Add missing file.

examples/skinning/skinning.h

@@ -0,0 +1,61 @@
+#ifndef EXAMPLE_SKINNING_H_
+#define EXAMPLE_SKINNING_H_
+
+#include <vector>
+
+namespace example {
+
+struct mat4 {
+  float m[4][4];
+};
+
+///
+/// Utility function to build transformation matrix from translate/rotation/scale
+///
+/// https://github.com/KhronosGroup/glTF-Tutorials/blob/master/gltfTutorial/gltfTutorial_004_ScenesNodes.md
+///
+/// M = T * R * S
+///
+void BuildTransofrmMatrix(
+  const float translate[3],
+  const float rotation[4], // as quaternion in glTF
+  const float scale[3],
+  mat4 *transform_matrix);
+  
+
+///
+/// Compute joint matrices.
+///
+/// jointMatrix(j) =
+///   globalTransformOfNodeThatTheMeshIsAttachedTo^-1 *
+///   globalTransformOfJointNode(j) *
+///   inverseBindMatrixForJoint(j);
+///
+
+void ComputeJointMatrices(
+  const std::vector<mat4> global_transform_of_nodes,
+  const std::vector<mat4> global_transform_of_joint_nodes,
+  const std::vector<mat4> inverse_bind_matrix_for_joints,
+  std::vector<mat4> output_joint_matrices);
+
+
+///
+///
+/// @param[in] vertices Input vertices(# of elements = num_vertices * 4(xyzw))
+/// @param[in] weights Linearized weights(# of elements = num_vertices * num_skinning_weights)
+/// @param[in] weights Linearized weights(# of elements = num_vertices * num_skinning_weights)
+/// @param[in] num_weights Linearized weights(# of elements = num_vertices * 
+/// @param[in] joint_matrices Array of joint matricies.
+/// @param[in] t Interpolator. [0.0, 1.0]
+/// @param[in] skinned_vertices Resulting skinned vertices
+///
+void Skining(const std::vector<float> vertices,
+             const std::vector<float> weights, const std::vector<size_t> joints,
+             const size_t num_skinning_weights,
+             const std::vector<mat4> joint_matrices,
+             const float t,
+             std::vector<float> *skinned_vertices);
+
+}  // namespace example
+
+#endif  // EXAMPLE_SKINNING_H_