Package com.openinventor.inventor

Class SoOffscreenRenderArea

java.lang.Object
com.openinventor.inventor.Inventor
com.openinventor.inventor.SoOffscreenRenderArea
All Implemented Interfaces:
SafeDisposable, SiRenderArea, SiRenderAreaAntialiasing, SiRenderAreaTransparency
public class SoOffscreenRenderArea extends Inventor implements SiRenderArea, SiRenderAreaAntialiasing, SiRenderAreaTransparency, SafeDisposable
Render to an off-screen buffer for printing or generating textures. This class is used to render a scene graph and to write the the result into a file or a buffer.

This is not a screen capture class. The specified scene graph is rendered to generate an image. This allows generation of images larger (higher resolution) than the user's screen and/or using different (e.g. higher quality) rendering parameters. The offscreen rendering may take more or less time than the same rendering on screen.

The renderer can render very large images because it is able to render the scene as multiple "tiles" and assemble the tiles into a complete image. Of course this requires multiple render traversals of the specified scene graph (one for each tile).

Rendering a "snapshot":

Your application may want to render the same image that the user sees on the screen. There are several things to consider. First, the scene graph given to the renderer must include the camera node that the viewer is using. If the application allows the viewer to create a camera automatically, the scene graph returned by the viewer's getSceneGraph() method does not include the camera. It's always safer to get the SoSceneManager object then get the scene graph. Second, some rendering options are set on the viewer object, not in the scene graph. These options, which include background color and transparency mode, must be explicitly queried from the viewer and set on the renderer object.

Notes & Limitations:

  • The default tile size is set to the maximum viewport size supported by the hardware (GL_MAX_VIEWPORT_DIMS), which means that tiling will be enabled only when large viewport sizes are requested.
  • When tiling is enabled, the elements SoViewportRegionElement, SoLogicalViewportElement and SoModifyViewVolumeElement are set with different values for each tile, which means that scenegraphs that manage sub-viewports will need to take these elements into account in order for the final rendering to be correct.
  • Maximum output image size is 25000 x 25000 pixels.

    EXAMPLE 

 SoOffscreenRenderArea myOffscreen = new SoOffscreenRenderArea();
 // Set the size of the output
 myOffscreen.setSize( new SbVec2i32( 15360, 8640 ) );
 // Set the sceneGraph to render
 myOffscreen.setSceneGraph(mySceneGraph);
 // If you want to render by tile
 if ( tileRendering )
   myOffscreen.setTile(new SbVec2i32(3840, 2160), 2);
 
 // Specify the color of the clear performed before rendering, here clear with white color
 myOffscreen.setClearColor( new SbColorRGBA(1.f, 1.f, 1.f, 1.f) );
 
 // Save the render as a PNG file
 // Specify that we also want to write the alpha component
 myOffscreen.renderToFile("result.png", SoOffscreenRenderArea.OutputFormats.RGBA);
 
 // Save the render in a buffer
 myOffscreen.renderToBuffer(myBuffer);

Since:
Open Inventor 10.0

  • Field Details

  • Constructor Details

    • SoOffscreenRenderArea

      public SoOffscreenRenderArea(SoGLContext glContex)
      Builds a new offscreen render area by sharing the given SoGlContext.

    • SoOffscreenRenderArea

      public SoOffscreenRenderArea()
      Default constructor. NOTE: An internally created SoGLContext will be shared with the current context or an existing one if possible. In order to have control over the SoGLContext sharing, use the alternate constructor.

    • SoOffscreenRenderArea

      public SoOffscreenRenderArea(SoRenderAreaCore renderAreaCore)
      Builds a new offscreen render area by using the given renderAreaCore. Any following call to setSceneGraph will change the scene graph used by this instance.

  • Method Details

    • onStartRender

      public SbEventHandler<SiRenderArea.RenderEventArg> onStartRender()
      Returns the event handler that raises when a new render starts.
      Specified by:
      onStartRender in interface SiRenderArea

    • isDisposable

      public boolean isDisposable()
      Description copied from interface: SafeDisposable
      Returns a boolean flag which indicates if it is safe to call SafeDisposable.dispose() on the object.
      Specified by:
      isDisposable in interface SafeDisposable
      Returns:
      true if the object can be disposed in a safe manner

    • renderToBuffer

      public boolean renderToBuffer(SoBufferObject buffer)
      Calls renderToBuffer(buffer, SoOffscreenRenderArea.OutputFormats.valueOf( SoOffscreenRenderArea.OutputFormats.RGB.getValue() )).

    • renderToFile

      public boolean renderToFile(String filename)
      Calls renderToFile(filename, SoOffscreenRenderArea.OutputFormats.valueOf( SoOffscreenRenderArea.OutputFormats.RGB.getValue() )).

    • dispose

      public boolean dispose()
      Description copied from class: Inventor
      Explicitly call this method to force object to dispose its unmanaged resources. The object may not be reused in the application code after this call.
      Specified by:
      dispose in interface SafeDisposable
      Overrides:
      dispose in class Inventor
      Returns:
      true if this object native resources were successfully disposed; false if it was already disposed or no native resources has been registered for this object.

    • setTransparencyType

      public void setTransparencyType(SoGLRenderAction.TransparencyTypes type)
      Defines the algorithm for rendering transparent objects. Default is NO_SORT. See SoGLRenderAction for possible transparency types. See also SoGLRenderAction.TransparencyType.

      Note: When using OPAQUE_FIRST, SORTED_OBJECT or SORTED_PIXEL transparency, the depth buffer is not updated (depth buffer writes are disabled) while rendering transparent objects. As a result complex 3D shapes may not be rendered correctly.

      Specified by:
      setTransparencyType in interface SiRenderAreaTransparency

    • getViewportRegion

      public SbViewportRegion getViewportRegion()
      See Also:

    • render

      public SiRenderArea.RenderStatus render()
      Performs an offscreen rendering of the scene graph without saving the result. This method initiates the rendering process but does not store the resulting image in any buffer or file. It is useful for scenarios where only the rendering process is required, such as for benchmarking or updating the internal state of the scene without needing to keep the rendered output.

      Unlike renderToFile, which saves the rendered image to a provided buffer object, or renderToBuffer, which writes the rendered image directly to a file, this method does not retain the rendered image in any form.

      Specified by:
      render in interface SiRenderArea

    • getTransparencyType

      public SoGLRenderAction.TransparencyTypes getTransparencyType()
      Specified by:
      getTransparencyType in interface SiRenderAreaTransparency
      See Also:

    • setAntialiasingQuality

      public void setAntialiasingQuality(float quality)
      Define the antialiasing quality value.

      Specified by:
      setAntialiasingQuality in interface SiRenderAreaAntialiasing
      Parameters:
      quality - The quality is a factor in the range [0.0,1.0].
      Default is 0.0. The value 0.0 turns off antialiasing.

    • getSceneManager

      public SoSceneManager getSceneManager()
      Returns the encapsulated scene manager.

    • getAntialiasingQuality

      public float getAntialiasingQuality()
      Specified by:
      getAntialiasingQuality in interface SiRenderAreaAntialiasing
      See Also:

    • getMaxTileSize

      public static SbVec2i32 getMaxTileSize()
      Gets the maximum subimage (tile) size for rendering.

    • setClearPolicy

      public void setClearPolicy(SiRenderArea.ClearPolicies policy)
      Defines the color buffer and depth buffer clear policy. Default value is ClearPolicy.COLORBUFFER_AND_DEPTHBUFFER. Effects such as motion blur can be created by disabling clear color buffer or depth buffer. . See also setClearColor and setClearDepth.

      Specified by:
      setClearPolicy in interface SiRenderArea
      Parameters:
      policy - color buffer and depth buffer clear policy.

    • setViewportRegion

      public void setViewportRegion(SbViewportRegion newRegion)
      Defines viewport region (within the image) to use for rendering.

    • getSceneGraph

      public SoNode getSceneGraph()
      Specified by:
      getSceneGraph in interface SiRenderArea
      See Also:

    • setSceneGraph

      public void setSceneGraph(SoNode newScene)
      Defines the scene graph which will be traversed for rendering.
      Specified by:
      setSceneGraph in interface SiRenderArea
      Parameters:
      newScene - scene graph.

    • getSize

      public SbVec2i32 getSize()
      Specified by:
      getSize in interface SiRenderArea
      See Also:

    • setClearColor

      public void setClearColor(SbColorRGBA color)
      Defines the RGBA value used when the color buffer is cleared. Default is transparent black (0,0,0,0). This is the value used to clear the color buffer when renderToFile() or renderToBuffer() are called with setClearPolicy() method set to COLORBUFFER or COLORBUFFER_AND_DEPTHBUFFER . See also setClearPolicy.

      Specified by:
      setClearColor in interface SiRenderArea
      Parameters:
      color - RGBA value used to clear the color buffer.

    • getClearPolicy

      public SiRenderArea.ClearPolicies getClearPolicy()
      Specified by:
      getClearPolicy in interface SiRenderArea
      See Also:

    • setGLRenderAction

      public void setGLRenderAction(SoGLRenderAction glAction)
      Defines the render action used for rendering.

    • getClearDepth

      public float getClearDepth()
      Specified by:
      getClearDepth in interface SiRenderArea
      See Also:

    • setClearDepth

      public void setClearDepth(float depth)
      Defines the depth value used when the depth buffer is cleared. The default value is 1. This is the value used to clear the depth buffer when renderToFile() or renderToBuffer() are called with setClearPolicy() method set to DEPTHBUFFER or COLORBUFFER_AND_DEPTHBUFFER . See also setClearPolicy.

      Specified by:
      setClearDepth in interface SiRenderArea
      Parameters:
      depth - value used to clear the depth buffer. Value is clamped to the range [0,1].

    • setSize

      public void setSize(SbVec2i32 size)
      Defines the image size to use for rendering.
      Specified by:
      setSize in interface SiRenderArea

    • getClearColor

      public SbColorRGBA getClearColor()
      Specified by:
      getClearColor in interface SiRenderArea
      See Also:

    • setAntialiasingMode

      public void setAntialiasingMode(SoSceneManager.AntialiasingModes mode)
      Define the antialiasing mode.

      Specified by:
      setAntialiasingMode in interface SiRenderAreaAntialiasing
      Parameters:
      mode - The antialiasing algorithm. Default is NO_ANTIALIASING which turns off antialiasing.

    • renderToBuffer

      public boolean renderToBuffer(SoBufferObject buffer, SoOffscreenRenderArea.OutputFormats outputFormat)
      Render the given scene graph and save the result in the given buffer. The buffer is resized if its current size is not equal to the the necessary size to store the rendering result.

      If your application needs more control over creation of an output file, the SoBufferObject can be converted into an SbRasterImage using the appropriate constructor. Once instantiated, the SbRasterImage can be passed as a parameter to the write function of any class inheriting from SoRasterImageRW (SoJPEGImageRW for example to generate a JPEG file).

      Parameters:
      buffer - stores the result of the rendering.

      outputFormat - defines which components to write to the output. If set to RGBA, the alpha component of the rendering is also written to the buffer.

    • getAntialiasingMode

      public SoSceneManager.AntialiasingModes getAntialiasingMode()
      Specified by:
      getAntialiasingMode in interface SiRenderAreaAntialiasing
      See Also:

    • renderToFile

      public boolean renderToFile(String filename, SoOffscreenRenderArea.OutputFormats outputFormat)
      Render the given scene graph and save the result in the given file. The format of the generated image is chosen automatically according to the file extension. Returns true if successful.

      If your application needs more control over creation of the file, please see the renderToBuffer() method.

      Supported file types are:

        extension file (case insensitive) raster image type Alpha Component Support
        .bmp Windows bitmap YES
        .dds DirectDraw surface YES
        .gif Graphics Interchange Format YES
        .hdr hdr NO
        .jp2, .j2c, .j2k, .jpc, .jpx, .ecw, .ecwp jpeg 2000 YES
        .jpg, .jpeg, .jif, .jfif Joint Photographic Experts Group NO
        .png Portable Network Graphics YES
        .ps PostScript NO
        .rgb .sgi sgi YES
        .tif .tiff Tagged Image File Format YES

      Parameters:
      filename - path and name of the image file to be generated. If the file extension is not one of the above type, no file is generated.

      outputFormat - defines which components to write to the output. If set to RGBA, the alpha component of the rendering is also written to the file. However if the targeted file type does not support alpha component, the file will be generated with RGB components only. See the 3rd column of the above table.

    • getNumEdgePixels

      public int getNumEdgePixels()
      See Also:

    • getGLRenderAction

      public SoGLRenderAction getGLRenderAction()
      Returns the render action used for rendering.

    • setTile

      public void setTile(SbVec2i32 size, int numEdgePixels)
      Defines the maximum sub-image (tile) size for rendering and the number of pixels on the border of each sub-image that are not written on the final image. The default tile size is set to the maximum viewport size supported by the hardware (GL_MAX_VIEWPORT_DIMS) and can be queried using the getMaxTileSize() method. The default value for the number of edge pixels is 2 pixels.

      Edge pixels are usually required to avoid visual "artifacts" at the subimage boundaries. One source of artifacts is that when OpenGL clips lines, it draws a line between the points where the line exits and re-enters the visible region. This additional segment is not part of the actual geometry. A two pixel border will hide this undesired segment unless the line width is greater than two, in which case you may need to specify a larger number of edge pixels.

      Parameters:
      size - is dimension of the tile.

      numEdgePixels - is the number of pixels on the edge of the tile which will not be included in the final image.

    • getTileSize

      public SbVec2i32 getTileSize()
      See Also: