Add full-colour function-based pigment pattern.

Author: c-lipka

changes.txt

@@ -49,6 +49,9 @@ Prior to the release of 3.7.1, the following items still need urgent attention:
 New Features
 ------------
 
+- A new special pigment pattern, `user_defined`, has been added to define the
+  pigment colour directly in terms of a set of functions.
+
 - A new pattern, `potential`, has been added to define a pattern based on the
   potential field of a blob or isosurface object.
 

source/core/material/pattern.cpp

@@ -400,6 +400,65 @@ ColourBlendMapConstPtr CubicPattern::GetDefaultBlendMap() const { return gpDefau
 unsigned int CubicPattern::NumDiscreteBlendMapEntries() const { return 6; }
 
 
+ColourFunctionPattern::ColourFunctionPattern()
+{
+    for (int iChannel = 0; iChannel < 5; ++iChannel)
+    {
+        pFn[iChannel] = NULL;
+    }
+}
+
+ColourFunctionPattern::ColourFunctionPattern(const ColourFunctionPattern& obj) :
+    ColourPattern(obj)
+{
+    for (int iChannel = 0; iChannel < 5; ++iChannel)
+    {
+        if (obj.pFn[iChannel])
+            pFn[iChannel] = obj.pFn[iChannel]->Clone();
+        else
+            pFn[iChannel] = NULL;
+    }
+}
+
+ColourFunctionPattern::~ColourFunctionPattern()
+{
+    for (int iChannel = 0; iChannel < 5; ++iChannel)
+    {
+        if (pFn[iChannel])
+            delete pFn[iChannel];
+    }
+}
+
+bool ColourFunctionPattern::Evaluate(TransColour& result, const Vector3d& EPoint, const Intersection *pIsection, const Ray *pRay, TraceThreadData *pThread) const
+{
+    for (int iChannel = 0; iChannel < 5; ++iChannel)
+    {
+        ColourChannel channelValue = 0.0;
+        if (pFn[iChannel])
+        {
+            GenericFunctionContextPtr pCtx = pFn[iChannel]->AcquireContext(pThread);
+            pFn[iChannel]->InitArguments(pCtx);
+            for (int iDimension = 0; iDimension < 3; ++iDimension)
+                pFn[iChannel]->PushArgument(pCtx, EPoint[iDimension]);
+            channelValue = pFn[iChannel]->Execute(pCtx);
+            pFn[iChannel]->ReleaseContext(pCtx);
+        }
+        switch (iChannel)
+        {
+        case 3:  result.filter()           = channelValue; break;
+        case 4:  result.transm()           = channelValue; break;
+        default: result.colour()[iChannel] = channelValue; break;
+        }
+    }
+    return true;
+}
+
+bool ColourFunctionPattern::HasTransparency() const
+{
+    return (pFn[3] || pFn[4]);
+}
+
+
 bool ColourImagePattern::Evaluate(TransColour& result, const Vector3d& EPoint, const Intersection *pIsection, const Ray *pRay, TraceThreadData *pThread) const
 {
     // TODO ALPHA - the caller does expect non-premultiplied data, but maybe he could profit from premultiplied data?

source/core/material/pattern.h

@@ -455,6 +455,22 @@ struct CheckerPattern : public DiscretePattern
     virtual unsigned int NumDiscreteBlendMapEntries() const;
 };
 
+/// Implements the `user_defined` pattern.
+///
+/// @todo   The additional member variables should possibly be encapsulated.
+///
+struct ColourFunctionPattern : public ColourPattern
+{
+    GenericScalarFunctionPtr pFn[5];
+
+    ColourFunctionPattern();
+    ColourFunctionPattern(const ColourFunctionPattern& obj);
+    virtual ~ColourFunctionPattern();
+    virtual PatternPtr Clone() const { return BasicPattern::Clone(*this); }
+    virtual bool Evaluate(TransColour& result, const Vector3d& EPoint, const Intersection *pIsection, const Ray *pRay, TraceThreadData *pThread) const;
+    virtual bool HasTransparency() const;
+};
+
 /// Implements the `image_map` pattern.
 struct ColourImagePattern : public ColourPattern, public ImagePatternImpl
 {

source/parser/parser.cpp

@@ -8377,6 +8377,16 @@ bool Parser::Parse_Comma (void)
         return true;
 }
 
+//******************************************************************************
+
+bool Parser::Peek_Token (TOKEN tokenId)
+{
+    Get_Token();
+    bool tokenMatches = ((Token.Token_Id    == tokenId) ||
+                         (Token.Function_Id == tokenId));
+    Unget_Token();
+    return tokenMatches;
+}
 
 
 /*****************************************************************************

source/parser/parser.h

@@ -312,6 +312,7 @@ class Parser : public SceneTask
         bool Parse_Begin (bool mandatory = true);
         void Parse_End (void);
         bool Parse_Comma (void);
+        bool Peek_Token (TOKEN tokenId);
         void Parse_Semi_Colon (bool force_semicolon);
         void Destroy_Frame (void);
         void MAError (const char *str, long size);
@@ -446,7 +447,7 @@ class Parser : public SceneTask
         FUNCTION_PTR Parse_Function(void);
         FUNCTION_PTR Parse_FunctionContent(void);
         FUNCTION_PTR Parse_FunctionOrContent(void);
-        void Parse_FunctionOrContentList(GenericScalarFunctionPtr* apFn, unsigned int count);
+        void Parse_FunctionOrContentList(GenericScalarFunctionPtr* apFn, unsigned int count, bool mandatory = true);
         FUNCTION_PTR Parse_DeclareFunction(int *token_id, const char *fn_name, bool is_local);
 
         // parsestr.h/parsestr.cpp

source/parser/parser_functions_utilities.cpp

@@ -163,13 +163,18 @@ FUNCTION_PTR Parser::Parse_FunctionOrContent(void)
 }
 
 
-void Parser::Parse_FunctionOrContentList(GenericScalarFunctionPtr* apFn, unsigned int count)
+void Parser::Parse_FunctionOrContentList(GenericScalarFunctionPtr* apFn, unsigned int count, bool mandatory)
 {
     for (unsigned int i = 0; i < count; ++i)
     {
-        if (i > 0)
-            Parse_Comma();
+        if (!mandatory && (Peek_Token(RIGHT_CURLY_TOKEN) || Parse_Comma()))
+        {
+            apFn[i] = NULL;
+            continue;
+        }
         apFn[i] = new FunctionVM::CustomFunction(fnVMContext->functionvm, Parse_FunctionOrContent());
+        if (i < count-1)
+            Parse_Comma();
     }
 }
 

source/parser/parser_materials.cpp

@@ -1022,6 +1022,16 @@ void Parser::Parse_Pattern (PATTERN_T *New, BlendMapTypeId TPat_Type)
                 dynamic_cast<FunctionVM*>(sceneData->functionContextFactory), Parse_Function());
         END_CASE
 
+        CASE (USER_DEFINED_TOKEN)
+            if ((TPat_Type != kBlendMapType_Pigment) || (TPat_Type != kBlendMapType_Density))
+                Only_In("user_defined", "pigment or density");
+            New->Type = COLOUR_PATTERN;
+            New->pattern = PatternPtr(new ColourFunctionPattern());
+            Parse_Begin();
+            Parse_FunctionOrContentList (dynamic_cast<ColourFunctionPattern*>(New->pattern.get())->pFn, 5, false);
+            Parse_End();
+        END_CASE
+
         CASE(PIGMENT_PATTERN_TOKEN)
             Parse_Begin();
             New->Type = GENERIC_PATTERN;
@@ -4798,6 +4808,10 @@ void Parser::Parse_PatternFunction(TPATTERN *New)
             dynamic_cast<FunctionPattern*>(New->pattern.get())->pFn = new FunctionVM::CustomFunction(dynamic_cast<FunctionVM*>(sceneData->functionContextFactory), Parse_Function());
         END_CASE
 
+        CASE (USER_DEFINED_TOKEN)
+            Not_With("user_defined", "function pattern");
+        END_CASE
+
         CASE(PIGMENT_PATTERN_TOKEN)
             Parse_Begin();
             New->Type = GENERIC_PATTERN;