Some animation work

src/dusk/animation/animation.c

@@ -16,7 +16,9 @@ void animationInit(
 ) {
   assertNotNull(anim, "Animation pointer cannot be null.");
 
-  keyframeSetInit(&anim->keyframes, tracks, trackCounts, trackCount);
+  keyframeSetInit(
+    &anim->keyframes, tracks, trackCounts, NULL, NULL, trackCount, NULL
+  );
   anim->time = 0.0f;
   anim->speed = 1.0f;
   anim->loop = false;

src/dusk/animation/keyframeset.c

@@ -10,7 +10,10 @@ void keyframeSetInit(
   keyframeset_t *set,
   keyframe_t **tracks,
   uint16_t *trackCounts,
-  uint16_t trackCount
+  keyframesetcallback_t *callbacks,
+  void **users,
+  uint16_t trackCount,
+  void *user
 ) {
   assertNotNull(set, "Keyframe set pointer cannot be null.");
   assertNotNull(tracks, "Tracks pointer cannot be null.");
@@ -20,6 +23,9 @@ void keyframeSetInit(
   set->tracks = tracks;
   set->trackCounts = trackCounts;
   set->trackCount = trackCount;
+  set->callbacks = callbacks;
+  set->users = users;
+  set->user = user;
 }
 
 float_t keyframeSetGetValue(
@@ -58,3 +64,13 @@ float_t keyframeSetGetDuration(keyframeset_t *set) {
   }
   return duration;
 }
+
+void keyframeSetFireCallback(keyframeset_t *set, const uint16_t trackIndex) {
+  assertNotNull(set, "Keyframe set pointer cannot be null.");
+  assertTrue(trackIndex < set->trackCount, "Track index out of bounds.");
+
+  if(!set->callbacks || !set->callbacks[trackIndex]) return;
+  set->callbacks[trackIndex](
+    set, trackIndex, set->users ? set->users[trackIndex] : NULL
+  );
+}

src/dusk/animation/keyframeset.h

@@ -6,35 +6,68 @@
 #pragma once
 #include "keyframe.h"
 
+typedef struct keyframeset_t keyframeset_t;
+
+/**
+ * Callback associated with one track of a keyframe set (see
+ * keyframeSetFireCallback()).
+ *
+ * @param set The keyframe set the track belongs to.
+ * @param trackIndex The track this callback is registered for.
+ * @param user The per-track user pointer passed to keyframeSetInit().
+ */
+typedef void (*keyframesetcallback_t)(
+  keyframeset_t *set,
+  const uint16_t trackIndex,
+  void *user
+);
+
 /**
  * A group of N parallel keyframe tracks (e.g. one per animated channel --
  * position.x/y/z, bone rotations, etc.) sharing a single timeline. Each
  * track is independent: its own keyframe array and count, evaluated at
  * whatever time is asked for.
  */
-typedef struct {
+typedef struct keyframeset_t {
   /** Caller-owned array of trackCount keyframe_t arrays. */
   keyframe_t **tracks;
   /** Caller-owned array of trackCount counts, one per entry in tracks. */
   uint16_t *trackCounts;
   uint16_t trackCount;
+
+  /** Caller-owned array of trackCount callbacks, one per track. Entries
+   * (or the whole array) may be NULL for tracks with no callback. */
+  keyframesetcallback_t *callbacks;
+  /** Caller-owned array of trackCount user pointers, one per track,
+   * passed to that track's callbacks[] entry. May be NULL. */
+  void **users;
+  /** Extra user data for the set as a whole, not tied to any one track. */
+  void *user;
 } keyframeset_t;
 
 /**
- * Initializes a keyframe set. Neither tracks, trackCounts, nor the
- * keyframe_t arrays they point to are copied -- they must outlive this
- * keyframeset_t.
+ * Initializes a keyframe set. None of the passed-in arrays (or the
+ * keyframe_t arrays tracks points to) are copied -- they must outlive
+ * this keyframeset_t.
  *
  * @param set The keyframe set to initialize.
  * @param tracks Array of trackCount keyframe_t arrays.
  * @param trackCounts Array of trackCount keyframe counts, matching tracks.
+ * @param callbacks Array of trackCount callbacks, one per track, or NULL
+ * if no track has one.
+ * @param users Array of trackCount user pointers, matching callbacks, or
+ * NULL.
  * @param trackCount The number of tracks.
+ * @param user Extra user data for the set as a whole; may be NULL.
  */
 void keyframeSetInit(
   keyframeset_t *set,
   keyframe_t **tracks,
   uint16_t *trackCounts,
-  uint16_t trackCount
+  keyframesetcallback_t *callbacks,
+  void **users,
+  uint16_t trackCount,
+  void *user
 );
 
 /**
@@ -72,3 +105,12 @@ void keyframeSetGetValues(
  * @return The set's duration, in seconds.
  */
 float_t keyframeSetGetDuration(keyframeset_t *set);
+
+/**
+ * Invokes a track's callback, if it (and its callbacks array) is set.
+ * No-op otherwise.
+ *
+ * @param set The keyframe set the track belongs to.
+ * @param trackIndex The track whose callback to invoke.
+ */
+void keyframeSetFireCallback(keyframeset_t *set, const uint16_t trackIndex);

src/dusk/asset/loader/CMakeLists.txt

@@ -15,4 +15,5 @@ target_sources(${DUSK_LIBRARY_TARGET_NAME}
 add_subdirectory(display)
 add_subdirectory(locale)
 add_subdirectory(json)
-add_subdirectory(dmf)
+add_subdirectory(dmf)
+add_subdirectory(animation)

src/dusk/asset/loader/animation/CMakeLists.txt

@@ -0,0 +1,9 @@
+# Copyright (c) 2026 Dominic Masters
+#
+# This software is released under the MIT License.
+# https://opensource.org/licenses/MIT
+
+target_sources(${DUSK_LIBRARY_TARGET_NAME}
+  PUBLIC
+    assetanimationloader.c
+)

src/dusk/asset/loader/animation/assetanimationloader.c

@@ -0,0 +1,234 @@
+/**
+ * Copyright (c) 2026 Dominic Masters
+ *
+ * This software is released under the MIT License.
+ * https://opensource.org/licenses/MIT
+ */
+
+#include "assetanimationloader.h"
+#include "util/memory.h"
+#include "util/string.h"
+#include "assert/assert.h"
+#include "asset/loader/assetloading.h"
+#include "asset/loader/assetentry.h"
+
+errorret_t assetAnimationLoaderAsync(assetloading_t *loading) {
+  assertNotNull(loading, "Loading cannot be NULL");
+  assertNotMainThread("Async loader should not be on main thread.");
+
+  if(
+    loading->loading.animation.state != ASSET_ANIMATION_LOADING_STATE_READ_FILE
+  ) {
+    errorOk();
+  }
+
+  assertNull(loading->loading.animation.buffer, "Buffer already defined?");
+
+  assetfile_t *file = &loading->loading.animation.file;
+  assetLoaderErrorChain(
+    loading, assetFileInit(file, loading->entry->name, NULL, NULL)
+  );
+
+  if(file->size > ASSET_ANIMATION_FILE_SIZE_MAX) {
+    assetLoaderErrorThrow(
+      loading, "Animation JSON exceeds maximum allowed size"
+    );
+  }
+
+  uint8_t *buffer;
+  size_t size;
+  assetLoaderErrorChain(loading, assetFileReadEntire(file, &buffer, &size));
+  assetLoaderErrorChain(loading, assetFileDispose(file));
+
+  loading->loading.animation.buffer = buffer;
+  loading->loading.animation.size = size;
+  loading->loading.animation.state = ASSET_ANIMATION_LOADING_STATE_PARSE;
+  loading->entry->state = ASSET_ENTRY_STATE_PENDING_SYNC;
+  errorOk();
+}
+
+errorret_t assetAnimationLoaderSync(assetloading_t *loading) {
+  assertNotNull(loading, "Loading cannot be NULL");
+  assertTrue(loading->type == ASSET_LOADER_TYPE_ANIMATION, "Invalid type.");
+  assertIsMainThread("Must be called from the main thread.");
+
+  switch(loading->loading.animation.state) {
+    case ASSET_ANIMATION_LOADING_STATE_INITIAL:
+      loading->loading.animation.state =
+        ASSET_ANIMATION_LOADING_STATE_READ_FILE;
+      loading->entry->state = ASSET_ENTRY_STATE_PENDING_ASYNC;
+      errorOk();
+      break;
+
+    case ASSET_ANIMATION_LOADING_STATE_PARSE:
+      break;
+
+    default:
+      errorOk();
+  }
+
+  uint8_t *buffer = loading->loading.animation.buffer;
+  assertNotNull(buffer, "Animation buffer should have been loaded by now.");
+
+  yyjson_doc *doc = yyjson_read(
+    (char *)buffer,
+    loading->loading.animation.size,
+    YYJSON_READ_ALLOW_COMMENTS | YYJSON_READ_ALLOW_TRAILING_COMMAS
+  );
+  memoryFree(buffer);
+  loading->loading.animation.buffer = NULL;
+
+  if(!doc) assetLoaderErrorThrow(loading, "Failed to parse animation JSON");
+
+  yyjson_val *root = yyjson_doc_get_root(doc);
+  yyjson_val *channelsVal = yyjson_obj_get(root, "channels");
+  if(!channelsVal || !yyjson_is_arr(channelsVal)) {
+    yyjson_doc_free(doc);
+    assetLoaderErrorThrow(loading, "Animation JSON missing 'channels' array");
+  }
+
+  uint16_t channelCount = (uint16_t)yyjson_arr_size(channelsVal);
+  if(channelCount == 0) {
+    yyjson_doc_free(doc);
+    assetLoaderErrorThrow(loading, "Animation must have at least one channel");
+  }
+
+  keyframe_t **tracks = memoryAllocate(channelCount * sizeof(keyframe_t *));
+  uint16_t *trackCounts = memoryAllocate(channelCount * sizeof(uint16_t));
+
+  size_t idx, max;
+  yyjson_val *channelJson;
+  uint16_t parsed = 0;
+  yyjson_arr_foreach(channelsVal, idx, max, channelJson) {
+    keyframe_t *keyframes;
+    uint16_t count;
+    errorret_t ret =
+      assetAnimationParseChannel(channelJson, &keyframes, &count);
+    if(errorIsNotOk(ret)) {
+      assetAnimationFreeChannels(tracks, parsed);
+      memoryFree(trackCounts);
+      yyjson_doc_free(doc);
+      loading->entry->state = ASSET_ENTRY_STATE_ERROR;
+      errorChain(ret);
+    }
+
+    tracks[idx] = keyframes;
+    trackCounts[idx] = count;
+    parsed++;
+  }
+
+  animationInit(
+    &loading->entry->data.animation, tracks, trackCounts, channelCount
+  );
+
+  yyjson_val *loopVal = yyjson_obj_get(root, "loop");
+  if(loopVal) loading->entry->data.animation.loop = yyjson_get_bool(loopVal);
+
+  yyjson_val *speedVal = yyjson_obj_get(root, "speed");
+  if(speedVal) {
+    loading->entry->data.animation.speed = (float_t)yyjson_get_num(speedVal);
+  }
+
+  yyjson_doc_free(doc);
+
+  loading->entry->state = ASSET_ENTRY_STATE_LOADED;
+  errorOk();
+}
+
+errorret_t assetAnimationDispose(assetentry_t *entry) {
+  assertNotNull(entry, "Asset entry cannot be NULL");
+  assertTrue(entry->type == ASSET_LOADER_TYPE_ANIMATION, "Invalid type.");
+  assertIsMainThread("Must be called from the main thread.");
+
+  // A load that failed before animationInit() ran (e.g. a parse error)
+  // never populated these -- nothing to free in that case.
+  keyframeset_t *set = &entry->data.animation.keyframes;
+  if(set->tracks) {
+    assetAnimationFreeChannels(set->tracks, set->trackCount);
+    memoryFree(set->trackCounts);
+    set->tracks = NULL;
+    set->trackCounts = NULL;
+    set->trackCount = 0;
+  }
+
+  errorOk();
+}
+
+errorret_t assetAnimationParseEasing(
+  const char_t *name,
+  easingtype_t *outEasing
+) {
+  if(stringEquals(name, "LINEAR")) *outEasing = EASING_LINEAR;
+  else if(stringEquals(name, "IN_SINE")) *outEasing = EASING_IN_SINE;
+  else if(stringEquals(name, "OUT_SINE")) *outEasing = EASING_OUT_SINE;
+  else if(stringEquals(name, "IN_OUT_SINE")) *outEasing = EASING_IN_OUT_SINE;
+  else if(stringEquals(name, "IN_QUAD")) *outEasing = EASING_IN_QUAD;
+  else if(stringEquals(name, "OUT_QUAD")) *outEasing = EASING_OUT_QUAD;
+  else if(stringEquals(name, "IN_OUT_QUAD")) *outEasing = EASING_IN_OUT_QUAD;
+  else if(stringEquals(name, "IN_CUBIC")) *outEasing = EASING_IN_CUBIC;
+  else if(stringEquals(name, "OUT_CUBIC")) *outEasing = EASING_OUT_CUBIC;
+  else if(stringEquals(name, "IN_OUT_CUBIC")) *outEasing = EASING_IN_OUT_CUBIC;
+  else if(stringEquals(name, "IN_QUART")) *outEasing = EASING_IN_QUART;
+  else if(stringEquals(name, "OUT_QUART")) *outEasing = EASING_OUT_QUART;
+  else if(stringEquals(name, "IN_OUT_QUART")) *outEasing = EASING_IN_OUT_QUART;
+  else if(stringEquals(name, "IN_BACK")) *outEasing = EASING_IN_BACK;
+  else if(stringEquals(name, "OUT_BACK")) *outEasing = EASING_OUT_BACK;
+  else if(stringEquals(name, "IN_OUT_BACK")) *outEasing = EASING_IN_OUT_BACK;
+  else errorThrow("Unknown easing type '%s'", name);
+
+  errorOk();
+}
+
+errorret_t assetAnimationParseChannel(
+  yyjson_val *channelJson,
+  keyframe_t **outKeyframes,
+  uint16_t *outCount
+) {
+  if(!yyjson_is_arr(channelJson)) {
+    errorThrow("Animation channel must be an array");
+  }
+
+  size_t count = yyjson_arr_size(channelJson);
+  if(count == 0) {
+    errorThrow("Animation channel must have at least one keyframe");
+  }
+
+  keyframe_t *keyframes = memoryAllocate(count * sizeof(keyframe_t));
+
+  size_t idx, max;
+  yyjson_val *keyframeJson;
+  yyjson_arr_foreach(channelJson, idx, max, keyframeJson) {
+    yyjson_val *timeVal = yyjson_obj_get(keyframeJson, "time");
+    yyjson_val *valueVal = yyjson_obj_get(keyframeJson, "value");
+    if(!timeVal || !valueVal) {
+      memoryFree(keyframes);
+      errorThrow("Animation keyframe missing 'time' or 'value'");
+    }
+
+    keyframes[idx].time = (float_t)yyjson_get_num(timeVal);
+    keyframes[idx].value = (float_t)yyjson_get_num(valueVal);
+
+    yyjson_val *easingVal = yyjson_obj_get(keyframeJson, "easing");
+    if(!easingVal) {
+      keyframes[idx].easing = EASING_LINEAR;
+      continue;
+    }
+
+    errorret_t ret = assetAnimationParseEasing(
+      yyjson_get_str(easingVal), &keyframes[idx].easing
+    );
+    if(errorIsNotOk(ret)) {
+      memoryFree(keyframes);
+      errorChain(ret);
+    }
+  }
+
+  *outKeyframes = keyframes;
+  *outCount = (uint16_t)count;
+  errorOk();
+}
+
+void assetAnimationFreeChannels(keyframe_t **tracks, const uint16_t count) {
+  for(uint16_t i = 0; i < count; i++) memoryFree(tracks[i]);
+  memoryFree(tracks);
+}

src/dusk/asset/loader/animation/assetanimationloader.h

@@ -0,0 +1,101 @@
+/**
+ * Copyright (c) 2026 Dominic Masters
+ *
+ * This software is released under the MIT License.
+ * https://opensource.org/licenses/MIT
+ */
+
+#pragma once
+#include "error/error.h"
+#include "asset/assetfile.h"
+#include "animation/animation.h"
+#include "yyjson.h"
+
+#define ASSET_ANIMATION_FILE_SIZE_MAX 1024*256
+
+typedef struct assetloading_s assetloading_t;
+typedef struct assetentry_s assetentry_t;
+
+/**
+ * JSON animation file format:
+ * {
+ *   "loop": false,
+ *   "speed": 1.0,
+ *   "channels": [
+ *     [
+ *       { "time": 0.0, "value": 0.0, "easing": "LINEAR" },
+ *       { "time": 1.0, "value": 10.0 }
+ *     ]
+ *   ]
+ * }
+ *
+ * "loop" and "speed" are optional, defaulting to false and 1.0 (see
+ * animationInit()). "channels" is required and must have at least one
+ * entry; each entry is itself a non-empty array of keyframes, ascending
+ * by "time", sharing one timeline with every other channel (see
+ * keyframeset_t). Each keyframe requires "time" and "value"; "easing" is
+ * optional and defaults to "LINEAR" (see easingtype_t for the full set of
+ * names, e.g. "IN_QUAD", "OUT_BACK", "IN_OUT_CUBIC").
+ */
+
+typedef enum {
+  ASSET_ANIMATION_LOADING_STATE_INITIAL,
+  ASSET_ANIMATION_LOADING_STATE_READ_FILE,
+  ASSET_ANIMATION_LOADING_STATE_PARSE,
+  ASSET_ANIMATION_LOADING_STATE_DONE
+} assetanimationloadingstate_t;
+
+typedef struct {
+  assetfile_t file;
+  assetanimationloadingstate_t state;
+  uint8_t *buffer;
+  size_t size;
+} assetanimationloaderloading_t;
+
+typedef animation_t assetanimationoutput_t;
+
+errorret_t assetAnimationLoaderAsync(assetloading_t *loading);
+errorret_t assetAnimationLoaderSync(assetloading_t *loading);
+errorret_t assetAnimationDispose(assetentry_t *entry);
+
+/**
+ * Internal. Maps a JSON easing name (e.g. "IN_OUT_QUAD") to its
+ * easingtype_t.
+ *
+ * @param name The easing name to parse.
+ * @param outEasing Destination for the parsed easing type.
+ * @return Error state; fails if name doesn't match any easingtype_t.
+ */
+errorret_t assetAnimationParseEasing(
+  const char_t *name,
+  easingtype_t *outEasing
+);
+
+/**
+ * Internal. Parses one "channels" array entry into a heap-allocated
+ * keyframe_t array (memoryAllocate) -- freed later by
+ * assetAnimationFreeChannels() (on a parse failure) or
+ * assetAnimationDispose() (once loaded).
+ *
+ * @param channelJson The channel's JSON array of keyframe objects.
+ * @param outKeyframes Destination for the newly allocated keyframe array.
+ * @param outCount Destination for the number of keyframes parsed.
+ * @return Error state.
+ */
+errorret_t assetAnimationParseChannel(
+  yyjson_val *channelJson,
+  keyframe_t **outKeyframes,
+  uint16_t *outCount
+);
+
+/**
+ * Internal. Frees the first count entries of tracks (each a
+ * memoryAllocate'd keyframe_t array from assetAnimationParseChannel()),
+ * then frees tracks itself. Used both to unwind a partially-parsed
+ * channel list on failure and to free a fully-loaded animation's
+ * channels in assetAnimationDispose().
+ *
+ * @param tracks The channel array to free.
+ * @param count The number of entries in tracks to free.
+ */
+void assetAnimationFreeChannels(keyframe_t **tracks, const uint16_t count);

src/dusk/asset/loader/assetloader.c

@@ -45,4 +45,10 @@ assetloadercallbacks_t ASSET_LOADER_CALLBACKS[ASSET_LOADER_TYPE_COUNT] = {
     .loadAsync = assetJsonLoaderAsync,
     .dispose = assetJsonDispose
   },
+
+  [ASSET_LOADER_TYPE_ANIMATION] = {
+    .loadSync = assetAnimationLoaderSync,
+    .loadAsync = assetAnimationLoaderAsync,
+    .dispose = assetAnimationDispose
+  },
 };

src/dusk/asset/loader/assetloader.h

@@ -12,6 +12,7 @@
 #include "asset/loader/display/assettilesetloader.h"
 #include "asset/loader/locale/assetlocaleloader.h"
 #include "asset/loader/json/assetjsonloader.h"
+#include "asset/loader/animation/assetanimationloader.h"
 
 typedef enum {
   ASSET_LOADER_TYPE_NULL,
@@ -22,6 +23,7 @@ typedef enum {
   ASSET_LOADER_TYPE_TILESET,
   ASSET_LOADER_TYPE_LOCALE,
   ASSET_LOADER_TYPE_JSON,
+  ASSET_LOADER_TYPE_ANIMATION,
 
   ASSET_LOADER_TYPE_COUNT
 } assetloadertype_t;
@@ -33,6 +35,7 @@ typedef union {
   assettilesetloaderloading_t tileset;
   assetlocaleloaderloading_t locale;
   assetjsonloaderloading_t json;
+  assetanimationloaderloading_t animation;
 } assetloaderloading_t;
 
 typedef union {
@@ -42,6 +45,7 @@ typedef union {
   assettilesetoutput_t tileset;
   assetlocaleoutput_t locale;
   assetjsonoutput_t json;
+  assetanimationoutput_t animation;
 } assetloaderoutput_t;
 
 typedef union {

test/animation/test_keyframeset.c

@@ -21,7 +21,7 @@ static void test_keyframeSetGetValuePerTrack(void **state) {
   uint16_t trackCounts[] = { 2, 2 };
 
   keyframeset_t set;
-  keyframeSetInit(&set, tracks, trackCounts, 2);
+  keyframeSetInit(&set, tracks, trackCounts, NULL, NULL, 2, NULL);
 
   assert_float_equal(keyframeSetGetValue(&set, 0, 0.5f), 5.0f, 0.0001f);
   assert_float_equal(keyframeSetGetValue(&set, 1, 0.5f), 150.0f, 0.0001f);
@@ -40,7 +40,7 @@ static void test_keyframeSetGetValuesFillsAllTracks(void **state) {
   uint16_t trackCounts[] = { 2, 2 };
 
   keyframeset_t set;
-  keyframeSetInit(&set, tracks, trackCounts, 2);
+  keyframeSetInit(&set, tracks, trackCounts, NULL, NULL, 2, NULL);
 
   float_t values[2];
   keyframeSetGetValues(&set, 0.5f, values);
@@ -61,16 +61,66 @@ static void test_keyframeSetGetDurationIsLongestTrack(void **state) {
   uint16_t trackCounts[] = { 2, 2 };
 
   keyframeset_t set;
-  keyframeSetInit(&set, tracks, trackCounts, 2);
+  keyframeSetInit(&set, tracks, trackCounts, NULL, NULL, 2, NULL);
 
   assert_float_equal(keyframeSetGetDuration(&set), 3.5f, 0.0001f);
 }
 
+static uint32_t TEST_CALLBACK_FIRE_COUNT;
+static uint16_t TEST_CALLBACK_LAST_TRACK;
+static void *TEST_CALLBACK_LAST_USER;
+
+static void test_onTrackCallback(
+  keyframeset_t *set,
+  const uint16_t trackIndex,
+  void *user
+) {
+  TEST_CALLBACK_FIRE_COUNT++;
+  TEST_CALLBACK_LAST_TRACK = trackIndex;
+  TEST_CALLBACK_LAST_USER = user;
+}
+
+static void test_keyframeSetFireCallbackInvokesPerTrackCallback(void **state) {
+  TEST_CALLBACK_FIRE_COUNT = 0;
+  TEST_CALLBACK_LAST_TRACK = 0xFFFF;
+  TEST_CALLBACK_LAST_USER = NULL;
+
+  keyframe_t xKeyframes[] = {
+    { .time = 0.0f, .value = 0.0f, .easing = EASING_LINEAR },
+    { .time = 1.0f, .value = 10.0f, .easing = EASING_LINEAR }
+  };
+  keyframe_t yKeyframes[] = {
+    { .time = 0.0f, .value = 0.0f, .easing = EASING_LINEAR },
+    { .time = 1.0f, .value = 10.0f, .easing = EASING_LINEAR }
+  };
+  keyframe_t *tracks[] = { xKeyframes, yKeyframes };
+  uint16_t trackCounts[] = { 2, 2 };
+
+  int32_t trackOneUser = 42;
+  keyframesetcallback_t callbacks[] = { NULL, test_onTrackCallback };
+  void *users[] = { NULL, &trackOneUser };
+  int32_t setUser = 7;
+
+  keyframeset_t set;
+  keyframeSetInit(&set, tracks, trackCounts, callbacks, users, 2, &setUser);
+
+  // Track 0 has no callback registered -- no-op.
+  keyframeSetFireCallback(&set, 0);
+  assert_int_equal(TEST_CALLBACK_FIRE_COUNT, 0);
+
+  keyframeSetFireCallback(&set, 1);
+  assert_int_equal(TEST_CALLBACK_FIRE_COUNT, 1);
+  assert_int_equal(TEST_CALLBACK_LAST_TRACK, 1);
+  assert_ptr_equal(TEST_CALLBACK_LAST_USER, &trackOneUser);
+  assert_ptr_equal(set.user, &setUser);
+}
+
 int main(int argc, char **argv) {
   const struct CMUnitTest tests[] = {
     cmocka_unit_test(test_keyframeSetGetValuePerTrack),
     cmocka_unit_test(test_keyframeSetGetValuesFillsAllTracks),
     cmocka_unit_test(test_keyframeSetGetDurationIsLongestTrack),
+    cmocka_unit_test(test_keyframeSetFireCallbackInvokesPerTrackCallback),
   };
 
   return cmocka_run_group_tests(tests, NULL, NULL);

test/asset/CMakeLists.txt

@@ -9,3 +9,4 @@ dusktest(test_assetlocale.c)
 dusktest(test_asset.c)
 dusktest(test_assetjsonloader.c)
 dusktest(test_assettilesetloader.c)
+dusktest(test_assetanimationloader.c)

test/asset/test_assetanimationloader.c

@@ -0,0 +1,329 @@
+/**
+ * Copyright (c) 2026 Dominic Masters
+ *
+ * This software is released under the MIT License.
+ * https://opensource.org/licenses/MIT
+ */
+
+#include "dusktest.h"
+#include "asset/asset.h"
+#include "asset/loader/assetloader.h"
+#include "asset/loader/assetentry.h"
+#include "asset/loader/animation/assetanimationloader.h"
+#include "thread/thread.h"
+#include "util/memory.h"
+#include <zip.h>
+
+// ============================================================
+// Fixtures
+// ============================================================
+
+static const char_t *ANIMATION_VALID =
+  "{"
+  "  \"loop\": true,"
+  "  \"speed\": 2.0,"
+  "  \"channels\": ["
+  "    ["
+  "      { \"time\": 0.0, \"value\": 0.0, \"easing\": \"LINEAR\" },"
+  "      { \"time\": 1.0, \"value\": 10.0 }"
+  "    ],"
+  "    ["
+  "      { \"time\": 0.0, \"value\": 100.0, \"easing\": \"IN_QUAD\" },"
+  "      { \"time\": 2.0, \"value\": 200.0 }"
+  "    ]"
+  "  ]"
+  "}";
+static const char_t *ANIMATION_INVALID_JSON =
+  "{ this is definitely not valid json !!!";
+static const char_t *ANIMATION_MISSING_CHANNELS = "{ \"loop\": false }";
+static const char_t *ANIMATION_EMPTY_CHANNELS = "{ \"channels\": [] }";
+static const char_t *ANIMATION_BAD_EASING =
+  "{"
+  "  \"channels\": ["
+  "    ["
+  "      { \"time\": 0.0, \"value\": 0.0, \"easing\": \"NOT_A_REAL_EASING\" },"
+  "      { \"time\": 1.0, \"value\": 10.0 }"
+  "    ]"
+  "  ]"
+  "}";
+
+// ============================================================
+// Async thread helper
+// ============================================================
+
+typedef struct {
+  assetloading_t *loading;
+  bool_t ok;
+} animation_async_run_t;
+
+static void animation_async_thread_cb(thread_t *thread) {
+  animation_async_run_t *run = (animation_async_run_t *)thread->data;
+  errorret_t ret = assetAnimationLoaderAsync(run->loading);
+  run->ok = errorIsOk(ret);
+  if(errorIsNotOk(ret)) errorCatch(ret);
+}
+
+static bool_t run_animation_async(assetloading_t *loading) {
+  animation_async_run_t run = { .loading = loading, .ok = false };
+  thread_t thread;
+  threadInit(&thread, animation_async_thread_cb);
+  thread.data = &run;
+  threadStart(&thread);
+  threadStop(&thread);
+  return run.ok;
+}
+
+// ============================================================
+// In-memory ZIP
+// ============================================================
+
+static zip_t *g_zip = NULL;
+
+static int zip_setup(void **state) {
+  zip_error_t err;
+  zip_error_init(&err);
+
+  zip_source_t *write_src = zip_source_buffer_create(NULL, 0, 1, &err);
+  if(!write_src) return -1;
+
+  zip_t *za = zip_open_from_source(write_src, ZIP_TRUNCATE, &err);
+  if(!za) { zip_source_free(write_src); return -1; }
+
+  zip_source_t *s;
+  s = zip_source_buffer(za, ANIMATION_VALID, strlen(ANIMATION_VALID), 0);
+  if(zip_file_add(za, "valid.anim.json", s, ZIP_FL_OVERWRITE) < 0) {
+    zip_close(za); return -1;
+  }
+  s = zip_source_buffer(
+    za, ANIMATION_INVALID_JSON, strlen(ANIMATION_INVALID_JSON), 0
+  );
+  if(zip_file_add(za, "invalid.anim.json", s, ZIP_FL_OVERWRITE) < 0) {
+    zip_close(za); return -1;
+  }
+  s = zip_source_buffer(
+    za, ANIMATION_MISSING_CHANNELS, strlen(ANIMATION_MISSING_CHANNELS), 0
+  );
+  if(zip_file_add(za, "missingchannels.anim.json", s, ZIP_FL_OVERWRITE) < 0) {
+    zip_close(za); return -1;
+  }
+  s = zip_source_buffer(
+    za, ANIMATION_EMPTY_CHANNELS, strlen(ANIMATION_EMPTY_CHANNELS), 0
+  );
+  if(zip_file_add(za, "emptychannels.anim.json", s, ZIP_FL_OVERWRITE) < 0) {
+    zip_close(za); return -1;
+  }
+  s = zip_source_buffer(
+    za, ANIMATION_BAD_EASING, strlen(ANIMATION_BAD_EASING), 0
+  );
+  if(zip_file_add(za, "badeasing.anim.json", s, ZIP_FL_OVERWRITE) < 0) {
+    zip_close(za); return -1;
+  }
+
+  zip_source_keep(write_src);
+  if(zip_close(za) != 0) { zip_source_free(write_src); return -1; }
+
+  zip_stat_t zs;
+  memset(&zs, 0, sizeof(zs));
+  if(zip_source_stat(write_src, &zs) != 0 || !(zs.valid & ZIP_STAT_SIZE)) {
+    zip_source_free(write_src); return -1;
+  }
+
+  void *zipbuf = malloc((size_t)zs.size);
+  if(!zipbuf) { zip_source_free(write_src); return -1; }
+
+  if(zip_source_open(write_src) != 0) {
+    free(zipbuf); zip_source_free(write_src); return -1;
+  }
+  zip_source_read(write_src, zipbuf, (zip_uint64_t)zs.size);
+  zip_source_close(write_src);
+  zip_source_free(write_src);
+
+  zip_error_init(&err);
+  zip_source_t *read_src = zip_source_buffer_create(
+    zipbuf, (zip_uint64_t)zs.size, 1, &err
+  );
+  if(!read_src) { free(zipbuf); return -1; }
+
+  g_zip = zip_open_from_source(read_src, 0, &err);
+  if(!g_zip) { zip_source_free(read_src); return -1; }
+
+  ASSET.zip = g_zip;
+  return 0;
+}
+
+static int zip_teardown(void **state) {
+  if(g_zip) { zip_close(g_zip); g_zip = NULL; }
+  ASSET.zip = NULL;
+  return 0;
+}
+
+// ============================================================
+// Loader pipeline helper
+// ============================================================
+
+typedef struct {
+  assetentry_t entry;
+  assetloading_t loading;
+} loader_ctx_t;
+
+static void loader_ctx_init(loader_ctx_t *ctx, const char_t *name) {
+  assetEntryInit(&ctx->entry, name, ASSET_LOADER_TYPE_ANIMATION, NULL);
+  threadMutexInit(&ctx->loading.mutex);
+  memoryZero(&ctx->loading.loading, sizeof(ctx->loading.loading));
+  ctx->loading.type = ASSET_LOADER_TYPE_ANIMATION;
+  ctx->loading.entry = &ctx->entry;
+  ctx->entry.state = ASSET_ENTRY_STATE_PENDING_SYNC;
+}
+
+// Drives sync(INITIAL) -> async(READ) -> sync(PARSE).
+static errorret_t loader_ctx_run(loader_ctx_t *ctx) {
+  errorret_t ret = assetAnimationLoaderSync(&ctx->loading);
+  if(errorIsNotOk(ret)) return ret;
+
+  if(!run_animation_async(&ctx->loading)) {
+    ctx->entry.state = ASSET_ENTRY_STATE_ERROR;
+    errorThrow("Async animation load failed");
+  }
+
+  return assetAnimationLoaderSync(&ctx->loading);
+}
+
+static void loader_ctx_dispose(loader_ctx_t *ctx) {
+  if(ctx->entry.type != ASSET_LOADER_TYPE_NULL) {
+    errorret_t ret = assetEntryDispose(&ctx->entry);
+    if(errorIsNotOk(ret)) errorCatch(ret);
+  }
+  threadMutexDispose(&ctx->loading.mutex);
+}
+
+// ============================================================
+// Tests
+// ============================================================
+
+static void test_animation_valid_loads(void **state) {
+  loader_ctx_t ctx;
+  loader_ctx_init(&ctx, "valid.anim.json");
+
+  errorret_t ret = loader_ctx_run(&ctx);
+  assert_true(errorIsOk(ret));
+  assert_int_equal(ctx.entry.state, ASSET_ENTRY_STATE_LOADED);
+
+  animation_t *anim = &ctx.entry.data.animation;
+  assert_true(anim->loop);
+  assert_float_equal(anim->speed, 2.0f, 0.0001f);
+  assert_int_equal(anim->keyframes.trackCount, 2);
+
+  assert_float_equal(
+    keyframeSetGetValue(&anim->keyframes, 0, 0.5f), 5.0f, 0.0001f
+  );
+  // Channel 1's first keyframe uses IN_QUAD -- a segment's easing comes
+  // from its starting keyframe, not its end. easingInQuad(0.5) = 0.25 ->
+  // lerp(100, 200, 0.25) = 125.
+  assert_float_equal(
+    keyframeSetGetValue(&anim->keyframes, 1, 1.0f), 125.0f, 0.0001f
+  );
+
+  loader_ctx_dispose(&ctx);
+  assert_int_equal(memoryGetAllocatedCount(), 0);
+}
+
+static void test_animation_parse_error(void **state) {
+  loader_ctx_t ctx;
+  loader_ctx_init(&ctx, "invalid.anim.json");
+
+  errorret_t ret = assetAnimationLoaderSync(&ctx.loading);
+  assert_true(errorIsOk(ret));
+  assert_true(run_animation_async(&ctx.loading));
+
+  ret = assetAnimationLoaderSync(&ctx.loading);
+  assert_true(errorIsNotOk(ret));
+  errorCatch(ret);
+  assert_int_equal(ctx.entry.state, ASSET_ENTRY_STATE_ERROR);
+
+  loader_ctx_dispose(&ctx);
+  assert_int_equal(memoryGetAllocatedCount(), 0);
+}
+
+static void test_animation_missing_channels(void **state) {
+  loader_ctx_t ctx;
+  loader_ctx_init(&ctx, "missingchannels.anim.json");
+
+  errorret_t ret = loader_ctx_run(&ctx);
+  assert_true(errorIsNotOk(ret));
+  errorCatch(ret);
+  assert_int_equal(ctx.entry.state, ASSET_ENTRY_STATE_ERROR);
+
+  loader_ctx_dispose(&ctx);
+  assert_int_equal(memoryGetAllocatedCount(), 0);
+}
+
+static void test_animation_empty_channels(void **state) {
+  loader_ctx_t ctx;
+  loader_ctx_init(&ctx, "emptychannels.anim.json");
+
+  errorret_t ret = loader_ctx_run(&ctx);
+  assert_true(errorIsNotOk(ret));
+  errorCatch(ret);
+  assert_int_equal(ctx.entry.state, ASSET_ENTRY_STATE_ERROR);
+
+  loader_ctx_dispose(&ctx);
+  assert_int_equal(memoryGetAllocatedCount(), 0);
+}
+
+static void test_animation_bad_easing(void **state) {
+  loader_ctx_t ctx;
+  loader_ctx_init(&ctx, "badeasing.anim.json");
+
+  errorret_t ret = loader_ctx_run(&ctx);
+  assert_true(errorIsNotOk(ret));
+  errorCatch(ret);
+  assert_int_equal(ctx.entry.state, ASSET_ENTRY_STATE_ERROR);
+
+  // Confirms the mid-parse cleanup path frees the channel array it had
+  // already allocated before hitting the bad easing name.
+  loader_ctx_dispose(&ctx);
+  assert_int_equal(memoryGetAllocatedCount(), 0);
+}
+
+static void test_animation_missing_file(void **state) {
+  loader_ctx_t ctx;
+  loader_ctx_init(&ctx, "nonexistent.anim.json");
+
+  errorret_t ret = assetAnimationLoaderSync(&ctx.loading);
+  assert_true(errorIsOk(ret));
+
+  assert_false(run_animation_async(&ctx.loading));
+  assert_int_equal(ctx.entry.state, ASSET_ENTRY_STATE_ERROR);
+
+  loader_ctx_dispose(&ctx);
+  assert_int_equal(memoryGetAllocatedCount(), 0);
+}
+
+// ============================================================
+// main
+// ============================================================
+
+int main(void) {
+  assertInit();
+  const struct CMUnitTest tests[] = {
+    cmocka_unit_test_setup_teardown(
+      test_animation_valid_loads, zip_setup, zip_teardown
+    ),
+    cmocka_unit_test_setup_teardown(
+      test_animation_parse_error, zip_setup, zip_teardown
+    ),
+    cmocka_unit_test_setup_teardown(
+      test_animation_missing_channels, zip_setup, zip_teardown
+    ),
+    cmocka_unit_test_setup_teardown(
+      test_animation_empty_channels, zip_setup, zip_teardown
+    ),
+    cmocka_unit_test_setup_teardown(
+      test_animation_bad_easing, zip_setup, zip_teardown
+    ),
+    cmocka_unit_test_setup_teardown(
+      test_animation_missing_file, zip_setup, zip_teardown
+    ),
+  };
+  return cmocka_run_group_tests(tests, NULL, NULL);
+}