sneeker
d397f61046
scenegen.py compiles each scene into a C source and header, driven by a rule block with per-input stem expansion.
103 lines
3.8 KiB
Python
Executable File
103 lines
3.8 KiB
Python
Executable File
#!/usr/bin/env python3
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"""Turn a .scene description into a C translation unit and its header.
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usage: scenegen.py <input.scene> <output.c> <output.h>
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"""
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import os
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import sys
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KINDS = {"lambert": "MAT_LAMBERT", "metal": "MAT_METAL", "light": "MAT_LIGHT"}
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def die(path, lineno, msg):
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sys.stderr.write("%s:%d: %s\n" % (path, lineno, msg))
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raise SystemExit(1)
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def parse(path):
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scene = {
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"background": (0.0, 0.0, 0.0),
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"look_from": (0.0, 0.0, 6.0),
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"look_at": (0.0, 0.0, 0.0),
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"fov": 40.0,
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"spheres": [],
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}
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with open(path) as fh:
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for lineno, raw in enumerate(fh, 1):
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line = raw.split("#", 1)[0].strip()
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if not line:
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continue
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word = line.split()
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head, rest = word[0], word[1:]
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try:
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if head == "background":
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scene["background"] = tuple(float(v) for v in rest[:3])
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elif head == "camera":
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scene["look_from"] = tuple(float(v) for v in rest[0:3])
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scene["look_at"] = tuple(float(v) for v in rest[3:6])
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scene["fov"] = float(rest[6])
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elif head == "sphere":
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centre = tuple(float(v) for v in rest[0:3])
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radius = float(rest[3])
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kind = rest[4]
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if kind not in KINDS:
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die(path, lineno, "unknown material %r" % kind)
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albedo = tuple(float(v) for v in rest[5:8])
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fuzz = float(rest[8]) if len(rest) > 8 else 0.0
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scene["spheres"].append((centre, radius, kind, albedo, fuzz))
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else:
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die(path, lineno, "unknown directive %r" % head)
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except (IndexError, ValueError):
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die(path, lineno, "malformed %s line" % head)
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if not scene["spheres"]:
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die(path, 0, "scene declares no spheres")
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return scene
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def v3(t):
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return "{%.6f, %.6f, %.6f}" % t
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def main():
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if len(sys.argv) != 4:
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sys.stderr.write(__doc__)
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raise SystemExit(2)
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src, out_c, out_h = sys.argv[1], sys.argv[2], sys.argv[3]
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name = os.path.splitext(os.path.basename(src))[0]
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scene = parse(src)
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guard = ("%s_SCENE_H" % name).upper()
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for path in (out_c, out_h):
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d = os.path.dirname(path)
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if d:
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os.makedirs(d, exist_ok=True)
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with open(out_h, "w") as fh:
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fh.write("/* Generated from %s by scenegen.py. */\n" % src)
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fh.write("#ifndef %s\n#define %s\n\n#include \"rt_scene.h\"\n\n" % (guard, guard))
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fh.write("extern const sphere %s_spheres[];\n" % name)
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fh.write("extern const int %s_sphere_count;\n" % name)
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fh.write("extern const vec3 %s_background;\n" % name)
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fh.write("extern const vec3 %s_look_from;\n" % name)
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fh.write("extern const vec3 %s_look_at;\n" % name)
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fh.write("extern const double %s_fov;\n\n#endif\n" % name)
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with open(out_c, "w") as fh:
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fh.write("/* Generated from %s by scenegen.py. */\n" % src)
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fh.write("#include \"%s_scene.h\"\n\n" % name)
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fh.write("const sphere %s_spheres[] = {\n" % name)
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for centre, radius, kind, albedo, fuzz in scene["spheres"]:
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fh.write(" {%s, %.6f, {%s, %s, %.6f}},\n"
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% (v3(centre), radius, KINDS[kind], v3(albedo), fuzz))
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fh.write("};\n\n")
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fh.write("const int %s_sphere_count = %d;\n" % (name, len(scene["spheres"])))
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fh.write("const vec3 %s_background = %s;\n" % (name, v3(scene["background"])))
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fh.write("const vec3 %s_look_from = %s;\n" % (name, v3(scene["look_from"])))
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fh.write("const vec3 %s_look_at = %s;\n" % (name, v3(scene["look_at"])))
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fh.write("const double %s_fov = %.6f;\n" % (name, scene["fov"]))
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if __name__ == "__main__":
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main()
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