Some cleanups to make the shader a bit simpler

Some minor cleanups and added timing code

Rendering/OpenGL2/CMakeLists.txt

@@ -140,7 +140,6 @@ set(shader_files
   glsl/vtkPolyDataVS.glsl
   glsl/vtkPolyDataWideLineGS.glsl
   glsl/vtkSSAAPassFS.glsl
-  glsl/vtkSSAAPassVS.glsl
   glsl/vtkSobelGradientMagnitudePass1FS.glsl
   glsl/vtkSobelGradientMagnitudePass2FS.glsl
   glsl/vtkTextureObjectFS.glsl

Rendering/OpenGL2/Testing/Cxx/TestSSAAPass.cxx

@@ -37,6 +37,8 @@
 #include "vtkSSAAPass.h"
 #include "vtkRenderStepsPass.h"
 
+#include "vtkCellArray.h"
+#include "vtkTimerLog.h"
 
 int TestSSAAPass(int argc, char* argv[])
 {
@@ -87,6 +89,32 @@ int TestSSAAPass(int argc, char* argv[])
   actor->GetProperty()->SetSpecularPower(20.0);
   actor->GetProperty()->SetOpacity(1.0);
 
+ vtkNew<vtkTimerLog> timer;
+  timer->StartTimer();
+  renWin->Render();
+  timer->StopTimer();
+  double firstRender = timer->GetElapsedTime();
+  cerr << "first render time: " << firstRender << endl;
+
+  timer->StartTimer();
+  int numRenders = 4;
+  for (int i = 0; i < numRenders; ++i)
+    {
+    renderer->GetActiveCamera()->Azimuth(80.0/numRenders);
+    renderer->GetActiveCamera()->Elevation(88.0/numRenders);
+    renWin->Render();
+    }
+  timer->StopTimer();
+  double elapsed = timer->GetElapsedTime();
+  cerr << "interactive render time: " << elapsed / numRenders << endl;
+  unsigned int numTris = reader->GetOutput()->GetPolys()->GetNumberOfCells();
+  cerr << "number of triangles: " <<  numTris << endl;
+  cerr << "triangles per second: " <<  numTris*(numRenders/elapsed) << endl;
+
+  renderer->GetActiveCamera()->SetPosition(0,0,1);
+  renderer->GetActiveCamera()->SetFocalPoint(0,0,0);
+  renderer->GetActiveCamera()->SetViewUp(0,1,0);
+  renderer->ResetCamera();
   renWin->Render();
 
   int retVal = vtkRegressionTestImage( renWin.Get() );

Rendering/OpenGL2/glsl/vtkSSAAPassFS.glsl

@@ -15,21 +15,17 @@
 //
 // ============================================================================
 
+// thanks to Brad Larson for posting sample code that helped get this started
+
 uniform sampler2D source;
 
 // the output of this shader
 //VTK::Output::Dec
 
+uniform float texelWidthOffset;
+uniform float texelHeightOffset;
 
-varying vec2 centerTextureCoordinate;
-varying vec2 oneStepLeftTextureCoordinate;
-varying vec2 twoStepsLeftTextureCoordinate;
-varying vec2 threeStepsLeftTextureCoordinate;
-varying vec2 fourStepsLeftTextureCoordinate;
-varying vec2 oneStepRightTextureCoordinate;
-varying vec2 twoStepsRightTextureCoordinate;
-varying vec2 threeStepsRightTextureCoordinate;
-varying vec2 fourStepsRightTextureCoordinate;
+varying vec2 tcoordVC;
 
 // Note that the texel offsets should be 3/8 of a pixel in the
 // resulting image not the source image. Also note that this
@@ -42,19 +38,21 @@ varying vec2 fourStepsRightTextureCoordinate;
 
 void main()
 {
-  lowp vec4 fragmentColor = texture2D(source, centerTextureCoordinate) * 0.38026;
+  vec2 firstOffset = vec2(texelWidthOffset, texelHeightOffset);
+
+  vec4 fragmentColor = texture2D(source, tcoordVC) * 0.38026;
 
-  fragmentColor += texture2D(source, oneStepLeftTextureCoordinate) * 0.27667;
-  fragmentColor += texture2D(source, oneStepRightTextureCoordinate) * 0.27667;
+  fragmentColor += texture2D(source, tcoordVC - firstOffset) * 0.27667;
+  fragmentColor += texture2D(source, tcoordVC + firstOffset) * 0.27667;
 
-  fragmentColor += texture2D(source, twoStepsLeftTextureCoordinate) * 0.08074;
-  fragmentColor += texture2D(source, twoStepsRightTextureCoordinate) * 0.08074;
+  fragmentColor += texture2D(source, tcoordVC - 2.0*firstOffset) * 0.08074;
+  fragmentColor += texture2D(source, tcoordVC + 2.0*firstOffset) * 0.08074;
 
-  fragmentColor += texture2D(source, threeStepsLeftTextureCoordinate) * -0.02612;
-  fragmentColor += texture2D(source, threeStepsRightTextureCoordinate) * -0.02612;
+  fragmentColor += texture2D(source, tcoordVC - 3.0*firstOffset) * -0.02612;
+  fragmentColor += texture2D(source, tcoordVC + 3.0*firstOffset) * -0.02612;
 
-  fragmentColor += texture2D(source, fourStepsLeftTextureCoordinate) * -0.02143;
-  fragmentColor += texture2D(source, fourStepsRightTextureCoordinate) * -0.02143;
+  fragmentColor += texture2D(source, tcoordVC - 4.0*firstOffset) * -0.02143;
+  fragmentColor += texture2D(source, tcoordVC + 4.0*firstOffset) * -0.02143;
 
   gl_FragData[0] = fragmentColor;
-}
\ No newline at end of file
+}

Rendering/OpenGL2/glsl/vtkSSAAPassVS.glsl

-//VTK::System::Dec
-
-/*=========================================================================
-
-  Program:   Visualization Toolkit
-  Module:    vtkSSAAPassVS.glsl
-
-  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.
-
-=========================================================================*/
-
-attribute vec4 vertexMC;
-attribute vec2 tcoordMC;
-
-// Note that the texel offsets should be 3/8 of a pixel in the
-// resulting image not the source image. Also note that this
-// filter is meant to be run one dimension at a time.
-uniform float texelWidthOffset;
-uniform float texelHeightOffset;
-
-varying vec2 centerTextureCoordinate;
-varying vec2 oneStepLeftTextureCoordinate;
-varying vec2 twoStepsLeftTextureCoordinate;
-varying vec2 threeStepsLeftTextureCoordinate;
-varying vec2 fourStepsLeftTextureCoordinate;
-varying vec2 oneStepRightTextureCoordinate;
-varying vec2 twoStepsRightTextureCoordinate;
-varying vec2 threeStepsRightTextureCoordinate;
-varying vec2 fourStepsRightTextureCoordinate;
-
-void main()
-{
-  vec2 firstOffset = vec2(texelWidthOffset, texelHeightOffset);
-  vec2 secondOffset = vec2(2.0 * texelWidthOffset, 2.0 * texelHeightOffset);
-  vec2 thirdOffset = vec2(3.0 * texelWidthOffset, 3.0 * texelHeightOffset);
-  vec2 fourthOffset = vec2(4.0 * texelWidthOffset, 4.0 * texelHeightOffset);
-
-  centerTextureCoordinate = tcoordMC;
-  oneStepLeftTextureCoordinate = tcoordMC - firstOffset;
-  twoStepsLeftTextureCoordinate = tcoordMC - secondOffset;
-  threeStepsLeftTextureCoordinate = tcoordMC - thirdOffset;
-  fourStepsLeftTextureCoordinate = tcoordMC - fourthOffset;
-  oneStepRightTextureCoordinate = tcoordMC + firstOffset;
-  twoStepsRightTextureCoordinate = tcoordMC + secondOffset;
-  threeStepsRightTextureCoordinate = tcoordMC + thirdOffset;
-  fourStepsRightTextureCoordinate = tcoordMC + fourthOffset;
-
-  gl_Position = vertexMC;
-}

Rendering/OpenGL2/vtkSSAAPass.cxx

@@ -30,7 +30,7 @@
 #include "vtkOpenGLHelper.h"
 
 #include "vtkSSAAPassFS.h"
-#include "vtkSSAAPassVS.h"
+#include "vtkTextureObjectVS.h"  // a pass through shader
 
 vtkStandardNewMacro(vtkSSAAPass);
 
@@ -245,7 +245,8 @@ void vtkSSAAPass::Render(const vtkRenderState *s)
     {
     this->SSAAProgram = new vtkOpenGLHelper;
     // build the shader source code
-    std::string VSSource = vtkSSAAPassVS;
+//    std::string VSSource = vtkSSAAPassVS;
+    std::string VSSource = vtkTextureObjectVS;
     std::string FSSource = vtkSSAAPassFS;
     std::string GSSource;