Rendering/OpenGL2/vtkOpenGLRenderer.cxx

/*=========================================================================

Program:   Visualization Toolkit
Module:    vtkOpenGLRenderer.cxx

Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
All rights reserved.
See Copyright.txt or http://www.kitware.com/Copyright.htm for details.

This software is distributed WITHOUT ANY WARRANTY; without even
the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
PURPOSE.  See the above copyright notice for more information.

=========================================================================*/
#include "vtkOpenGLRenderer.h"

#include "vtkOpenGLHelper.h"

#include "vtkCellArray.h"
#include "vtkDepthPeelingPass.h"
#include "vtkDualDepthPeelingPass.h"
#include "vtkFloatArray.h"
#include "vtkHardwareSelector.h"
#include "vtkHiddenLineRemovalPass.h"
#include "vtkLight.h"
#include "vtkLightCollection.h"
#include "vtkNew.h"
#include "vtkObjectFactory.h"
#include "vtkOpenGLCamera.h"
#include "vtkOpenGLError.h"
#include "vtkOpenGLFXAAFilter.h"
#include "vtkOpenGLRenderWindow.h"
#include "vtkOpenGLState.h"
#include "vtkOrderIndependentTranslucentPass.h"
#include "vtkPointData.h"
#include "vtkPoints.h"
#include "vtkPolyData.h"
#include "vtkPolyDataMapper2D.h"
#include "vtkRenderPass.h"
#include "vtkRenderState.h"
#include "vtkRenderTimerLog.h"
#include "vtkShaderProgram.h"
#include "vtkShadowMapBakerPass.h"
#include "vtkShadowMapPass.h"
#include "vtkTexture.h"
#include "vtkTextureObject.h"
#include "vtkTexturedActor2D.h"
#include "vtkTimerLog.h"
#include "vtkTransform.h"
#include "vtkTranslucentPass.h"
#include "vtkTrivialProducer.h"
#include "vtkUnsignedCharArray.h"
#include "vtkVolumetricPass.h"

#include <vtksys/RegularExpression.hxx>

#include <cmath>
#include <cassert>
#include <cstdlib>
#include <list>
#include <sstream>
#include <string>

#if defined(__APPLE__) && ! defined(VTK_OPENGL_HAS_OSMESA)
#include <CoreFoundation/CoreFoundation.h>
#endif

vtkStandardNewMacro(vtkOpenGLRenderer);

vtkOpenGLRenderer::vtkOpenGLRenderer()
{
  this->FXAAFilter = nullptr;
  this->DepthPeelingPass = nullptr;
  this->TranslucentPass = nullptr;
  this->ShadowMapPass = nullptr;
  this->DepthPeelingHigherLayer=0;

  this->HaveApplePrimitiveIdBugValue = false;
  this->HaveApplePrimitiveIdBugChecked = false;

  this->LightingCount = -1;
  this->LightingComplexity = -1;
}

// Ask lights to load themselves into graphics pipeline.
int vtkOpenGLRenderer::UpdateLights ()
{
  // consider the lighting complexity to determine which case applies
  // simple headlight, Light Kit, the whole feature set of VTK
  vtkLightCollection *lc = this->GetLights();
  vtkLight *light;

  int lightingComplexity = 0;
  int lightingCount = 0;

  vtkMTimeType ltime = lc->GetMTime();

  vtkCollectionSimpleIterator sit;
  for(lc->InitTraversal(sit);
      (light = lc->GetNextLight(sit)); )
  {
    float status = light->GetSwitch();
    if (status > 0.0)
    {
      ltime = vtkMath::Max(ltime, light->GetMTime());
      lightingCount++;
      if (lightingComplexity == 0)
      {
        lightingComplexity = 1;
      }
    }

    if (lightingComplexity == 1
        && (lightingCount > 1
          || light->GetLightType() != VTK_LIGHT_TYPE_HEADLIGHT))
    {
      lightingComplexity = 2;
    }
    if (lightingComplexity < 3
        && (light->GetPositional()))
    {
      lightingComplexity = 3;
    }
  }

  // create alight if needed
  if( !lightingCount )
  {
    if (this->AutomaticLightCreation)
    {
      vtkDebugMacro(<<"No lights are on, creating one.");
      this->CreateLight();
      lc->InitTraversal(sit);
      light = lc->GetNextLight(sit);
      ltime = lc->GetMTime();
      lightingCount = 1;
      lightingComplexity = light->GetLightType() == VTK_LIGHT_TYPE_HEADLIGHT ? 1 : 2;
      ltime = vtkMath::Max(ltime, light->GetMTime());
    }
  }

  if (lightingComplexity != this->LightingComplexity ||
      lightingCount != this->LightingCount)
  {
    this->LightingComplexity = lightingComplexity;
    this->LightingCount = lightingCount;

    this->LightingUpdateTime = ltime;

    // rebuild the standard declarations
    std::ostringstream toString;
    switch (this->LightingComplexity)
    {
      case 0: // no lighting or RENDER_VALUES
        this->LightingDeclaration = "";
        break;

      case 1:  // headlight
        this->LightingDeclaration = "uniform vec3 lightColor0;\n";
        break;

      case 2: // light kit
        toString.clear();
        toString.str("");
        for (int i = 0; i < this->LightingCount; ++i)
        {
          toString <<
          "uniform vec3 lightColor" << i << ";\n"
          "  uniform vec3 lightDirectionVC" << i << "; // normalized\n";
        }
        this->LightingDeclaration = toString.str();
        break;

      case 3: // positional
        toString.clear();
        toString.str("");
        for (int i = 0; i < this->LightingCount; ++i)
        {
          toString <<
          "uniform vec3 lightColor" << i << ";\n"
          "uniform vec3 lightDirectionVC" << i << "; // normalized\n"
          "uniform vec3 lightPositionVC" << i << ";\n"
          "uniform vec3 lightAttenuation" << i << ";\n"
          "uniform float lightConeAngle" << i << ";\n"
          "uniform float lightExponent" << i << ";\n"
          "uniform int lightPositional" << i << ";";
        }
        this->LightingDeclaration = toString.str();
        break;
    }
  }

  this->LightingUpdateTime = ltime;

  return this->LightingCount;
}

// ----------------------------------------------------------------------------
// Description:
// Is rendering at translucent geometry stage using depth peeling and
// rendering a layer other than the first one? (Boolean value)
// If so, the uniform variables UseTexture and Texture can be set.
// (Used by vtkOpenGLProperty or vtkOpenGLTexture)
int vtkOpenGLRenderer::GetDepthPeelingHigherLayer()
{
  return this->DepthPeelingHigherLayer;
}

// ----------------------------------------------------------------------------
// Concrete open gl render method.
void vtkOpenGLRenderer::DeviceRender(void)
{
  vtkTimerLog::MarkStartEvent("OpenGL Dev Render");

  if(this->Pass!=nullptr)
  {
    vtkRenderState s(this);
    s.SetPropArrayAndCount(this->PropArray, this->PropArrayCount);
    s.SetFrameBuffer(nullptr);
    this->Pass->Render(&s);
  }
  else
  {
    // Do not remove this MakeCurrent! Due to Start / End methods on
    // some objects which get executed during a pipeline update,
    // other windows might get rendered since the last time
    // a MakeCurrent was called.
    this->RenderWindow->MakeCurrent();
    vtkOpenGLClearErrorMacro();

    this->UpdateCamera();
    this->UpdateLightGeometry();
    this->UpdateLights();
    this->UpdateGeometry();

    vtkOpenGLCheckErrorMacro("failed after DeviceRender");
  }

  vtkTimerLog::MarkEndEvent("OpenGL Dev Render");
}

// Ask actors to render themselves. As a side effect will cause
// visualization network to update.
int vtkOpenGLRenderer::UpdateGeometry()
{
  vtkRenderTimerLog *timer = this->GetRenderWindow()->GetRenderTimer();
  VTK_SCOPED_RENDER_EVENT("vtkOpenGLRenderer::UpdateGeometry", timer);

  int        i;

  this->NumberOfPropsRendered = 0;

  if ( this->PropArrayCount == 0 )
  {
    return 0;
  }

  if (this->Selector)
  {
    VTK_SCOPED_RENDER_EVENT2("Selection", timer, selectionEvent);

    // When selector is present, we are performing a selection,
    // so do the selection rendering pass instead of the normal passes.
    // Delegate the rendering of the props to the selector itself.

    // use pickfromprops ?
    if (this->PickFromProps)
    {
      vtkProp **pa;
      vtkProp *aProp;
      if ( this->PickFromProps->GetNumberOfItems() > 0 )
      {
        pa = new vtkProp *[this->PickFromProps->GetNumberOfItems()];
        int pac = 0;

        vtkCollectionSimpleIterator pit;
        for ( this->PickFromProps->InitTraversal(pit);
              (aProp = this->PickFromProps->GetNextProp(pit)); )
        {
          if ( aProp->GetVisibility() )
          {
            pa[pac++] = aProp;
          }
        }

        this->NumberOfPropsRendered = this->Selector->Render(this, pa, pac);
        delete [] pa;
      }
    }
    else
    {
      this->NumberOfPropsRendered = this->Selector->Render(this,
        this->PropArray, this->PropArrayCount);
    }

    this->RenderTime.Modified();
    vtkDebugMacro("Rendered " << this->NumberOfPropsRendered << " actors" );
    return this->NumberOfPropsRendered;
  }

  // if we are suing shadows then let the renderpasses handle it
  // for opaque and translucent
  int hasTranslucentPolygonalGeometry = 0;
  if (this->UseShadows)
  {
    VTK_SCOPED_RENDER_EVENT2("Shadows", timer, shadowsEvent);

    if (!this->ShadowMapPass)
    {
      this->ShadowMapPass = vtkShadowMapPass::New();
    }
    vtkRenderState s(this);
    s.SetPropArrayAndCount(this->PropArray, this->PropArrayCount);
    //s.SetFrameBuffer(0);
    this->ShadowMapPass->GetShadowMapBakerPass()->Render(&s);
    this->ShadowMapPass->Render(&s);
  }
  else
  {
    // Opaque geometry first:
    timer->MarkStartEvent("Opaque Geometry");
    this->DeviceRenderOpaqueGeometry();
    timer->MarkEndEvent();

    // do the render library specific stuff about translucent polygonal geometry.
    // As it can be expensive, do a quick check if we can skip this step
    for ( i = 0; !hasTranslucentPolygonalGeometry && i < this->PropArrayCount;
          i++ )
    {
      hasTranslucentPolygonalGeometry=
        this->PropArray[i]->HasTranslucentPolygonalGeometry();
    }
    if(hasTranslucentPolygonalGeometry)
    {
      timer->MarkStartEvent("Translucent Geometry");
      this->DeviceRenderTranslucentPolygonalGeometry();
      timer->MarkEndEvent();
    }
  }

  // Apply FXAA before volumes and overlays. Volumes don't need AA, and overlays
  // are usually things like text, which are already antialiased.
  if (this->UseFXAA)
  {
    timer->MarkStartEvent("FXAA");
    if (!this->FXAAFilter)
    {
      this->FXAAFilter = vtkOpenGLFXAAFilter::New();
    }
    if (this->FXAAOptions)
    {
      this->FXAAFilter->UpdateConfiguration(this->FXAAOptions);
    }

    this->FXAAFilter->Execute(this);
    timer->MarkEndEvent();
  }

  // loop through props and give them a chance to
  // render themselves as volumetric geometry.
  if (hasTranslucentPolygonalGeometry == 0 ||
      !this->UseDepthPeeling ||
      !this->UseDepthPeelingForVolumes)
  {
    timer->MarkStartEvent("Volumes");
    for ( i = 0; i < this->PropArrayCount; i++ )
    {
      this->NumberOfPropsRendered +=
        this->PropArray[i]->RenderVolumetricGeometry(this);
    }
    timer->MarkEndEvent();
  }

  // loop through props and give them a chance to
  // render themselves as an overlay (or underlay)
  timer->MarkStartEvent("Overlay");
  for ( i = 0; i < this->PropArrayCount; i++ )
  {
    this->NumberOfPropsRendered +=
      this->PropArray[i]->RenderOverlay(this);
  }
  timer->MarkEndEvent();

  this->RenderTime.Modified();

  vtkDebugMacro( << "Rendered " <<
                    this->NumberOfPropsRendered << " actors" );

  return  this->NumberOfPropsRendered;
}

//----------------------------------------------------------------------------
vtkTexture* vtkOpenGLRenderer::GetCurrentTexturedBackground()
{
  if (!this->GetRenderWindow()->GetStereoRender() && this->BackgroundTexture)
  {
    return this->BackgroundTexture;
  }
  else if (this->GetRenderWindow()->GetStereoRender() && this->GetActiveCamera()->GetLeftEye() == 1 && this->BackgroundTexture)
  {
    return this->BackgroundTexture;
  }
  else if (this->GetRenderWindow()->GetStereoRender() && this->RightBackgroundTexture)
  {
    return this->RightBackgroundTexture;
  }
  else
  {
    return nullptr;
  }
}

// ----------------------------------------------------------------------------
void vtkOpenGLRenderer::DeviceRenderOpaqueGeometry()
{
  // Do we need hidden line removal?
  bool useHLR =
      this->UseHiddenLineRemoval &&
      vtkHiddenLineRemovalPass::WireframePropsExist(this->PropArray,
                                                    this->PropArrayCount);

  if (useHLR)
  {
    vtkNew<vtkHiddenLineRemovalPass> hlrPass;
    vtkRenderState s(this);
    s.SetPropArrayAndCount(this->PropArray, this->PropArrayCount);
    s.SetFrameBuffer(nullptr);
    hlrPass->Render(&s);
    this->NumberOfPropsRendered += hlrPass->GetNumberOfRenderedProps();
  }
  else
  {
    this->Superclass::DeviceRenderOpaqueGeometry();
  }
}

// ----------------------------------------------------------------------------
// Description:
// Render translucent polygonal geometry. Default implementation just call
// UpdateTranslucentPolygonalGeometry().
// Subclasses of vtkRenderer that can deal with depth peeling must
// override this method.
void vtkOpenGLRenderer::DeviceRenderTranslucentPolygonalGeometry()
{
  vtkOpenGLClearErrorMacro();

  vtkOpenGLRenderWindow *context
    = vtkOpenGLRenderWindow::SafeDownCast(this->RenderWindow);

  if(this->UseDepthPeeling && !context)
  {
    vtkErrorMacro("OpenGL render window is required.")
    return;
  }

  if(!this->UseDepthPeeling)
  {
    // old code
    // this->UpdateTranslucentPolygonalGeometry();

    // new approach
    if (!this->TranslucentPass)
    {
      vtkOrderIndependentTranslucentPass *oit =
        vtkOrderIndependentTranslucentPass::New();
      this->TranslucentPass = oit;
    }
    vtkTranslucentPass *tp = vtkTranslucentPass::New();
    this->TranslucentPass->SetTranslucentPass(tp);
    tp->Delete();

    vtkRenderState s(this);
    s.SetPropArrayAndCount(this->PropArray, this->PropArrayCount);
    s.SetFrameBuffer(nullptr);
    this->LastRenderingUsedDepthPeeling=0;
    this->TranslucentPass->Render(&s);
    this->NumberOfPropsRendered += this->TranslucentPass->GetNumberOfRenderedProps();
  }
  else   // depth peeling.
  {
#if GL_ES_VERSION_3_0 == 1
    vtkErrorMacro("Built in Dual Depth Peeling is not supported on ES3. "
      "Please see TestFramebufferPass.cxx for an example that should work "
      "on OpenGL ES 3.");
    this->UpdateTranslucentPolygonalGeometry();
#else
    if (!this->DepthPeelingPass)
    {
      if (this->IsDualDepthPeelingSupported())
      {
        vtkDebugMacro("Using dual depth peeling.");
        vtkDualDepthPeelingPass *ddpp = vtkDualDepthPeelingPass::New();
        this->DepthPeelingPass = ddpp;
      }
      else
      {
        vtkDebugMacro("Using standard depth peeling (dual depth peeling not "
                      "supported by the graphics card/driver).");
        this->DepthPeelingPass = vtkDepthPeelingPass::New();
      }
      vtkTranslucentPass *tp = vtkTranslucentPass::New();
      this->DepthPeelingPass->SetTranslucentPass(tp);
      tp->Delete();
    }

    if (this->UseDepthPeelingForVolumes)
    {
      vtkDualDepthPeelingPass *ddpp = vtkDualDepthPeelingPass::SafeDownCast(
            this->DepthPeelingPass);
      if (!ddpp)
      {
        vtkWarningMacro("UseDepthPeelingForVolumes requested, but unsupported "
                        "since DualDepthPeeling is not available.");
        this->UseDepthPeelingForVolumes = false;
      }
      else if (!ddpp->GetVolumetricPass())
      {
        vtkVolumetricPass *vp = vtkVolumetricPass::New();
        ddpp->SetVolumetricPass(vp);
        vp->Delete();
      }
    }
    else
    {
      vtkDualDepthPeelingPass *ddpp = vtkDualDepthPeelingPass::SafeDownCast(
            this->DepthPeelingPass);
      if (ddpp)
      {
        ddpp->SetVolumetricPass(nullptr);
      }
    }

    this->DepthPeelingPass->SetMaximumNumberOfPeels(this->MaximumNumberOfPeels);
    this->DepthPeelingPass->SetOcclusionRatio(this->OcclusionRatio);
    vtkRenderState s(this);
    s.SetPropArrayAndCount(this->PropArray, this->PropArrayCount);
    s.SetFrameBuffer(nullptr);
    this->LastRenderingUsedDepthPeeling=1;
    this->DepthPeelingPass->Render(&s);
    this->NumberOfPropsRendered += this->DepthPeelingPass->GetNumberOfRenderedProps();
#endif
  }

  vtkOpenGLCheckErrorMacro("failed after DeviceRenderTranslucentPolygonalGeometry");
}


// ----------------------------------------------------------------------------
void vtkOpenGLRenderer::PrintSelf(ostream& os, vtkIndent indent)
{
  this->Superclass::PrintSelf(os,indent);
}


void vtkOpenGLRenderer::Clear(void)
{
  vtkOpenGLClearErrorMacro();

  GLbitfield  clear_mask = 0;
  vtkOpenGLState *ostate = this->GetState();

  if (! this->Transparent())
  {
    ostate->vtkglClearColor(static_cast<GLclampf>(this->Background[0]),
      static_cast<GLclampf>(this->Background[1]), static_cast<GLclampf>(this->Background[2]),
      static_cast<GLclampf>(this->BackgroundAlpha));
    clear_mask |= GL_COLOR_BUFFER_BIT;
  }

  if (!this->GetPreserveDepthBuffer())
  {
    ostate->vtkglClearDepth(static_cast<GLclampf>(1.0));
    clear_mask |= GL_DEPTH_BUFFER_BIT;
    ostate->vtkglDepthMask(GL_TRUE);
  }

  vtkDebugMacro(<< "glClear\n");
  ostate->vtkglColorMask(GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE);
  ostate->vtkglClear(clear_mask);

  // If gradient background is turned on, draw it now.
  if (!this->Transparent() &&
      (this->GradientBackground || this->TexturedBackground))
  {
    int size[2];
    size[0] = this->GetSize()[0];
    size[1] = this->GetSize()[1];

    double tile_viewport[4];
    this->GetRenderWindow()->GetTileViewport(tile_viewport);

    vtkNew<vtkTexturedActor2D> actor;
    vtkNew<vtkPolyDataMapper2D> mapper;
    vtkNew<vtkPolyData> polydata;
    vtkNew<vtkPoints> points;
    points->SetNumberOfPoints(4);
    points->SetPoint(0, 0, 0, 0);
    points->SetPoint(1, size[0], 0, 0);
    points->SetPoint(2, size[0], size[1], 0);
    points->SetPoint(3, 0, size[1], 0);
    polydata->SetPoints(points);

    vtkNew<vtkCellArray> tris;
    tris->InsertNextCell(3);
    tris->InsertCellPoint(0);
    tris->InsertCellPoint(1);
    tris->InsertCellPoint(2);
    tris->InsertNextCell(3);
    tris->InsertCellPoint(0);
    tris->InsertCellPoint(2);
    tris->InsertCellPoint(3);
    polydata->SetPolys(tris);

    vtkNew<vtkTrivialProducer> prod;
    prod->SetOutput(polydata);

    // Set some properties.
    mapper->SetInputConnection(prod->GetOutputPort());
    actor->SetMapper(mapper);

    if(this->TexturedBackground && this->GetCurrentTexturedBackground())
    {
      this->GetCurrentTexturedBackground()->InterpolateOn();
      actor->SetTexture(this->GetCurrentTexturedBackground());

      vtkNew<vtkFloatArray> tcoords;
      float tmp[2];
      tmp[0] = 0;
      tmp[1] = 0;
      tcoords->SetNumberOfComponents(2);
      tcoords->SetNumberOfTuples(4);
      tcoords->SetTuple(0,tmp);
      tmp[0] = 1.0;
      tcoords->SetTuple(1,tmp);
      tmp[1] = 1.0;
      tcoords->SetTuple(2,tmp);
      tmp[0] = 0.0;
      tcoords->SetTuple(3,tmp);
      polydata->GetPointData()->SetTCoords(tcoords);
    }
    else // gradient
    {
      vtkNew<vtkUnsignedCharArray> colors;
      float tmp[4];
      tmp[0] = this->Background[0]*255;
      tmp[1] = this->Background[1]*255;
      tmp[2] = this->Background[2]*255;
      tmp[3] = 255;
      colors->SetNumberOfComponents(4);
      colors->SetNumberOfTuples(4);
      colors->SetTuple(0,tmp);
      colors->SetTuple(1,tmp);
      tmp[0] = this->Background2[0]*255;
      tmp[1] = this->Background2[1]*255;
      tmp[2] = this->Background2[2]*255;
      colors->SetTuple(2,tmp);
      colors->SetTuple(3,tmp);
      polydata->GetPointData()->SetScalars(colors);
    }

    ostate->vtkglDisable(GL_DEPTH_TEST);
    actor->RenderOverlay(this);
  }

  ostate->vtkglEnable(GL_DEPTH_TEST);

  vtkOpenGLCheckErrorMacro("failed after Clear");
}

void vtkOpenGLRenderer::ReleaseGraphicsResources(vtkWindow *w)
{
  if (w && this->Pass)
  {
    this->Pass->ReleaseGraphicsResources(w);
  }
  if (this->FXAAFilter)
  {
    this->FXAAFilter->ReleaseGraphicsResources();
  }
  if (w && this->DepthPeelingPass)
  {
    this->DepthPeelingPass->ReleaseGraphicsResources(w);
  }
  if (w && this->TranslucentPass)
  {
    this->TranslucentPass->ReleaseGraphicsResources(w);
  }
  if (w && this->ShadowMapPass)
  {
    this->ShadowMapPass->ReleaseGraphicsResources(w);
  }
  this->Superclass::ReleaseGraphicsResources(w);
}

vtkOpenGLRenderer::~vtkOpenGLRenderer()
{
  if(this->Pass != nullptr)
  {
    this->Pass->UnRegister(this);
    this->Pass = nullptr;
  }

  if (this->FXAAFilter)
  {
    this->FXAAFilter->Delete();
    this->FXAAFilter = nullptr;
  }

  if (this->ShadowMapPass)
  {
    this->ShadowMapPass->Delete();
    this->ShadowMapPass = nullptr;
  }

  if (this->DepthPeelingPass)
  {
    this->DepthPeelingPass->Delete();
    this->DepthPeelingPass = nullptr;
  }

  if (this->TranslucentPass)
  {
    this->TranslucentPass->Delete();
    this->TranslucentPass = nullptr;
  }
}

bool vtkOpenGLRenderer::HaveApplePrimitiveIdBug()
{
  if (this->HaveApplePrimitiveIdBugChecked)
  {
    return this->HaveApplePrimitiveIdBugValue;
  }

#if defined(__APPLE__) && ! defined(VTK_OPENGL_HAS_OSMESA)
  // Known working Apple+AMD systems:
  // OpenGL vendor string:  ATI Technologies Inc.
  // OpenGL version string:   4.1 ATI-1.38.3
  // OpenGL version string:   4.1 ATI-1.40.15
  // OpenGL renderer string:    AMD Radeon R9 M370X OpenGL Engine

  // OpenGL version string:   4.1 ATI-1.40.16
  // OpenGL renderer string:    AMD Radeon HD - FirePro D500 OpenGL Engine
  // OpenGL renderer string:    AMD Radeon HD 5770 OpenGL Engine
  // OpenGL renderer string:    AMD Radeon R9 M395 OpenGL Engine

  // OpenGL vendor string:  ATI Technologies Inc.
  // OpenGL renderer string:  ATI Radeon HD 5770 OpenGL Engine
  // OpenGL version string:  4.1 ATI-1.42.6

  // Known buggy Apple+AMD systems:
  // OpenGL vendor string:  ATI Technologies Inc.
  // OpenGL version string:   3.3 ATI-10.0.40
  // OpenGL renderer string:    ATI Radeon HD 2600 PRO OpenGL Engine

  // OpenGL vendor string:  ATI Technologies Inc.
  // OpenGL renderer string:  AMD Radeon HD - FirePro D300 OpenGL Engine
  // OpenGL version string:  4.1 ATI-1.24.39

  std::string vendor = (const char *)glGetString(GL_VENDOR);
  if (vendor.find("ATI") != std::string::npos ||
      vendor.find("AMD") != std::string::npos ||
      vendor.find("amd") != std::string::npos)
  {
    // assume we have the bug if we are running on <= macOS 10.10.x
    // Apple fixed this bug in OS X 10.11 beta 15A216g.
    // kCFCoreFoundationVersionNumber10_10_Max = 1199, we use the raw number
    // because the constant isn't present in older SDKs.
    if (kCFCoreFoundationVersionNumber <= 1199)
    {
      this->HaveApplePrimitiveIdBugValue = true;
    }

    // but exclude systems we know do not have it
    std::string renderer = (const char *)glGetString(GL_RENDERER);
    std::string version = (const char *)glGetString(GL_VERSION);
    int minorVersion = 0;
    int patchVersion = 0;
    // try to extract some minor version numbers
    if (version.find("4.1 ATI-1.") == 0)
    {
      std::string minorVer = version.substr(strlen("4.1 ATI-1."),std::string::npos);
      if (minorVer.find('.') == 2)
      {
        minorVersion = atoi(minorVer.substr(0,2).c_str());
        patchVersion = atoi(minorVer.substr(3,std::string::npos).c_str());
      }
    }
    if (
        ((version.find("4.1 ATI-1.38.3") != std::string::npos ||
          version.find("4.1 ATI-1.40.15") != std::string::npos) &&
          (renderer.find("AMD Radeon R9 M370X OpenGL Engine") != std::string::npos)) ||
          // assume anything with 1.40.16 or later is good?
          minorVersion > 40 ||
          (minorVersion == 40 && patchVersion >= 16)
         )
    {
      this->HaveApplePrimitiveIdBugValue = false;
    }
  }

  // On all versions of macOS and with all GPUs,
  // allow an env var to force the workaround to be used.
  const char* forceWorkaround = std::getenv("VTK_FORCE_APPLE_PRIMITIVEID_WORKAROUND");
  if (forceWorkaround)
  {
    this->HaveApplePrimitiveIdBugValue = true;
  }

#else
  this->HaveApplePrimitiveIdBugValue = false;
#endif

  this->HaveApplePrimitiveIdBugChecked = true;
  return this->HaveApplePrimitiveIdBugValue;
}

//------------------------------------------------------------------------------
bool vtkOpenGLRenderer::HaveAppleQueryAllocationBug()
{
#if defined(__APPLE__) && ! defined(VTK_OPENGL_HAS_OSMESA)
  enum class QueryAllocStatus { NotChecked, Yes, No };
  static QueryAllocStatus hasBug = QueryAllocStatus::NotChecked;

  if (hasBug == QueryAllocStatus::NotChecked)
  {
    // We can restrict this to a specific version, etc, as we get more
    // information about the bug, but for now just disable query allocations on
    // all apple NVIDIA cards.
    std::string v = reinterpret_cast<const char *>(glGetString(GL_VENDOR));
    hasBug = (v.find("NVIDIA") != std::string::npos) ? QueryAllocStatus::Yes
                                                     : QueryAllocStatus::No;
  }

  return hasBug == QueryAllocStatus::Yes;
#else
  return false;
#endif
}

//------------------------------------------------------------------------------
bool vtkOpenGLRenderer::IsDualDepthPeelingSupported()
{
  vtkOpenGLRenderWindow *context
    = vtkOpenGLRenderWindow::SafeDownCast(this->RenderWindow);
  if (!context)
  {
    vtkDebugMacro("Cannot determine if dual depth peeling is support -- no "
                  "vtkRenderWindow set.");
    return false;
  }

  // Dual depth peeling requires:
  // - float textures (ARB_texture_float)
  // - RG textures (ARB_texture_rg)
  // - MAX blending (added in ES3).
  // requires that RG textures be color renderable (they are not in ES3)
#if GL_ES_VERSION_3_0 == 1
  // ES3 is not supported, see TestFramebufferPass.cxx for how to do it
  bool dualDepthPeelingSupported = false;
#else
  bool dualDepthPeelingSupported = true;
#endif

  // There's a bug on current mesa master that prevents dual depth peeling
  // from functioning properly, something in the texture sampler is causing
  // all lookups to return NaN. See discussion on
  // https://bugs.freedesktop.org/show_bug.cgi?id=94955
  // This has been fixed in Mesa 17.2.
  const char *glVersionC =
      reinterpret_cast<const char *>(glGetString(GL_VERSION));
  std::string glVersion = std::string(glVersionC ? glVersionC : "");
  if (dualDepthPeelingSupported &&
      glVersion.find("Mesa") != std::string::npos)
  {
    bool mesaCompat = false;
    // The bug has been fixed with mesa 17.2.0. The version string is approx:
    // 3.3 (Core Profile) Mesa 17.2.0-devel (git-08cb8cf256)
    vtksys::RegularExpression re("Mesa ([0-9]+)\\.([0-9]+)\\.");
    if (re.find(glVersion))
    {
      int majorVersion;
      std::string majorStr = re.match(1);
      std::istringstream majorParse(majorStr);
      majorParse >> majorVersion;
      if (majorVersion > 17)
      {
        mesaCompat = true;
      }
      else if (majorVersion == 17)
      {
        int minorVersion;
        std::string minorStr = re.match(2);
        std::istringstream minorParse(minorStr);
        minorParse >> minorVersion;
        if (minorVersion >= 2)
        {
          mesaCompat = true;
        }
      }
    }

    if (!mesaCompat)
    {
      vtkDebugMacro("Disabling dual depth peeling -- mesa bug detected. "
                    "GL_VERSION = '" << glVersion << "'.");
      dualDepthPeelingSupported = false;
    }
  }

  // The old implementation can be forced by defining the environment var
  // "VTK_USE_LEGACY_DEPTH_PEELING":
  if (dualDepthPeelingSupported)
  {
    const char *forceLegacy = getenv("VTK_USE_LEGACY_DEPTH_PEELING");
    if (forceLegacy)
    {
      vtkDebugMacro("Disabling dual depth peeling -- "
                    "VTK_USE_LEGACY_DEPTH_PEELING defined in environment.");
      dualDepthPeelingSupported = false;
    }
  }

  return dualDepthPeelingSupported;
}

vtkOpenGLState *vtkOpenGLRenderer::GetState()
{
  return this->VTKWindow ? static_cast<vtkOpenGLRenderWindow *>(this->VTKWindow)->GetState() : nullptr;
}

const char *vtkOpenGLRenderer::GetLightingUniforms()
{
  return this->LightingDeclaration.c_str();
}

void vtkOpenGLRenderer::UpdateLightingUniforms(vtkShaderProgram *program)
{
  vtkMTimeType ptime = program->GetUniformGroupUpdateTime(vtkShaderProgram::LightingGroup);
  vtkMTimeType ltime = this->LightingUpdateTime;

  // for lighting complexity 2,3 camera has an impact
  vtkCamera *cam = this->GetActiveCamera();
  if (this->LightingComplexity > 1)
  {
    ltime = vtkMath::Max(ltime, cam->GetMTime());
  }

  if (ltime <= ptime)
  {
    return;
  }

  // for lightkit case there are some parameters to set
  vtkTransform* viewTF = cam->GetModelViewTransformObject();

  // bind some light settings
  int numberOfLights = 0;
  vtkLightCollection *lc = this->GetLights();
  vtkLight *light;

  vtkCollectionSimpleIterator sit;
  float lightColor[3];
  float lightDirection[3];
  std::string lcolor("lightColor");
  std::string ldir("lightDirectionVC");
  std::string latten("lightAttenuation");
  std::string lpositional("lightPositional");
  std::string lpos("lightPositionVC");
  std::string lexp("lightExponent");
  std::string lcone("lightConeAngle");

  std::ostringstream toString;
  for (lc->InitTraversal(sit); (light = lc->GetNextLight(sit)); )
  {
    float status = light->GetSwitch();
    if (status > 0.0)
    {
      toString.str("");
      toString << numberOfLights;
      std::string count = toString.str();

      double *dColor = light->GetDiffuseColor();
      double intensity = light->GetIntensity();
      // if (renderLuminance)
      // {
      //   lightColor[0] = intensity;
      //   lightColor[1] = intensity;
      //   lightColor[2] = intensity;
      // }
      // else
      {
        lightColor[0] = dColor[0] * intensity;
        lightColor[1] = dColor[1] * intensity;
        lightColor[2] = dColor[2] * intensity;
      }
      program->SetUniform3f((lcolor + count).c_str(), lightColor);

      // we are done unless we have non headlights
      if (this->LightingComplexity >= 2)
      {
        // get required info from light
        double *lfp = light->GetTransformedFocalPoint();
        double *lp = light->GetTransformedPosition();
        double lightDir[3];
        vtkMath::Subtract(lfp,lp,lightDir);
        vtkMath::Normalize(lightDir);
        double tDirView[3];
        viewTF->TransformNormal(lightDir, tDirView);

        if (!light->LightTypeIsSceneLight() && this->UserLightTransform.GetPointer() != nullptr)
        {
          double *tDir = this->UserLightTransform->TransformNormal(tDirView);
          lightDirection[0] = tDir[0];
          lightDirection[1] = tDir[1];
          lightDirection[2] = tDir[2];
        }
        else
        {
          lightDirection[0] = tDirView[0];
          lightDirection[1] = tDirView[1];
          lightDirection[2] = tDirView[2];
        }

        program->SetUniform3f((ldir + count).c_str(), lightDirection);

        // we are done unless we have positional lights
        if (this->LightingComplexity >= 3)
        {
          // if positional lights pass down more parameters
          float lightAttenuation[3];
          float lightPosition[3];
          double *attn = light->GetAttenuationValues();
          lightAttenuation[0] = attn[0];
          lightAttenuation[1] = attn[1];
          lightAttenuation[2] = attn[2];
          double tlpView[3];
          viewTF->TransformPoint(lp, tlpView);
          if (!light->LightTypeIsSceneLight() && this->UserLightTransform.GetPointer() != nullptr)
          {
            double *tlp = this->UserLightTransform->TransformPoint(tlpView);
            lightPosition[0] = tlp[0];
            lightPosition[1] = tlp[1];
            lightPosition[2] = tlp[2];
          }
          else
          {
            lightPosition[0] = tlpView[0];
            lightPosition[1] = tlpView[1];
            lightPosition[2] = tlpView[2];
          }

          program->SetUniform3f((latten + count).c_str(), lightAttenuation);
          program->SetUniformi((lpositional + count).c_str(), light->GetPositional());
          program->SetUniform3f((lpos + count).c_str(), lightPosition);
          program->SetUniformf((lexp + count).c_str(), light->GetExponent());
          program->SetUniformf((lcone + count).c_str(), light->GetConeAngle());
        }
      }
      numberOfLights++;
    }
  }

  program->SetUniformGroupUpdateTime(vtkShaderProgram::LightingGroup, ltime);
}

void vtkOpenGLRenderer::SetUserLightTransform(vtkTransform* transform)
{
  this->UserLightTransform = transform;
}