inpGetMouseYSpeed

Returns vertical mouse movement delta since last frame. Takes no parameters. Returns integer delta Y (vertical movement in pixels, positive=moved down, negative=moved up, 0=no vertical movement). Calculates mouse movement between current and previous frame, useful for mouse look and camera control.

Delta calculation: delta = current frame Y - previous frame Y, positive values=mouse moved down (downward motion, screen coordinates), negative values=mouse moved up (upward motion), 0=no vertical movement (stationary or horizontal-only movement), resets to 0 when mouse stationary (no accumulation).

Use cases: (1) Mouse look/camera control (rotate camera vertically based on mouse movement: cameraPitch#=cameraPitch#-inpGetMouseYSpeed()*sensitivity#), (2) First-person controls (FPS games, flight simulators, vertical camera rotation), (3) 3D object rotation (rotate model with mouse drag: rotationX#=rotationX#-inpGetMouseYSpeed()), (4) Gesture detection (detect swipe up/down based on speed threshold), (5) Smooth tracking (integrate small movements for precise control).

Common patterns: mouse look = pitch#=pitch#-inpGetMouseYSpeed()*0.1 (rotate camera vertically, note negative for inverted Y); drag rotation = If inpIsMouseDown(0) Then objectRotX#=objectRotX#-inpGetMouseYSpeed(); movement threshold = If mathAbs(inpGetMouseYSpeed())>10 Then significant movement detected; scroll = scrollOffset#=scrollOffset#-inpGetMouseYSpeed()*scrollSpeed#.

Inverted Y-axis: note negative sign in mouse look (pitch -= deltaY, not +=), convention for FPS games (move mouse up = look up, requires negative delta), screen Y increases downward (positive deltaY = mouse moved down), camera pitch often inverted (moving mouse down should look down, not up), user preference option recommended (some players prefer non-inverted Y).

Mouse look implementation: hide cursor with inpHidePointer (prevent cursor hitting screen edge), re-center mouse each frame with inpMoveMouse(centerX, centerY) (infinite rotation, prevents edge stops), multiply delta by sensitivity (speedY * sensitivity = rotation amount), accumulate into camera rotation (pitch += deltaY, clamp pitch to prevent gimbal lock).

Pitch clamping: typical FPS games clamp pitch to -89 degrees to +89 degrees (prevent flipping upside-down), prevent gimbal lock at vertical (straight up/down causes rotation issues), pattern: pitch#=pitch#-inpGetMouseYSpeed()*sensitivity#: If pitch#<-89.0 Then pitch#=-89.0: If pitch#>89.0 Then pitch#=89.0.

Sensitivity tuning: raw delta often too large (multiply by 0.05-0.2 for comfortable sensitivity), higher sensitivity = faster camera movement (larger multiplier), lower sensitivity = precise control (smaller multiplier), user-configurable sensitivity recommended (different players prefer different speeds).

Performance: very fast query (~0.0001ms, simple subtraction), safe for per-frame calls (intended usage, must call every frame for accurate deltas), no input polling required (system tracks mouse automatically).

Delta range: typically -50 to +50 pixels per frame at 60 FPS (normal mouse movement), can exceed 100+ for fast movements (quick flicks or high DPI mice), 0 most common value (mouse often stationary or horizontal-only movement), extreme values possible (rapid movements or input lag).

Related: inpGetMouseXSpeed returns horizontal movement delta, inpGetMouseX/Y return absolute cursor position, inpMoveMouse sets cursor position programmatically, inpHidePointer/ShowPointer control cursor visibility.