Add surface probe volume mapper

Rendering/VolumeOpenGL2/CMakeLists.txt

@@ -4,6 +4,7 @@ set(classes
   vtkOpenGLGPUVolumeRayCastMapper
   vtkOpenGLProjectedTetrahedraMapper
   vtkOpenGLRayCastImageDisplayHelper
+  vtkOpenGLSurfaceProbeVolumeMapper
   vtkSmartVolumeMapper
   vtkVolumeTexture)
 

Rendering/VolumeOpenGL2/vtkOpenGLSurfaceProbeVolumeMapper.h

+// SPDX-FileCopyrightText: Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
+// SPDX-License-Identifier: BSD-3-Clause
+/**
+ * @class   vtkOpenGLSurfaceProbeVolumeMapper
+ * @brief   PolyDataMapper colored with probed volume data.
+ *
+ * PolyDataMapper that probes volume data at the points positions specified in its input data.
+ * The rendered surface is colored using the scalar values that were probed in the source volume.
+ * The mapper accepts three inputs: the Input, the Source and an optional ProbeInput.
+ * The Source data defines the vtkImageData from which scalar values are interpolated.
+ * The Input data defines the rendered surface.
+ * The ProbeInput defines the geometry used to interpolate the source data.
+ * If the ProbeInput is not specified, the Input is used both for probing and rendering.
+ *
+ * Projecting the scalar values from the ProbeInput to the Input is done thanks to texture
+ * coordinates. Both inputs must provide texture coordinates in the [0, 1] range.
+ *
+ * The sampled scalar values can be computed with different blending strategy that use surface
+ * normals to perform thick probing of the Source data.
+ *
+ * @note The following features are not supported yet but should be considered in the future.
+ *
+ * - The volume texture is always uploaded using linear interpolation.
+ *   The public API could provide a setter to use nearest neighbor interpolation instead.
+ *
+ * - If the source is rendered by a volume mapper, any transform applied to the volume
+ *   is ignored as there is no interface to pass this information.
+ *
+ * - Only the first scalar component is used for rendering and rescaled with Window/Level.
+ *   Consider supporting RGB volumes without W/L mapping, and independent component.
+ *   Consider supporting Color and opacity transfer function to replace W/L mapping.
+ *
+ * Passing a vtkVolumeProperty to this mapper should be considered to address the above points.
+ *
+ * - A background value of (0, 0, 0, 0) is used when probing outside the volume, but this
+ *   parameters could be exposed in the public API
+ *
+ * - A step value corresponding to the half of the minimum spacing value of the source is used for
+ *   blend modes, but it could be configured from the public API.
+ */
+
+#ifndef vtkOpenGLSurfaceProbeVolumeMapper_h
+#define vtkOpenGLSurfaceProbeVolumeMapper_h
+
+#include "vtkNew.h" // For vtkNew
+#include "vtkOpenGLPolyDataMapper.h"
+#include "vtkRenderingVolumeOpenGL2Module.h" // For export macro
+
+VTK_ABI_NAMESPACE_BEGIN
+class vtkOpenGLFramebufferObject;
+class vtkOpenGLRenderWindow;
+class vtkTextureObject;
+class vtkVolumeTexture;
+
+class VTKRENDERINGVOLUMEOPENGL2_EXPORT vtkOpenGLSurfaceProbeVolumeMapper
+  : public vtkOpenGLPolyDataMapper
+{
+public:
+  static vtkOpenGLSurfaceProbeVolumeMapper* New();
+  vtkTypeMacro(vtkOpenGLSurfaceProbeVolumeMapper, vtkOpenGLPolyDataMapper);
+
+  ///@{
+  /**
+   * Specify the input data used for probing (optional).
+   * If no probe data is specified, the input is used.
+   */
+  void SetProbeInputData(vtkPolyData* in);
+  vtkPolyData* GetProbeInput();
+  void SetProbeInputConnection(vtkAlgorithmOutput* algOutput);
+  ///@}
+
+  ///@{
+  /**
+   * Specify the input data to be probed.
+   */
+  void SetSourceData(vtkImageData* in);
+  vtkImageData* GetSource();
+  void SetSourceConnection(vtkAlgorithmOutput* algOutput);
+  ///@}
+
+  ///@{
+  /**
+   * Set/Get the current window and level values used for scalar coloring.
+   */
+  vtkGetMacro(Window, double);
+  vtkSetMacro(Window, double);
+
+  vtkGetMacro(Level, double);
+  vtkSetMacro(Level, double);
+  ///@}
+
+  ///@{
+  /**
+   * Set/Get the blend mode.
+   * Default is none.
+   *
+   * \sa vtkVolumeMapper::GetBlendMode()
+   */
+  enum class BlendModes : unsigned int
+  {
+    NONE = 0,
+    MAX,
+    MIN,
+    AVERAGE
+  };
+
+  vtkGetEnumMacro(BlendMode, BlendModes);
+  vtkSetEnumMacro(BlendMode, BlendModes);
+  void SetBlendModeToNone() { this->SetBlendMode(BlendModes::NONE); }
+  void SetBlendModeToMaximumIntensity() { this->SetBlendMode(BlendModes::MAX); }
+  void SetBlendModeToMinimumIntensity() { this->SetBlendMode(BlendModes::MIN); }
+  void SetBlendModeToAverageIntensity() { this->SetBlendMode(BlendModes::AVERAGE); }
+  ///@}
+
+  ///@{
+  /**
+   * Set/Get the blend width in world coordinates.
+   */
+  vtkGetMacro(BlendWidth, double);
+  vtkSetMacro(BlendWidth, double);
+  ///@}
+
+  void RenderPiece(vtkRenderer* ren, vtkActor* act) override;
+
+  void UpdateShaders(vtkOpenGLHelper& cellBO, vtkRenderer* ren, vtkActor* act) override;
+
+protected:
+  int FillInputPortInformation(int port, vtkInformation* info) override;
+
+  virtual void ReplaceShaderPositionPass(vtkActor* act);
+  virtual void ReplaceShaderProbePass(vtkActor* act);
+  virtual void UpdateShadersProbePass(vtkOpenGLHelper& cellBO, vtkRenderer* ren);
+
+private:
+  vtkOpenGLSurfaceProbeVolumeMapper();
+  ~vtkOpenGLSurfaceProbeVolumeMapper() override = default;
+
+  void CreateTexture(vtkTextureObject*, vtkOpenGLRenderWindow*);
+  void ReplaceActiveFBO(vtkRenderer*);
+  void RestoreActiveFBO(vtkRenderer*);
+
+  vtkNew<vtkOpenGLFramebufferObject> FBO;
+
+  vtkNew<vtkTextureObject> PositionsTextureObject;
+  vtkNew<vtkTextureObject> NormalsTextureObject;
+  vtkNew<vtkVolumeTexture> VolumeTexture;
+
+  vtkNew<vtkImageData> TransformedSource;
+
+  // Internal pass type used for shader updates
+  enum class PassTypes : unsigned int
+  {
+    DEFAULT = 0,
+    POSITION_TEXTURE,
+    PROBE
+  };
+  PassTypes CurrentPass = PassTypes::DEFAULT;
+
+  // Window / level
+  double Window = 1.0;
+  double Level = 0.0;
+
+  // Blend mode
+  BlendModes BlendMode = BlendModes::NONE;
+  double BlendWidth = 1.0;
+
+  // Saved state
+  bool SavedScissorTestState = false;
+  bool SavedBlendState = false;
+  int SavedViewport[4] = {};
+};
+
+VTK_ABI_NAMESPACE_END
+#endif