crown-engine/engine/world/scene_graph.cpp

/*
 * Copyright (c) 2012-2014 Daniele Bartolini and individual contributors.
 * License: https://github.com/taylor001/crown/blob/master/LICENSE
 */

#include "scene_graph.h"
#include "quaternion.h"
#include "vector3.h"
#include "matrix4x4.h"
#include "allocator.h"
#include "string_utils.h"
#include "murmur.h"
#include <string.h>

#define CLEAN		0
#define LOCAL_DIRTY	1
#define WORLD_DIRTY	1 << 2

namespace crown
{

using namespace matrix4x4;

SceneGraph::SceneGraph(Allocator& a, uint32_t index)
	: m_allocator(&a)
	, m_index(index)
	, m_num_nodes(0)
	, m_flags(NULL)
	, m_world_poses(NULL)
	, m_local_poses(NULL)
	, m_parents(NULL)
	, m_names(NULL)
{
}

void SceneGraph::create(const Matrix4x4& root, uint32_t count, const UnitNode* nodes)
{
	m_num_nodes = count;

	m_flags = (uint8_t*) m_allocator->allocate(sizeof(uint8_t) * count);
	m_world_poses = (Matrix4x4*) m_allocator->allocate(sizeof(Matrix4x4) * count);
	m_local_poses = (Matrix4x4*) m_allocator->allocate(sizeof(Matrix4x4) * count);
	m_parents = (int32_t*) m_allocator->allocate(sizeof(int32_t) * count);
	m_names = (StringId32*) m_allocator->allocate(sizeof(StringId32) * count);

	for (uint32_t i = 0; i < count; i++)
	{
		m_flags[i] = (int) CLEAN;
		m_local_poses[i] = nodes[i].pose;
		m_parents[i] = -1;
		m_names[i] = nodes[i].name;
	}

	// Compute initial world poses
	for (uint32_t i = 1; i < m_num_nodes; i++)
	{
		m_world_poses[i] = root * m_local_poses[i];
	}

	m_world_poses[0] = root;
	m_flags[0] = WORLD_DIRTY;

	update();
}

void SceneGraph::destroy()
{
	m_allocator->deallocate(m_flags);
	m_allocator->deallocate(m_world_poses);
	m_allocator->deallocate(m_local_poses);
	m_allocator->deallocate(m_parents);
	m_allocator->deallocate(m_names);
}

int32_t SceneGraph::node(const char* name) const
{
	return node(murmur2_32(name, strlen(name)));
}

int32_t SceneGraph::node(StringId32 name) const
{
	for (uint32_t i = 0; i < m_num_nodes; i++)
	{
		if (m_names[i] == name)
		{
			return i;
		}
	}

	CE_FATAL("Node not found");
	return 0;
}

bool SceneGraph::has_node(const char* name) const
{
	StringId32 name_hash = murmur2_32(name, strlen(name), 0);

	for (uint32_t i = 0; i < m_num_nodes; i++)
	{
		if (m_names[i] == name_hash)
		{
			return true;
		}
	}

	return false;
}

uint32_t SceneGraph::num_nodes() const
{
	return m_num_nodes;
}

bool SceneGraph::can_link(int32_t child, int32_t parent) const
{
	return parent < child;
}

void SceneGraph::link(int32_t child, int32_t parent)
{
	CE_ASSERT(child < (int32_t) m_num_nodes, "Child node does not exist");
	CE_ASSERT(parent < (int32_t) m_num_nodes, "Parent node does not exist");
	CE_ASSERT(can_link(child, parent), "Parent must be < child");

	m_world_poses[child] = matrix4x4::IDENTITY;
	m_local_poses[child] = matrix4x4::IDENTITY;
	m_parents[child] = parent;
}

void SceneGraph::unlink(int32_t child)
{
	CE_ASSERT(child < (int32_t) m_num_nodes, "Child node does not exist");

	if (m_parents[child] != -1)
	{
		// Copy world pose before unlinking from parent
		m_local_poses[child] = m_world_poses[child];
		m_parents[child] = -1;
	}
}

void SceneGraph::set_local_position(int32_t node, const Vector3& pos)
{
	CE_ASSERT(node < (int32_t) m_num_nodes, "Node does not exist");

	m_flags[node] |= LOCAL_DIRTY;
	set_translation(m_local_poses[node], pos);
}

void SceneGraph::set_local_rotation(int32_t node, const Quaternion& rot)
{
	CE_ASSERT(node < (int32_t) m_num_nodes, "Node does not exist");

	m_flags[node] |= LOCAL_DIRTY;
	set_rotation(m_local_poses[node], rot);
}

void SceneGraph::set_local_pose(int32_t node, const Matrix4x4& pose)
{
	CE_ASSERT(node < (int32_t) m_num_nodes, "Node does not exist");

	m_flags[node] |= LOCAL_DIRTY;
	m_local_poses[node] = pose;
}

Vector3 SceneGraph::local_position(int32_t node) const
{
	CE_ASSERT(node < (int32_t) m_num_nodes, "Node does not exist");

	return translation(m_local_poses[node]);
}

Quaternion SceneGraph::local_rotation(int32_t node) const
{
	CE_ASSERT(node < (int32_t) m_num_nodes, "Node does not exist");

	return rotation(m_local_poses[node]);
}

Matrix4x4 SceneGraph::local_pose(int32_t node) const
{
	CE_ASSERT(node < (int32_t) m_num_nodes, "Node does not exist");

	return m_local_poses[node];
}

void SceneGraph::set_world_position(int32_t node, const Vector3& pos)
{
	CE_ASSERT(node < (int32_t) m_num_nodes, "Node does not exist");

	m_flags[node] |= WORLD_DIRTY;
	set_translation(m_world_poses[node], pos);
}

void SceneGraph::set_world_rotation(int32_t node, const Quaternion& rot)
{
	CE_ASSERT(node < (int32_t) m_num_nodes, "Node does not exist");

	m_flags[node] |= WORLD_DIRTY;
	set_rotation(m_world_poses[node], rot);
}

void SceneGraph::set_world_pose(int32_t node, const Matrix4x4& pose)
{
	CE_ASSERT(node < (int32_t) m_num_nodes, "Node does not exist");

	m_flags[node] |= WORLD_DIRTY;
	m_world_poses[node] = pose;
}

Vector3 SceneGraph::world_position(int32_t node) const
{
	CE_ASSERT(node < (int32_t) m_num_nodes, "Node does not exist");

	return translation(m_world_poses[node]);
}

Quaternion SceneGraph::world_rotation(int32_t node) const
{
	CE_ASSERT(node < (int32_t) m_num_nodes, "Node does not exist");

	return rotation(m_world_poses[node]);
}

Matrix4x4 SceneGraph::world_pose(int32_t node) const
{
	CE_ASSERT(node < (int32_t) m_num_nodes, "Node does not exist");

	return m_world_poses[node];
}

void SceneGraph::update()
{
	for (uint32_t i = 0; i < m_num_nodes; i++)
	{
		const uint8_t my_flags = m_flags[i];
		const uint8_t parent_flags = m_flags[m_parents[i]];

		if (my_flags & LOCAL_DIRTY || parent_flags & WORLD_DIRTY)
		{
			if (m_parents[i] == -1)
			{
				m_world_poses[i] = m_local_poses[i];
			}
			else
			{
				m_world_poses[i] = m_world_poses[m_parents[i]] * m_local_poses[i];
			}

			m_flags[i] = CLEAN;
		}
	}
}

} // namespace crown