[Bf-blender-cvs] [72381da8008] xr-controller-support: XR: Don't store controller node world transforms

[Peter Kim]

Commit: 72381da80085a689eb1c90dd9db11d5b26116a24
Author: Peter Kim
Date:   Mon Aug 16 18:55:36 2021 +0900
Branches: xr-controller-support
https://developer.blender.org/rB72381da80085a689eb1c90dd9db11d5b26116a24

XR: Don't store controller node world transforms

Removes unnecessary storage of world space transforms for controller
model nodes. Now, only local space transforms are stored and the
world transforms are calculated from these local transforms when
needed.

===================================================================

M	intern/ghost/GHOST_Types.h
M	intern/ghost/intern/GHOST_XrControllerModel.cpp

===================================================================

diff --git a/intern/ghost/GHOST_Types.h b/intern/ghost/GHOST_Types.h
index eaf21c738dc..b16e3b4b041 100644
--- a/intern/ghost/GHOST_Types.h
+++ b/intern/ghost/GHOST_Types.h
@@ -748,7 +748,7 @@ typedef struct GHOST_XrActionProfileInfo {
   const char *profile_path;
   uint32_t count_subaction_paths;
   const char **subaction_paths;
-  /* Bindings for each subaction path. */
+  /** Bindings for each subaction path. */
   const GHOST_XrActionBindingInfo *bindings;
 } GHOST_XrActionProfileInfo;
 
@@ -758,6 +758,7 @@ typedef struct GHOST_XrControllerModelVertex {
 } GHOST_XrControllerModelVertex;
 
 typedef struct GHOST_XrControllerModelComponent {
+  /** World space transform. */
   float transform[4][4];
   uint32_t vertex_offset;
   uint32_t vertex_count;
diff --git a/intern/ghost/intern/GHOST_XrControllerModel.cpp b/intern/ghost/intern/GHOST_XrControllerModel.cpp
index fdd1c12af5b..4c240d73239 100644
--- a/intern/ghost/intern/GHOST_XrControllerModel.cpp
+++ b/intern/ghost/intern/GHOST_XrControllerModel.cpp
@@ -39,7 +39,6 @@ struct GHOST_XrControllerModelNode {
   int32_t parent_idx = -1;
   int32_t component_idx = -1;
   float local_transform[4][4];
-  float world_transform[4][4];
 };
 
 /* -------------------------------------------------------------------- */
@@ -228,10 +227,11 @@ static GHOST_XrPrimitive read_primitive(const tinygltf::Model &gltf_model,
   return primitive;
 }
 
-/* Calculate node transform in world space. */
-static void calc_node_transform(const tinygltf::Node &gltf_node,
-                                const float parent_transform[4][4],
-                                GHOST_XrControllerModelNode &node)
+/* Calculate node local and world transforms. */
+static void calc_node_transforms(const tinygltf::Node &gltf_node,
+                                 const float parent_transform[4][4],
+                                 float r_local_transform[4][4],
+                                 float r_world_transform[4][4])
 {
   /* A node may specify either a 4x4 matrix or TRS (Translation - Rotation - Scale) values, but not
    * both. */
@@ -253,14 +253,14 @@ static void calc_node_transform(const tinygltf::Node &gltf_node,
                      (float)dm[13],
                      (float)dm[14],
                      (float)dm[15]};
-    memcpy(node.local_transform, m, sizeof(node.local_transform));
+    memcpy(r_local_transform, m, sizeof(float) * 16);
   }
   else {
     /* No matrix is present, so construct a matrix from the TRS values (each one is optional). */
     std::vector<double> translation = gltf_node.translation;
     std::vector<double> rotation = gltf_node.rotation;
     std::vector<double> scale = gltf_node.scale;
-    Eigen::Matrix4f &m = *(Eigen::Matrix4f *)node.local_transform;
+    Eigen::Matrix4f &m = *(Eigen::Matrix4f *)r_local_transform;
     Eigen::Quaternionf q;
     Eigen::Matrix3f scalemat;
 
@@ -295,8 +295,8 @@ static void calc_node_transform(const tinygltf::Node &gltf_node,
         (float)translation[0], (float)translation[1], (float)translation[2]);
   }
 
-  *(Eigen::Matrix4f *)node.world_transform = *(Eigen::Matrix4f *)parent_transform *
-                                             *(Eigen::Matrix4f *)node.local_transform;
+  *(Eigen::Matrix4f *)r_world_transform = *(Eigen::Matrix4f *)parent_transform *
+                                          *(Eigen::Matrix4f *)r_local_transform;
 }
 
 static void load_node(tinygltf::Model gltf_model,
@@ -312,11 +312,12 @@ static void load_node(tinygltf::Model gltf_model,
                       std::vector<int32_t> &node_state_indices)
 {
   const tinygltf::Node &gltf_node = gltf_model.nodes.at(gltf_node_id);
+  float world_transform[4][4];
 
   GHOST_XrControllerModelNode &node = nodes.emplace_back();
   const int32_t node_idx = (int32_t)(nodes.size() - 1);
   node.parent_idx = parent_idx;
-  calc_node_transform(gltf_node, parent_transform, node);
+  calc_node_transforms(gltf_node, parent_transform, node.local_transform, world_transform);
 
   for (size_t i = 0; i < node_properties.size(); ++i) {
     if ((node_state_indices[i] < 0) && (parent_name == node_properties[i].parentNodeName) &&
@@ -331,7 +332,7 @@ static void load_node(tinygltf::Model gltf_model,
 
     GHOST_XrControllerModelComponent &component = components.emplace_back();
     node.component_idx = components.size() - 1;
-    memcpy(component.transform, node.world_transform, sizeof(component.transform));
+    memcpy(component.transform, world_transform, sizeof(component.transform));
     component.vertex_offset = vertices.size();
     component.index_offset = indices.size();
 
@@ -366,7 +367,7 @@ static void load_node(tinygltf::Model gltf_model,
     load_node(gltf_model,
               child_node_id,
               node_idx,
-              node.world_transform,
+              world_transform,
               gltf_node.name,
               node_properties,
               vertices,
@@ -557,17 +558,19 @@ void GHOST_XrControllerModel::updateComponents(XrSession session)
     }
   }
 
-  /* Update node/component world transforms. */
-  for (GHOST_XrControllerModelNode &node : m_nodes) {
-    *(Eigen::Matrix4f *)node.world_transform =
-        (node.parent_idx > 0) ? *(Eigen::Matrix4f *)m_nodes[node.parent_idx].world_transform *
-                                    *(Eigen::Matrix4f *)node.local_transform :
-                                *(Eigen::Matrix4f *)node.local_transform;
+  /* Calculate component transforms (in world space). */
+  std::vector<Eigen::Matrix4f> world_transforms(m_nodes.size());
+  uint32_t i = 0;
+  for (const GHOST_XrControllerModelNode &node : m_nodes) {
+    world_transforms[i] = (node.parent_idx > 0) ? world_transforms[node.parent_idx] *
+                                                      *(Eigen::Matrix4f *)node.local_transform :
+                                                  *(Eigen::Matrix4f *)node.local_transform;
     if (node.component_idx > 0) {
       memcpy(m_components[node.component_idx].transform,
-             node.world_transform,
+             world_transforms[i].data(),
              sizeof(m_components[node.component_idx].transform));
     }
+    ++i;
   }
 }