0032198: Visualization, TKOpenGl - per-vertex lighting ignores back/front material colors

Graphic3d_ShaderManager::stdComputeLighting() now multiplies vertex color by material color.

dox/upgrade/upgrade.md

@@ -2221,3 +2221,11 @@ The same is applicable to *Poly_PolygonOnTriangulation* interface.
 
 Accessors to standard materials have been modified within *Declarations.glsl* (*occFrontMaterial_Diffuse()* -> *occMaterial_Diffuse(bool)* and similar).
 Applications defining custom GLSL programs should take into account syntax changes.
+
+@subsection upgrade_occt760_noral_colors Nodal color modulation
+
+Nodal color vertex attribute is now modulated in the same way as a color texture - color is multiplied by material coefficients (diffuse/ambient/specular in case of a common material definition).
+Existing code defining nodal colors should be updated to:
+- Use *Graphic3d_TOSM_UNLIT* shading model when lighting is not needed.
+- Adjust diffuse/ambient material coefficients, which have been previously ignored.
+- Remove code multiplying nodal colors, intended to compensate over-brightness due to addition of specular color from material definition, as specular component is now also modulated by a vertex color.

src/AIS/AIS_Triangulation.cxx

@@ -133,7 +133,7 @@ void AIS_Triangulation::Compute (const Handle(PrsMgr_PresentationManager)& ,
   Handle(Graphic3d_Group) aGroup = thePrs->CurrentGroup();
   Handle(Graphic3d_AspectFillArea3d) anAspect = myDrawer->ShadingAspect()->Aspect();
 
-  const Standard_Real anAmbient = 0.2;
+  const Standard_Real anAmbient = 1.0;
   if (hasVNormals)
   {
     gp_Vec3f aNormal;

src/Graphic3d/Graphic3d_ShaderManager.cxx

@@ -1296,14 +1296,6 @@ TCollection_AsciiString Graphic3d_ShaderManager::stdComputeLighting (Standard_In
     }
   }
 
-  TCollection_AsciiString aGetMatAmbient = "occMaterial_Ambient(theIsFront);";
-  TCollection_AsciiString aGetMatDiffuse = "occMaterial_Diffuse(theIsFront);";
-  if (theHasVertColor)
-  {
-    aGetMatAmbient = "getVertColor().rgb;";
-    aGetMatDiffuse = "getVertColor();";
-  }
-
   if (!theIsPBR)
   {
     return TCollection_AsciiString()
@@ -1321,10 +1313,12 @@ TCollection_AsciiString Graphic3d_ShaderManager::stdComputeLighting (Standard_In
       EOL"  Specular = vec3 (0.0);"
       EOL"  vec3 aPoint = thePoint.xyz / thePoint.w;"
     + aLightsLoop
-    + EOL"  vec3 aMatAmbient  = " + aGetMatAmbient
+    + EOL"  vec3 aMatAmbient  = occMaterial_Ambient(theIsFront);"
-    + EOL"  vec4 aMatDiffuse  = " + aGetMatDiffuse
+      EOL"  vec4 aMatDiffuse  = occMaterial_Diffuse(theIsFront);"
-    + EOL"  vec3 aMatSpecular = occMaterial_Specular(theIsFront);"
+      EOL"  vec3 aMatSpecular = occMaterial_Specular(theIsFront);"
       EOL"  vec4 aColor = vec4(Ambient * aMatAmbient + Diffuse * aMatDiffuse.rgb + Specular * aMatSpecular, aMatDiffuse.a);"
+    + (theHasVertColor ?
+      EOL"  aColor *= getVertColor();" : "")
     + (theHasTexColor ?
       EOL"#if defined(THE_HAS_TEXTURE_COLOR) && defined(FRAGMENT_SHADER)"
       EOL"  aColor *= occTexture2D(occSamplerBaseColor, TexCoord.st / TexCoord.w);"
@@ -1348,7 +1342,7 @@ TCollection_AsciiString Graphic3d_ShaderManager::stdComputeLighting (Standard_In
       EOL"                      in bool theIsFront)"
       EOL"{"
       EOL"  DirectLighting = vec3(0.0);"
-      EOL"  BaseColor = " + (theHasVertColor ? "getVertColor();" : "occMaterialBaseColor(theIsFront, TexCoord.st / TexCoord.w);")
+      EOL"  BaseColor           = occMaterialBaseColor(theIsFront, TexCoord.st / TexCoord.w)" + (theHasVertColor ? " * getVertColor()" : "") + ";"
     + EOL"  Emission            = occMaterialEmission(theIsFront, TexCoord.st / TexCoord.w);"
       EOL"  Metallic            = occMaterialMetallic(theIsFront, TexCoord.st / TexCoord.w);"
       EOL"  NormalizedRoughness = occMaterialRoughness(theIsFront, TexCoord.st / TexCoord.w);"

src/MeshVS/MeshVS_NodalColorPrsBuilder.cxx

@@ -274,7 +274,7 @@ void MeshVS_NodalColorPrsBuilder::Build ( const Handle(Prs3d_Presentation)& Prs,
   gp_Dir aDefNorm( 0., 0., 1. );
 
   // Prepare for scaling the incoming colors
-  const Standard_Real anColorRatio = !IsReflect ? 0.44f : 0.5f;
+  const Standard_Real anColorRatio = 1.0;
 
   for (it.Reset(); it.More(); it.Next())
   {
@@ -454,7 +454,7 @@ void MeshVS_NodalColorPrsBuilder::Build ( const Handle(Prs3d_Presentation)& Prs,
 //      aStyle = (Aspect_InteriorStyle)aStyleInt;
 
     anAsp = new Graphic3d_AspectFillArea3d (
-      Aspect_IS_SOLID, Quantity_NOC_GRAY, anEdgeColor,
+      Aspect_IS_SOLID, Quantity_NOC_WHITE, anEdgeColor,
       anEdgeType, anEdgeWidth, aMaterial[ 0 ], aMaterial[ 1 ] );
   }
 

src/ViewerTest/ViewerTest_ObjectCommands.cxx

@@ -3014,7 +3014,7 @@ static int VDrawSphere (Draw_Interpretor& /*di*/, Standard_Integer argc, const c
   aMat.SetSpecularColor(Quantity_Color (Graphic3d_Vec3 (0.50f)));
   Handle(Graphic3d_AspectFillArea3d) anAspect
     = new Graphic3d_AspectFillArea3d (Aspect_IS_SOLID,
-                                      Quantity_NOC_RED,
+                                      Quantity_NOC_WHITE,
                                       Quantity_NOC_YELLOW,
                                       Aspect_TOL_SOLID,
                                       1.0,
@@ -3438,6 +3438,17 @@ Standard_Boolean MyPArrayObject::Init (Graphic3d_TypeOfPrimitiveArray thePrimTyp
   if (myPArray.IsNull())
   {
     myPArray = Graphic3d_ArrayOfPrimitives::CreateArray (thePrimType, aVertexNum, aBoundNum, aEdgeNum, anArrayFlags);
+    if (myPArray->HasVertexColors())
+    {
+      myDrawer->SetupOwnShadingAspect();
+      Graphic3d_MaterialAspect aMat (Graphic3d_NameOfMaterial_Plastified);
+      aMat.SetSpecularColor (Quantity_NOC_BLACK);
+      aMat.SetEmissiveColor (Quantity_NOC_BLACK);
+      aMat.SetAmbientColor (Quantity_Color (Graphic3d_Vec3 (0.5f)));
+      aMat.SetDiffuseColor (Quantity_Color (Graphic3d_Vec3 (0.5f)));
+      myDrawer->ShadingAspect()->SetMaterial (aMat);
+      myDrawer->ShadingAspect()->SetColor (Quantity_NOC_WHITE);
+    }
   }
   else
   {

tests/bugs/vis/bug30076

@@ -13,6 +13,6 @@ vdrawparray a        triangles -deinterleaved -mutable v 10 0 0 {*}$c1 v 11 0 0
 vfit
 vdump $imagedir/${casename}_1.png
 vdrawparray a -patch triangles -deinterleaved -mutable v 10 0 0 {*}$c2 v 11 0 0 {*}$c2 v 11 1 0 {*}$c2 v 11 1 0 {*}$c1 v 10 1 0 {*}$c1 v 10 0 0 {*}$c1
-if { [vreadpixel 200 150 rgb name] != "RED"   } { puts "Error: array was not updated" }
+if { [vreadpixel 200 150 rgb name] != "RED2"  } { puts "Error: array was not updated" }
-if { [vreadpixel 200 250 rgb name] != "BLUE" } { puts "Error: array was not updated" }
+if { [vreadpixel 200 250 rgb name] != "BLUE2" } { puts "Error: array was not updated" }
 vdump $imagedir/${casename}_2.png

tests/v3d/glsl/vert_color

@@ -0,0 +1,76 @@
+puts "============"
+puts "0032198: Visualization, TKOpenGl - per-vertex lighting ignores back/front material colors"
+puts "============"
+puts ""
+
+set aVerts {
+  {{0 55 0} { 0 75  0} {20 55  0}}
+  {{0 75 0} { 0 55 20} {20 55  0}}
+  {{0 55 0} { 0 55 20} { 0 75  0}}
+  {{0 55 0} {20 55  0} { 0 55 20}}
+}
+set aColors {
+  {{1.0 0.0 0.0} {0.0 1.0 0.0} {0.0 0.0 1.0}}
+  {{1.0 1.0 0.0} {1.0 1.0 1.0} {0.0 1.0 1.0}}
+  {{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 aNormals {
+  { 0  0 -1}
+  { 1  1  1}
+  {-1  0  0}
+  { 0 -1  0}
+}
+
+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 aCol  [lindex $::aColors  $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]" }
+    }
+  }
+  return $aTris
+}
+
+set aTris1  [genTris 0 3 0]
+set aTris1c [genTris 0 3 1]
+set aTris2  [genTris 0 1 0]
+set aTris2c [genTris 0 1 1]
+
+pload MODELING VISUALIZATION
+vclear
+vinit View1
+vviewparams -scale 10 -proj -0.3 -0.7 0.6 -up 0.013 0.65 0.75 -at 35.4 61.8 31.5
+vdrawparray t1  triangles {*}$aTris1
+vdrawparray t1c triangles {*}$aTris1c
+vdrawparray t2  triangles {*}$aTris2
+vdrawparray t2c triangles {*}$aTris2c
+vdrawparray t3  triangles {*}$aTris2
+vdrawparray t3c triangles {*}$aTris2c
+vlocation t1  -location  0 0  0
+vlocation t2  -location 30 0  0
+vlocation t3  -location 60 0  0
+vlocation t1c -location  0 0 30
+vlocation t2c -location 30 0 30
+vlocation t3c -location 60 0 30
+vaspects t1  -color GREEN -backfaceColor RED
+vaspects t2  -color GREEN -backfaceColor RED
+vaspects t1c -color GREEN -backfaceColor RED
+vaspects t2c -color GREEN -backfaceColor RED
+vaspects t3  -color WHITE -backfaceColor WHITE
+vaspects t3c -color WHITE -backfaceColor WHITE
+
+vrenderparams -shadingModel VERT
+vdump ${imagedir}/${casename}_vert.png
+vrenderparams -shadingModel PHONG
+vdump ${imagedir}/${casename}_phong.png
+vrenderparams -shadingModel FLAT
+vdump ${imagedir}/${casename}_flat.png
+vrenderparams -shadingModel UNLIT
+vdump ${imagedir}/${casename}_unlit.png
+vrenderparams -shadingModel PBR
+vdump ${imagedir}/${casename}_pbr.png