0028369: Visualization, Path Tracing - Expose radiance clamping setting in path tracing mode

New parameter was added in the vrenderparams command:
vrenderparams -maxrad <value>

src/Graphic3d/Graphic3d_RenderingParams.hxx

@@ -60,6 +60,7 @@ public:
     AdaptiveScreenSampling      (Standard_False),
     ShowSamplingTiles           (Standard_False),
     TwoSidedBsdfModels          (Standard_False),
+    RadianceClampingValue       (30.0),
     RebuildRayTracingShaders    (Standard_False),
     // stereoscopic parameters
     StereoMode (Graphic3d_StereoMode_QuadBuffer),
@@ -102,6 +103,7 @@ public:
   Standard_Boolean        AdaptiveScreenSampling;      //!< enables/disables adaptive screen sampling mode for path tracing, FALSE by default
   Standard_Boolean        ShowSamplingTiles;           //!< enables/disables debug mode for adaptive screen sampling, FALSE by default
   Standard_Boolean        TwoSidedBsdfModels;          //!< forces path tracing to use two-sided versions of original one-sided scattering models
+  Standard_ShortReal      RadianceClampingValue;       //!< maximum radiance value used for clamping radiance estimation.
   Standard_Boolean        RebuildRayTracingShaders;    //!< forces rebuilding ray tracing shaders at the next frame
 
   Graphic3d_StereoMode    StereoMode;                  //!< stereoscopic output mode, Graphic3d_StereoMode_QuadBuffer by default

src/OpenGl/OpenGl_View.hxx

@@ -581,10 +581,13 @@ protected: //! @name data types related to ray-tracing
     OpenGl_RT_uOffsetY,
     OpenGl_RT_uSamples,
 
-    // adaptive path tracing images
+    // images used by ISS mode
     OpenGl_RT_uRenderImage,
     OpenGl_RT_uOffsetImage,
 
+    // maximum radiance value
+    OpenGl_RT_uMaxRadiance,
+
     OpenGl_RT_NbVariables // special field
   };
 
@@ -702,6 +705,12 @@ protected: //! @name data types related to ray-tracing
     //! Enables/disables adaptive screen sampling for path tracing.
     Standard_Boolean AdaptiveScreenSampling;
 
+    //! Enables/disables environment map for background.
+    Standard_Boolean UseEnvMapForBackground;
+
+    //! Maximum radiance value used for clamping radiance estimation.
+    Standard_ShortReal RadianceClampingValue;
+
     //! Creates default compile-time ray-tracing parameters.
     RaytracingParams()
     : StackSize              (THE_DEFAULT_STACK_SIZE),
@@ -710,7 +719,9 @@ protected: //! @name data types related to ray-tracing
       GlobalIllumination     (Standard_False),
       UseBindlessTextures    (Standard_False),
       TwoSidedBsdfModels     (Standard_False),
-      AdaptiveScreenSampling (Standard_False) { }
+      AdaptiveScreenSampling (Standard_False),
+      UseEnvMapForBackground (Standard_False),
+      RadianceClampingValue  (30.0)            { }
   };
 
   //! Describes state of OpenGL structure.

src/OpenGl/OpenGl_View_Raytrace.cxx

@@ -1731,6 +1731,9 @@ Standard_Boolean OpenGl_View::initRaytraceResources (const Handle(OpenGl_Context
         aShaderProgram->GetUniformLocation (theGlContext, "uBackColorTop");
       myUniformLocations[anIndex][OpenGl_RT_uBackColorBot] =
         aShaderProgram->GetUniformLocation (theGlContext, "uBackColorBot");
+
+      myUniformLocations[anIndex][OpenGl_RT_uMaxRadiance] =
+        aShaderProgram->GetUniformLocation (theGlContext, "uMaxRadiance");
     }
 
     theGlContext->BindProgram (myOutImageProgram);
@@ -2465,38 +2468,24 @@ Standard_Boolean OpenGl_View::setUniformState (const Standard_Integer        the
   theProgram->SetUniform (theGlContext,
     myUniformLocations[theProgramId][OpenGl_RT_uUnviewMat], anUnviewMat);
 
-  // Set ray-tracing intersection parameters
-  theProgram->SetUniform (theGlContext,
-    myUniformLocations[theProgramId][OpenGl_RT_uSceneRad], myRaytraceSceneRadius);
-  theProgram->SetUniform (theGlContext,
-    myUniformLocations[theProgramId][OpenGl_RT_uSceneEps], myRaytraceSceneEpsilon);
-
-  const Standard_Integer aLightSourceBufferSize =
-    static_cast<Standard_Integer> (myRaytraceGeometry.Sources.size());
-
-  // Set ray-tracing light source parameters
-  theProgram->SetUniform (theGlContext,
-    myUniformLocations[theProgramId][OpenGl_RT_uLightCount], aLightSourceBufferSize);
-  theProgram->SetUniform (theGlContext,
-    myUniformLocations[theProgramId][OpenGl_RT_uLightAmbnt], myRaytraceGeometry.Ambient);
-
-  // Enable/disable run-time rendering effects
-  theProgram->SetUniform (theGlContext,
-    myUniformLocations[theProgramId][OpenGl_RT_uShadowsEnabled], myRenderParams.IsShadowEnabled ?  1 : 0);
-  theProgram->SetUniform (theGlContext,
-    myUniformLocations[theProgramId][OpenGl_RT_uReflectEnabled], myRenderParams.IsReflectionEnabled ?  1 : 0);
-
   // Set screen dimensions
   myRaytraceProgram->SetUniform (theGlContext,
     myUniformLocations[theProgramId][OpenGl_RT_uWinSizeX], theWinSizeX);
   myRaytraceProgram->SetUniform (theGlContext,
     myUniformLocations[theProgramId][OpenGl_RT_uWinSizeY], theWinSizeY);
 
-  if (myRenderParams.IsGlobalIlluminationEnabled) // if Monte-Carlo sampling enabled
+  // Set 3D scene parameters
-  {
   theProgram->SetUniform (theGlContext,
-      myUniformLocations[theProgramId][OpenGl_RT_uBlockedRngEnabled], myRenderParams.CoherentPathTracingMode ?  1 : 0);
+    myUniformLocations[theProgramId][OpenGl_RT_uSceneRad], myRaytraceSceneRadius);
-  }
+  theProgram->SetUniform (theGlContext,
+    myUniformLocations[theProgramId][OpenGl_RT_uSceneEps], myRaytraceSceneEpsilon);
+
+  // Set light source parameters
+  const Standard_Integer aLightSourceBufferSize =
+    static_cast<Standard_Integer> (myRaytraceGeometry.Sources.size());
+  
+  theProgram->SetUniform (theGlContext,
+    myUniformLocations[theProgramId][OpenGl_RT_uLightCount], aLightSourceBufferSize);
 
   // Set array of 64-bit texture handles
   if (theGlContext->arbTexBindless != NULL && myRaytraceGeometry.HasTextures())
@@ -2525,6 +2514,7 @@ Standard_Boolean OpenGl_View::setUniformState (const Standard_Integer        the
       myUniformLocations[theProgramId][OpenGl_RT_uBackColorBot], aBackColor);
   }
 
+  // Set environment map parameters
   const Standard_Boolean toDisableEnvironmentMap = myTextureEnv.IsNull() || !myTextureEnv->IsValid();
   
   theProgram->SetUniform (theGlContext,
@@ -2533,6 +2523,37 @@ Standard_Boolean OpenGl_View::setUniformState (const Standard_Integer        the
   theProgram->SetUniform (theGlContext,
     myUniformLocations[theProgramId][OpenGl_RT_uSphereMapForBack], myRenderParams.UseEnvironmentMapBackground ?  1 : 0);
 
+  if (myRenderParams.IsGlobalIlluminationEnabled) // GI parameters
+  {
+    theProgram->SetUniform (theGlContext,
+      myUniformLocations[theProgramId][OpenGl_RT_uMaxRadiance], myRenderParams.RadianceClampingValue);
+
+    theProgram->SetUniform (theGlContext,
+      myUniformLocations[theProgramId][OpenGl_RT_uBlockedRngEnabled], myRenderParams.CoherentPathTracingMode ? 1 : 0);
+
+    // Check whether we should restart accumulation for run-time parameters
+    if (myRenderParams.RadianceClampingValue       != myRaytraceParameters.RadianceClampingValue
+     || myRenderParams.UseEnvironmentMapBackground != myRaytraceParameters.UseEnvMapForBackground)
+    {
+      myAccumFrames = 0; // accumulation should be restarted
+
+      myRaytraceParameters.RadianceClampingValue  = myRenderParams.RadianceClampingValue;
+      myRaytraceParameters.UseEnvMapForBackground = myRenderParams.UseEnvironmentMapBackground;
+    }
+  }
+  else // RT parameters
+  {
+    // Set ambient light source
+    theProgram->SetUniform (theGlContext,
+      myUniformLocations[theProgramId][OpenGl_RT_uLightAmbnt], myRaytraceGeometry.Ambient);
+
+    // Enable/disable run-time ray-tracing effects
+    theProgram->SetUniform (theGlContext,
+      myUniformLocations[theProgramId][OpenGl_RT_uShadowsEnabled], myRenderParams.IsShadowEnabled ?  1 : 0);
+    theProgram->SetUniform (theGlContext,
+      myUniformLocations[theProgramId][OpenGl_RT_uReflectEnabled], myRenderParams.IsReflectionEnabled ?  1 : 0);
+  }
+
   return Standard_True;
 }
 

src/Shaders/PathtraceBase.fs

@@ -785,7 +785,7 @@ vec4 PathTrace (in SRay theRay, in vec3 theInverse)
       vec4 aTexColor = textureLod (
         sampler2D (uTextureSamplers[int (aMaterial.Kd.w)]), aTexCoord.st, 0.f);
 
-      aMaterial.Kd.rgb *= (aTexColor.rgb, aTexColor.rgb) * aTexColor.w; // de-gamma correction (for gamma = 2)
+      aMaterial.Kd.rgb *= (aTexColor.rgb * aTexColor.rgb) * aTexColor.w; // de-gamma correction (for gamma = 2)
 
       if (aTexColor.w != 1.0f)
       {

src/Shaders/RaytraceRender.fs

@@ -13,9 +13,9 @@ uniform int uBlockedRngEnabled;
   uniform sampler2D uAccumTexture;
 #endif
 
-//! Maximum radiance that can be added to the pixel. Decreases noise
+//! Maximum radiance that can be added to the pixel.
-//! level, but introduces some bias.
+//! Decreases noise level, but introduces some bias.
-#define MAX_RADIANCE vec3 (50.f)
+uniform float uMaxRadiance = 50.f;
 
 // =======================================================================
 // function : main
@@ -64,7 +64,7 @@ void main (void)
     aColor.rgb = ZERO;
   }
 
-  aColor.rgb = min (aColor.rgb, MAX_RADIANCE);
+  aColor.rgb = min (aColor.rgb, vec3 (uMaxRadiance));
 
 #ifdef ADAPTIVE_SAMPLING
 

src/Shaders/Shaders_PathtraceBase_fs.pxx

@@ -788,7 +788,7 @@ static const char Shaders_PathtraceBase_fs[] =
   "      vec4 aTexColor = textureLod (\n"
   "        sampler2D (uTextureSamplers[int (aMaterial.Kd.w)]), aTexCoord.st, 0.f);\n"
   "\n"
-  "      aMaterial.Kd.rgb *= (aTexColor.rgb, aTexColor.rgb) * aTexColor.w; // de-gamma correction (for gamma = 2)\n"
+  "      aMaterial.Kd.rgb *= (aTexColor.rgb * aTexColor.rgb) * aTexColor.w; // de-gamma correction (for gamma = 2)\n"
   "\n"
   "      if (aTexColor.w != 1.0f)\n"
   "      {\n"

src/Shaders/Shaders_RaytraceRender_fs.pxx

@@ -16,9 +16,9 @@ static const char Shaders_RaytraceRender_fs[] =
   "  uniform sampler2D uAccumTexture;\n"
   "#endif\n"
   "\n"
-  "//! Maximum radiance that can be added to the pixel. Decreases noise\n"
+  "//! Maximum radiance that can be added to the pixel.\n"
-  "//! level, but introduces some bias.\n"
+  "//! Decreases noise level, but introduces some bias.\n"
-  "#define MAX_RADIANCE vec3 (50.f)\n"
+  "uniform float uMaxRadiance = 50.f;\n"
   "\n"
   "// =======================================================================\n"
   "// function : main\n"
@@ -67,7 +67,7 @@ static const char Shaders_RaytraceRender_fs[] =
   "    aColor.rgb = ZERO;\n"
   "  }\n"
   "\n"
-  "  aColor.rgb = min (aColor.rgb, MAX_RADIANCE);\n"
+  "  aColor.rgb = min (aColor.rgb, vec3 (uMaxRadiance));\n"
   "\n"
   "#ifdef ADAPTIVE_SAMPLING\n"
   "\n"

src/ViewerTest/ViewerTest_ViewerCommands.cxx

@@ -9075,6 +9075,7 @@ static Standard_Integer VRenderParams (Draw_Interpretor& theDI,
     theDI << "iss:            " << (aParams.AdaptiveScreenSampling      ? "on" : "off") << "\n";
     theDI << "iss debug:      " << (aParams.ShowSamplingTiles           ? "on" : "off") << "\n";
     theDI << "two-sided BSDF: " << (aParams.TwoSidedBsdfModels          ? "on" : "off") << "\n";
+    theDI << "max radiance:   " <<  aParams.RadianceClampingValue                       << "\n";
     theDI << "shadingModel: ";
     switch (aView->ShadingModel())
     {
@@ -9300,6 +9301,37 @@ static Standard_Integer VRenderParams (Draw_Interpretor& theDI,
       }
       aParams.CoherentPathTracingMode = toEnable;
     }
+    else if (aFlag == "-maxrad")
+    {
+      if (toPrint)
+      {
+        theDI << aParams.RadianceClampingValue << " ";
+        continue;
+      }
+      else if (++anArgIter >= theArgNb)
+      {
+        std::cerr << "Error: wrong syntax at argument '" << anArg << "'\n";
+        return 1;
+      }
+
+      const TCollection_AsciiString aMaxRadStr = theArgVec[anArgIter];
+      if (!aMaxRadStr.IsRealValue())
+      {
+        std::cerr << "Error: wrong syntax at argument '" << anArg << "'\n";
+        return 1;
+      }
+
+      const Standard_Real aMaxRadiance = aMaxRadStr.RealValue();
+      if (aMaxRadiance <= 0.0)
+      {
+        std::cerr << "Error: invalid radiance clamping value " << aMaxRadiance << ".\n";
+        return 1;
+      }
+      else
+      {
+        aParams.RadianceClampingValue = static_cast<Standard_ShortReal> (aMaxRadiance);
+      }
+    }
     else if (aFlag == "-iss")
     {
       if (toPrint)
@@ -10906,6 +10938,7 @@ void ViewerTest::ViewerCommands(Draw_Interpretor& theCommands)
     "\n      '-twoside      on|off'  Enables/disables two-sided BSDF models (PT mode)"
     "\n      '-iss          on|off'  Enables/disables adaptive screen sampling (PT mode)"
     "\n      '-issd         on|off'  Shows screen sampling distribution in ISS mode"
+    "\n      '-maxrad       > 0.0'   Value used for clamping radiance estimation (PT mode)"
     "\n      '-rebuildGlsl  on|off'  Rebuild Ray-Tracing GLSL programs (for debugging)"
     "\n      '-shadingModel model'   Controls shading model from enumeration"
     "\n                              color, flat, gouraud, phong"

tests/v3d/raytrace/sample_cube_clamp

@@ -0,0 +1,22 @@
+puts "============"
+puts "Visualization - Path Tracing, Cube sample with radiance clamping"
+puts "============"
+puts ""
+
+source $env(CSF_OCCTSamplesPath)/tcl/pathtrace_cube.tcl
+
+vrenderparams -maxrad 1.0
+vfps 100
+vdump $imagedir/${casename}_1.png
+
+vrenderparams -maxrad 2.0
+vfps 100
+vdump $imagedir/${casename}_2.png
+
+vrenderparams -maxrad 10.0
+vfps 100
+vdump $imagedir/${casename}_10.png
+
+vrenderparams -maxrad 100.0
+vfps 100
+vdump $imagedir/${casename}_100.png