From cd1f604ffe6130fd7d3a8358a8cebd7f821f9a11 Mon Sep 17 00:00:00 2001
From: Perttu Ahola <celeron55@gmail.com>
Date: Sun, 2 Dec 2012 14:24:58 +0200
Subject: Handle day-night transition in shader and make light sources brighter
 when shaders are used

---
 client/shaders/test_shader_1/opengl_vertex.glsl | 45 ++++++++++++++++++++-----
 client/shaders/test_shader_2/opengl_vertex.glsl | 37 ++++++++++++++++++--
 2 files changed, 72 insertions(+), 10 deletions(-)

(limited to 'client')

diff --git a/client/shaders/test_shader_1/opengl_vertex.glsl b/client/shaders/test_shader_1/opengl_vertex.glsl
index 498085053..e24f58c09 100644
--- a/client/shaders/test_shader_1/opengl_vertex.glsl
+++ b/client/shaders/test_shader_1/opengl_vertex.glsl
@@ -2,6 +2,7 @@
 uniform mat4 mWorldViewProj;
 uniform mat4 mInvWorld;
 uniform mat4 mTransWorld;
+uniform float dayNightRatio;
 
 varying vec3 vPosition;
 
@@ -11,15 +12,43 @@ void main(void)
 
 	vPosition = (mWorldViewProj * gl_Vertex).xyz;
 
-	if(gl_Normal.y > 0.5)
-		gl_FrontColor = gl_BackColor = gl_Color;
-	else
-		gl_FrontColor = gl_BackColor = gl_Color * 0.7;
+	vec4 color;
+	//color = vec4(1.0, 1.0, 1.0, 1.0);
 
-	/*if(gl_Normal.y > 0.5)
-		gl_FrontColor = gl_BackColor = vec4(1.0, 1.0, 1.0, 1.0);
-	else
-		gl_FrontColor = gl_BackColor = vec4(1.0, 1.0, 1.0, 1.0) * 0.7;*/
+	float day = gl_Color.r;
+	float night = gl_Color.g;
+	float light_source = gl_Color.b;
+
+	/*color.r = mix(night, day, dayNightRatio);
+	color.g = color.r;
+	color.b = color.r;*/
+
+	float rg = mix(night, day, dayNightRatio);
+	rg += light_source * 1.0; // Make light sources brighter
+	float b = rg;
+
+	// Moonlight is blue
+	b += (day - night) / 13.0;
+	rg -= (day - night) / 13.0;
+
+	// Emphase blue a bit in darker places
+	// See C++ implementation in mapblock_mesh.cpp finalColorBlend()
+	b += max(0.0, (1.0 - abs(b - 0.13)/0.17) * 0.025);
+
+	// Artificial light is yellow-ish
+	// See C++ implementation in mapblock_mesh.cpp finalColorBlend()
+	rg += max(0.0, (1.0 - abs(rg - 0.85)/0.15) * 0.065);
+
+	color.r = rg;
+	color.g = rg;
+	color.b = b;
+
+	if(gl_Normal.y <= 0.5)
+		color *= 0.7;
+
+	color.a = gl_Color.a;
+
+	gl_FrontColor = gl_BackColor = color;
 
 	gl_TexCoord[0] = gl_MultiTexCoord0;
 }
diff --git a/client/shaders/test_shader_2/opengl_vertex.glsl b/client/shaders/test_shader_2/opengl_vertex.glsl
index 6286fc0d7..80fd6d427 100644
--- a/client/shaders/test_shader_2/opengl_vertex.glsl
+++ b/client/shaders/test_shader_2/opengl_vertex.glsl
@@ -2,6 +2,7 @@
 uniform mat4 mWorldViewProj;
 uniform mat4 mInvWorld;
 uniform mat4 mTransWorld;
+uniform float dayNightRatio;
 
 varying vec3 vPosition;
 
@@ -13,8 +14,40 @@ void main(void)
 
 	vPosition = (mWorldViewProj * gl_Vertex).xyz;
 
-	gl_FrontColor = gl_BackColor = gl_Color;
-	//gl_FrontColor = gl_BackColor = vec4(1.0, 1.0, 1.0, 1.0);
+	vec4 color;
+	//color = vec4(1.0, 1.0, 1.0, 1.0);
+
+	float day = gl_Color.r;
+	float night = gl_Color.g;
+	float light_source = gl_Color.b;
+
+	/*color.r = mix(night, day, dayNightRatio);
+	color.g = color.r;
+	color.b = color.r;*/
+
+	float rg = mix(night, day, dayNightRatio);
+	rg += light_source * 1.0; // Make light sources brighter
+	float b = rg;
+
+	// Moonlight is blue
+	b += (day - night) / 13.0;
+	rg -= (day - night) / 13.0;
+
+	// Emphase blue a bit in darker places
+	// See C++ implementation in mapblock_mesh.cpp finalColorBlend()
+	b += max(0.0, (1.0 - abs(b - 0.13)/0.17) * 0.025);
+
+	// Artificial light is yellow-ish
+	// See C++ implementation in mapblock_mesh.cpp finalColorBlend()
+	rg += max(0.0, (1.0 - abs(rg - 0.85)/0.15) * 0.065);
+
+	color.r = rg;
+	color.g = rg;
+	color.b = b;
+
+	color.a = gl_Color.a;
+
+	gl_FrontColor = gl_BackColor = color;
 
 	gl_TexCoord[0] = gl_MultiTexCoord0;
 }
-- 
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