Add OpenGL renderer

SConstruct

@@ -15,6 +15,8 @@ from collections import OrderedDict
 # Local
 import methods
 import glsl_builders
+import opengl_builders
+from platform_methods import run_in_subprocess
 
 # Scan possible build platforms
 
@@ -706,6 +708,17 @@ if selected_platform in platform_list:
     }
     env.Append(BUILDERS=GLSL_BUILDERS)
 
+    if not env["platform"] == "server":
+        env.Append(
+            BUILDERS={
+                "OpenGL_GLSL": env.Builder(
+                    action=run_in_subprocess(opengl_builders.build_opengl_headers),
+                    suffix="glsl.gen.h",
+                    src_suffix=".glsl",
+                )
+            }
+        )
+
     scons_cache_path = os.environ.get("SCONS_CACHE")
     if scons_cache_path != None:
         CacheDir(scons_cache_path)

core/core_bind.cpp

@@ -603,8 +603,8 @@ void OS::_bind_methods() {
 	ADD_PROPERTY_DEFAULT("low_processor_usage_mode", false);
 	ADD_PROPERTY_DEFAULT("low_processor_usage_mode_sleep_usec", 6900);
 
-	BIND_ENUM_CONSTANT(VIDEO_DRIVER_GLES2);
 	BIND_ENUM_CONSTANT(VIDEO_DRIVER_VULKAN);
+	BIND_ENUM_CONSTANT(VIDEO_DRIVER_OPENGL);
 
 	BIND_ENUM_CONSTANT(DAY_SUNDAY);
 	BIND_ENUM_CONSTANT(DAY_MONDAY);

core/core_bind.h

@@ -119,8 +119,8 @@ class OS : public Object {
 
 public:
 	enum VideoDriver {
-		VIDEO_DRIVER_GLES2,
 		VIDEO_DRIVER_VULKAN,
+		VIDEO_DRIVER_OPENGL,
 	};
 
 	enum Weekday {

core/os/os.h

@@ -68,6 +68,11 @@ class OS {
 	bool restart_on_exit = false;
 	List<String> restart_commandline;
 
+	// for the user interface we keep a record of the current display driver
+	// so we can retrieve the rendering drivers available
+	int _display_driver_id = -1;
+	String _current_rendering_driver_name = "";
+
 protected:
 	void _set_logger(CompositeLogger *p_logger);
 
@@ -81,20 +86,29 @@ class OS {
 		RENDER_SEPARATE_THREAD
 	};
 
+	enum RenderMainThreadMode {
+		RENDER_MAIN_THREAD_ONLY,
+		RENDER_ANY_THREAD,
+	};
+
 protected:
 	friend class Main;
 	// Needed by tests to setup command-line args.
 	friend int test_main(int argc, char *argv[]);
 
 	HasServerFeatureCallback has_server_feature_callback = nullptr;
 	RenderThreadMode _render_thread_mode = RENDER_THREAD_SAFE;
+	RenderMainThreadMode _render_main_thread_mode = RENDER_ANY_THREAD;
 
 	// Functions used by Main to initialize/deinitialize the OS.
 	void add_logger(Logger *p_logger);
 
 	virtual void initialize() = 0;
 	virtual void initialize_joypads() = 0;
 
+	void set_current_rendering_driver_name(String p_driver_name) { _current_rendering_driver_name = p_driver_name; }
+	void set_display_driver_id(int p_display_driver_id) { _display_driver_id = p_display_driver_id; }
+
 	virtual void set_main_loop(MainLoop *p_main_loop) = 0;
 	virtual void delete_main_loop() = 0;
 
@@ -110,6 +124,9 @@ class OS {
 
 	static OS *get_singleton();
 
+	String get_current_rendering_driver_name() const { return _current_rendering_driver_name; }
+	int get_display_driver_id() const { return _display_driver_id; }
+
 	void print_error(const char *p_function, const char *p_file, int p_line, const char *p_code, const char *p_rationale, bool p_editor_notify = false, Logger::ErrorType p_type = Logger::ERR_ERROR);
 	void print(const char *p_format, ...) _PRINTF_FORMAT_ATTRIBUTE_2_3;
 	void printerr(const char *p_format, ...) _PRINTF_FORMAT_ATTRIBUTE_2_3;
@@ -241,6 +258,8 @@ class OS {
 	virtual uint64_t get_free_static_memory() const;
 
 	RenderThreadMode get_render_thread_mode() const { return _render_thread_mode; }
+	RenderMainThreadMode get_render_main_thread_mode() const { return _render_main_thread_mode; }
+	void set_render_main_thread_mode(RenderMainThreadMode p_thread_mode) { _render_main_thread_mode = p_thread_mode; }
 
 	virtual String get_locale() const;
 	String get_locale_language() const;

doc/classes/Environment.xml

@@ -128,10 +128,10 @@
 			The bleed scale of the HDR glow.
 		</member>
 		<member name="glow_hdr_threshold" type="float" setter="set_glow_hdr_bleed_threshold" getter="get_glow_hdr_bleed_threshold" default="1.0">
-			The lower threshold of the HDR glow. When using the GLES2 renderer (which doesn't support HDR), this needs to be below [code]1.0[/code] for glow to be visible. A value of [code]0.9[/code] works well in this case.
+			The lower threshold of the HDR glow. When using the OpenGL renderer (which doesn't support HDR), this needs to be below [code]1.0[/code] for glow to be visible. A value of [code]0.9[/code] works well in this case.
 		</member>
 		<member name="glow_intensity" type="float" setter="set_glow_intensity" getter="get_glow_intensity" default="0.8">
-			The overall brightness multiplier of the glow effect. When using the GLES2 renderer, this should be increased to 1.5 to compensate for the lack of HDR rendering.
+			The overall brightness multiplier of the glow effect. When using the OpenGL renderer, this should be increased to 1.5 to compensate for the lack of HDR rendering.
 		</member>
 		<member name="glow_levels/1" type="float" setter="set_glow_level" getter="get_glow_level" default="0.0">
 			The intensity of the 1st level of glow. This is the most "local" level (least blurry).
@@ -160,7 +160,7 @@
 			If [code]true[/code], glow levels will be normalized so that summed together their intensities equal [code]1.0[/code].
 		</member>
 		<member name="glow_strength" type="float" setter="set_glow_strength" getter="get_glow_strength" default="1.0">
-			The strength of the glow effect. This applies as the glow is blurred across the screen and increases the distance and intensity of the blur. When using the GLES2 renderer, this should be increased to 1.3 to compensate for the lack of HDR rendering.
+			The strength of the glow effect. This applies as the glow is blurred across the screen and increases the distance and intensity of the blur. When using the OpenGL renderer, this should be increased to 1.3 to compensate for the lack of HDR rendering.
 		</member>
 		<member name="reflected_light_source" type="int" setter="set_reflection_source" getter="get_reflection_source" enum="Environment.ReflectionSource" default="0">
 		</member>

doc/classes/NinePatchRect.xml

@@ -68,11 +68,11 @@
 		</constant>
 		<constant name="AXIS_STRETCH_MODE_TILE" value="1" enum="AxisStretchMode">
 			Repeats the center texture across the NinePatchRect. This won't cause any visible distortion. The texture must be seamless for this to work without displaying artifacts between edges.
-			[b]Note:[/b] Only supported when using the GLES3 renderer. When using the GLES2 renderer, this will behave like [constant AXIS_STRETCH_MODE_STRETCH].
+			[b]Note:[/b] Only supported when using the Vulkan renderer. When using the OpenGL renderer, this will behave like [constant AXIS_STRETCH_MODE_STRETCH].
 		</constant>
 		<constant name="AXIS_STRETCH_MODE_TILE_FIT" value="2" enum="AxisStretchMode">
 			Repeats the center texture across the NinePatchRect, but will also stretch the texture to make sure each tile is visible in full. This may cause the texture to be distorted, but less than [constant AXIS_STRETCH_MODE_STRETCH]. The texture must be seamless for this to work without displaying artifacts between edges.
-			[b]Note:[/b] Only supported when using the GLES3 renderer. When using the GLES2 renderer, this will behave like [constant AXIS_STRETCH_MODE_STRETCH].
+			[b]Note:[/b] Only supported when using the Vulkan renderer. When using the OpenGL renderer, this will behave like [constant AXIS_STRETCH_MODE_STRETCH].
 		</constant>
 	</constants>
 </class>

doc/classes/OS.xml

@@ -455,12 +455,12 @@
 		</member>
 	</members>
 	<constants>
-		<constant name="VIDEO_DRIVER_GLES2" value="0" enum="VideoDriver">
-			The GLES2 rendering backend. It uses OpenGL ES 2.0 on mobile devices, OpenGL 2.1 on desktop platforms and WebGL 1.0 on the web.
-		</constant>
-		<constant name="VIDEO_DRIVER_VULKAN" value="1" enum="VideoDriver">
+		<constant name="VIDEO_DRIVER_VULKAN" value="0" enum="VideoDriver">
 			The Vulkan rendering backend.
 		</constant>
+		<constant name="VIDEO_DRIVER_OPENGL" value="1" enum="VideoDriver">
+			The OpenGL rendering backend. It uses OpenGL ES 3.0 on mobile devices, OpenGL 3.3 on desktop platforms and WebGL 2.0 on the web.
+		</constant>
 		<constant name="DAY_SUNDAY" value="0" enum="Weekday">
 			Sunday.
 		</constant>

doc/classes/ProjectSettings.xml

@@ -1475,6 +1475,18 @@
 			The number of fixed iterations per second. This controls how often physics simulation and [method Node._physics_process] methods are run.
 			[b]Note:[/b] This property is only read when the project starts. To change the physics FPS at runtime, set [member Engine.physics_ticks_per_second] instead.
 		</member>
+		<member name="rendering/2d/opengl/batching_send_null" type="int" setter="" getter="" default="0">
+		</member>
+		<member name="rendering/2d/opengl/batching_stream" type="int" setter="" getter="" default="0">
+		</member>
+		<member name="rendering/2d/opengl/legacy_orphan_buffers" type="int" setter="" getter="" default="0">
+		</member>
+		<member name="rendering/2d/opengl/legacy_stream" type="int" setter="" getter="" default="0">
+		</member>
+		<member name="rendering/2d/options/ninepatch_mode" type="int" setter="" getter="" default="1">
+		</member>
+		<member name="rendering/2d/options/use_software_skinning" type="bool" setter="" getter="" default="true">
+		</member>
 		<member name="rendering/2d/sdf/oversize" type="int" setter="" getter="" default="1">
 		</member>
 		<member name="rendering/2d/sdf/scale" type="int" setter="" getter="" default="1">
@@ -1504,6 +1516,32 @@
 		</member>
 		<member name="rendering/anti_aliasing/screen_space_roughness_limiter/limit" type="float" setter="" getter="" default="0.18">
 		</member>
+		<member name="rendering/batching/debug/diagnose_frame" type="bool" setter="" getter="" default="false">
+		</member>
+		<member name="rendering/batching/debug/flash_batching" type="bool" setter="" getter="" default="false">
+		</member>
+		<member name="rendering/batching/lights/max_join_items" type="int" setter="" getter="" default="32">
+		</member>
+		<member name="rendering/batching/lights/scissor_area_threshold" type="float" setter="" getter="" default="1.0">
+		</member>
+		<member name="rendering/batching/options/single_rect_fallback" type="bool" setter="" getter="" default="false">
+		</member>
+		<member name="rendering/batching/options/use_batching" type="bool" setter="" getter="" default="false">
+		</member>
+		<member name="rendering/batching/options/use_batching_in_editor" type="bool" setter="" getter="" default="false">
+		</member>
+		<member name="rendering/batching/parameters/batch_buffer_size" type="int" setter="" getter="" default="16384">
+		</member>
+		<member name="rendering/batching/parameters/colored_vertex_format_threshold" type="float" setter="" getter="" default="0.25">
+		</member>
+		<member name="rendering/batching/parameters/item_reordering_lookahead" type="int" setter="" getter="" default="4">
+		</member>
+		<member name="rendering/batching/parameters/max_join_item_commands" type="int" setter="" getter="" default="16">
+		</member>
+		<member name="rendering/batching/precision/uv_contract" type="bool" setter="" getter="" default="false">
+		</member>
+		<member name="rendering/batching/precision/uv_contract_amount" type="int" setter="" getter="" default="100">
+		</member>
 		<member name="rendering/camera/depth_of_field/depth_of_field_bokeh_quality" type="int" setter="" getter="" default="1">
 			Sets the quality of the depth of field effect. Higher quality takes more samples, which is slower but looks smoother.
 		</member>
@@ -1582,6 +1620,10 @@
 		</member>
 		<member name="rendering/environment/volumetric_fog/volume_size" type="int" setter="" getter="" default="64">
 		</member>
+		<member name="rendering/gles2/compatibility/disable_half_float" type="bool" setter="" getter="" default="false">
+		</member>
+		<member name="rendering/gles2/compatibility/enable_high_float.Android" type="bool" setter="" getter="" default="false">
+		</member>
 		<member name="rendering/global_illumination/gi/use_half_resolution" type="bool" setter="" getter="" default="false">
 		</member>
 		<member name="rendering/global_illumination/sdfgi/frames_to_converge" type="int" setter="" getter="" default="4">

drivers/SCsub

@@ -25,6 +25,10 @@ SConscript("winmidi/SCsub")
 # Graphics drivers
 if env["vulkan"]:
     SConscript("vulkan/SCsub")
+    SConscript("opengl/SCsub")
+    SConscript("gl_context/SCsub")
+else:
+    SConscript("dummy/SCsub")
 
 # Core dependencies
 SConscript("png/SCsub")

drivers/gl_context/SCsub

@@ -0,0 +1,23 @@
+#!/usr/bin/env python
+
+Import("env")
+
+if env["platform"] in ["haiku", "osx", "windows", "linuxbsd"]:
+    # Thirdparty source files
+    thirdparty_dir = "#thirdparty/glad/"
+    thirdparty_sources = [
+        "glad.c",
+    ]
+    thirdparty_sources = [thirdparty_dir + file for file in thirdparty_sources]
+
+    env.Prepend(CPPPATH=[thirdparty_dir])
+
+    env.Append(CPPDEFINES=["GLAD_ENABLED"])
+    env.Append(CPPDEFINES=["GLES_OVER_GL"])
+
+    env_thirdparty = env.Clone()
+    env_thirdparty.disable_warnings()
+    env_thirdparty.add_source_files(env.drivers_sources, thirdparty_sources)
+
+# Godot source files
+env.add_source_files(env.drivers_sources, "*.cpp")

drivers/opengl/SCsub

@@ -0,0 +1,7 @@
+#!/usr/bin/env python
+
+Import("env")
+
+env.add_source_files(env.drivers_sources, "*.cpp")
+
+SConscript("shaders/SCsub")