Implement gloss-mapping (feature #6541)

CHANGELOG.md

@@ -132,6 +132,7 @@
     Feature #6419: Topics shouldn't be greyed out if they can produce another topic reference
     Feature #6443: NiStencilProperty is not fully supported
     Feature #6534: Shader-based object texture blending
+    Feature #6541: Gloss-mapping
     Feature #6592: Missing support for NiTriShape particle emitters
     Feature #6600: Support NiSortAdjustNode
     Task #6201: Remove the "Note: No relevant classes found. No output generated" warnings

components/nifosg/nifloader.cpp

@@ -1552,14 +1552,8 @@ namespace NifOsg
                         case Nif::NiTexturingProperty::BumpTexture:
                         case Nif::NiTexturingProperty::DetailTexture:
                         case Nif::NiTexturingProperty::DecalTexture:
-                            break;
                         case Nif::NiTexturingProperty::GlossTexture:
-                        {
-                            // Not used by the vanilla engine. MCP (Morrowind Code Patch) adds an option to use Gloss maps:
-                            // "- Gloss map fix. Morrowind removed gloss map entries from model files after loading them. This stops Morrowind from removing them."
-                            // Log(Debug::Info) << "NiTexturingProperty::GlossTexture in " << mFilename << " not currently used.";
-                            continue;
-                        }
+                            break;
                         default:
                         {
                             Log(Debug::Info) << "Unhandled texture stage " << i << " on shape \"" << nodeName << "\" in " << mFilename;
@@ -1651,6 +1645,12 @@ namespace NifOsg
                         stateset->addUniform(new osg::Uniform("bumpMapMatrix", bumpMapMatrix));
                         stateset->addUniform(new osg::Uniform("envMapLumaBias", texprop->envMapLumaBias));
                     }
+                    else if (i == Nif::NiTexturingProperty::GlossTexture)
+                    {
+                        // A gloss map is an environment map mask.
+                        // Gloss maps are only implemented in the object shaders as well.
+                        stateset->setTextureMode(texUnit, GL_TEXTURE_2D, osg::StateAttribute::OFF);
+                    }
                     else if (i == Nif::NiTexturingProperty::DecalTexture)
                     {
                         // This is only an inaccurate imitation of the original implementation,
@@ -1694,6 +1694,9 @@ namespace NifOsg
                     case Nif::NiTexturingProperty::DecalTexture:
                         texture2d->setName("decalMap");
                         break;
+                    case Nif::NiTexturingProperty::GlossTexture:
+                        texture2d->setName("glossMap");
+                        break;
                     default:
                         break;
                     }

components/shader/shadervisitor.cpp

@@ -244,7 +244,7 @@ namespace Shader
         addedState->setName("addedState");
     }
 
-    const char* defaultTextures[] = { "diffuseMap", "normalMap", "emissiveMap", "darkMap", "detailMap", "envMap", "specularMap", "decalMap", "bumpMap" };
+    const char* defaultTextures[] = { "diffuseMap", "normalMap", "emissiveMap", "darkMap", "detailMap", "envMap", "specularMap", "decalMap", "bumpMap", "glossMap" };
     bool isTextureNameRecognized(const std::string& name)
     {
         for (unsigned int i=0; i<sizeof(defaultTextures)/sizeof(defaultTextures[0]); ++i)
@@ -325,6 +325,14 @@ namespace Shader
                             {
                                 mRequirements.back().mShaderRequired = true;
                             }
+                            else if (texName == "glossMap")
+                            {
+                                mRequirements.back().mShaderRequired = true;
+                                if (!writableStateSet)
+                                    writableStateSet = getWritableStateSet(node);
+                                // As well as gloss maps
+                                writableStateSet->setTextureMode(unit, GL_TEXTURE_2D, osg::StateAttribute::ON);
+                            }
                         }
                         else
                             Log(Debug::Error) << "ShaderVisitor encountered unknown texture " << texture;

files/shaders/objects_fragment.glsl

@@ -58,6 +58,11 @@ uniform vec2 envMapLumaBias;
 uniform mat2 bumpMapMatrix;
 #endif
 
+#if @glossMap
+uniform sampler2D glossMap;
+varying vec2 glossMapUV;
+#endif
+
 uniform bool simpleWater;
 
 varying float euclideanDepth;
@@ -168,8 +173,14 @@ void main()
     envLuma = clamp(bumpTex.b * envMapLumaBias.x + envMapLumaBias.y, 0.0, 1.0);
 #endif
 
+    vec3 envEffect = texture2D(envMap, envTexCoordGen).xyz * envMapColor.xyz * envLuma;
+
+#if @glossMap
+    envEffect *= texture2D(glossMap, glossMapUV).xyz;
+#endif
+
 #if @preLightEnv
-    gl_FragData[0].xyz += texture2D(envMap, envTexCoordGen).xyz * envMapColor.xyz * envLuma;
+    gl_FragData[0].xyz += envEffect;
 #endif
 
 #endif
@@ -189,7 +200,7 @@ void main()
     gl_FragData[0].xyz *= lighting;
 
 #if @envMap && !@preLightEnv
-    gl_FragData[0].xyz += texture2D(envMap, envTexCoordGen).xyz * envMapColor.xyz * envLuma;
+    gl_FragData[0].xyz += envEffect;
 #endif
 
 #if @emissiveMap

files/shaders/objects_vertex.glsl

@@ -47,6 +47,10 @@ varying vec2 bumpMapUV;
 varying vec2 specularMapUV;
 #endif
 
+#if @glossMap
+varying vec2 glossMapUV;
+#endif
+
 varying float euclideanDepth;
 varying float linearDepth;
 
@@ -120,6 +124,10 @@ void main(void)
     specularMapUV = (gl_TextureMatrix[@specularMapUV] * gl_MultiTexCoord@specularMapUV).xy;
 #endif
 
+#if @glossMap
+    glossMapUV = (gl_TextureMatrix[@glossMapUV] * gl_MultiTexCoord@glossMapUV).xy;
+#endif
+
     passColor = gl_Color;
     passViewPos = viewPos.xyz;
     passNormal = gl_Normal.xyz;