From 923ad5e83be561dcadfec113177cd7cbcaea56d9 Mon Sep 17 00:00:00 2001
From: Adrian Kummerlaender
Date: Thu, 19 Dec 2019 13:07:02 +0100
Subject: Basic sky rendering using the model by Nishita et al.

See "Display of the earth taking into account atmospheric scattering" (Nishita et al., 1993)

`bluedot.py` renders the full earth disk while rotating the sun around it.

`sunrise.py` renders the rise of the sun.

Physical model constants may be changed in `planets.py`.
---
 bluedot.py | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)
 create mode 100644 bluedot.py

(limited to 'bluedot.py')

diff --git a/bluedot.py b/bluedot.py
new file mode 100644
index 0000000..036ae7f
--- /dev/null
+++ b/bluedot.py
@@ -0,0 +1,50 @@
+import numpy
+import matplotlib.pyplot as plt
+from string import Template
+
+import pyopencl as cl
+from pyopencl.cltypes import make_double3
+
+mf = cl.mem_flags
+
+from planets import earth
+
+config = {
+    'size_x': 1000,
+    'size_y': 1000,
+
+    'ray_samples':   16,
+    'light_samples': 8,
+
+    'exposure': 20.0,
+
+    'eye_pos': (0, -3, 1.1),
+    'eye_dir': (0, 1, -0.35)
+}
+
+cl_platform = cl.get_platforms()[0]
+cl_context = cl.Context(properties=[(cl.context_properties.PLATFORM, cl_platform)])
+cl_queue   = cl.CommandQueue(cl_context)
+
+cl_picture = cl.Buffer(cl_context, mf.WRITE_ONLY, size=config['size_x']*config['size_y']*3*numpy.float64(0).nbytes)
+program = None
+
+with open('raymarch.cl') as f:
+    program = cl.Program(cl_context, Template(f.read()).substitute(
+        {**config, **earth}
+    )).build()
+
+for i in range(0,360):
+    sun = make_double3(numpy.cos(i*2*numpy.pi/360),numpy.sin(i*2*numpy.pi/360),0)
+    print(sun)
+
+    program.render(
+        cl_queue, (config['size_x'], config['size_y']), None, cl_picture,
+        make_double3(*config['eye_pos']),
+        make_double3(*config['eye_dir']),
+        sun)
+
+    np_picture = numpy.ndarray(shape=(config['size_y'], config['size_x'], 3), dtype=numpy.float64)
+    cl.enqueue_copy(cl_queue, np_picture, cl_picture).wait();
+
+    plt.imsave('sky_%03d.png' % i, np_picture, origin='lower')
-- 
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