Improve sun illumination based on angular size and astronomical twilight

5 files changed, 34 insertions, 16 deletions

diff --git a/game/environment.cpp b/game/environment.cpp
index 5aa1f09..acb4f21 100644
--- a/game/environment.cpp
+++ b/game/environment.cpp
@@ -18,8 +18,8 @@ Environment::render(const SceneRenderer & renderer, const SceneProvider & scene)
 	constexpr RGB relativeAmbient {0.3F, 0.3F, 0.4F}, relativeDirectional {0.6F, 0.6F, 0.5F};
 
 	const LightDirection sunPos = getSunPos({}, worldTime);
-	const auto ambient = baseAmbient + relativeAmbient * sunPos.vertical();
-	const auto directional = baseDirectional + relativeDirectional * sunPos.vertical();
+	const auto ambient = baseAmbient + relativeAmbient * sunPos.ambient();
+	const auto directional = baseDirectional + relativeDirectional * sunPos.directional();
 
 	renderer.setAmbientLight(ambient);
 	renderer.setDirectionalLight(directional, sunPos, scene);
diff --git a/gfx/lightDirection.cpp b/gfx/lightDirection.cpp
index 6d7d1ea..3932872 100644
--- a/gfx/lightDirection.cpp
+++ b/gfx/lightDirection.cpp
@@ -1,8 +1,12 @@
 #include "lightDirection.h"
 #include "maths.h"
 
+constexpr auto ASTRONOMICAL_TWILIGHT = 18.0_degrees;
+constexpr auto SUN_ANGLUAR_SIZE = 0.5_degrees;
+
 LightDirection::LightDirection(const Direction2D sunPos) :
 	pos {sunPos}, vec {glm::mat3 {rotate_yp(pi + sunPos.x, -sunPos.y)} * north},
-	vert {-glm::clamp(-1.F, 0.F, vec.z - 0.1F)}
+	amb {glm::clamp(sunPos.y + ASTRONOMICAL_TWILIGHT, 0.F, 1.F)},
+	dir {glm::clamp(sunPos.y + SUN_ANGLUAR_SIZE, 0.F, 1.F)}
 {
 }
diff --git a/gfx/lightDirection.h b/gfx/lightDirection.h
index f1e1cc4..789830b 100644
--- a/gfx/lightDirection.h
+++ b/gfx/lightDirection.h
@@ -20,13 +20,20 @@ public:
 	}
 
 	[[nodiscard]] float
-	vertical() const noexcept
+	ambient() const noexcept
 	{
-		return vert;
+		return amb;
+	}
+
+	[[nodiscard]] float
+	directional() const noexcept
+	{
+		return dir;
 	}
 
 private:
 	Direction2D pos;
 	Direction3D vec;
-	float vert;
+	float amb;
+	float dir;
 };
diff --git a/lib/maths.h b/lib/maths.h
index 90ddb69..14a29d1 100644
--- a/lib/maths.h
+++ b/lib/maths.h
@@ -422,3 +422,9 @@ kph_to_ms(T v)
 // ... literals are handy for now, probably go away when we load stuff externally
 float operator"" _mph(const long double v);
 float operator"" _kph(const long double v);
+
+constexpr float
+operator"" _degrees(long double degrees)
+{
+	return static_cast<float>(degrees) * degreesToRads;
+}
diff --git a/test/test-environment.cpp b/test/test-environment.cpp
index 76144a4..8bd64be 100644
--- a/test/test-environment.cpp
+++ b/test/test-environment.cpp
@@ -12,7 +12,7 @@
 #include <maths.h>
 
 using sunPosTestData = std::tuple<Direction2D, time_t, Direction2D>;
-using sunDirTestData = std::tuple<Direction2D, Direction3D, float>;
+using sunDirTestData = std::tuple<Direction2D, Direction3D, float, float>;
 constexpr Direction2D Doncaster = {-1.1, 53.5};
 constexpr Direction2D NewYork = {74.0, 40.7};
 constexpr Direction2D Syndey = {-151.2, -33.9};
@@ -40,23 +40,24 @@ BOOST_DATA_TEST_CASE(sun_position,
 
 BOOST_DATA_TEST_CASE(sun_direction,
 		boost::unit_test::data::make<sunDirTestData>({
-				{{0.F, 0.F}, south, 0.1F},
-				{{90.F, 0.F}, west, 0.1F},
-				{{-90.F, 0.F}, east, 0.1F},
+				{{0.F, 0.F}, south, 0.314F, 0.0087F},
+				{{90.F, 0.F}, west, 0.314F, 0.0087F},
+				{{-90.F, 0.F}, east, 0.314F, 0.0087F},
 				// From above
 				// EqGM midnight, sun below horizon, shining upwards
-				{{181.52F, -66.86F}, {-0.01F, 0.39F, 0.919F}, 0},
+				{{181.52F, -66.86F}, {-0.01F, 0.39F, 0.919F}, 0, 0.F},
 				// EqGM just before sunrise, mostly west, north a bit, up a bit
-				{{113.12F, -0.85F}, {-0.92F, 0.39F, 0.015F}, 0.085F},
+				{{113.12F, -0.85F}, {-0.92F, 0.39F, 0.015F}, 0.299F, 0.F},
 				// EqGM just after sunrise, mostly west, north a bit, down a bit
-				{{113.12F, 6.05F}, {-0.92F, 0.39F, -0.015F}, 0.205F},
+				{{113.12F, 6.05F}, {-0.92F, 0.39F, -0.015F}, 0.42F, 0.114F},
 				// Doncaster noon, roughly from south to north, high in the sky, downward
-				{{176.34F, 59.64F}, {-0.03F, 0.5F, -0.86F}, 0.96F},
+				{{176.34F, 59.64F}, {-0.03F, 0.5F, -0.86F}, 1, 1},
 		}),
-		position, direction, vert)
+		position, direction, amb, dir)
 {
 	const LightDirection ld {position * degreesToRads};
 	BOOST_CHECK_CLOSE_VEC(ld.vector(), direction);
 	BOOST_CHECK_CLOSE(glm::length(ld.vector()), 1.F, 1);
-	BOOST_CHECK_CLOSE(ld.vertical(), vert, 5);
+	BOOST_CHECK_CLOSE(ld.ambient(), amb, 5);
+	BOOST_CHECK_CLOSE(ld.directional(), dir, 5);
 }