From c64dc2c8312d1177fdeb38b11adea7c776e40b9e Mon Sep 17 00:00:00 2001
From: scrawl <scrawl@baseoftrash.de>
Date: Sat, 11 Jan 2014 00:51:03 +0100
Subject: [PATCH] Terrain specular mapping: use a "_diffusespec" postfix to
 indicate specular information is present in the alpha channel. Use alpha
 directly instead of 1-alpha.

---
 components/terrain/material.cpp |  3 +++
 components/terrain/storage.cpp  |  9 +++++++++
 components/terrain/storage.hpp  |  1 +
 files/materials/terrain.shader  | 26 +++++++++++++-------------
 4 files changed, 26 insertions(+), 13 deletions(-)

diff --git a/components/terrain/material.cpp b/components/terrain/material.cpp
index 5dcdb7fed..be468866b 100644
--- a/components/terrain/material.cpp
+++ b/components/terrain/material.cpp
@@ -281,6 +281,7 @@ namespace Terrain
                         // normal map (optional)
                         bool useNormalMap = mNormalMapping && !mLayerList[layerOffset+i].mNormalMap.empty() && !renderCompositeMap;
                         bool useParallax = useNormalMap && mParallaxMapping && layer.mParallax;
+                        bool useSpecular = layer.mSpecular;
                         if (useNormalMap)
                         {
                             anyNormalMaps = true;
@@ -292,6 +293,8 @@ namespace Terrain
                                                           sh::makeProperty (new sh::BooleanValue(useNormalMap)));
                         p->mShaderProperties.setProperty ("use_parallax_" + Ogre::StringConverter::toString(i),
                                                           sh::makeProperty (new sh::BooleanValue(useParallax)));
+                        p->mShaderProperties.setProperty ("use_specular_" + Ogre::StringConverter::toString(i),
+                                                          sh::makeProperty (new sh::BooleanValue(useSpecular)));
                         boost::hash_combine(normalMaps, useNormalMap);
                         boost::hash_combine(normalMaps, useNormalMap && layer.mParallax);
 
diff --git a/components/terrain/storage.cpp b/components/terrain/storage.cpp
index 9d6b44de8..398ebac01 100644
--- a/components/terrain/storage.cpp
+++ b/components/terrain/storage.cpp
@@ -475,6 +475,7 @@ namespace Terrain
 
         LayerInfo info;
         info.mParallax = false;
+        info.mSpecular = false;
         info.mDiffuseMap = "textures\\" + texture;
         std::string texture_ = texture;
         boost::replace_last(texture_, ".", "_nh.");
@@ -491,6 +492,14 @@ namespace Terrain
                 info.mNormalMap = "textures\\" + texture_;
         }
 
+        texture_ = texture;
+        boost::replace_last(texture_, ".", "_diffusespec.");
+        if (Ogre::ResourceGroupManager::getSingleton().resourceExistsInAnyGroup("textures\\" + texture_))
+        {
+            info.mDiffuseMap = "textures\\" + texture_;
+            info.mSpecular = true;
+        }
+
         mLayerInfoMap[texture] = info;
 
         return info;
diff --git a/components/terrain/storage.hpp b/components/terrain/storage.hpp
index 68fae01af..18d05b100 100644
--- a/components/terrain/storage.hpp
+++ b/components/terrain/storage.hpp
@@ -16,6 +16,7 @@ namespace Terrain
         std::string mDiffuseMap;
         std::string mNormalMap;
         bool mParallax; // Height info in normal map alpha channel?
+        bool mSpecular; // Specular info in diffuse map alpha channel?
     };
 
     /// We keep storage of terrain data abstract here since we need different implementations for game and editor
diff --git a/files/materials/terrain.shader b/files/materials/terrain.shader
index 86eef36ff..1436de0c3 100644
--- a/files/materials/terrain.shader
+++ b/files/materials/terrain.shader
@@ -337,6 +337,7 @@ float2 blendUV = (UV - 0.5) * (16.0 / (16.0+1.0)) + 0.5;
         float2 layerUV = float2(UV.x, 1.f-UV.y) * 16; // Reverse Y, required to get proper tangents
         float2 thisLayerUV;
         float4 normalTex;
+        float4 diffuseTex;
 
         float3 eyeDir = normalize(cameraPos.xyz - worldPos);
 #if PARALLAX
@@ -358,19 +359,18 @@ float2 blendUV = (UV - 0.5) * (16.0 / (16.0+1.0)) + 0.5;
         thisLayerUV += TSeyeDir.xy * ( normalTex.a * PARALLAX_SCALE + PARALLAX_BIAS );
 #endif
 
-#if IS_FIRST_PASS
-        #if @shIterator == 0
-        // first layer of first pass is the base layer and doesn't need a blend map
-        albedo = shSample(diffuseMap0, layerUV);
-        #else
-        albedo = shLerp(albedo, shSample(diffuseMap@shIterator, thisLayerUV), blendValues@shPropertyString(blendmap_component_@shIterator));
-        #endif
+        diffuseTex = shSample(diffuseMap@shIterator, layerUV);
+#if !@shPropertyBool(use_specular_@shIterator)
+        diffuseTex.a = 0;
+#endif
+
+#if @shIterator == 0
+albedo = diffuseTex;
 #else
-        #if @shIterator == 0
-        albedo = shSample(diffuseMap@shIterator, layerUV);
-        #else
-        albedo = shLerp(albedo, shSample(diffuseMap@shIterator, thisLayerUV), blendValues@shPropertyString(blendmap_component_@shIterator));
-        #endif
+albedo = shLerp(albedo, diffuseTex, blendValues@shPropertyString(blendmap_component_@shIterator));
+#endif
+
+#if !IS_FIRST_PASS
         previousAlpha *= 1.f-blendValues@shPropertyString(blendmap_component_@shIterator);
 #endif
 
@@ -448,7 +448,7 @@ float2 blendUV = (UV - 0.5) * (16.0 / (16.0+1.0)) + 0.5;
         float3 halfVec = normalize (light0Dir + eyeDir);
 
         float3 specular = pow(max(dot(normal, halfVec), 0), 32) * lightSpec0;
-        shOutputColour(0).xyz += specular * (1.f-albedo.a) * shadow;
+        shOutputColour(0).xyz += specular * (albedo.a) * shadow;
 #endif
 
 #if FOG