move vca parsing to a separate module

res/modules/internal/formats/vca.lua

@@ -0,0 +1,98 @@
+local internals = __vc_internals
+
+local DEFAULT_FPS = 60
+local INT_BEZIER = animation.INT_BEZIER
+
+local action_to_channel = {
+    move = animation.CH_TRANSLATE,
+    rotate = animation.CH_ROTATE
+}
+
+local curve_to_interp = {
+    const = animation.INT_CONST,
+    linear = animation.INT_LINEAR,
+    bezier = animation.INT_BEZIER,
+}
+
+local function parse_configure(raw_track, node)
+    if node.fps then
+        raw_track.fps = node.fps
+    end
+    if node.frames then
+        raw_track.duration = node.frames / node.fps
+    elseif node.duration then
+        raw_track.duration = node.duration
+    end
+end
+
+local function parse_curve(line, node)
+    line.interp = curve_to_interp[node.curve]
+    line.keys = {}
+    for j, key_node in ipairs(node) do
+        local keyframe = {
+            frame = tonumber(key_node.frame),
+            value = tonumber(key_node.value),
+        }
+        if line.interp == INT_BEZIER then
+            keyframe.lx = tonumber(key_node.lx)
+            keyframe.ly = tonumber(key_node.ly)
+            keyframe.rx = tonumber(key_node.rx)
+            keyframe.ry = tonumber(key_node.ry)
+        end
+        table.insert(line.keys, keyframe)
+    end
+end
+
+local function parse_track(root)
+    local raw_track = {
+        duration = math.huge,
+        fps = DEFAULT_FPS,
+        linesets = {},
+    }
+    local linesets = raw_track.linesets
+    for i, node in ipairs(root) do
+        if type(node) == "string" then
+            goto continue
+        end
+        local tag = node['#']
+        if tag == "configure" then
+            parse_configure(raw_track, node)
+            goto continue
+        end
+
+        local bone = node.bone
+
+        local lineset = linesets[bone]
+        if not lineset then
+            lineset = {lines = {}}
+            linesets[bone] = lineset
+        end
+
+        local line = {
+            axis = ("xyz"):find(node.by),
+            channel = action_to_channel[tag]
+        }
+        if node.func then
+            line.expression = node.func
+        elseif node.curve then
+            parse_curve(line, node)
+        else
+            error("not implemented")
+        end
+
+        table.insert(lineset.lines, line)
+        ::continue::
+    end
+    return raw_track
+end
+
+local function load_vca(filepath)
+    local source = file.read(filepath)
+    local raw_track = parse_track(xml.parse_vcd(source, "track"))
+    return animation.compile_track(raw_track, filepath)
+end
+
+function internals.load_vca_animation(filepath, identifier)
+    local track = load_vca(filepath)
+    internals.store_animation(identifier, track)
+end