Create Pong with GDNative C++ demo

.gitmodules

@@ -10,3 +10,6 @@
 [submodule "cpp/simple/godot-cpp"]
 	path = cpp/simple/godot-cpp
 	url = https://github.com/godotengine/godot-cpp.git
+[submodule "cpp/pong/godot-cpp"]
+	path = cpp/pong/godot-cpp
+	url = https://github.com/godotengine/godot-cpp.git

cpp/pong/README.md

@@ -0,0 +1,44 @@
+# Pong with GDNative C++
+
+A simple Pong game, made with GDNative C++. This demo shows best practices
+for game development in Godot, including
+[signals](https://docs.godotengine.org/en/latest/getting_started/step_by_step/signals.html).
+
+Language: C++
+
+Renderer: GLES 2
+
+Note: There is a GDScript version available [here](https://github.com/godotengine/godot-demo-projects/tree/master/2d/pong).
+
+Note: There is a C# version available [here](https://github.com/godotengine/godot-demo-projects/tree/master/mono/pong).
+
+Note: There is a VisualScript version available [here](https://github.com/godotengine/godot-demo-projects/tree/master/visual_script/pong).
+
+## Compiling
+
+You can use SCons to compile the library:
+
+```
+scons platform=PLATFORM
+```
+
+Where PLATFORM is: `windows`, `linux`, or `osx`.
+
+This creates the file `libsimple` in the respective
+subfolders in the `project/gdnative` directory.
+
+Dependencies:
+ * You need [godot-cpp](https://github.com/godotengine/godot-cpp),
+   this is now a Git submodule of this repo.
+ * `clang`, `gcc`, or any decent C compiler that's C++14 compatible.
+
+## How does it work?
+
+The walls, paddle, and ball are all
+[`Area2D`](https://docs.godotengine.org/en/latest/classes/class_area2d.html)
+nodes. When the ball touches the walls or the paddles,
+they emit signals and modify the ball.
+
+## Screenshots
+
+![Screenshot](screenshots/pong.png)

cpp/pong/SConstruct

@@ -0,0 +1,111 @@
+#!python
+import os
+
+opts = Variables([], ARGUMENTS)
+
+# Gets the standard flags CC, CCX, etc.
+env = DefaultEnvironment()
+
+godot_headers_path = "godot-cpp/godot-headers"
+godot_bindings_path = "godot-cpp"
+
+# Define our options. Use future-proofed names for platforms.
+platform_array = ["", "windows", "linuxbsd", "macos", "x11", "linux", "osx"]
+opts.Add(EnumVariable("target", "Compilation target", "debug", ["d", "debug", "r", "release"]))
+opts.Add(EnumVariable("platform", "Compilation platform", "", platform_array))
+opts.Add(EnumVariable("p", "Alias for 'platform'", "", platform_array))
+opts.Add(BoolVariable("use_llvm", "Use the LLVM / Clang compiler", "no"))
+opts.Add(PathVariable("target_path", "The path where the lib is installed.", "project/gdnative/"))
+opts.Add(PathVariable("target_name", "The library name.", "libpong", PathVariable.PathAccept))
+
+# Updates the environment with the option variables.
+opts.Update(env)
+
+# Process platform arguments. Here we use the same names as GDNative.
+if env["p"] != "":
+    env["platform"] = env["p"]
+
+if env["platform"] == "macos":
+    env["platform"] = "osx"
+elif env["platform"] in ("x11", "linuxbsd"):
+    env["platform"] = "linux"
+elif env["platform"] == "bsd":
+    env["platform"] = "freebsd"
+
+if env["platform"] == "":
+    print("No valid target platform selected.")
+    quit()
+
+platform = env["platform"]
+
+# Process other arguments.
+if env["platform"] == "osx" and not env["use_llvm"]:
+    env["use_llvm"] = "yes"
+
+if env["use_llvm"] == "yes":
+    env["CC"] = "clang"
+    env["CXX"] = "clang++"
+
+# put stuff that is the same for all first, saves duplication
+if env["platform"] == "osx":
+    if env["target"] in ("debug", "d"):
+        env.Append(CCFLAGS=["-g", "-O2", "-arch", "x86_64", "-std=c++14"])
+        env.Append(LINKFLAGS=["-arch", "x86_64"])
+    else:
+        env.Append(CCFLAGS=["-g", "-O3", "-arch", "x86_64", "-std=c++14"])
+        env.Append(LINKFLAGS=["-arch", "x86_64"])
+elif env["platform"] == "linux":
+    if env["target"] in ("debug", "d"):
+        env.Append(CCFLAGS=["-fPIC", "-g3", "-Og"])
+    else:
+        env.Append(CCFLAGS=["-fPIC", "-g", "-O3"])
+elif env["platform"] == "windows":
+    # This makes sure to keep the session environment variables
+    # on Windows, so that you can run scons in a VS 2017 prompt
+    # and it will find all the required tools.
+    env = Environment(ENV=os.environ)
+    opts.Update(env)
+
+    env.Append(CCFLAGS=["-DWIN32", "-D_WIN32", "-D_WINDOWS", "-W3", "-GR", "-D_CRT_SECURE_NO_WARNINGS"])
+    if env["target"] in ("debug", "d"):
+        env.Append(CCFLAGS=["-EHsc", "-D_DEBUG", "-MDd"])
+    else:
+        env.Append(CCFLAGS=["-O2", "-EHsc", "-DNDEBUG", "-MD"])
+
+SConscript("godot-cpp/SConstruct")
+
+
+def add_sources(sources, dir):
+    for f in os.listdir(dir):
+        if f.endswith(".cpp"):
+            sources.append(dir + "/" + f)
+
+
+env.Append(
+    CPPPATH=[
+        godot_headers_path,
+        godot_bindings_path + "/include",
+        godot_bindings_path + "/include/gen/",
+        godot_bindings_path + "/include/core/",
+    ]
+)
+
+env.Append(
+    LIBS=[
+        env.File(
+            os.path.join(
+                "godot-cpp/bin", "libgodot-cpp.%s.%s.64%s" % (env["platform"], env["target"], env["LIBSUFFIX"])
+            )
+        )
+    ]
+)
+
+env.Append(LIBPATH=[godot_bindings_path + "/bin/"])
+
+sources = []
+add_sources(sources, "src")
+
+library = env.SharedLibrary(
+    target=env["target_path"] + "/" + env["platform"] + "/" + env["target_name"], source=sources
+)
+Default(library)

cpp/pong/project/ball.png.import

@@ -0,0 +1,34 @@
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+}
+
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+
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+process/HDR_as_SRGB=false
+process/invert_color=false
+stream=false
+size_limit=0
+detect_3d=true
+svg/scale=1.0

cpp/pong/project/gdnative/linux/.gitignore

@@ -0,0 +1,2 @@
+*
+!.gitignore

cpp/pong/project/gdnative/osx/.gitignore

@@ -0,0 +1,2 @@
+*
+!.gitignore

cpp/pong/project/gdnative/pong.gdnlib

@@ -0,0 +1,18 @@
+[general]
+
+singleton=false
+load_once=true
+symbol_prefix="godot_"
+reloadable=true
+
+[entry]
+
+Windows.64="res://gdnative/windows/libpong.dll"
+X11.64="res://gdnative/linux/libpong.so"
+OSX.64="res://gdnative/osx/libpong.dylib"
+
+[dependencies]
+
+Windows.64=[  ]
+X11.64=[  ]
+OSX.64=[  ]

cpp/pong/project/gdnative/windows/.gitignore

@@ -0,0 +1,2 @@
+*
+!.gitignore

cpp/pong/project/icon.png.import

@@ -0,0 +1,34 @@
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+
+importer="texture"
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+svg/scale=1.0

cpp/pong/project/logic/ball.gdns

@@ -0,0 +1,9 @@
+[gd_resource type="NativeScript" load_steps=2 format=2]
+
+[ext_resource path="res://gdnative/pong.gdnlib" type="GDNativeLibrary" id=1]
+
+[resource]
+
+resource_name = "Ball"
+class_name = "Ball"
+library = ExtResource( 1 )

cpp/pong/project/logic/ceiling_floor.gdns

@@ -0,0 +1,9 @@
+[gd_resource type="NativeScript" load_steps=2 format=2]
+
+[ext_resource path="res://gdnative/pong.gdnlib" type="GDNativeLibrary" id=1]
+
+[resource]
+
+resource_name = "CeilingFloor"
+class_name = "CeilingFloor"
+library = ExtResource( 1 )

cpp/pong/project/logic/paddle.gdns

@@ -0,0 +1,9 @@
+[gd_resource type="NativeScript" load_steps=2 format=2]
+
+[ext_resource path="res://gdnative/pong.gdnlib" type="GDNativeLibrary" id=1]
+
+[resource]
+
+resource_name = "Paddle"
+class_name = "Paddle"
+library = ExtResource( 1 )

cpp/pong/project/logic/wall.gdns

@@ -0,0 +1,9 @@
+[gd_resource type="NativeScript" load_steps=2 format=2]
+
+[ext_resource path="res://gdnative/pong.gdnlib" type="GDNativeLibrary" id=1]
+
+[resource]
+
+resource_name = "Wall"
+class_name = "Wall"
+library = ExtResource( 1 )

cpp/pong/project/paddle.png.import

@@ -0,0 +1,34 @@
+[remap]
+
+importer="texture"
+type="StreamTexture"
+path="res://.import/paddle.png-0e798fb0912613386507c9904d5cc01a.stex"
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+"vram_texture": false
+}
+
+[deps]
+
+source_file="res://paddle.png"
+dest_files=[ "res://.import/paddle.png-0e798fb0912613386507c9904d5cc01a.stex" ]
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+process/HDR_as_SRGB=false
+process/invert_color=false
+stream=false
+size_limit=0
+detect_3d=true
+svg/scale=1.0

cpp/pong/project/pong.tscn

@@ -0,0 +1,107 @@
+[gd_scene load_steps=12 format=2]
+
+[ext_resource path="res://logic/paddle.gdns" type="Script" id=1]
+[ext_resource path="res://paddle.png" type="Texture" id=2]
+[ext_resource path="res://logic/ball.gdns" type="Script" id=4]
+[ext_resource path="res://ball.png" type="Texture" id=5]
+[ext_resource path="res://separator.png" type="Texture" id=6]
+[ext_resource path="res://logic/wall.gdns" type="Script" id=7]
+[ext_resource path="res://logic/ceiling_floor.gdns" type="Script" id=8]
+
+[sub_resource type="RectangleShape2D" id=1]
+extents = Vector2( 4, 16 )
+
+[sub_resource type="RectangleShape2D" id=2]
+extents = Vector2( 4, 4 )
+
+[sub_resource type="RectangleShape2D" id=3]
+extents = Vector2( 10, 200 )
+
+[sub_resource type="RectangleShape2D" id=4]
+extents = Vector2( 320, 10 )
+
+[node name="Pong" type="Node2D"]
+
+[node name="Background" type="ColorRect" parent="."]
+margin_right = 640.0
+margin_bottom = 400.0
+color = Color( 0.141176, 0.152941, 0.164706, 1 )
+__meta__ = {
+"_edit_use_anchors_": false
+}
+
+[node name="Left" type="Area2D" parent="."]
+modulate = Color( 0, 1, 1, 1 )
+position = Vector2( 67.6285, 192.594 )
+script = ExtResource( 1 )
+
+[node name="Sprite" type="Sprite" parent="Left"]
+texture = ExtResource( 2 )
+
+[node name="Collision" type="CollisionShape2D" parent="Left"]
+shape = SubResource( 1 )
+
+[node name="Right" type="Area2D" parent="."]
+modulate = Color( 1, 0, 1, 1 )
+position = Vector2( 563.815, 188.919 )
+script = ExtResource( 1 )
+
+[node name="Sprite" type="Sprite" parent="Right"]
+texture = ExtResource( 2 )
+
+[node name="Collision" type="CollisionShape2D" parent="Right"]
+shape = SubResource( 1 )
+
+[node name="Ball" type="Area2D" parent="."]
+position = Vector2( 320.5, 191.124 )
+script = ExtResource( 4 )
+
+[node name="Sprite" type="Sprite" parent="Ball"]
+texture = ExtResource( 5 )
+
+[node name="Collision" type="CollisionShape2D" parent="Ball"]
+shape = SubResource( 2 )
+
+[node name="Separator" type="Sprite" parent="."]
+position = Vector2( 320, 200 )
+texture = ExtResource( 6 )
+
+[node name="LeftWall" type="Area2D" parent="."]
+position = Vector2( -10, 200 )
+script = ExtResource( 7 )
+
+[node name="Collision" type="CollisionShape2D" parent="LeftWall"]
+shape = SubResource( 3 )
+
+[node name="RightWall" type="Area2D" parent="."]
+position = Vector2( 650, 200 )
+script = ExtResource( 7 )
+
+[node name="Collision" type="CollisionShape2D" parent="RightWall"]
+shape = SubResource( 3 )
+
+[node name="Ceiling" type="Area2D" parent="."]
+position = Vector2( 320, -10 )
+script = ExtResource( 8 )
+
+[node name="Collision" type="CollisionShape2D" parent="Ceiling"]
+shape = SubResource( 4 )
+
+[node name="Floor" type="Area2D" parent="."]
+position = Vector2( 320, 410 )
+script = ExtResource( 8 )
+bounce_direction = -1
+
+[node name="Collision" type="CollisionShape2D" parent="Floor"]
+shape = SubResource( 4 )
+
+[node name="Camera2D" type="Camera2D" parent="."]
+offset = Vector2( 320, 200 )
+current = true
+
+[connection signal="area_entered" from="Left" to="Left" method="_on_area_entered"]
+[connection signal="area_entered" from="Right" to="Right" method="_on_area_entered"]
+[connection signal="area_entered" from="LeftWall" to="LeftWall" method="_on_wall_area_entered"]
+[connection signal="area_entered" from="RightWall" to="RightWall" method="_on_wall_area_entered"]
+[connection signal="area_entered" from="Ceiling" to="Ceiling" method="_on_area_entered"]
+[connection signal="area_entered" from="Floor" to="Floor" method="_on_area_entered"]

cpp/pong/project/project.godot

@@ -0,0 +1,72 @@
+; Engine configuration file.
+; It's best edited using the editor UI and not directly,
+; since the parameters that go here are not all obvious.
+;
+; Format:
+;   [section] ; section goes between []
+;   param=value ; assign values to parameters
+
+config_version=4
+
+[application]
+
+config/name="Pong with GDNative C++"
+config/description="A simple Pong game. This demo shows best practices
+for game development in Godot, including signals."
+run/main_scene="pong.tscn"
+config/icon="res://icon.png"
+
+[display]
+
+window/size/width=640
+window/size/height=400
+window/dpi/allow_hidpi=true
+window/stretch/mode="2d"
+window/stretch/aspect="expand"
+stretch_2d=true
+
+[gdnative]
+
+singletons=[  ]
+
+[input]
+
+left_move_down={
+"deadzone": 0.5,
+"events": [ Object(InputEventKey,"resource_local_to_scene":false,"resource_name":"","device":0,"alt":false,"shift":false,"control":false,"meta":false,"command":false,"pressed":false,"scancode":90,"unicode":0,"echo":false,"script":null)
+, Object(InputEventJoypadButton,"resource_local_to_scene":false,"resource_name":"","device":0,"button_index":13,"pressure":0.0,"pressed":false,"script":null)
+, Object(InputEventJoypadMotion,"resource_local_to_scene":false,"resource_name":"","device":0,"axis":1,"axis_value":1.0,"script":null)
+, Object(InputEventKey,"resource_local_to_scene":false,"resource_name":"","device":0,"alt":false,"shift":false,"control":false,"meta":false,"command":false,"pressed":false,"scancode":83,"unicode":0,"echo":false,"script":null)
+ ]
+}
+left_move_up={
+"deadzone": 0.5,
+"events": [ Object(InputEventKey,"resource_local_to_scene":false,"resource_name":"","device":0,"alt":false,"shift":false,"control":false,"meta":false,"command":false,"pressed":false,"scancode":65,"unicode":0,"echo":false,"script":null)
+, Object(InputEventJoypadButton,"resource_local_to_scene":false,"resource_name":"","device":0,"button_index":12,"pressure":0.0,"pressed":false,"script":null)
+, Object(InputEventJoypadMotion,"resource_local_to_scene":false,"resource_name":"","device":0,"axis":1,"axis_value":-1.0,"script":null)
+, Object(InputEventKey,"resource_local_to_scene":false,"resource_name":"","device":0,"alt":false,"shift":false,"control":false,"meta":false,"command":false,"pressed":false,"scancode":87,"unicode":0,"echo":false,"script":null)
+ ]
+}
+right_move_down={
+"deadzone": 0.5,
+"events": [ Object(InputEventKey,"resource_local_to_scene":false,"resource_name":"","device":0,"alt":false,"shift":false,"control":false,"meta":false,"command":false,"pressed":false,"scancode":16777234,"unicode":0,"echo":false,"script":null)
+, Object(InputEventJoypadButton,"resource_local_to_scene":false,"resource_name":"","device":1,"button_index":13,"pressure":0.0,"pressed":false,"script":null)
+, Object(InputEventJoypadMotion,"resource_local_to_scene":false,"resource_name":"","device":1,"axis":1,"axis_value":1.0,"script":null)
+ ]
+}
+right_move_up={
+"deadzone": 0.5,
+"events": [ Object(InputEventKey,"resource_local_to_scene":false,"resource_name":"","device":0,"alt":false,"shift":false,"control":false,"meta":false,"command":false,"pressed":false,"scancode":16777232,"unicode":0,"echo":false,"script":null)
+, Object(InputEventJoypadButton,"resource_local_to_scene":false,"resource_name":"","device":1,"button_index":12,"pressure":0.0,"pressed":false,"script":null)
+, Object(InputEventJoypadMotion,"resource_local_to_scene":false,"resource_name":"","device":1,"axis":1,"axis_value":-1.0,"script":null)
+ ]
+}
+
+[rendering]
+
+quality/driver/driver_name="GLES2"
+2d/snapping/use_gpu_pixel_snap=true
+vram_compression/import_etc=true
+vram_compression/import_etc2=false
+quality/2d/use_pixel_snap=true
+viewport/default_clear_color=Color( 0, 0, 0, 1 )

cpp/pong/project/separator.png.import

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+
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+
+[deps]
+
+source_file="res://separator.png"
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+
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+flags/mipmaps=false
+flags/anisotropic=false
+flags/srgb=2
+process/fix_alpha_border=true
+process/premult_alpha=false
+process/HDR_as_SRGB=false
+process/invert_color=false
+stream=false
+size_limit=0
+detect_3d=true
+svg/scale=1.0

cpp/pong/src/ball.cpp

@@ -0,0 +1,24 @@
+#include "ball.hpp"
+
+void Ball::_ready() {
+	_initial_pos = get_position();
+}
+
+void Ball::_process(double p_delta) {
+	_speed += p_delta * 2;
+	godot::Vector2 position = get_position();
+	position += _speed * p_delta * direction;
+	set_position(position);
+}
+
+void Ball::reset() {
+	direction = godot::Vector2(-1, 0);
+	set_position(_initial_pos);
+	_speed = DEFAULT_SPEED;
+}
+
+void Ball::_register_methods() {
+	godot::register_method("_ready", &Ball::_ready);
+	godot::register_method("_process", &Ball::_process);
+	godot::register_method("reset", &Ball::reset);
+}

cpp/pong/src/ball.hpp

@@ -0,0 +1,25 @@
+#ifndef BALL_H
+#define BALL_H
+
+#include <Area2D.hpp>
+#include <Godot.hpp>
+
+class Ball : public godot::Area2D {
+	GODOT_CLASS(Ball, godot::Area2D)
+
+	const int DEFAULT_SPEED = 100;
+	real_t _speed = DEFAULT_SPEED;
+	godot::Vector2 _initial_pos;
+
+public:
+	godot::Vector2 direction = godot::Vector2(-1, 0);
+
+	void _init() {}
+	void _ready();
+	void _process(double p_delta);
+	void reset();
+
+	static void _register_methods();
+};
+
+#endif // BALL_H

cpp/pong/src/ceiling_floor.cpp

@@ -0,0 +1,12 @@
+#include "ceiling_floor.hpp"
+
+void CeilingFloor::_on_area_entered(Ball *p_ball) {
+	if (p_ball->get_name() == "Ball") {
+		p_ball->direction = (p_ball->direction + godot::Vector2(0, bounce_direction)).normalized();
+	}
+}
+
+void CeilingFloor::_register_methods() {
+	godot::register_method("_on_area_entered", &CeilingFloor::_on_area_entered);
+	godot::register_property("bounce_direction", &CeilingFloor::bounce_direction, 1);
+}

cpp/pong/src/ceiling_floor.hpp

@@ -0,0 +1,21 @@
+#ifndef CEILING_FLOOR_H
+#define CEILING_FLOOR_H
+
+#include <Area2D.hpp>
+#include <Godot.hpp>
+
+#include "ball.hpp"
+
+class CeilingFloor : public godot::Area2D {
+	GODOT_CLASS(CeilingFloor, godot::Area2D)
+
+public:
+	int bounce_direction = 1;
+
+	void _init() {}
+	void _on_area_entered(Ball *p_ball);
+
+	static void _register_methods();
+};
+
+#endif // CEILING_FLOOR_H

cpp/pong/src/entry.cpp

@@ -0,0 +1,23 @@
+#include <Godot.hpp>
+
+#include "ball.hpp"
+#include "ceiling_floor.hpp"
+#include "paddle.hpp"
+#include "wall.hpp"
+
+extern "C" void GDN_EXPORT godot_gdnative_init(godot_gdnative_init_options *o) {
+	godot::Godot::gdnative_init(o);
+}
+
+extern "C" void GDN_EXPORT godot_gdnative_terminate(godot_gdnative_terminate_options *o) {
+	godot::Godot::gdnative_terminate(o);
+}
+
+extern "C" void GDN_EXPORT godot_nativescript_init(void *handle) {
+	godot::Godot::nativescript_init(handle);
+
+	godot::register_class<Ball>();
+	godot::register_class<CeilingFloor>();
+	godot::register_class<Paddle>();
+	godot::register_class<Wall>();
+}

cpp/pong/src/paddle.cpp

@@ -0,0 +1,40 @@
+#include "paddle.hpp"
+
+#include <Input.hpp>
+#include <RandomNumberGenerator.hpp>
+
+void Paddle::_ready() {
+	_screen_size_y = get_viewport_rect().size.y;
+	godot::String n = godot::String(get_name()).to_lower();
+	_up = n + "_move_up";
+	_down = n + "_move_down";
+	if (n == "left") {
+		_ball_dir = 1;
+	} else {
+		_ball_dir = -1;
+	}
+}
+
+void Paddle::_process(double delta) {
+	godot::Input *input = godot::Input::get_singleton();
+	// Move up and down based on input.
+	real_t keyboard_input = input->get_action_strength(_down) - input->get_action_strength(_up);
+	godot::Vector2 position = get_position();
+	position.y = godot::Math::clamp(position.y + keyboard_input * MOVE_SPEED * delta, 16.0, _screen_size_y - 16.0);
+	set_position(position);
+}
+
+void Paddle::_on_area_entered(Ball *p_ball) {
+	if (p_ball->get_name() == "Ball") {
+		godot::Ref<godot::RandomNumberGenerator> random = godot::RandomNumberGenerator::_new();
+		random->randomize();
+		// Assign new direction.
+		p_ball->direction = godot::Vector2(_ball_dir, random->randf() * 2 - 1).normalized();
+	}
+}
+
+void Paddle::_register_methods() {
+	godot::register_method("_ready", &Paddle::_ready);
+	godot::register_method("_process", &Paddle::_process);
+	godot::register_method("_on_area_entered", &Paddle::_on_area_entered);
+}

cpp/pong/src/paddle.hpp

@@ -0,0 +1,29 @@
+#ifndef PADDLE_H
+#define PADDLE_H
+
+#include <Area2D.hpp>
+#include <Godot.hpp>
+
+#include "ball.hpp"
+
+class Paddle : public godot::Area2D {
+	GODOT_CLASS(Paddle, godot::Area2D)
+
+	const int MOVE_SPEED = 100;
+
+	int _ball_dir;
+	godot::String _up;
+	godot::String _down;
+
+	real_t _screen_size_y;
+
+public:
+	void _init() {}
+	void _ready();
+	void _process(double p_delta);
+	void _on_area_entered(Ball *p_area);
+
+	static void _register_methods();
+};
+
+#endif // PADDLE_H

cpp/pong/src/wall.cpp

@@ -0,0 +1,12 @@
+#include "wall.hpp"
+
+void Wall::_on_wall_area_entered(Ball *p_ball) {
+	if (p_ball->get_name() == "Ball") {
+		// Ball went out of game area, reset.
+		p_ball->reset();
+	}
+}
+
+void Wall::_register_methods() {
+	godot::register_method("_on_wall_area_entered", &Wall::_on_wall_area_entered);
+}

cpp/pong/src/wall.hpp

@@ -0,0 +1,19 @@
+#ifndef WALL_H
+#define WALL_H
+
+#include <Area2D.hpp>
+#include <Godot.hpp>
+
+#include "ball.hpp"
+
+class Wall : public godot::Area2D {
+	GODOT_CLASS(Wall, godot::Area2D)
+
+public:
+	void _init() {}
+	void _on_wall_area_entered(Ball *p_area);
+
+	static void _register_methods();
+};
+
+#endif // WALL_H