From 48fa82f6ea2b4769de2389e0f5f99308134d0f80 Mon Sep 17 00:00:00 2001
From: Simon Wendsche <simon.wendsche@gmx.de>
Date: Sun, 18 Mar 2018 10:48:25 +0100
Subject: [PATCH] add option to sync sun and sky gain

---
 export/light.py     |  4 ++++
 properties/light.py |  2 +-
 properties/world.py |  7 +++++++
 ui/world.py         | 27 +++++++++++++++++++++------
 4 files changed, 33 insertions(+), 7 deletions(-)

diff --git a/export/light.py b/export/light.py
index dca490a9..49826e7f 100644
--- a/export/light.py
+++ b/export/light.py
@@ -196,6 +196,10 @@ def convert_world(world, scene):
             if world.luxcore.sun:
                 definitions["dir"] = _calc_sun_dir(world.luxcore.sun)
 
+                if world.luxcore.use_sun_gain_for_sky:
+                    gain = [x * world.luxcore.sun.data.luxcore.gain for x in world.luxcore.rgb_gain]
+                    definitions["gain"] = gain
+
             if world.luxcore.sun and world.luxcore.sun.data:
                 # Use sun turbidity so the user does not have to keep two values in sync
                 definitions["turbidity"] = world.luxcore.sun.data.luxcore.turbidity
diff --git a/properties/light.py b/properties/light.py
index 36a6c2fa..2e06d8a9 100644
--- a/properties/light.py
+++ b/properties/light.py
@@ -70,7 +70,7 @@ def update_is_laser(self, context):
     ##############################################
     # BlendLuxCore specific properties needed to translate LuxCore light concepts to Blender
     sun_types = [
-        ("sun", "Sun", "Sun", 0),
+        ("sun", "Sun", "Physically correct sun that emits parallel light rays and changes color with elevation", 0),
         ("distant", "Distant", "Distant star without atmosphere simulation (emits parallel light)", 1),
     ]
     sun_type = EnumProperty(name="Sun Type", items=sun_types, default="sun")
diff --git a/properties/world.py b/properties/world.py
index 8f252c7e..a7009170 100644
--- a/properties/world.py
+++ b/properties/world.py
@@ -10,6 +10,10 @@
     VISIBILITYMAP_ENABLE_DESC,
 )
 
+USE_SUN_GAIN_FOR_SKY_DESC = (
+    "Use the gain setting of the attached sun "
+    "(so you adjust both sun and sky gain at the same time)"
+)
 
 def init():
     bpy.types.World.luxcore = PointerProperty(type=LuxCoreWorldProps)
@@ -33,6 +37,9 @@ class LuxCoreWorldProps(bpy.types.PropertyGroup):
 
     # sky2 settings
     sun = PointerProperty(name="Sun", type=bpy.types.Object, description="Used to specify the sun direction")
+    # Only shown in UI when light is sky2 and a sun is attached
+    use_sun_gain_for_sky = BoolProperty(name="Use Sun Gain", default=True,
+                                        description=USE_SUN_GAIN_FOR_SKY_DESC)
     turbidity = FloatProperty(name="Turbidity", default=2.2, min=0, max=30)
     groundalbedo = FloatVectorProperty(name="Ground Albedo", default=(0.5, 0.5, 0.5), min=0, max=1, subtype="COLOR")
     ground_enable = BoolProperty(name="Use Ground Color", default=False)
diff --git a/ui/world.py b/ui/world.py
index d907f71f..8a962c07 100644
--- a/ui/world.py
+++ b/ui/world.py
@@ -23,10 +23,20 @@ def draw(self, context):
         layout.prop(world.luxcore, "light", expand=True)
 
         if world.luxcore.light != "none":
+            # TODO: id (light group)
             split = layout.split(percentage=0.33)
             split.prop(world.luxcore, "rgb_gain", text="")
-            split.prop(world.luxcore, "gain")
-            # TODO: id (light group)
+
+            is_sky = world.luxcore.light == "sky2"
+            has_sun = world.luxcore.sun and world.luxcore.sun.type == "LAMP"
+
+            if is_sky and has_sun and world.luxcore.use_sun_gain_for_sky:
+                split.prop(world.luxcore.sun.data.luxcore, "gain")
+            else:
+                split.prop(world.luxcore, "gain")
+
+            if is_sky and has_sun:
+                split.prop(world.luxcore, "use_sun_gain_for_sky")
 
         layout.label("Default Volume (used on materials without attached volume):")
         utils_ui.template_node_tree(layout, world.luxcore, "volume", ICON_VOLUME,
@@ -54,10 +64,15 @@ def draw(self, context):
         world = context.world
 
         layout.prop(world.luxcore, "sun")
-        sun_obj = world.luxcore.sun
-        if sun_obj and sun_obj.data and sun_obj.data.type == "SUN":
-            layout.label("Using turbidity of sun light:", icon="INFO")
-            layout.prop(sun_obj.data.luxcore, "turbidity")
+        sun = world.luxcore.sun
+        if sun:
+            is_really_a_sun = sun.type == "LAMP" and sun.data and sun.data.type == "SUN"
+
+            if is_really_a_sun:
+                layout.label("Using turbidity of sun light:", icon="INFO")
+                layout.prop(sun.data.luxcore, "turbidity")
+            else:
+                layout.label("Not a sun lamp", icon="ERROR")
         else:
             layout.prop(world.luxcore, "turbidity")