Various playdate optimizations, increasing unused CPU to hopefully drive audio or something. Moved the Lua project into playdate/matrix_lua

playdate/matrix_lua/main.lua

@@ -1,14 +1,16 @@
 local gfx <const> = playdate.graphics
+local floor <const> = math.floor
+local random <const> = math.random
 
 local screenWidth <const> = playdate.display.getWidth()
 local screenHeight <const> = playdate.display.getHeight()
 local glyphWidth <const> = 20
-local numColumns <const> = math.floor(screenWidth / glyphWidth)
-local numRows <const> = math.floor(screenHeight / glyphWidth)
+local numColumns <const> = floor(screenWidth / glyphWidth)
+local numRows <const> = floor(screenHeight / glyphWidth)
 local numCells <const> = numColumns * numRows
 
 local numGlyphs <const> = 133
-local numFades <const> = 15
+local numFades <const> = 16
 local blackImage = gfx.image.new(glyphWidth, glyphWidth, gfx.kColorBlack)
 local glyphTable = gfx.imagetable.new('images/matrix')
 local ditherType = gfx.image.kDitherTypeAtkinson
@@ -26,31 +28,45 @@ local maxSpeed <const> = 1
 local time = 0
 local speed = maxSpeed
 
-local sqrt2 <const> = math.sqrt(2)
-local sqrt5 <const> = math.sqrt(5)
-function wobble(x)
-	return x + 0.3 * math.sin(sqrt2 * x) + 0.2 * math.sin(sqrt5 * x)
+local sineTable = {}
+for i = 1,360 do
+	sineTable[i] = math.sin(math.pi / 180 * i)
 end
 
+-- function fastSin(x)
+-- 	x = x / 360 % 1
+-- 	local sign
+-- 	if x < 0.5 then
+-- 		sign = -1
+-- 	else
+-- 		sign = 1
+-- 	end
+-- 	x = (x % 0.5) * 2 - 0.5
+-- 	return sign * x * x * 4 - 1
+-- end
+
+local wobbleA <const> = math.sqrt(2) / 50
+local wobbleB <const> = math.sqrt(5) / 50
+
 local cells = {}
 for x = 1, numColumns do
-	local columnTimeOffset = math.random() * 1000
-	local columnSpeedOffset = math.random() * 0.5 + 0.5
+	local columnTimeOffset = random() * 1000
+	local columnSpeedOffset = random() * 0.5 + 0.5
 	for y = 1, numRows do
 		local cell = {}
 		cell.x = x
 		cell.y = y
-		cell.glyphCycle = math.random()
+		cell.glyphCycle = random()
 		cell.columnTimeOffset = columnTimeOffset
 		cell.columnSpeedOffset = columnSpeedOffset
-		cell.glyphIndex = math.floor(math.random() * numGlyphs) + 1
+		cell.glyphIndex = floor(random() * numGlyphs) + 1
 		cell.fadeIndex = -1
 
 		cells[#cells + 1] = cell
 	end
 end
 
-playdate.display.setRefreshRate(0)
+playdate.display.setRefreshRate(24)
 playdate.resetElapsedTime()
 
 function playdate.update()
@@ -68,10 +84,18 @@ function playdate.update()
 	for i = 1, numCells do
 		local mustDraw = false
 		local cell = cells[i]
-		local cellTime = cell.y * -0.03 + cell.columnTimeOffset + time * cell.columnSpeedOffset
 
-		local brightness = math.log((1 - wobble(cellTime) % 1) * 1.25) * 6
-		local fadeIndex = math.max(1, math.min(numFades, math.floor(numFades * (1 - brightness))))
+		local cellTime = cell.y * -0.03 + cell.columnTimeOffset + time * cell.columnSpeedOffset
+		local brightness = 4 * (
+			(
+				cellTime
+				+ 0.3 * sineTable[floor((wobbleA * cellTime) % 360) + 1]
+				+ 0.2 * sineTable[floor((wobbleB * cellTime) % 360) + 1]
+			) % 1
+		)
+		local fadeIndex = floor(brightness * numFades)
+		if fadeIndex < 1 then fadeIndex = 1 end
+		if fadeIndex > numFades then fadeIndex = numFades end
 		if cell.fadeIndex ~= fadeIndex then
 			cell.fadeIndex = fadeIndex
 			mustDraw = true
@@ -80,7 +104,7 @@ function playdate.update()
 		cell.glyphCycle = cell.glyphCycle + delta * 2
 		if cell.glyphCycle > 1 then
 			cell.glyphCycle = cell.glyphCycle % 1
-			local glyphIndex = (cell.glyphIndex + math.random(20)) % numGlyphs + 1
+			local glyphIndex = (cell.glyphIndex + random(20)) % numGlyphs + 1
 			if cell.glyphIndex ~= glyphIndex then
 				cell.glyphIndex = glyphIndex
 				if fadeIndex < numFades then
@@ -93,5 +117,4 @@ function playdate.update()
 			glyphs[cell.glyphIndex][cell.fadeIndex]:draw((cell.x - 1) * glyphWidth, (cell.y - 1) * glyphWidth)
 		end
 	end
-
 end