColormap(["k","k"])
#add shadow to plot
ax3.contourf(x,y,z, [0.5,1.50001], cmap=cmap,alpha=0.5)
结合图形:
def plot_results(datafile, plot_names):
plot_names.append("occultation_track_" + starname)
fig2 = plt.figure(figsize=(9,9))
ax3 = fig2.add_subplot(111, projection='3d')
setup_saturn_plot(ax3, phi, theta, False, False, "star")
draw_saturn(ax3, phi, theta)
draw_rings(ax3, phi, theta, 'back')
draw_rings(ax3, phi, theta, 'front')
draw_shadowboundary(ax3,sundir)
ax3.set_xlim([-200, 200])
ax3.set_ylim([-200, 200])
ax3.set_zlim([-200, 200])
代码生成如下图像:
灰色阴影应该存在于行星前面的环上.然而,它不会显示在行星的前方,因此只有行星右侧的小阴影实际上出现了.阴影在所有场景中都能正确显示,除非它需要走在地球前方.
对此有任何修复？
目前我正在研究这段代码，但与此同时，至少到目前为止，这似乎是 matplotlib3d 的一个已知问题。
\n\n正如 @TheImportanceOfBeingErnest 很久以前指出的那样，这个问题出现在mpl3d faq中
\n\n\n\n我的 3D 绘图在某些视角下看起来不\xe2\x80\x99t
\n\n这可能是 mplot3d 最常报告的问题。问题是 \xe2\x80\x93 从某些视角 \xe2\x80\x93 一个 3D 对象会出现在另一个对象的前面，即使它实际上位于另一个对象的后面。这可能会导致绘图在物理上看起来不正确。\xe2\x80\x9c。\xe2\x80\x9d
\n\n不幸的是，虽然我们正在做一些工作来减少这种伪像的发生，但它目前是一个棘手的问题，并且在 matplotlib 支持其核心的 3D 图形渲染之前无法完全解决。
\n\n出现此问题的原因是 3D 数据减少为 2D + z 顺序标量。单个值表示集合中 3D 对象所有部分的第三维。因此，当两个集合的边界框相交时，就有可能出现这种伪影。此外，两个 3D 对象（例如多边形或面片）的交集无法在 matplotlib\xe2\x80\x99s 2D 渲染引擎中正确渲染。
\n\n在所有后端添加 OpenGL 支持之前，这个问题可能不会得到解决（非常欢迎补丁）。在此之前，如果您需要复杂的 3D 场景，我们建议使用 MayaVi。
\n
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