refactor the animation script a bit

diff --git a/animate.lua b/animate.lua
index b9fb1be73c995bf31013172f8e2bcceac4e7e4bd..ad16db9363d29c9a93cd56b95457c83c16bbfe6c 100755 (executable)
--- a/animate.lua
+++ b/animate.lua
@@ -60,7 +60,7 @@ s 10 10 10
 -- ImageMagick is used to scale the frames back down to size; if ImageMagick
 -- is not installed, the resulting frames will end up bigger than they should
 -- be and the aliasing problem will not be fixed.
-local supersample = 4
+local supersample = 2
 
 -- Set the width and height of the viewport.
 local size = {w = 640, h = 480}
@@ -68,14 +68,12 @@ local size = {w = 640, h = 480}
 -- Set the number of concurrent renderings (for multi-core machines).
 local jobs = 6
 
+-- Set the options to be passed directly to ffmpeg.
+local ffmpeg_opts = "-b 1024k"
 
 -- end of configuration
 ---------------------------------------------------------------------------
 
-local fmt   = string.format
-local write = function(...) return io.write(fmt(...)) end
-local run   = function(...) return os.execute(fmt(...)) end
-
 function vec_new(x, y, z)
     return {x = x, y = y, z = z}
 end
@@ -88,6 +86,10 @@ function vec_scale(v, s)
     return vec_new(v.x * s, v.y * s, v.z * s)
 end
 
+local fmt   = string.format
+local write = function(...) io.write(fmt(...)) io.flush() end
+local run   = function(...) return os.execute(fmt(...)) end
+
 function render(i)
     while i do
         local w, h = size.w, size.h
@@ -100,7 +102,7 @@ function render(i)
         local out = io.popen(command, "w")
         local e = eye(i)
         local l = look(i)
-        write("\27[80D\27[2Kframe\t %4d / %d", i + 1, frames)
+        write("\27[80D\27[2Kframe\t %4d / %d", i, frames)
         out:write(fmt([[
 U3
 %d %d
@@ -119,21 +121,31 @@ X
     end
 end
 
-print("Animating scene...")
-
-local threads = {}
-for i = 1,jobs do
-    table.insert(threads, coroutine.wrap(render))
+function renderings()
+    local t = {}
+    for i = 1,jobs do
+        table.insert(t, coroutine.wrap(render))
+    end
+    local iterations = frames + jobs
+    local frame = 0
+    return function()
+        frame = frame + 1
+        if frame <= iterations then
+            local i = frame
+            if frames < i then i = null end
+            return t[1 + frame % jobs], i
+        end
+    end
 end
 
+print("Animating scene...")
+
 run("rm -rf frames && mkdir frames >/dev/null 2>&1")
-for i = 0,(frames-1) do
-    threads[1 + (i % jobs)](i)
-end
-for _,thread in ipairs(threads) do thread(null) end
+for render,frame in renderings() do render(frame) end
+
 print()
 
-if run("ffmpeg -i frames/anim%04d.bmp -b 1024k -y -an scene.avi") == 0 then
+if run("ffmpeg -i frames/anim%%04d.bmp %s -y -an scene.avi", ffmpeg_opts) == 0 then
     print("Animation written to scene.avi.")
 end