1 files changed, 85 insertions, 0 deletions
diff --git a/src/blucat/animation/frame.hpp b/src/blucat/animation/frame.hpp
new file mode 100644
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+++ b/src/blucat/animation/frame.hpp
@@ -0,0 +1,85 @@
+/*
+ * Copyright 2022-2024 Frederico de Oliveira Linhares
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef CANDY_GEAR_BLUCAT_FRAME_H
+#define CANDY_GEAR_BLUCAT_FRAME_H 1
+
+#include <vector>
+
+#include "../core.hpp"
+
+namespace BluCat
+{
+
+template<typename T>
+struct Frame
+{
+  const T value;
+  const float timestamp;
+
+  Frame(T value, float timestamp):
+  value{value},
+  timestamp{timestamp}
+  {
+  }
+
+};
+
+template<typename T>
+struct Channel
+{
+  int current_index{0};
+  std::vector<Frame<T>> key_frames;
+
+  inline glm::mat4
+  interpolate(
+    float animation_time,
+    glm::mat4 (*single_frame)(T frame),
+    glm::mat4 (*multiple_frames)(T current_frame, T next_frame, float scale))
+  {
+    if(this->key_frames.size() == 1)
+      return single_frame(this->key_frames[0].value);
+    else
+    {
+      while(animation_time > this->key_frames[current_index].timestamp)
+        this->current_index++;
+
+      float scale_factor;
+      Frame<T> *previous_frame;
+      Frame<T> *next_frame{&(this->key_frames[this->current_index])};
+      if(this->current_index == 0)
+      {
+	previous_frame = &(this->key_frames[this->key_frames.size() - 1]);
+        float midway_length{animation_time - 0};
+        float frames_diff{next_frame->timestamp - 0};
+        scale_factor = midway_length / frames_diff;
+      }
+      else
+      {
+	previous_frame = &(this->key_frames[this->current_index - 1]);
+        float midway_length{animation_time - previous_frame->timestamp};
+        float frames_diff{next_frame->timestamp - previous_frame->timestamp};
+        scale_factor = midway_length / frames_diff;
+      }
+
+      return multiple_frames(
+	previous_frame->value, next_frame->value, scale_factor);
+    }
+  };
+};
+
+}
+#endif /* CANDY_GEAR_BLUCAT_FRAME_H */