From 086067cfa95dfbf8c1f4f9c0b9453f520dcdeadf Mon Sep 17 00:00:00 2001
From: MihailRis <mexaruc@gmail.com>
Date: Mon, 29 Jun 2026 23:55:52 +0300
Subject: [PATCH] add declarative skeleton animation component (WIP)

---
 res/scripts/components/animator.lua | 154 ++++++++++++++++++++++++++++
 1 file changed, 154 insertions(+)
 create mode 100644 res/scripts/components/animator.lua

diff --git a/res/scripts/components/animator.lua b/res/scripts/components/animator.lua
new file mode 100644
index 000000000..2bcaadc6b
--- /dev/null
+++ b/res/scripts/components/animator.lua
@@ -0,0 +1,154 @@
+local tsf = entity.transform
+local rig = entity.skeleton
+local body = entity.rigidbody
+
+
+local body_idx = rig:index("body")
+
+local leg_left = rig:index("leg_left")
+local leg_right = rig:index("leg_right")
+
+local leg_left_btm = rig:index("leg_left_btm")
+local leg_right_btm = rig:index("leg_right_btm")
+
+local hand_left = rig:index("hand_left")
+local hand_right = rig:index("hand_right")
+
+local hand_left_btm = rig:index("hand_left_btm")
+local hand_right_btm = rig:index("hand_right_btm")
+
+
+local tm_offset = random.random(10)
+local prev_speed = 0.0
+
+local CH_TRANSLATE = 1
+local CH_ROTATE = 2
+
+local AX_X = 1
+local AX_Y = 2
+local AX_Z = 3
+
+local function compile_track(bone_index, lines)
+    local env = {
+        mat4 = mat4,
+    }
+    table.extend(env, math)
+
+    local code = ""
+    local translation = {false, false, false}
+    local rotation = {false, false, false}
+    for i, line in ipairs(lines) do
+        code = code .. "\n  local l" .. i .. " = (" .. line.expression .. ")"
+        if line.channel == CH_TRANSLATE then
+            translation[line.axis] = i
+        elseif line.channel == CH_ROTATE then
+            rotation[line.axis] = i
+        end
+    end
+
+    code = code .. "\n  mat4.idt(dst)"
+    if translation[1] or translation[2] or translation[3] then
+        code = code .. "\n  mat4.translate(dst, {" ..
+        (translation[1] and ("l" .. translation[1]) or '0').. ", " ..
+        (translation[2] and ("l" .. translation[2]) or '0').. ", " ..
+        (translation[3] and ("l" .. translation[3]) or '0').. "}, dst)"
+    end
+
+    for axis, var in ipairs(rotation) do
+        if var then
+            code = code .. "\n  mat4.rotate(dst, {"
+            .. ((axis == 1) and '1' or '0') .. ", "
+            .. ((axis == 2) and '1' or '0') .. ", "
+            .. ((axis == 3) and '1' or '0') .. "}, l" ..  var .. ", dst)"
+        end
+    end
+
+    local src = "return function(dst, t, m)" .. code .. "\n  return dst\nend"
+    local generator, err = load(src, "<expr>", "bt", env)
+    if not generator then
+        error(err)
+    end
+    print(src)
+    return {
+        bone_index = bone_index,
+        generator = generator()
+    }
+end
+
+local tracks = {
+    compile_track(body_idx, {{
+        channel = CH_TRANSLATE,
+        axis = AX_Y,
+        expression = "sin(t * 2) * 0.1 * m"
+    }}),
+    compile_track(leg_left, {{
+        channel = CH_ROTATE,
+        axis = AX_X,
+        expression = "sin(t) * 45 * m"
+    }}),
+    compile_track(leg_right, {{
+        channel = CH_ROTATE,
+        axis = AX_X,
+        expression = "-sin(t) * 45 * m"
+    }}),
+    compile_track(leg_left_btm, {{
+        channel = CH_ROTATE,
+        axis = AX_X,
+        expression = "(-sin(t * 2) * 45 - 45) * m"
+    }}),
+    compile_track(leg_right_btm, {{
+        channel = CH_ROTATE,
+        axis = AX_X,
+        expression = "(-sin(t * 2) * 45 - 45) * m"
+    }}),
+    compile_track(hand_left, {{
+        channel = CH_ROTATE,
+        axis = AX_X,
+        expression = "-sin(t) * 45 * m"
+    }}),
+    compile_track(hand_right, {{
+        channel = CH_ROTATE,
+        axis = AX_X,
+        expression = "sin(t) * 45 * m"
+    }}),
+    compile_track(hand_left_btm, {{
+        channel = CH_ROTATE,
+        axis = AX_X,
+        expression = "(sin(t * 2) * 45 + 45) * m"
+    }}),
+    compile_track(hand_right_btm, {{
+        channel = CH_ROTATE,
+        axis = AX_X,
+        expression = "(sin(t * 2) * 45 + 45) * m"
+    }}),
+}
+
+function on_render()
+    local tm = time.uptime() * 10 + tm_offset
+    local speed = vec3.length(body:get_vel()) / 7.0
+    local delta = time.delta()
+
+    prev_speed = prev_speed * (1.0 - delta * 10) + speed * delta * 10
+    speed = prev_speed
+
+    local ttm = time.precise_time()
+    local matrix = mat4.idt()
+    for i, track in ipairs(tracks) do
+        rig:set_matrix(track.bone_index, track.generator(matrix, tm, speed))
+    end
+
+    -- rig:set_matrix(body_idx, mat4.translate({0, math.sin(tm * 2) * 0.1 * speed, 0}))
+
+    -- rig:set_matrix(leg_left, mat4.rotate({1, 0, 0}, (math.sin(tm) * 45) * speed))
+    -- rig:set_matrix(leg_right, mat4.rotate({1, 0, 0}, (-math.sin(tm) * 45) * speed))
+
+    -- rig:set_matrix(leg_left_btm, mat4.rotate({1, 0, 0}, (-math.sin(tm * 2) * 45 - 45) * speed))
+    -- rig:set_matrix(leg_right_btm, mat4.rotate({1, 0, 0}, (-math.sin(tm * 2) * 45 - 45) * speed))
+
+    -- rig:set_matrix(hand_left, mat4.rotate({1, 0, 0}, (-math.sin(tm) * 45) * speed))
+    -- rig:set_matrix(hand_right, mat4.rotate({1, 0, 0}, (math.sin(tm) * 45) * speed))
+
+    -- rig:set_matrix(hand_left_btm, mat4.rotate({1, 0, 0}, (math.sin(tm * 2) * 45 + 45) * speed))
+    -- rig:set_matrix(hand_right_btm, mat4.rotate({1, 0, 0}, (math.sin(tm * 2) * 45 + 45) * speed))
+    print(math.floor((time.precise_time() - ttm) * 1e6), "mcs")
+end