steak dancers

data/scripts/game.lua

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+local traxx = require "traxx"
+require "utils"
+require "string"
+require "math"
+
+function start_blasting(track)
+    local blast = table.shallow_copy(traxx[track])
+    blast.channel = "blast"
+    ctx.udata.blast = blast
+    ctx.udata.last_beat = ctx.udata.time + 60 / blast.bpm
+    audio_play(ctx.udata.blast)
+end
+
+function game_tick()
+    if ctx.initialization_needed then
+        ctx.udata = {
+            time = 0,
+            beat = 0
+        }
+        start_blasting("mod22")
+    end
+
+    local state = ctx.udata
+
+    draw_rectangle {
+        rect = { w = 960, h = 540 },
+        color = { r = 125, a = 255 }
+    }
+
+    state.time = state.time + ctx.frame_duration
+    if state.time - state.last_beat > 60 / state.blast.bpm then
+        state.last_beat = state.last_beat + 60 / state.blast.bpm
+        state.beat = state.beat + 1
+        -- draw_rectangle {
+        --     rect = { w = 64, h = 64 },
+        --     color = { r = 255, a = 255 }
+        -- }
+    end
+
+    local wobble = sinease(12, state.time - state.beat * (60 / state.blast.bpm) , (60 / state.blast.bpm) / 1.5, 0)
+
+    for i = 0,10 do
+        draw_sprite {
+            texture = "art/creatures/meathead/" .. string.format("dance-%s.png", pingpong(state.beat, 3)),
+            rect = { w = 64, h = 64 + wobble, x = 300 + i * 32, y = 300 - wobble }
+        }
+    end
+end

data/scripts/traxx.lua

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+-- listing of all traxx to blast
+return {
+    mod4 = {
+        audio = "traxx/mod4.xm",
+        bpm = 101.5,
+        loops = true,
+    },
+
+    mod22 = {
+        audio = "traxx/mod22.xm",
+        bpm = 177 / 2,
+        loops = true,
+    },
+}

data/scripts/utils.lua

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+require "math"
+
+function table.shallow_copy(t)
+    local t2 = {}
+    for k,v in pairs(t) do
+        t2[k] = v
+    end
+    return t2
+end
+
+function thisorthat(c, a, b)
+    if c then return a else return b end
+end
+
+function pingpong(at, over)
+    local c = (over - 1) * 2
+    if math.fmod(at, c) >= over then
+        return c - math.fmod(at, c)
+    else
+        return math.fmod(at, c)
+    end
+end
+
+function linease(c, t, d, b)
+    return c * t / d + b
+end
+
+function sinease(c, t, d, b)
+    return -c*math.cos(t/d*(math.pi/2)) + c + b
+end