Package eu.svjatoslav.sixth.e3d.gui

Class RenderingContext

java.lang.Object
eu.svjatoslav.sixth.e3d.gui.RenderingContext
Direct Known Subclasses:
SegmentRenderingContext
public class RenderingContext extends Object
Contains all state needed to render a single frame: the pixel buffer, graphics context, screen dimensions, and mouse event tracking.

A new RenderingContext is created whenever the view panel is resized. During rendering, shapes use this context to:

The context also manages mouse interaction detection: as shapes are painted back-to-front, each shape can report itself as the object under the mouse cursor. After painting completes, the topmost shape receives the mouse event.

See Also:

  • Field Details

    • bufferedImageType

      public static final int bufferedImageType
      The BufferedImage pixel format used for the rendering buffer. TYPE_INT_RGB provides optimal performance for Java2D blitting.
      See Also:

    • numRenderSegments

      public final int numRenderSegments
      Number of horizontal segments (bands) for parallel rendering. Bands are finer than the paint thread count: paint threads steal bands off a shared ticket until all bands are done, so a thread that finishes a cheap band immediately picks up more work. Derived from the render thread count via ViewPanel.setNumRenderThreads(int).

      Equals tilesX * tilesY * viewportCount: the tile grid covers one viewport, and in stereo mode a second grid covers the other eye (segment indices for the right eye start at tilesX * tilesY).

    • tilesX

      public final int tilesX
      Tile columns per viewport (1 = horizontal bands only).

    • tilesY

      public final int tilesY
      Tile rows per viewport.

    • viewportCount

      public final int viewportCount
      Number of side-by-side viewports (2 in stereo mode, else 1).

    • graphics

      public final Graphics2D graphics
      Java2D graphics context for drawing text, anti-aliased shapes, and other high-level graphics operations onto the render buffer.

    • pixels

      public final int[] pixels
      Pixels of the rendering area. Each pixel is a single int in RGB format: (r << 16) | (g << 8) | b.

    • width

      public final int width
      Width of the rendering area in pixels.

    • height

      public final int height
      Height of the rendering area in pixels.

    • centerCoordinate

      public final Point2D centerCoordinate
      Center of the screen in screen space (pixels). This is the point where (0,0) coordinate of the world space is rendered.

    • projectionScale

      public double projectionScale
      Scale factor for perspective projection, derived from screen width. Used to convert normalized device coordinates to screen pixels. This is mutable to support stereo rendering where each eye has a different viewport width.

    • renderMinY

      public final int renderMinY
      Minimum Y coordinate (inclusive) to render. Used for multi-threaded rendering where each thread renders a horizontal segment.

    • renderMaxY

      public final int renderMaxY
      Maximum Y coordinate (exclusive) to render. Used for multi-threaded rendering where each thread renders a horizontal segment.

    • transformCycleId

      public long transformCycleId
      Unique id of the current transform cycle, assigned by ShapeCollection.transformShapes() from a global counter. Unlike frameNumber (per-context, can repeat across context instances), this never collides, so per-cycle memoization such as composite subtree weights can safely key on it.

    • vertexSlot

      public int vertexSlot
      Which projection buffer slot this context writes/reads: 0, 1 or 2. Cycles per render pass (per eye in stereo) when the triple-buffered pipeline is active, so the transform phase of a pass never overwrites the vertex state either of the two previous passes' paints may still be reading. Always 0 when the pipeline is off (tests, single-pass rendering).

    • nearPlaneDistance

      public double nearPlaneDistance
      Near-plane distance in camera-space Z units. Polygons whose vertices straddle this plane are clipped against it (new intersection vertices are generated with interpolated UVs); polygons fully behind it are culled. Must be > 0 so the perspective divide stays safe.

    • frameNumber

      public int frameNumber
      Number of frame that is currently being rendered. Every frame has its own number.

    • developerTools

      public DeveloperTools developerTools
      Developer tools for this rendering context. Controls diagnostic features like logging and visualization.

    • debugLogBuffer

      public DebugLogBuffer debugLogBuffer
      Debug log buffer for capturing diagnostic output. Shapes can log messages here that appear in the Developer Tools panel.

    • lightingManager

      public LightingManager lightingManager
      Global lighting manager for the scene. All shaded polygons use this to calculate lighting. Contains all light sources and ambient light settings for the world.

    • stereoEye

      public StereoEye stereoEye
      Which eye is being rendered in stereo mode. NONE for normal single-view rendering.

    • stereoViewportWidth

      public int stereoViewportWidth
      Width of the viewport for the current eye in stereo mode. Equals width when not in stereo mode.

    • stereoViewportOffsetX

      public int stereoViewportOffsetX
      X offset of the current eye's viewport within the full buffer. 0 for left eye, width/2 for right eye, 0 in normal mode.

    • renderMinX

      public int renderMinX
      Minimum X coordinate (inclusive) for rendering. In stereo mode, this is stereoViewportOffsetX. In normal mode, this is 0.

    • renderMaxX

      public int renderMaxX
      Maximum X coordinate (exclusive) for rendering. In stereo mode, this is stereoViewportOffsetX + stereoViewportWidth. In normal mode, this is width.

    • frustum

      public Frustum frustum
      View frustum for frustum culling. Updated each frame from camera state and screen dimensions. Shapes can test their bounding boxes against this frustum to determine if they are potentially visible before expensive vertex transformations.

    • viewerPosition

      public final Point3D viewerPosition
      World-space position of the viewer for this pass, copied from the camera in ShapeCollection.transformShapesBegin(eu.svjatoslav.sixth.e3d.gui.ViewPanel, eu.svjatoslav.sixth.e3d.gui.RenderingContext). Used by BSP painter ordering (viewpoint for tree traversal). Fresh instance per context, including per-pass copies, so overlapping pipeline passes each see their own viewpoint.

    • cullingStatistics

      public CullingStatistics cullingStatistics
      Statistics for frustum culling performance tracking. Updated each frame: total shapes counted at start, visible shapes incremented during rendering, culled composites tracked during transform.

    • transformExecutor

      public ExecutorService transformExecutor
      Executor for the parallel transform phase. When non-null, composites with enough children split their render lists into chunks transformed concurrently. When null, the transform phase runs serially on the render thread.

    • transformCoordinator

      public ParallelTransformCoordinator transformCoordinator
      Per-frame coordinator for the non-blocking parallel transform fork. Set by ShapeCollection.transformShapes() for the duration of the root transform when transformExecutor is available; composites at any nesting level submit chunk tasks to it. Null outside the transform phase and when transforming serially.

    • presentGate

      public volatile CountDownLatch presentGate
      Present gate for this framebuffer: fires when the frame currently held in this buffer has been presented to the display (or dropped from the presentation mailbox). The render thread installs a fresh gate at the start of each frame that reuses the buffer, and the frame's paint continuation awaits the PREVIOUS gate before writing pixels — without it, painting frame F+3 would overwrite the buffer while the present thread is still blitting frame F from it.

    • lastTransformTaskCount

      public int lastTransformTaskCount
      Chunk tasks submitted during the last transform phase, across all nesting levels. Diagnostics: proves nested composites forked.

  • Constructor Details

    • RenderingContext

      public RenderingContext(int width, int height, int numRenderSegments)
      Creates a new rendering context for full-screen rendering.

      Equivalent to RenderingContext(width, height, 0, height, numRenderSegments).

      Parameters:
      width - the rendering area width in pixels
      height - the rendering area height in pixels
      numRenderSegments - number of parallel render segments (threads)

    • RenderingContext

      public RenderingContext(int width, int height, int tilesX, int tilesY, int viewportCount)
      Creates a new rendering context with a rectangular tile grid.

      Equivalent to the band-only constructors when tilesX == 1. In stereo mode (viewportCount == 2) each viewport gets its own tile grid; segment indices for viewport v start at v * tilesX * tilesY.

      Parameters:
      width - the rendering area width in pixels
      height - the rendering area height in pixels
      tilesX - tile columns per viewport (1 = bands only)
      tilesY - tile rows per viewport
      viewportCount - number of side-by-side viewports (2 = stereo)

    • RenderingContext

      protected RenderingContext(RenderingContext parent, int renderMinY, int renderMaxY)
      Protected constructor for creating segment views. Shares the pixel buffer and graphics context with the parent.
      Parameters:
      parent - the parent rendering context
      renderMinY - minimum Y coordinate (inclusive) for this segment
      renderMaxY - maximum Y coordinate (exclusive) for this segment

    • RenderingContext

      public RenderingContext(RenderingContext parent)
      Creates an independent pass context for one pipeline pass (one eye in stereo): shares the frame's pixel buffer, graphics and services, but owns the per-pass projection fields (center, scale, stereo viewport, slot, frame/cycle stamps). The next pass's setup writes to its own copy, so it cannot disturb this pass's in-flight transform chunks or its asynchronous sort/bin/paint continuation.
      Parameters:
      parent - the frame rendering context to copy from

  • Method Details

    • prepareForNewFrameRendering

      public void prepareForNewFrameRendering()
      Resets per-frame state in preparation for rendering a new frame. Increments the frame number and clears the mouse event state.

    • getImage

      public BufferedImage getImage()
      Returns the backing image whose pixel buffer the rasterizer paints into.

      Exposed for headless rendering: after a transform/sort/paint pass the image holds the finished frame and can be saved or compared directly.

      Returns:
      the backing buffered image

    • getSegmentGraphics

      public Graphics2D getSegmentGraphics(int segmentIndex)
      Returns the Graphics2D context for a specific render segment. Each segment's Graphics2D is pre-clipped to its Y bounds.
      Parameters:
      segmentIndex - the segment index (0 to numRenderSegments-1)
      Returns:
      the Graphics2D for that segment
      Throws:
      NullPointerException - if called on a segment view (not the main context)

    • dispose

      public void dispose()
      Disposes all Graphics2D resources associated with this context. Should be called when the context is no longer needed (e.g., on resize).

    • executeWithGraphics

      public void executeWithGraphics(Consumer<Graphics2D> operation)
      Executes a graphics operation in a thread-safe manner. This must be used for all Graphics2D operations (text, lines, etc.) during multi-threaded rendering.
      Parameters:
      operation - the graphics operation to execute

    • getMouseEvent

      public MouseEvent getMouseEvent()
      Returns the pending mouse event for this frame, or null if none.
      Returns:
      the mouse event to process, or null

    • setMouseEvent

      public void setMouseEvent(MouseEvent mouseEvent)
      Sets the mouse event to be processed during this frame's rendering.
      Parameters:
      mouseEvent - the mouse event with position and button information

    • setCurrentObjectUnderMouseCursor

      public void setCurrentObjectUnderMouseCursor(MouseInteractionController currentObjectUnderMouseCursor)
      Called when given object was detected under mouse cursor, while processing mouseEvent. Because objects are rendered back to front. The last method caller will set the top-most object, if there are multiple objects under mouse cursor.
      Parameters:
      currentObjectUnderMouseCursor - the object that is currently under the mouse cursor

    • getCurrentObjectUnderMouseCursor

      public MouseInteractionController getCurrentObjectUnderMouseCursor()
      Returns the current object under the mouse cursor. Used by segment rendering to collect mouse results.
      Returns:
      the current object under mouse cursor, or null

    • handlePossibleComponentMouseEvent

      public boolean handlePossibleComponentMouseEvent()
      Handles mouse events for components and returns whether a view repaint is needed.
      Returns:
      true if view update is needed as a consequence of this mouse event