ENH:Added optional use of texture compression (fast but ugly result),…

… covered by a new regression test. ENH: if non-power-of-two texture is supported, don't resize the volume, the speed-up is more obsvious than the one about compressed texture. BUG: Fixed mismatch number of components in texture loading. BUG:Fixed totally wrong logic in IsTextureSizeSupported().

VolumeRendering/Testing/Tcl/CMakeLists.txt

@@ -18,6 +18,7 @@ IF (VTK_USE_RENDERING AND VTK_USE_DISPLAY)
       volRCRotateClip
       volTM2DCropRegions
       volTM2DRotateClip
+      volTM3DCompressedCropRegions
       volTM3DCropRegions
       volTM3DRotateClip
     )

VolumeRendering/Testing/Tcl/volTM3DCompressedCropRegions.tcl

@@ -0,0 +1,113 @@
+package require vtk
+package require vtkinteraction
+
+# Simple volume rendering example.
+vtkSLCReader reader
+    reader SetFileName "$VTK_DATA_ROOT/Data/sphere.slc"
+
+# Create transfer functions for opacity and color
+vtkPiecewiseFunction opacityTransferFunction
+    opacityTransferFunction AddPoint    0  0.0
+    opacityTransferFunction AddPoint   30  0.0
+    opacityTransferFunction AddPoint   80  0.5
+    opacityTransferFunction AddPoint  255  0.5
+
+vtkColorTransferFunction colorTransferFunction
+    colorTransferFunction AddRGBPoint      0.0 0.0 0.0 0.0
+    colorTransferFunction AddRGBPoint     64.0 1.0 0.0 0.0
+    colorTransferFunction AddRGBPoint    128.0 0.0 0.0 1.0
+    colorTransferFunction AddRGBPoint    192.0 0.0 1.0 0.0
+    colorTransferFunction AddRGBPoint    255.0 0.0 0.2 0.0
+
+# Create properties, mappers, volume actors, and ray cast function
+vtkVolumeProperty volumeProperty
+    volumeProperty SetColor colorTransferFunction
+    volumeProperty SetScalarOpacity opacityTransferFunction
+    volumeProperty SetInterpolationTypeToLinear
+    volumeProperty ShadeOn
+
+
+vtkRenderer ren1
+vtkRenderWindow renWin
+    renWin AddRenderer ren1
+    renWin SetSize 600 300
+vtkRenderWindowInteractor iren
+    iren SetRenderWindow renWin
+
+ren1 SetBackground 0.1 0.2 0.4
+renWin Render
+
+for { set i 0 } { $i < 2 } { incr i } {
+    for { set j 0 } { $j < 4 } { incr j } {
+       vtkVolumeTextureMapper3D volumeMapper_${i}_${j}
+       volumeMapper_${i}_${j} SetInputConnection [reader GetOutputPort]
+       volumeMapper_${i}_${j} SetSampleDistance 0.25
+       volumeMapper_${i}_${j} CroppingOn
+       volumeMapper_${i}_${j} SetUseCompressedTexture 1
+       volumeMapper_${i}_${j} SetCroppingRegionPlanes 17 33 17 33 17 33
+
+       vtkVolume volume_${i}_${j}
+       volume_${i}_${j} SetMapper volumeMapper_${i}_${j}
+       volume_${i}_${j} SetProperty volumeProperty
+
+       vtkTransform userMatrix_${i}_${j} 
+       userMatrix_${i}_${j} PostMultiply
+       userMatrix_${i}_${j} Identity
+       userMatrix_${i}_${j} Translate -25 -25 -25
+
+       if { $i == 0 } {
+          userMatrix_${i}_${j} RotateX [expr $j*90 + 20]
+          userMatrix_${i}_${j} RotateY 20
+       } else {
+          userMatrix_${i}_${j} RotateX 20
+          userMatrix_${i}_${j} RotateY [expr $j*90 + 20]
+       }
+
+       userMatrix_${i}_${j} Translate [expr $j*55 + 25] [expr $i*55 + 25] 0
+
+       volume_${i}_${j} SetUserTransform userMatrix_${i}_${j}
+
+       ren1 AddViewProp volume_${i}_${j}
+    }
+}
+
+volumeMapper_0_0 SetCroppingRegionFlagsToSubVolume
+volumeMapper_0_1 SetCroppingRegionFlagsToCross
+volumeMapper_0_2 SetCroppingRegionFlagsToInvertedCross
+volumeMapper_0_3 SetCroppingRegionFlags 24600
+
+volumeMapper_1_0 SetCroppingRegionFlagsToFence
+volumeMapper_1_1 SetCroppingRegionFlagsToInvertedFence
+volumeMapper_1_2 SetCroppingRegionFlags 1
+volumeMapper_1_3 SetCroppingRegionFlags 67117057
+
+[ren1 GetCullers] InitTraversal
+set culler [[ren1 GetCullers] GetNextItem]
+$culler SetSortingStyleToBackToFront
+
+set valid [volumeMapper_0_0 IsRenderSupported volumeProperty]
+
+if {!$valid} {
+   ren1 RemoveAllViewProps
+   vtkTextActor t
+   t SetInput "Required Extensions Not Supported"
+   t SetDisplayPosition 300 150
+   [t GetTextProperty] SetJustificationToCentered
+   ren1 AddViewProp t
+}
+
+ren1 ResetCamera
+[ren1 GetActiveCamera] Zoom 3.0
+renWin Render
+
+proc TkCheckAbort {} {
+  set foo [renWin GetEventPending]
+  if {$foo != 0} {renWin SetAbortRender 1}
+}
+renWin AddObserver AbortCheckEvent {TkCheckAbort}
+
+
+iren AddObserver UserEvent {wm deiconify .vtkInteract}
+iren Initialize
+
+wm withdraw .