Editing Openai/690e4c4b-5530-800d-ae72-e702400813d4 (section)

=== Assistant: Excellent — let’s add smooth easing so the velocity bar decays naturally toward zero when you stop turning the crank. ===
Excellent — let’s add smooth easing so the velocity bar decays naturally toward zero when you stop turning the crank.

This version adds a small physics-style damping effect for realism — so when you stop turning, the velocity bar “coasts” back smoothly to center.

<syntaxhighlight lang="lua">-- main.lua
import "CoreLibs/graphics"
import "CoreLibs/timer"

local gfx = playdate.graphics

local W, H = 400, 240
local CX, CY = W/2, H/2
local RADIUS = 70

-- Crank tracking
local lastCrank = playdate.getCrankPosition()
local lastTime = playdate.getCurrentTimeMilliseconds()
local crankVelocity = 0
local displayedVelocity = 0
local direction = 0  -- 1 = clockwise, -1 = counterclockwise, 0 = still

-- Damping factor for easing (lower = slower return to zero)
local damping = 0.15

-- Helper: draw dial tick marks
local function drawDial(cx, cy, radius)
    for deg = 0, 330, 30 do
        local rad = math.rad(deg)
        local x1 = cx + math.cos(rad) * (radius - 8)
        local y1 = cy + math.sin(rad) * (radius - 8)
        local x2 = cx + math.cos(rad) * radius
        local y2 = cy + math.sin(rad) * radius
        gfx.drawLine(x1, y1, x2, y2)
    end
end

function playdate.update()
    gfx.clear()

    local now = playdate.getCurrentTimeMilliseconds()
    local crank = playdate.getCrankPosition()
    local deltaAngle = crank - lastCrank

    -- Handle wrap-around (359° → 0°)
    if deltaAngle > 180 then deltaAngle = deltaAngle - 360 end
    if deltaAngle < -180 then deltaAngle = deltaAngle + 360 end

    -- Time delta in seconds
    local dt = (now - lastTime) / 1000
    if dt > 0 then
        crankVelocity = deltaAngle / dt  -- degrees per second
    end

    -- Direction
    if deltaAngle > 0 then
        direction = 1
    elseif deltaAngle < 0 then
        direction = -1
    else
        direction = 0
    end

    lastCrank = crank
    lastTime = now

    -- Ease displayed velocity toward actual
    local lerpRate = 0.2
    displayedVelocity = displayedVelocity + (crankVelocity - displayedVelocity) * lerpRate

    -- Apply damping to gently return to zero
    if math.abs(crankVelocity) < 2 then
        displayedVelocity = displayedVelocity * (1 - damping)
    end

    -- Draw dial
    gfx.setLineWidth(2)
    gfx.drawCircleAtPoint(CX, CY, RADIUS)
    drawDial(CX, CY, RADIUS)

    -- Draw needle
    local needleAngle = math.rad(crank - 90)
    local nx = CX + math.cos(needleAngle) * (RADIUS - 12)
    local ny = CY + math.sin(needleAngle) * (RADIUS - 12)
    gfx.setLineWidth(6)
    gfx.drawLine(CX + 1, CY + 1, nx + 1, ny + 1) -- shadow
    gfx.setLineWidth(4)
    gfx.drawLine(CX, CY, nx, ny)
    gfx.fillCircleAtPoint(CX, CY, 6)

    -- Velocity bar (left side)
    local barX = CX - RADIUS - 40
    local barY = CY - 50
    local barW = 16
    local barH = 100
    gfx.drawRect(barX, barY, barW, barH)

    local maxVel = 300  -- degrees/sec range
    local clampedVel = math.max(-maxVel, math.min(maxVel, displayedVelocity))
    local filled = (clampedVel / maxVel) * (barH / 2)
    gfx.fillRect(barX + 1, CY - filled, barW - 2, filled)

    -- Text info
    local angleText = string.format("Angle: %.1f°", crank)
    local dirText = "Direction: " .. (direction == 1 and "clockwise" or (direction == -1 and "counterclockwise" or "still"))
    local velText = string.format("Velocity: %.1f°/s", displayedVelocity)

    gfx.setFont(gfx.getSystemFont())
    gfx.drawTextAligned(angleText, CX, CY + RADIUS + 10, kTextAlignment.center)
    gfx.drawTextAligned(dirText, CX, CY + RADIUS + 30, kTextAlignment.center)
    gfx.drawTextAligned(velText, CX, CY + RADIUS + 50, kTextAlignment.center)

    gfx.drawTextAligned("Turn the crank to see velocity and direction", CX, 10, kTextAlignment.center)

    playdate.drawFPS(2, 2)
end

</syntaxhighlight>

===== - Eased velocity bar: displayedVelocity smoothly approaches actual crank velocity. =====
* Damping: when crank stops, bar gently returns to center instead of snapping.
* Smooth transitions: you’ll see momentum-like lag when reversing direction.

Would you like me to add a color gradient (e.g., light gray → dark for speed intensity) or leave it monochrome for now?