Batching - Add MultiRect command

Large groups of similar rects can be processed more efficiently using the MultiRect command. Processing common to the group can be done as a one off, instead of per rect.

Adds the new API to VisualServerCanvas, and uses the new functionality from Font, BitmapFont, DynamicFont and TileMap, via the VisualServerCanvasHelper class.

core/fixed_array.h

@@ -0,0 +1,136 @@
+/**************************************************************************/
+/*  fixed_array.h                                                         */
+/**************************************************************************/
+/*                         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.                 */
+/**************************************************************************/
+
+#ifndef FIXED_ARRAY_H
+#define FIXED_ARRAY_H
+
+#include "core/local_vector.h"
+
+// High performance fixed size array, single threaded.
+// Especially useful if you need to create an array on the stack, to
+// prevent dynamic allocations (especially in bottleneck code).
+
+template <class T, uint32_t CAPACITY = 8, bool force_trivial = false, uint32_t ALIGN = 1>
+class FixedArray {
+	static_assert(ALIGN > 0, "ALIGN must be at least 1.");
+	const static uint32_t UNIT_SIZE = ((sizeof(T) + ALIGN - 1) / ALIGN * ALIGN);
+	const static bool CONSTRUCT = !std::is_trivially_constructible<T>::value && !force_trivial;
+	const static bool DESTRUCT = !std::is_trivially_destructible<T>::value && !force_trivial;
+
+	uint32_t _size = 0;
+	uint8_t _data[CAPACITY * UNIT_SIZE];
+
+	const T &get(uint32_t p_index) const {
+		return *(const T *)&_data[p_index * UNIT_SIZE];
+	}
+	T &get(uint32_t p_index) {
+		return *(T *)&_data[p_index * UNIT_SIZE];
+	}
+
+public:
+	uint32_t size() const { return _size; }
+	bool is_empty() const { return !_size; }
+	bool is_full() const { return _size == CAPACITY; }
+	uint32_t capacity() const { return CAPACITY; }
+
+	T *request(bool p_construct = true) {
+		if (size() < CAPACITY) {
+			T *ele = &get(_size++);
+			if (CONSTRUCT && p_construct) {
+				memnew_placement(ele, T);
+			}
+			return ele;
+		}
+		return nullptr;
+	}
+	void push_back(const T &p_val) {
+		T *mem = request(false);
+		ERR_FAIL_NULL(mem);
+		*mem = p_val;
+	}
+	void clear() {
+		resize(0);
+	}
+	void remove_unordered(uint32_t p_index) {
+		ERR_FAIL_UNSIGNED_INDEX(p_index, _size);
+
+		_size--;
+		if (_size > p_index) {
+			get(p_index) = get(_size);
+		}
+
+		if (DESTRUCT) {
+			get(_size).~T();
+		}
+	}
+	void resize(uint32_t p_size) {
+		ERR_FAIL_COND(p_size > CAPACITY);
+
+		if (DESTRUCT && (p_size < _size)) {
+			for (uint32_t i = p_size; i < _size; i++) {
+				get(i).~T();
+			}
+		}
+
+		if (CONSTRUCT && (p_size > _size)) {
+			for (uint32_t i = _size; i < p_size; i++) {
+				memnew_placement(&get(i), T);
+			}
+		}
+
+		_size = p_size;
+	}
+	const T &operator[](uint32_t p_index) const {
+		DEV_ASSERT(p_index < size());
+		return get(p_index);
+	}
+	T &operator[](uint32_t p_index) {
+		DEV_ASSERT(p_index < size());
+		return get(p_index);
+	}
+
+	operator Vector<T>() const {
+		Vector<T> ret;
+		if (size()) {
+			ret.resize(size());
+			T *dest = ret.ptrw();
+			if (ALIGN <= 1) {
+				memcpy(dest, _data, sizeof(T) * _size);
+			} else {
+				for (uint32_t n = 0; n < _size; n++) {
+					dest[n] = get(n);
+				}
+			}
+		}
+		return ret;
+	}
+};
+
+#endif // FIXED_ARRAY_H

doc/classes/ProjectSettings.xml

@@ -1477,6 +1477,10 @@
 		<member name="rendering/batching/options/use_batching_in_editor" type="bool" setter="" getter="" default="true">
 			Switches on 2D batching within the editor.
 		</member>
+		<member name="rendering/batching/options/use_multirect" type="bool" setter="" getter="" default="true">
+			Allows use of the [code]MultiRect[/code] command in the Rasterizer.
+			This can provide some acceleration for large groups of rects, especially text and tilemaps.
+		</member>
 		<member name="rendering/batching/parameters/batch_buffer_size" type="int" setter="" getter="" default="16384">
 			Size of buffer reserved for batched vertices. Larger size enables larger batches, but there are diminishing returns for the memory used. This should only have a minor effect on performance.
 		</member>