Add test for back vertex color

src/Graphic3d/Graphic3d_ArrayOfPrimitives.cxx

@@ -150,7 +150,7 @@ void Graphic3d_ArrayOfPrimitives::init (Graphic3d_TypeOfPrimitiveArray theType,
     myIndices->NbElements = 0;
   }
 
-  Graphic3d_Attribute anAttribs[4];
+  Graphic3d_Attribute anAttribs[5];
   Standard_Integer    aNbAttribs = 0;
   anAttribs[aNbAttribs].Id       = Graphic3d_TOA_POS;
   anAttribs[aNbAttribs].DataType = Graphic3d_TOD_VEC3;

src/Graphic3d/Graphic3d_ArrayOfPrimitives.hxx

@@ -381,6 +381,62 @@ public:
     }
   }
 
+  //! Change the vertex color back in the array.
+  //! @param[in] theIndex node index within [1, VertexNumberAllocated()] range
+  //! @param[in] theColor node color
+  void SetVertexColorBack (const Standard_Integer theIndex, const Quantity_Color& theColor)
+  {
+    SetVertexColorBack (theIndex, theColor.Red(), theColor.Green(), theColor.Blue());
+  }
+
+  //! Change the vertex color back in the array.
+  //! @param[in] theIndex node index within [1, VertexNumberAllocated()] range
+  //! @param[in] theR red   color value within [0, 1] range
+  //! @param[in] theG green color value within [0, 1] range
+  //! @param[in] theB blue  color value within [0, 1] range
+  void SetVertexColorBack (const Standard_Integer theIndex, const Standard_Real theR, const Standard_Real theG, const Standard_Real theB)
+  {
+    Standard_OutOfRange_Raise_if(theIndex < 1 || theIndex > myAttribs->NbMaxElements(), "BAD VERTEX index");
+    if (myColDataBack != NULL)
+    {
+      Graphic3d_Vec4ub* aColorPtr = reinterpret_cast<Graphic3d_Vec4ub* >(myColDataBack + myColStrideBack * ((Standard_Size)theIndex - 1));
+      aColorPtr->SetValues (Standard_Byte(theR * 255.0),
+                            Standard_Byte(theG * 255.0),
+                            Standard_Byte(theB * 255.0), 255);
+    }
+    myAttribs->NbElements = Max (theIndex, myAttribs->NbElements);
+  }
+
+  //! Change the vertex color back in the array.
+  //! @param[in] theIndex node index within [1, VertexNumberAllocated()] range
+  //! @param[in] theColor node RGBA color values within [0, 255] range
+  void SetVertexColorBack (const Standard_Integer  theIndex,
+                           const Graphic3d_Vec4ub& theColor)
+  {
+    Standard_OutOfRange_Raise_if(theIndex < 1 || theIndex > myAttribs->NbMaxElements(), "BAD VERTEX index");
+    if (myColDataBack != NULL)
+    {
+      Graphic3d_Vec4ub* aColorPtr = reinterpret_cast<Graphic3d_Vec4ub* >(myColDataBack + myColStrideBack * ((Standard_Size)theIndex - 1));
+      (*aColorPtr) = theColor;
+    }
+    myAttribs->NbElements = Max (theIndex, myAttribs->NbElements);
+  }
+
+  //! Change the vertex color back in the array.
+  //! @code
+  //!   theColor32 = Alpha << 24 + Blue << 16 + Green << 8 + Red
+  //! @endcode
+  //! @param[in] theIndex   node index within [1, VertexNumberAllocated()] range
+  //! @param[in] theColor32 packed RGBA color values
+  void SetVertexColorBack (const Standard_Integer theIndex, const Standard_Integer theColor32)
+  {
+    Standard_OutOfRange_Raise_if(theIndex < 1 || theIndex > myAttribs->NbMaxElements(), "BAD VERTEX index");
+    if (myColDataBack != NULL)
+    {
+      *reinterpret_cast<Standard_Integer* >(myColDataBack + myColStrideBack * ((Standard_Size)theIndex - 1)) = theColor32;
+    }
+  }
+
   //! Change the vertex normal in the array.
   //! @param[in] theIndex  node index within [1, VertexNumberAllocated()] range
   //! @param[in] theNormal normalized surface normal

src/Graphic3d/Graphic3d_ShaderManager.cxx

@@ -1327,7 +1327,7 @@ TCollection_AsciiString Graphic3d_ShaderManager::stdComputeLighting (Standard_In
       EOL"  vec3 aMatSpecular = occMaterial_Specular(theIsFront);"
       EOL"  vec4 aColor = vec4(Ambient * aMatAmbient + Diffuse * aMatDiffuse.rgb + Specular * aMatSpecular, aMatDiffuse.a);"
     + (theHasVertColor ?
-      EOL"  aColor *= getVertColor();" : "")
+      EOL"  aColor *= getVertColor(theIsFront);" : "")
     + (theHasTexColor ?
       EOL"#if defined(THE_HAS_TEXTURE_COLOR) && defined(FRAGMENT_SHADER)"
       EOL"  aColor *= occTexture2D(occSamplerBaseColor, TexCoord.st / TexCoord.w);"
@@ -1351,7 +1351,7 @@ TCollection_AsciiString Graphic3d_ShaderManager::stdComputeLighting (Standard_In
       EOL"                      in bool theIsFront)"
       EOL"{"
       EOL"  DirectLighting = vec3(0.0);"
-      EOL"  BaseColor           = occMaterialBaseColor(theIsFront, TexCoord.st / TexCoord.w)" + (theHasVertColor ? " * getVertColor()" : "") + ";"
+      EOL"  BaseColor           = occMaterialBaseColor(theIsFront, TexCoord.st / TexCoord.w)" + (theHasVertColor ? " * getVertColor(theIsFront)" : "") + ";"
     + EOL"  Emission            = occMaterialEmission(theIsFront, TexCoord.st / TexCoord.w);"
       EOL"  Metallic            = occMaterialMetallic(theIsFront, TexCoord.st / TexCoord.w);"
       EOL"  NormalizedRoughness = occMaterialRoughness(theIsFront, TexCoord.st / TexCoord.w);"
@@ -1408,7 +1408,7 @@ Handle(Graphic3d_ShaderProgram) Graphic3d_ShaderManager::getStdProgramGouraud (c
     {
       aProgramSrc->SetTextureSetBits (Graphic3d_TextureSetBits_BaseColor);
       aUniforms.Append (Graphic3d_ShaderObject::ShaderVariable ("sampler2D occSamplerBaseColor", Graphic3d_TOS_VERTEX));
-      aSrcVertColor = EOL"vec4 getVertColor(void) { return occTexture2D (occSamplerBaseColor, occTexCoord.xy); }";
+      aSrcVertColor = EOL"vec4 getVertColor(in bool theIsFront) { return occTexture2D (occSamplerBaseColor, occTexCoord.xy); }";
     }
   }
   else
@@ -1432,7 +1432,7 @@ Handle(Graphic3d_ShaderProgram) Graphic3d_ShaderManager::getStdProgramGouraud (c
 
   if ((theBits & Graphic3d_ShaderFlags_VertColor) != 0)
   {
-    aSrcVertColor = EOL"vec4 getVertColor(void) { return gl_FrontFacing ? VertColor : VertColorBack; }";
+    aSrcVertColor = EOL"vec4 getVertColor(in bool theIsFront) { return theIsFront ? occVertColor : occVertColorBack; }";
   }
 
   int aNbClipPlanes = 0;
@@ -1583,7 +1583,7 @@ Handle(Graphic3d_ShaderProgram) Graphic3d_ShaderManager::getStdProgramPhong (con
       aStageInOuts.Append (Graphic3d_ShaderObject::ShaderVariable ("vec4 VertColor", Graphic3d_TOS_VERTEX | Graphic3d_TOS_FRAGMENT));
 
       aSrcVertExtraMain   += EOL"  VertColor = occTexture2D (occSamplerBaseColor, occTexCoord.xy);";
-      aSrcFragGetVertColor = EOL"vec4 getVertColor(void) { return VertColor; }";
+      aSrcFragGetVertColor = EOL"vec4 getVertColor(in bool theIsFront) { return VertColor; }";
     }
   }
   else
@@ -1622,7 +1622,7 @@ Handle(Graphic3d_ShaderProgram) Graphic3d_ShaderManager::getStdProgramPhong (con
     aStageInOuts.Append (Graphic3d_ShaderObject::ShaderVariable ("vec4 VertColorBack", Graphic3d_TOS_VERTEX | Graphic3d_TOS_FRAGMENT));
     aSrcVertExtraMain   += EOL"  VertColor = occVertColor;";
     aSrcVertExtraMain   += EOL"  VertColorBack = occVertColorBack;";
-    aSrcFragGetVertColor = EOL"vec4 getVertColor(void) { return gl_FrontFacing ? VertColor : VertColorBack; }";
+    aSrcFragGetVertColor = EOL"vec4 getVertColor (in bool theIsFront) { return theIsFront ? VertColor : VertColorBack; }";
   }
 
   int aNbClipPlanes = 0;

src/OpenGl/OpenGl_BackgroundArray.cxx

@@ -201,8 +201,7 @@ Standard_Boolean OpenGl_BackgroundArray::createGradientArray (const Handle(OpenG
   Graphic3d_Attribute aGragientAttribInfo[] =
   {
     { Graphic3d_TOA_POS,   Graphic3d_TOD_VEC2 },
-    { Graphic3d_TOA_COLOR, Graphic3d_TOD_VEC3 },
+    { Graphic3d_TOA_COLOR, Graphic3d_TOD_VEC3 }
-    { Graphic3d_TOA_COLOR_BACK, Graphic3d_TOD_VEC3 }
   };
 
   if (!myAttribs->Init (4, aGragientAttribInfo, 2))

src/ViewerTest/ViewerTest_ObjectCommands.cxx

@@ -3432,6 +3432,12 @@ Standard_Boolean MyPArrayObject::Init (Graphic3d_TypeOfPrimitiveArray thePrimTyp
         anArrayFlags = anArrayFlags | Graphic3d_ArrayFlags_VertexColor;
       }
 
+      // vertex has a color back
+      if (CheckInputCommand("cb", theDesc, anArgIndex, 3, anArgsCount))
+      {
+        anArrayFlags = anArrayFlags | Graphic3d_ArrayFlags_VertexColorBack;
+      }
+
       // vertex has a texel
       if (CheckInputCommand ("t", theDesc, anArgIndex, 2, anArgsCount))
       {
@@ -3557,6 +3563,13 @@ Standard_Boolean MyPArrayObject::Init (Graphic3d_TypeOfPrimitiveArray thePrimTyp
                                     theDesc->Value (anArgIndex - 1).RealValue());
         myPArray->SetVertexColor (aVertIndex, aCol.r(), aCol.g(), aCol.b());
       }
+      if (CheckInputCommand("cb", theDesc, anArgIndex, 3, anArgsCount))
+      {
+        const Graphic3d_Vec3d aColBack (theDesc->Value(anArgIndex - 3).RealValue(),
+                                        theDesc->Value(anArgIndex - 2).RealValue(),
+                                        theDesc->Value(anArgIndex - 1).RealValue());
+        myPArray->SetVertexColorBack (aVertIndex, aColBack.r(), aColBack.g(), aColBack.b());
+      }
       if (CheckInputCommand ("t", theDesc, anArgIndex, 2, anArgsCount))
       {
         const Graphic3d_Vec2 aTex ((float )theDesc->Value (anArgIndex - 2).RealValue(),
@@ -7051,7 +7064,7 @@ Use vtop to see projected HLR shape.
 vdrawparray name TypeOfArray={points|segments|polylines|triangles
                    |trianglefans|trianglestrips|quads|quadstrips|polygons}
             [-deinterleaved|-mutable]
-            [vertex={'v' x y z [normal={'n' nx ny nz}] [color={'c' r g b}] [texel={'t' tx ty}]]
+            [vertex={'v' x y z [normal={'n' nx ny nz}] [color={'c' r g b}] [colorBack={'cb' r g b}] [texel={'t' tx ty}]]
             [bound= {'b' nbVertices [bound_color={'c' r g b}]]
             [edge=  {'e' vertexId]
             [-shape shapeName] [-patch]

tests/opengl/data/shading/vert_color

@@ -15,6 +15,12 @@ set aColors {
   {{0.5 0.0 0.0} {0.0 0.0 0.5} {0.0 0.5 0.0}}
   {{0.5 0.5 0.0} {0.0 0.5 0.5} {0.5 0.0 0.5}}
 }
+set aColorsBack {
+  {{1.0 0.0 0.0} {0.0 1.0 0.0} {1.0 0.0 0.0}}
+  {{0.0 1.0 0.0} {1.0 0.0 0.0} {0.0 1.0 0.0}}
+  {{0.0 0.0 1.0} {1.0 0.0 0.0} {0.0 0.0 1.0}}
+  {{1.0 1.0 1.0} {1.0 0.0 0.0} {1.0 1.0 1.0}}
+}
 set aNormals {
   { 0  0 -1}
   { 1  1  1}
@@ -26,11 +32,12 @@ proc genTris {theFrom theTo theColors} {
   set aTris ""
   for {set t $theFrom} {$t <= $theTo} {incr t} {
     for {set n 0} {$n < 3} {incr n} {
-      set aVert [lindex $::aVerts   $t]
+      set aVert    [lindex $::aVerts      $t]
-      set aCol  [lindex $::aColors  $t]
+      set aCol     [lindex $::aColors     $t]
-      set aNorm [lindex $::aNormals $t]
+      set aColBack [lindex $::aColorsBack $t]
+      set aNorm    [lindex $::aNormals    $t]
       set aTris "$aTris v [lindex $aVert $n] n $aNorm"
-      if { $theColors == 1 } { set aTris "$aTris c [lindex $aCol $n]" }
+      if { $theColors == 1 } { set aTris "$aTris c [lindex $aCol $n] cb [lindex $aColBack $n]" }
     }
   }
   return $aTris