pandemonium_engine/scene/3d/lod.cpp
lawnjelly 909acac329 Discrete Level of Detail
Add scene side discrete level of detail.

New node `LOD` for UI, and `LODManager` within `World` for automatically updating child visibilities based on distance from cameras.
2024-04-06 12:06:01 +02:00

251 lines
7.8 KiB
C++

/**************************************************************************/
/* lod.cpp */
/**************************************************************************/
/* This file is part of: */
/* GODOT ENGINE */
/* https://godotengine.org */
/**************************************************************************/
/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur. */
/* */
/* Permission is hereby granted, free of charge, to any person obtaining */
/* a copy of this software and associated documentation files (the */
/* "Software"), to deal in the Software without restriction, including */
/* without limitation the rights to use, copy, modify, merge, publish, */
/* distribute, sublicense, and/or sell copies of the Software, and to */
/* permit persons to whom the Software is furnished to do so, subject to */
/* the following conditions: */
/* */
/* The above copyright notice and this permission notice shall be */
/* included in all copies or substantial portions of the Software. */
/* */
/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */
/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */
/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. */
/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY */
/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, */
/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE */
/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
/**************************************************************************/
#include "lod.h"
#include "core/config/engine.h"
#include "scene/3d/visual_instance.h"
void LOD::_lod_register() {
if (!data.registered) {
Ref<World> world = get_world();
ERR_FAIL_COND(!world.is_valid());
world->_register_lod(this, data.queue_id);
data.registered = true;
}
}
void LOD::_lod_unregister() {
if (data.registered) {
Ref<World> world = get_world();
ERR_FAIL_COND(!world.is_valid());
world->_unregister_lod(this, data.queue_id);
data.registered = false;
}
}
void LOD::_notification(int p_what) {
switch (p_what) {
case NOTIFICATION_ENTER_TREE: {
if (is_visible_in_tree()) {
_lod_register();
}
} break;
case NOTIFICATION_EXIT_TREE: {
if (is_visible_in_tree()) {
_lod_unregister();
}
} break;
case NOTIFICATION_VISIBILITY_CHANGED: {
if (is_inside_tree()) {
if (is_visible_in_tree()) {
_lod_register();
} else {
_lod_unregister();
}
}
} break;
default:
break;
}
}
void LOD::_bind_methods() {
ClassDB::bind_method(D_METHOD("set_hysteresis", "distance"), &LOD::set_hysteresis);
ClassDB::bind_method(D_METHOD("get_hysteresis"), &LOD::get_hysteresis);
ADD_PROPERTY(PropertyInfo(Variant::REAL, "hysteresis", PROPERTY_HINT_RANGE, "0,1024,0.01,or_greater"), "set_hysteresis", "get_hysteresis");
ClassDB::bind_method(D_METHOD("set_lod_priority", "priority"), &LOD::set_lod_priority);
ClassDB::bind_method(D_METHOD("get_lod_priority"), &LOD::get_lod_priority);
ADD_PROPERTY(PropertyInfo(Variant::INT, "lod_priority", PROPERTY_HINT_RANGE, "0,4"), "set_lod_priority", "get_lod_priority");
}
void LOD::set_hysteresis(real_t p_distance) {
data.hysteresis = CLAMP((float)p_distance, 0.0f, 100000.0f);
}
void LOD::set_lod_priority(int p_priority) {
// We are just using priority as a user facing
// description. Internally we use queues.
int queue_id = CLAMP(p_priority, 0, 4);
if (queue_id == data.queue_id) {
return;
}
if (is_inside_tree()) {
// If already in the world, we must remove the LOD
// and re-add in a different queue.
Ref<World> world = get_world();
ERR_FAIL_COND(!world.is_valid());
world->_unregister_lod(this, data.queue_id);
data.queue_id = queue_id;
world->_register_lod(this, data.queue_id);
} else {
data.queue_id = queue_id;
}
}
void LOD::_lod_pre_save() {
// The pre-save is primarily for the editor,
// to ensure that saved scenes do not have unnecessary
// diffs because of changes to which LOD child is active.
// We standardize on just showing the first child in saved scenes.
_update_child_distances();
int32_t num_lods = data.lod_children.size();
// Make first visible, and all others invisible.
data.current_lod_child = 0;
for (int32_t n = 0; n < num_lods; n++) {
uint32_t child_id = data.lod_children[n].child_id;
Spatial *child = Object::cast_to<Spatial>(get_child(child_id));
if (child) {
child->set_visible(n == data.current_lod_child);
}
}
}
// Returns whether a visibility change was triggered.
bool LOD::_lod_update(float p_camera_dist_squared) {
// This should later be done as a one-off, as
// this is expensive.
_update_child_distances();
int32_t num_lods = data.lod_children.size();
// LOD node has no valid children to update.
if (!num_lods) {
return false;
}
data.current_lod_child = MIN(data.current_lod_child, num_lods - 1);
int32_t curr = data.current_lod_child;
float dist = Math::sqrt(p_camera_dist_squared);
bool changed = true;
while (changed) {
changed = false;
if ((curr < num_lods - 1) && (dist >= (data.lod_children[curr + 1].distance) + data.hysteresis)) {
// Lower detail.
curr += 1;
changed = true;
}
if (curr && (dist < data.lod_children[curr].distance)) {
// Increase detail.
curr -= 1;
changed = true;
}
}
// No change?
if ((curr == data.current_lod_child) && (data.current_lod_node == get_child(data.lod_children[curr].child_id))) {
return false;
}
data.current_lod_child = curr;
// Make current visible, and all others invisible.
for (int32_t n = 0; n < num_lods; n++) {
uint32_t child_id = data.lod_children[n].child_id;
Spatial *child = Object::cast_to<Spatial>(get_child(child_id));
if (child) {
child->set_visible(n == curr);
if (n == curr) {
data.current_lod_node = child;
}
}
}
return true;
}
void LOD::_update_child_distances() {
// Reserve enough space for all children, assuming they are all valid.
LODChild *lod_children = (LODChild *)alloca(sizeof(LODChild) * get_child_count());
// Reset prior to loop.
float total_dist = 0.0f;
uint32_t valid_count = 0;
#ifdef TOOLS_ENABLED
bool is_editor = Engine::get_singleton()->is_editor_hint();
uint32_t visible_count = 0;
#endif
// Check every possible node child, not all will be valid lod children.
for (int32_t n = 0; n < get_child_count(); n++) {
// Destination for a valid child.
LODChild &lod_child = lod_children[valid_count];
const Spatial *child = Object::cast_to<Spatial>(get_child(n));
if (child) {
// Fill the data.
lod_child.distance = total_dist;
lod_child.child_id = n;
// Keep running total of the distance range used by each lod child.
total_dist += child->get_lod_range();
#ifdef TOOLS_ENABLED
if (is_editor && child->is_visible()) {
visible_count++;
}
#endif
valid_count++;
}
}
// Size the actual vector, and copy data across.
data.lod_children.resize(valid_count);
if (valid_count) {
memcpy(&data.lod_children[0], lod_children, valid_count * sizeof(LODChild));
}
#ifdef TOOLS_ENABLED
// Something external has changed the visibilities of the children,
// such as the editor.
if (is_editor && visible_count != 1) {
// Force the current child to reset.
data.current_lod_child = -1;
}
#endif
}