From ba6377a8017ae20c80d52f178e25341701f4a5f1 Mon Sep 17 00:00:00 2001
From: Robin Gareus <robin@gareus.org>
Date: Sun, 21 Aug 2016 12:34:15 +0200
Subject: [PATCH] refurbish a-pong

* add code comments
* support no-inplace audio processing
* display score
* add re-init & difficulty settings
---
 scripts/_pong.lua | 114 ++++++++++++++++++++++++++++++++++++----------
 1 file changed, 89 insertions(+), 25 deletions(-)

diff --git a/scripts/_pong.lua b/scripts/_pong.lua
index 7ed17648fb..86ec8c3da7 100644
--- a/scripts/_pong.lua
+++ b/scripts/_pong.lua
@@ -1,10 +1,10 @@
 ardour {
 	["type"]    = "dsp",
 	name        = "a-Pong",
-	category    = "Visualization",
+	category    = "Toy",
 	license     = "MIT",
 	author      = "Ardour Lua Task Force",
-	description = [[classic game of mixer pong]]
+	description = [[A console classic for your console]]
 }
 
 -- return possible i/o configurations
@@ -13,15 +13,21 @@ function dsp_ioconfig ()
 	return { [1] = { audio_in = -1, audio_out = -1}, }
 end
 
+-- control port(s)
 function dsp_params ()
 	return
 	{
 		{ ["type"] = "input", name = "Bar", min = 0, max = 1, default = 0.5 },
+		{ ["type"] = "input", name = "Reset", min = 0, max = 1, default = 0, toggled = true },
+		{ ["type"] = "input", name = "Difficulty", min = 1, max = 10, default = 3},
 	}
 end
 
+
+-- NOTE: these variables are for the DSP part (not shared with the GUI instance)
 local fps -- audio samples per game-step
 local game_time -- counts up to fps
+local game_score
 local ball_x, ball_y -- ball position [0..1]
 local dx, dy -- current ball speed
 local lost_sound -- audio-sample counter for game-over [0..3*fps]
@@ -30,17 +36,17 @@ local ping_phase -- ping note phase
 local ping_pitch
 
 function dsp_init (rate)
-	self:shmem ():allocate (4)
+	-- allocate a "shared memory" area to transfer state to the GUI
+	self:shmem ():allocate (3)
 	self:shmem ():clear ()
+	-- initialize some variables
 	fps = rate / 25
 	ping_pitch = 752 / rate
 	ball_x = 0.5
 	ball_y = 0
-	dx = 0.011
-	dy = 0.0237
-end
-
-function dsp_configure (ins, outs)
+	dx = 0.00367
+	dy = 0.01063
+	game_score = 0
 	game_time  = fps -- start the ball immediately (notfiy GUI)
 	ping_sound = fps -- set to end of synth cycle
 	lost_sound = 3 * fps
@@ -54,54 +60,88 @@ function dsp_run (ins, outs, n_samples)
 	local changed = false -- flag to notify GUI on every game-step
 	game_time = game_time + n_samples
 
+	-- reset (allow to write automation from a given start-point)
+	if ctrl[2] > 0 then
+		game_time = 0
+		ball_x = 0.5
+		ball_y = 0
+		dx = 0.00367
+		dy = 0.01063
+		game_score = 0
+	end
+
 	-- simple game engine
-	while game_time > fps do
+	while game_time > fps and ctrl[2] <= 0 do
 		changed = true
 		game_time = game_time - fps
 
 		-- move the ball
-		ball_x = ball_x + dx
-		ball_y = ball_y + dy
+		ball_x = ball_x + dx * ctrl[3]
+		ball_y = ball_y + dy * ctrl[3]
 
 		-- reflect left/right
 		if ball_x >= 1 or ball_x <= 0 then dx = -dx end
+		-- keep the ball in the field
+		if ball_x >= 1 then ball_x = 1 end
+		if ball_x <= 0 then ball_x = 0 end
 
-		-- single player (reflect top) -- TODO "stereo" version, 2 ctrls
-		if ball_y <= 0 then dy = - dy end
+		-- single player (reflect top) -- TODO "stereo" version, 2 ctrls :)
+		if ball_y <= 0 then dy = - dy y = 0 end
 
+		-- bottom edge
 		if ball_y > 1 then
 			local bar = ctrl[1] -- get bar position
 			if math.abs (bar - ball_x) < 0.1 then
+				-- reflect the ball
 				dy = - dy
 				ball_y = 1.0
-				dx = dx + 0.1 * (bar - ball_x)
-				-- queue sound (unless it's playing)
+				dx = dx - 0.04 * (bar - ball_x)
+				-- make sure it's moving (not stuck on borders)
+				if math.abs (dx) < 0.0001 then dx = 0.0001 end
+				-- queue 'ping' sound (unless it's already playing to prevent clicks)
 				if (ping_sound >= fps) then
 					ping_sound = 0
 					ping_phase = 0
 				end
+				game_score = game_score + 1
 			else
 				-- game over
 				lost_sound = 0
 				ball_y = 0
-				dx = 0.011
+				dx = 0.00367
+				game_score = 0
 			end
 		end
 	end
 
+	-- forward audio if processing is not in-place
+	for c = 1,#outs do
+		-- check if output and input buffers for this channel are identical
+		-- http://manual.ardour.org/lua-scripting/class_reference/#C:FloatArray
+		if not ins[c]:sameinstance (outs[c]) then
+			-- fast (accellerated) memcpy
+			-- http://manual.ardour.org/lua-scripting/class_reference/#ARDOUR:DSP
+			ARDOUR.DSP.copy_vector (out[c], ins[c], n_samples)
+		end
+	end
+
 	-- simple synth -- TODO Optimize
 	if ping_sound < fps then
+		-- cache audio data buffers for direct access, later
 		local abufs = {}
 		for c = 1,#outs do
-			abufs[c] = outs[c]:array();
+			abufs[c] = outs[c]:array()
 		end
+		-- simple sine synth with a sine-envelope
 		for s = 1, n_samples do
 			ping_sound = ping_sound + 1
 			ping_phase = ping_phase + ping_pitch
 			local snd = 0.7 * math.sin(6.283185307 * ping_phase) * math.sin (3.141592 * ping_sound / fps)
+			-- add synthesized sound to all channels
 			for c = 1,#outs do
 				abufs[c][s] = abufs[c][s] + snd
 			end
+			-- break out of the loop when the sound finished
 			if ping_sound >= fps then goto ping_end end
 		end
 		::ping_end::
@@ -110,7 +150,7 @@ function dsp_run (ins, outs, n_samples)
 	if lost_sound < 3 * fps then
 		local abufs = {}
 		for c = 1,#outs do
-			abufs[c] = outs[c]:array();
+			abufs[c] = outs[c]:array()
 		end
 		for s = 1, n_samples do
 			lost_sound = lost_sound + 1
@@ -127,15 +167,21 @@ function dsp_run (ins, outs, n_samples)
 	if changed then
 		state[1] = ball_x
 		state[2] = ball_y
+		state[3] = game_score
 		self:queue_draw ()
 	end
 end
 
 
+-------------------------------------------------------------------------------
+--- inline display
+
+local txt = nil -- cache pango context (in GUI context)
+
 function render_inline (ctx, w, max_h)
-	local ctrl = CtrlPorts:array () -- get control port array (read/write)
-	local shmem = self:shmem () -- get shared memory region
-	local state = shmem:to_float (0):array () -- "cast" into lua-table
+	local ctrl = CtrlPorts:array () -- control port array
+	local shmem = self:shmem () -- shared memory region
+	local state = shmem:to_float (0):array () -- cast to lua-table
 
 	if (w > max_h) then
 		h = max_h
@@ -143,24 +189,42 @@ function render_inline (ctx, w, max_h)
 		h = w
 	end
 
+	-- prepare text rendering
+	if not txt then
+		-- allocate PangoLayout and set font
+		--http://manual.ardour.org/lua-scripting/class_reference/#Cairo:PangoLayout
+		txt = Cairo.PangoLayout (ctx, "Mono 10px")
+	end
+
 	-- clear background
 	ctx:rectangle (0, 0, w, h)
 	ctx:set_source_rgba (.2, .2, .2, 1.0)
 	ctx:fill ()
 
+	-- print score
+	if (state[3] > 0) then
+		txt:set_text (string.format ("%.0f", state[3]));
+		local tw, th = txt:get_pixel_size ()
+		ctx:set_source_rgba (1, 1, 1, 1.0)
+		ctx:move_to (w - tw - 3, 3)
+		txt:show_in_cairo_context (ctx)
+	end
+
+	-- prepare line and dot rendering
+	ctx:set_line_cap (Cairo.LineCap.Round)
+	ctx:set_line_width (3.0)
+	ctx:set_source_rgba (.8, .8, .8, 1.0)
+
 	-- display bar
 	local bar_width = w * .1
 	local bar_space = w - bar_width
 
-	ctx:set_line_cap (Cairo.LineCap.Round)
-	ctx:set_source_rgba (.8, .8, .8, 1.0)
-	ctx:set_line_width (3.0)
 	ctx:move_to (bar_space * ctrl[1], h - 3)
 	ctx:rel_line_to (bar_width, 0)
 	ctx:stroke ()
 
 	-- display ball
-	ctx:move_to (state[1] * w, state[2] * (h - 5))
+	ctx:move_to (1 + state[1] * (w - 3), state[2] * (h - 5))
 	ctx:close_path ()
 	ctx:stroke ()
 
-- 
2.30.2