more features

Content/Python/ue_workshop/lighting.py

@@ -1,7 +1,14 @@
+import math
+from types import SimpleNamespace
+
 import unreal
 
 from .camera import look_at
 
+# Calibrated in tools/smoke_basics.py against the fixed exposure from camera.create.
+_CUBEMAP_AMBIENT = 30.0
+_FOG_LUMINANCE = 30.0
+
 
 def _setup(actor, component_class, intensity, color):
     light = actor.get_component_by_class(component_class)
@@ -46,11 +53,50 @@ def sun(scene, name="Sun", location=(300, -300, 500), target=(0, 0, 0),
         intensity=500, color=(1, 1, 1)):
     """Parallel light for the whole scene; only the location-target direction matters."""
     actor = scene.spawn(unreal.DirectionalLight, name, location)
-    _setup(actor, unreal.DirectionalLightComponent, intensity, color)
+    light = _setup(actor, unreal.DirectionalLightComponent, intensity, color)
+    light.set_atmosphere_sun_light(True)
     look_at(actor, target)
     return actor
 
 
+def environment(scene, sky=True, sun_intensity=500, sun_angle=45, sun_yaw=-45,
+                ambient=1.0, fog=0.0, fog_color=(0.6, 0.7, 0.9)):
+    """Add a world around the scene: sky, sun, ambient light and height fog.
+
+    sun_angle is the height above the horizon in degrees (low = sunset), sun_yaw
+    its compass direction. sky=False keeps a black background with ambient light.
+    The sky is lit only by the sun: for night use sky=False, sun_intensity=0, ambient=0.3.
+    Returns .sun (None when sun_intensity=0), usable with shot.light_key.
+    """
+    for name, value in (("sun_intensity", sun_intensity), ("ambient", ambient), ("fog", fog)):
+        if value < 0:
+            raise ValueError(f"{name} nie moze byc ujemne.")
+    sun_actor = None
+    if sun_intensity > 0:
+        height, compass = math.radians(sun_angle), math.radians(sun_yaw)
+        direction = (math.cos(height) * math.cos(compass), math.cos(height) * math.sin(compass), math.sin(height))
+        sun_actor = sun(scene, location=tuple(1000 * value for value in direction), intensity=sun_intensity)
+        sun_actor.get_component_by_class(unreal.DirectionalLightComponent).set_atmosphere_sun_light(sky)
+    # Also for sky=False: an unlit atmosphere keeps the background black, not white.
+    scene.spawn(unreal.SkyAtmosphere, "Sky")
+    ambient_actor = scene.spawn(unreal.SkyLight, "Ambient")
+    light = ambient_actor.light_component
+    light.set_mobility(unreal.ComponentMobility.MOVABLE)
+    if sky:
+        light.set_editor_property("real_time_capture", True)
+        light.set_intensity(float(ambient))
+    else:
+        light.set_editor_property("source_type", unreal.SkyLightSourceType.SLS_SPECIFIED_CUBEMAP)
+        light.set_cubemap(unreal.load_asset("/Engine/MapTemplates/Sky/DaylightAmbientCubemap"))
+        light.set_intensity(float(ambient) * _CUBEMAP_AMBIENT)
+    if fog > 0:
+        component = scene.spawn(unreal.ExponentialHeightFog, "Fog").component
+        component.set_fog_density(float(fog))
+        component.set_editor_property("fog_inscattering_luminance", unreal.LinearColor(
+            *(value * _FOG_LUMINANCE for value in fog_color), 1.0))
+    return SimpleNamespace(sun=sun_actor)
+
+
 def studio(scene, key_color=(1.0, 0.82, 0.65), fill_color=(0.5, 0.7, 1.0)):
     return [area(scene, "Key", (200, -500, 350), color=key_color),
             area(scene, "Fill", (100, 300, 250), intensity=7000, color=fill_color),