Use true pitch/yaw/roll rotations without loss of precision by pgimeno (#8019)

Store the rotation in the node as a 4x4 transformation matrix internally (through IDummyTransformationSceneNode), which allows more manipulations without losing precision or having gimbal lock issues.

Network rotation is still transmitted as Eulers, though, not as matrix. But it will stay this way in 5.0.

2 files changed, 81 insertions, 46 deletions

diff --git a/src/client/content_cao.cpp b/src/client/content_cao.cpp
index 116a2e53b..6112edaff 100644
--- a/src/client/content_cao.cpp
+++ b/src/client/content_cao.cpp
@@ -23,7 +23,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include <IMeshManipulator.h>
 #include <IAnimatedMeshSceneNode.h>
 #include "content_cao.h"
-#include "util/numeric.h" // For IntervalLimiter
+#include "util/numeric.h" // For IntervalLimiter & setPitchYawRoll
 #include "util/serialize.h"
 #include "util/basic_macros.h"
 #include "client/sound.h"
@@ -365,7 +365,7 @@ void GenericCAO::processInitData(const std::string &data)
 		return;
 	}
 
-	// PROTOCOL_VERSION >= 37 
+	// PROTOCOL_VERSION >= 37
 	m_name = deSerializeString(is);
 	m_is_player = readU8(is);
 	m_id = readU16(is);
@@ -402,10 +402,9 @@ bool GenericCAO::getSelectionBox(aabb3f *toset) const
 
 v3f GenericCAO::getPosition()
 {
-	if (getParent() != NULL) {
-		scene::ISceneNode *node = getSceneNode();
-		if (node)
-			return node->getAbsolutePosition();
+	if (getParent() != nullptr) {
+		if (m_matrixnode)
+			return m_matrixnode->getAbsolutePosition();
 
 		return m_position;
 	}
@@ -486,7 +485,7 @@ void GenericCAO::removeFromScene(bool permanent)
 
 		LocalPlayer* player = m_env->getLocalPlayer();
 		if (this == player->parent) {
-			player->parent = NULL;
+			player->parent = nullptr;
 			player->isAttached = false;
 		}
 	}
@@ -494,24 +493,30 @@ void GenericCAO::removeFromScene(bool permanent)
 	if (m_meshnode) {
 		m_meshnode->remove();
 		m_meshnode->drop();
-		m_meshnode = NULL;
+		m_meshnode = nullptr;
 	} else if (m_animated_meshnode)	{
 		m_animated_meshnode->remove();
 		m_animated_meshnode->drop();
-		m_animated_meshnode = NULL;
+		m_animated_meshnode = nullptr;
 	} else if (m_wield_meshnode) {
 		m_wield_meshnode->remove();
 		m_wield_meshnode->drop();
-		m_wield_meshnode = NULL;
+		m_wield_meshnode = nullptr;
 	} else if (m_spritenode) {
 		m_spritenode->remove();
 		m_spritenode->drop();
-		m_spritenode = NULL;
+		m_spritenode = nullptr;
+	}
+
+	if (m_matrixnode) {
+		m_matrixnode->remove();
+		m_matrixnode->drop();
+		m_matrixnode = nullptr;
 	}
 
 	if (m_nametag) {
 		m_client->getCamera()->removeNametag(m_nametag);
-		m_nametag = NULL;
+		m_nametag = nullptr;
 	}
 }
 
@@ -534,8 +539,11 @@ void GenericCAO::addToScene(ITextureSource *tsrc)
 
 	if (m_prop.visual == "sprite") {
 		infostream<<"GenericCAO::addToScene(): single_sprite"<<std::endl;
+		m_matrixnode = RenderingEngine::get_scene_manager()->
+				addDummyTransformationSceneNode();
+		m_matrixnode->grab();
 		m_spritenode = RenderingEngine::get_scene_manager()->addBillboardSceneNode(
-				NULL, v2f(1, 1), v3f(0,0,0), -1);
+				m_matrixnode, v2f(1, 1), v3f(0,0,0), -1);
 		m_spritenode->grab();
 		m_spritenode->setMaterialTexture(0,
 				tsrc->getTextureForMesh("unknown_node.png"));
@@ -608,17 +616,24 @@ void GenericCAO::addToScene(ITextureSource *tsrc)
 			mesh->addMeshBuffer(buf);
 			buf->drop();
 		}
-		m_meshnode = RenderingEngine::get_scene_manager()->addMeshSceneNode(mesh, NULL);
+		m_matrixnode = RenderingEngine::get_scene_manager()->
+			addDummyTransformationSceneNode();
+		m_matrixnode->grab();
+		m_meshnode = RenderingEngine::get_scene_manager()->
+			addMeshSceneNode(mesh, m_matrixnode);
 		m_meshnode->grab();
 		mesh->drop();
 		// Set it to use the materials of the meshbuffers directly.
 		// This is needed for changing the texture in the future
 		m_meshnode->setReadOnlyMaterials(true);
-	}
-	else if(m_prop.visual == "cube") {
+	} else if (m_prop.visual == "cube") {
 		infostream<<"GenericCAO::addToScene(): cube"<<std::endl;
 		scene::IMesh *mesh = createCubeMesh(v3f(BS,BS,BS));
-		m_meshnode = RenderingEngine::get_scene_manager()->addMeshSceneNode(mesh, NULL);
+		m_matrixnode = RenderingEngine::get_scene_manager()->
+			addDummyTransformationSceneNode(nullptr);
+		m_matrixnode->grab();
+		m_meshnode = RenderingEngine::get_scene_manager()->
+			addMeshSceneNode(mesh, m_matrixnode);
 		m_meshnode->grab();
 		mesh->drop();
 
@@ -630,14 +645,15 @@ void GenericCAO::addToScene(ITextureSource *tsrc)
 		m_meshnode->setMaterialFlag(video::EMF_BILINEAR_FILTER, false);
 		m_meshnode->setMaterialType(material_type);
 		m_meshnode->setMaterialFlag(video::EMF_FOG_ENABLE, true);
-	}
-	else if(m_prop.visual == "mesh") {
+	} else if (m_prop.visual == "mesh") {
 		infostream<<"GenericCAO::addToScene(): mesh"<<std::endl;
 		scene::IAnimatedMesh *mesh = m_client->getMesh(m_prop.mesh, true);
-		if(mesh)
-		{
+		if (mesh) {
+			m_matrixnode = RenderingEngine::get_scene_manager()->
+				addDummyTransformationSceneNode(nullptr);
+			m_matrixnode->grab();
 			m_animated_meshnode = RenderingEngine::get_scene_manager()->
-				addAnimatedMeshSceneNode(mesh, NULL);
+				addAnimatedMeshSceneNode(mesh, m_matrixnode);
 			m_animated_meshnode->grab();
 			mesh->drop(); // The scene node took hold of it
 			m_animated_meshnode->animateJoints(); // Needed for some animations
@@ -655,8 +671,7 @@ void GenericCAO::addToScene(ITextureSource *tsrc)
 			m_animated_meshnode->setMaterialFlag(video::EMF_FOG_ENABLE, true);
 			m_animated_meshnode->setMaterialFlag(video::EMF_BACK_FACE_CULLING,
 				m_prop.backface_culling);
-		}
-		else
+		} else
 			errorstream<<"GenericCAO::addToScene(): Could not load mesh "<<m_prop.mesh<<std::endl;
 	} else if (m_prop.visual == "wielditem" || m_prop.visual == "item") {
 		ItemStack item;
@@ -674,8 +689,12 @@ void GenericCAO::addToScene(ITextureSource *tsrc)
 			infostream << "serialized form: " << m_prop.wield_item << std::endl;
 			item.deSerialize(m_prop.wield_item, m_client->idef());
 		}
+		m_matrixnode = RenderingEngine::get_scene_manager()->
+			addDummyTransformationSceneNode(nullptr);
+		m_matrixnode->grab();
 		m_wield_meshnode = new WieldMeshSceneNode(
 			RenderingEngine::get_scene_manager(), -1);
+		m_wield_meshnode->setParent(m_matrixnode);
 		m_wield_meshnode->setItem(item, m_client,
 			(m_prop.visual == "wielditem"));
 
@@ -763,10 +782,12 @@ void GenericCAO::updateNodePos()
 
 	if (node) {
 		v3s16 camera_offset = m_env->getCameraOffset();
-		node->setPosition(pos_translator.val_current - intToFloat(camera_offset, BS));
+		v3f pos = pos_translator.val_current -
+				intToFloat(camera_offset, BS);
+		getPosRotMatrix().setTranslation(pos);
 		if (node != m_spritenode) { // rotate if not a sprite
 			v3f rot = m_is_local_player ? -m_rotation : -rot_translator.val_current;
-			node->setRotation(rot);
+			setPitchYawRoll(getPosRotMatrix(), rot);
 		}
 	}
 }
@@ -858,8 +879,10 @@ void GenericCAO::step(float dtime, ClientEnvironment *env)
 			ClientActiveObject *obj = m_env->getActiveObject(*ci);
 			if (obj) {
 				scene::ISceneNode *child_node = obj->getSceneNode();
+				// The node's parent is always an IDummyTraformationSceneNode,
+				// so we need to reparent that one instead.
 				if (child_node)
-					child_node->setParent(m_smgr->getRootSceneNode());
+					child_node->getParent()->setParent(m_smgr->getRootSceneNode());
 			}
 			++ci;
 		}
@@ -1266,16 +1289,13 @@ void GenericCAO::updateBonePosition()
 
 void GenericCAO::updateAttachments()
 {
-
-	if (!getParent()) { // Detach or don't attach
-		scene::ISceneNode *node = getSceneNode();
-		if (node) {
-			v3f old_position = node->getAbsolutePosition();
-			v3f old_rotation = node->getRotation();
-			node->setParent(m_smgr->getRootSceneNode());
-			node->setPosition(old_position);
-			node->setRotation(old_rotation);
-			node->updateAbsolutePosition();
+	ClientActiveObject *parent = getParent();
+	if (!parent) { // Detach or don't attach
+		if (m_matrixnode) {
+			v3f old_pos = m_matrixnode->getAbsolutePosition();
+			m_matrixnode->setParent(m_smgr->getRootSceneNode());
+			getPosRotMatrix().setTranslation(old_pos);
+			m_matrixnode->updateAbsolutePosition();
 		}
 		if (m_is_local_player) {
 			LocalPlayer *player = m_env->getLocalPlayer();
@@ -1284,20 +1304,20 @@ void GenericCAO::updateAttachments()
 	}
 	else // Attach
 	{
-		scene::ISceneNode *my_node = getSceneNode();
-
-		scene::ISceneNode *parent_node = getParent()->getSceneNode();
+		scene::ISceneNode *parent_node = parent->getSceneNode();
 		scene::IAnimatedMeshSceneNode *parent_animated_mesh_node =
-				getParent()->getAnimatedMeshSceneNode();
+				parent->getAnimatedMeshSceneNode();
 		if (parent_animated_mesh_node && !m_attachment_bone.empty()) {
 			parent_node = parent_animated_mesh_node->getJointNode(m_attachment_bone.c_str());
 		}
 
-		if (my_node && parent_node) {
-			my_node->setParent(parent_node);
-			my_node->setPosition(m_attachment_position);
-			my_node->setRotation(m_attachment_rotation);
-			my_node->updateAbsolutePosition();
+		if (m_matrixnode && parent_node) {
+			m_matrixnode->setParent(parent_node);
+			getPosRotMatrix().setTranslation(m_attachment_position);
+			//setPitchYawRoll(getPosRotMatrix(), m_attachment_rotation);
+			// use Irrlicht eulers instead
+			getPosRotMatrix().setRotationDegrees(m_attachment_rotation);
+			m_matrixnode->updateAbsolutePosition();
 		}
 		if (m_is_local_player) {
 			LocalPlayer *player = m_env->getLocalPlayer();
diff --git a/src/client/content_cao.h b/src/client/content_cao.h
index 98932137e..4627800ee 100644
--- a/src/client/content_cao.h
+++ b/src/client/content_cao.h
@@ -25,6 +25,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "object_properties.h"
 #include "itemgroup.h"
 #include "constants.h"
+#include <cassert>
 
 class Camera;
 class Client;
@@ -81,6 +82,7 @@ private:
 	scene::IAnimatedMeshSceneNode *m_animated_meshnode = nullptr;
 	WieldMeshSceneNode *m_wield_meshnode = nullptr;
 	scene::IBillboardSceneNode *m_spritenode = nullptr;
+	scene::IDummyTransformationSceneNode *m_matrixnode = nullptr;
 	Nametag *m_nametag = nullptr;
 	v3f m_position = v3f(0.0f, 10.0f * BS, 0);
 	v3f m_velocity;
@@ -163,6 +165,19 @@ public:
 
 	scene::IAnimatedMeshSceneNode *getAnimatedMeshSceneNode();
 
+	// m_matrixnode controls the position and rotation of the child node
+	// for all scene nodes, as a workaround for an Irrlicht problem with
+	// rotations. The child node's position can't be used because it's
+	// rotated, and must remain as 0.
+	// Note that m_matrixnode.setPosition() shouldn't be called. Use
+	// m_matrixnode->getRelativeTransformationMatrix().setTranslation()
+	// instead (aka getPosRotMatrix().setTranslation()).
+	inline core::matrix4 &getPosRotMatrix()
+	{
+		assert(m_matrixnode);
+		return m_matrixnode->getRelativeTransformationMatrix();
+	}
+
 	inline f32 getStepHeight() const
 	{
 		return m_prop.stepheight;