ludic/packages/ludic.anim/read.ludic

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# read.ludic - every animation out of the document `gltf_load` just parsed: rotation and
# translation channels, flattened into a Clip each; a name already held is skipped
# Call it straight after a load and before the next one: `gltf_doc` and `gltf_bin` point at
# whichever file was read last, so a clip that is not taken now cannot be taken later.
export function anim_read_doc(anim_st: mut AnimState, render3d_st: mut Render3dState, dir: string) -> int {
clips_init()
if render3d_st.gltf_doc == null { return 0 }
if value_has(render3d_st.gltf_doc, "animations") == 0 { return 0 }
# REOPEN THE .bin. `gltf_load` closes it before it returns, and an accessor read through a closed
# handle returns a buffer of the right size full of zeros: right names, right counts, no motion.
let buffers = value_get(render3d_st.gltf_doc, "buffers")
if value_count(buffers) == 0 { return 0 }
let bin_uri = value_as_str(value_get(value_at(buffers, 0), "uri"))
render3d_st.gltf_bin = file_open(dir + "/" + bin_uri, "rb")
if render3d_st.gltf_bin == null {
print(`anim: cannot reopen {dir}/{bin_uri}`)
return 0
}
let arr = value_get(render3d_st.gltf_doc, "animations")
var got = 0
for ai in 0 .. value_count(arr) {
let c = read_one(anim_st, render3d_st, value_at(arr, ai))
if c != null {
push(anim_st.clips, c)
got += 1
}
}
file_close(render3d_st.gltf_bin)
render3d_st.gltf_bin = null
return got
}
function kept_path(ch: Val) -> string {
let tgt = value_get(ch, "target")
if value_has(tgt, "node") == 0 { return "" }
let path = value_as_str(value_get(tgt, "path"))
if path != "rotation" and path != "translation" { return "" }
return path
}
function read_one(anim_st: AnimState, render3d_st: mut Render3dState, a: Val) -> Clip {
var nm = ""
if value_has(a, "name") != 0 { nm = value_as_str(value_get(a, "name")) }
if anim_find(anim_st, nm) != null { return null } # a second rig's file, same clip
let chans = value_get(a, "channels")
let samps = value_get(a, "samplers")
let nc = value_count(chans)
# count first: the flat arrays are sized once rather than grown per channel
var n_keep = 0
var n_t = 0
var n_v = 0
for ci in 0 .. nc {
let ch = value_at(chans, ci)
let path = kept_path(ch)
if path == "" { continue }
let sp = value_at(samps, value_as_int(value_get(ch, "sampler")))
let cnt = gltf_accessor_count(render3d_st, value_as_int(value_get(sp, "input")))
n_keep += 1
n_t += cnt
if path == "rotation" { n_v += cnt * 4 } else { n_v += cnt * 3 }
}
if n_keep == 0 { return null }
let c = new Clip
c.name = nm
c.n = n_keep
c.cnode = words(n_keep)
c.cpath = words(n_keep)
c.ckeys = words(n_keep)
c.coff = words(n_keep)
c.cvoff = words(n_keep)
c.times = floats(n_t)
c.vals = floats(n_v)
var k = 0
var at = 0
var av = 0
for ci in 0 .. nc {
let ch = value_at(chans, ci)
let path = kept_path(ch)
if path == "" { continue }
let sp = value_at(samps, value_as_int(value_get(ch, "sampler")))
c.cnode[k] = value_as_int(value_get(value_get(ch, "target"), "node"))
if path == "rotation" { c.cpath[k] = AC_ROT } else { c.cpath[k] = AC_POS }
let tb = gltf_accessor_floats(render3d_st, value_as_int(value_get(sp, "input")))
let nk = render3d_st.gltf_count
c.ckeys[k] = nk
c.coff[k] = at
for i in 0 .. nk { c.times[at + i] = tb[i] }
if nk > 0 and c.times[at + nk - 1] > c.dur { c.dur = c.times[at + nk - 1] }
at += nk
let vb = gltf_accessor_floats(render3d_st, value_as_int(value_get(sp, "output")))
var comps = 3
if c.cpath[k] == AC_ROT { comps = 4 }
c.cvoff[k] = av
for i in 0 .. nk * comps { c.vals[av + i] = vb[i] }
av += nk * comps
k += 1
}
if anim_first_key(c) > 0.001 { print(`anim: {nm} starts at {anim_first_key(c)} s - key from frame zero, or every cycle holds its opening pose`) }
return c
}
# the earliest key of any channel: a clip keyed from frame 1 has 1/30 here, and a hitch every cycle
export function anim_first_key(c: Clip) -> float {
var t = 0.0
for ch in 0 .. c.n {
if c.ckeys[ch] == 0 { continue }
let s = c.times[c.coff[ch]]
if ch == 0 or s < t { t = s }
}
return t
}