From 1116df31c9150c4671178c82beb8ed1059660242 Mon Sep 17 00:00:00 2001
From: James Khan <jameskhan1983@gmail.com>
Date: Thu, 30 May 2019 15:31:18 +0100
Subject: [PATCH] Add fog to Single-Pass lighting.

---
 .../Common/MatDefs/Light/Lighting.j3md        |  6 ++++
 .../Common/MatDefs/Light/SPLighting.frag      | 35 +++++++++++++++++++
 .../Common/MatDefs/Light/SPLighting.vert      | 11 +++++-
 3 files changed, 51 insertions(+), 1 deletion(-)

diff --git a/jme3-core/src/main/resources/Common/MatDefs/Light/Lighting.j3md b/jme3-core/src/main/resources/Common/MatDefs/Light/Lighting.j3md
index dc3fbb943..824a17369 100644
--- a/jme3-core/src/main/resources/Common/MatDefs/Light/Lighting.j3md
+++ b/jme3-core/src/main/resources/Common/MatDefs/Light/Lighting.j3md
@@ -167,6 +167,12 @@ MaterialDef Phong Lighting {
             INSTANCING : UseInstancing
             NUM_MORPH_TARGETS: NumberOfMorphTargets
             NUM_TARGETS_BUFFERS: NumberOfTargetsBuffers
+
+            // fog - jayfella
+            USE_FOG : UseFog
+            FOG_LINEAR : LinearFog
+            FOG_EXP : ExpFog
+            FOG_EXPSQ : ExpSqFog
         }
     }
 
diff --git a/jme3-core/src/main/resources/Common/MatDefs/Light/SPLighting.frag b/jme3-core/src/main/resources/Common/MatDefs/Light/SPLighting.frag
index a510fc1db..2b5a4481c 100644
--- a/jme3-core/src/main/resources/Common/MatDefs/Light/SPLighting.frag
+++ b/jme3-core/src/main/resources/Common/MatDefs/Light/SPLighting.frag
@@ -6,6 +6,26 @@
     #import "Common/ShaderLib/Lighting.glsllib"
 #endif
 
+// fog - jayfella
+#ifdef USE_FOG
+#import "Common/ShaderLib/MaterialFog.glsllib"
+varying float fog_distance;
+uniform vec4 m_FogColor;
+
+#ifdef FOG_LINEAR
+uniform vec2 m_LinearFog;
+#endif
+
+#ifdef FOG_EXP
+uniform float m_ExpFog;
+#endif
+
+#ifdef FOG_EXPSQ
+uniform float m_ExpSqFog;
+#endif
+
+#endif // end fog
+
 varying vec2 texCoord;
 #ifdef SEPARATE_TEXCOORD
   varying vec2 texCoord2;
@@ -226,5 +246,20 @@ void main(){
         }
            
      #endif
+
+    // add fog after the lighting because shadows will cause the fog to darken
+    // which just results in the geometry looking like it's changed color
+    #ifdef USE_FOG
+        #ifdef FOG_LINEAR
+            gl_FragColor = getFogLinear(gl_FragColor, m_FogColor, m_LinearFog.x, m_LinearFog.y, fog_distance);
+        #endif
+        #ifdef FOG_EXP
+            gl_FragColor = getFogExp(gl_FragColor, m_FogColor, m_ExpFog, fog_distance);
+        #endif
+        #ifdef FOG_EXPSQ
+            gl_FragColor = getFogExpSquare(gl_FragColor, m_FogColor, m_ExpSqFog, fog_distance);
+        #endif
+    #endif // end fog
+
     gl_FragColor.a = alpha;
 }
diff --git a/jme3-core/src/main/resources/Common/MatDefs/Light/SPLighting.vert b/jme3-core/src/main/resources/Common/MatDefs/Light/SPLighting.vert
index f9fbe40cf..71233819b 100644
--- a/jme3-core/src/main/resources/Common/MatDefs/Light/SPLighting.vert
+++ b/jme3-core/src/main/resources/Common/MatDefs/Light/SPLighting.vert
@@ -8,6 +8,11 @@
     #import "Common/ShaderLib/BlinnPhongLighting.glsllib"
 #endif
 
+// fog - jayfella
+#ifdef USE_FOG
+varying float fog_distance;
+uniform vec3 g_CameraPosition;
+#endif
 
 uniform vec4 m_Ambient;
 uniform vec4 m_Diffuse;
@@ -187,5 +192,9 @@ void main(){
 
     #ifdef USE_REFLECTION
         computeRef(modelSpacePos);
-    #endif 
+    #endif
+
+    #ifdef USE_FOG
+    fog_distance = distance(g_CameraPosition, (g_WorldMatrix * modelSpacePos).xyz);
+    #endif
 }
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