From 64f351935b50e1d329445dc34c12902162c10de6 Mon Sep 17 00:00:00 2001
From: fredb <fredb>
Date: Sat, 10 Apr 2010 17:32:07 +0000
Subject: [PATCH] Add snow to urban shader

---
 Effects/urban.eff  | 15 +++++++++++++++
 Shaders/urban.frag | 26 ++++++++++++++++++++++++--
 2 files changed, 39 insertions(+), 2 deletions(-)

diff --git a/Effects/urban.eff b/Effects/urban.eff
index ab95140dd..f8eecd141 100644
--- a/Effects/urban.eff
+++ b/Effects/urban.eff
@@ -3,6 +3,7 @@
   <name>Effects/urban</name>
   <inherits-from>Effects/terrain-default</inherits-from>
   <parameters>
+    <snow-level><use>/sim/rendering/snow-level-m</use></snow-level>
     <depth-factor type="float">0.008</depth-factor>
     <night-color type="vec3d">0.75 0.59 0.05</night-color>
     <quality-level><use>/sim/rendering/quality-level</use></quality-level>
@@ -71,6 +72,10 @@
             <use>texture[2]/internal-format</use>
           </internal-format>
       </texture-unit>
+      <texture-unit>
+        <unit>2</unit>
+        <type>noise</type>
+      </texture-unit>
       <program>
         <vertex-shader>Shaders/urban.vert</vertex-shader>
         <fragment-shader>Shaders/urban.frag</fragment-shader>
@@ -97,6 +102,11 @@
         <type>sampler-2d</type>
         <value type="int">1</value>
       </uniform>
+      <uniform>
+        <name>NoiseTex</name>
+        <type>sampler-3d</type>
+        <value type="int">2</value>
+      </uniform>
       <uniform>
         <name>depth_factor</name>
         <type>float</type>
@@ -117,6 +127,11 @@
         <type>float</type>
         <value><use>quality-level</use></value>
       </uniform>
+      <uniform>
+        <name>snowlevel</name>
+        <type>float</type>
+        <value><use>snow-level</use></value>
+      </uniform>
     </pass>
   </technique>
 </PropertyList>
diff --git a/Shaders/urban.frag b/Shaders/urban.frag
index 33f9f3c7f..d991acc1c 100644
--- a/Shaders/urban.frag
+++ b/Shaders/urban.frag
@@ -13,13 +13,16 @@ varying vec3  VBinormal;
 varying vec3  Normal;
 varying vec4  constantColor;
 
+uniform sampler3D NoiseTex;
 uniform sampler2D BaseTex;
 uniform sampler2D NormalTex;
 uniform float depth_factor;
 uniform float tile_size;
 uniform float quality_level; // From /sim/rendering/quality-level
+uniform float snowlevel; // From /sim/rendering/snow-level-m
 uniform vec3 night_color;
 
+const float scale = 1.0;
 int linear_search_steps = 10;
 
 float ray_intersect(sampler2D reliefMap, vec2 dp, vec2 ds)
@@ -73,6 +76,7 @@ void main (void)
 
 	float emis = N.z;
 	N.z = sqrt(1.0 - min(1.0,dot(N.xy, N.xy)));
+	float Nz = N.z;
 	N = normalize(N.x * VTangent + N.y * VBinormal + N.z * VNormal);
 
 	vec3 l = gl_LightSource[0].position.xyz;
@@ -100,14 +104,32 @@ void main (void)
 	emission_factor *= 0.5*pow(tc.r+0.8*tc.g+0.2*tc.b, 2) -0.2;
 	ambient_light += (emission_factor * vec4(night_color, 0.0));
 
-	vec4 finalColor = texture2D(BaseTex, uv) * ambient_light;
-
 	float fogFactor;
 	float fogCoord = ecPos3.z / (1.0 + smoothstep(0.3, 0.7, emission_factor));
 	const float LOG2 = 1.442695;
 	fogFactor = exp2(-gl_Fog.density * gl_Fog.density * fogCoord * fogCoord * LOG2);
 	fogFactor = clamp(fogFactor, 0.0, 1.0);
 
+	vec4 noisevec   = texture3D(NoiseTex, (rawpos.xyz)*0.01*scale);
+	vec4 nvL   = texture3D(NoiseTex, (rawpos.xyz)*0.00066*scale);
+
+	float n=0.06;
+	n += nvL[0]*0.4;
+	n += nvL[1]*0.6;
+	n += nvL[2]*2.0;
+	n += nvL[3]*4.0;
+	n += noisevec[0]*0.1;
+	n += noisevec[1]*0.4;
+
+	n += noisevec[2]*0.8;
+	n += noisevec[3]*2.1;
+	n = mix(0.6, n, fogFactor);
+
+	vec4 finalColor = texture2D(BaseTex, uv);
+	finalColor = mix(finalColor, clamp(n+nvL[2]*4.1+vec4(0.1, 0.1, nvL[2]*2.2, 1.0), 0.7, 1.0),
+			step(0.8,Nz)*smoothstep(snowlevel+300.0, snowlevel+360.0, (rawpos.z)+nvL[1]*3000.0));
+	finalColor *= ambient_light;
+	
 	if (gl_Fog.density == 1.0)
 		fogFactor=1.0;