b2dClearCanvasFilter

Clears active canvas filter (reverts to default rendering, subsequent draw commands render to screen). Takes no parameters. Returns nothing. Sets g_activeCanvasFilter = -1 (clears active canvas, reverts to default rendering), restores dimensions (g_currentState width/height restored to current render target or main 3D window). Use to revert to screen rendering (after rendering to canvas, return to normal overlay rendering), finish render-to-texture pass (complete canvas rendering, switch back to screen), or reset state (ensure default rendering before next frame). Clear behavior: clears canvas ID (g_activeCanvasFilter set to -1, disables canvas filtering), restores dimensions (g_currentState width/height restored from g_2D_currentRenderTarget or g_3D_resolutionWidth/Height), affects subsequent draws (all b2d draw commands after this render to default target), doesn't affect canvas contents (canvas texture preserved, just stops rendering to it). Use cases: (1) Finish canvas rendering (b2dClearCanvasFilter() after drawing to canvas, switch back to screen), (2) Multi-pass workflow (b2dSetCanvasFilter(canvas1): draw layer1, b2dClearCanvasFilter(): draw layer2 to screen), (3) Reset state (b2dClearCanvasFilter() at frame start to ensure default rendering), (4) Conditional rendering (If renderToCanvas Then b2dSetCanvasFilter(canvas) Else b2dClearCanvasFilter()), (5) Restore after error (b2dClearCanvasFilter() in error handler to recover rendering state). Common patterns: clear = b2dClearCanvasFilter() revert to default; pair = b2dSetCanvasFilter(canvas): draw: b2dClearCanvasFilter() complete workflow. Typical workflow: set canvas filter (b2dSetCanvasFilter(canvas) activate canvas rendering), draw to canvas (b2d draw commands render to canvas texture), clear filter (this function, revert to default), draw canvas (draw canvas texture to screen using bgi functions or bind to 3D entity), repeat (cycle through multiple canvases or passes). Dimension restoration: checks custom render target (if g_2D_currentRenderTarget != 0, uses that target's dimensions from g_images map), uses main window dimensions (if default render target, uses g_3D_resolutionWidth/Height), ensures correct coordinates (draw commands use appropriate dimensions for coordinate space after clear). Default render target: main 3D window (screen dimensions g_3D_resolutionWidth/Height, overlay rendered on top of 3D scene), current render target (if custom render target active via g_2D_currentRenderTarget, uses that target's dimensions), coordinate space (0,0=top-left, width,height=bottom-right of target). Performance: clear cost zero (canvas ID assignment and dimension restore, trivial CPU operation), render target switch minimal (GPU render target change, ~0.01ms overhead), safe to call anytime (no GPU sync, instant state change). Validation: no parameters (nothing to validate, always succeeds), safe to call multiple times (clearing already-cleared state harmless, no-op), safe to call without prior set (clearing when no canvas active is harmless). Related: b2dSetCanvasFilter sets canvas filter (activates canvas as render target, pair with this function), bgiCreateCanvas creates canvas (creates offscreen texture used with canvas filter), bgiGetCanvasWidth queries canvas width (used by SetCanvasFilter to update dimensions), bgiGetCanvasHeight queries canvas height (used by SetCanvasFilter to update dimensions).