Shared data between processes

The two windows are now connected!

CMakeLists.txt

@@ -19,6 +19,7 @@ set(FLAGS
 	-Wall -Wextra -Wshadow -Wswitch-default -Wswitch-enum
 	-Wunreachable-code -Wstrict-prototypes -Wmissing-prototypes
 	-Wold-style-definition -Werror-implicit-function-declaration
+	-Werror -pedantic -std=c90
 	-Os)
 
 add_executable(${PROJECT_NAME} ${SOURCES} ${SOURCES_RAYLIB})

include/conf.h

@@ -10,4 +10,5 @@ static const int draw_offset_x = -2;
 static const int draw_offset_y = -8;
 static const int tile_width = 16;
 static const int tile_height = 16;
-static const int target_fps = 60;
+static const int editor_target_fps = 60;
+static const int picker_target_fps = 30;

include/editing_area/main.h

@@ -2,4 +2,7 @@
 /* Copyright (C) 2021 KikooDX */
 #pragma once
 
-int editing_area_main(int argc, char **argv);
+#include "shared_data.h"
+
+int editing_area_main(int argc, char **argv,
+                      struct SharedData *shared_data);

include/shared_data.h

@@ -0,0 +1,9 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+/* Copyright (C) 2021 KikooDX */
+#pragma once
+
+/* data shared between processes */
+struct SharedData {
+	int end_child;
+	int selected_tile;
+};

include/tile_picker/main.h

@@ -2,4 +2,7 @@
 /* Copyright (C) 2021 KikooDX */
 #pragma once
 
-int tile_picker_main(int argc, char **argv);
+#include "shared_data.h"
+
+int tile_picker_main(int argc, char **argv,
+                     struct SharedData *shared_data);

src/editing_area/main.c

@@ -4,10 +4,14 @@
 #include "conf.h"
 #include "editing_area/draw.h"
 #include "editing_area/level.h"
+#include "shared_data.h"
 #include <raylib.h>
+#include <stdbool.h>
 #include <stdlib.h>
+#include <sys/wait.h>
 
-int editing_area_main(int argc, char **argv)
+int editing_area_main(int argc, char **argv,
+                      struct SharedData *shared_data)
 {
 	struct Level level;
 	level.data = NULL;
@@ -15,11 +19,11 @@ int editing_area_main(int argc, char **argv)
 	/* initialize raylib */
 	InitWindow(game_window_width, game_window_height,
 	           "SLE main window");
-	SetTargetFPS(target_fps);
+	SetTargetFPS(editor_target_fps);
 	/* load textures */
 	const Texture2D tileset = LoadTexture(argv[1]);
 
-	/* only process if tileset is well loaded */
+	/* only proceed if tileset is well loaded */
 	if (tileset.width > 0) {
 		/* load level */
 		level_read(&level, argv[2]);
@@ -45,5 +49,11 @@ int editing_area_main(int argc, char **argv)
 	UnloadTexture(tileset);
 	CloseWindow();
 
+	/* tell to the child process it can end */
+	shared_data->end_child = true;
+
+	/* wait for child process to exit */
+	wait(NULL);
+
 	return EXIT_SUCCESS;
 }

src/main.c

@@ -2,19 +2,33 @@
 /* Copyright (C) 2021 KikooDX */
 
 #include "editing_area/main.h"
+#include "shared_data.h"
 #include "tile_picker/main.h"
+#include <raylib.h>
+#include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <sys/mman.h>
 #include <sys/types.h>
 #include <unistd.h>
 
+static void *create_shared_memory(size_t size);
+
 /* The editor fork to create two windows. One will be the level editor
  * and the other the tile selection. This is done to allow the user to
  * organize these panels in the way they want to. */
 int main(int argc, char **argv)
 {
+	struct SharedData *shared_data =
+	    (struct SharedData *)create_shared_memory(
+		sizeof(struct SharedData));
+	shared_data->end_child = false;
+	shared_data->selected_tile = 1;
 	pid_t child_process;
 
+	/* set log level */
+	SetTraceLogLevel(LOG_ERROR);
+
 	/* check for argument count */
 	if (argc != 3) {
 		fprintf(stderr, "ERROR: expected 2 arguments, got %d\n",
@@ -22,14 +36,27 @@ int main(int argc, char **argv)
 		return EXIT_FAILURE;
 	};
 
+	/* forking here */
 	child_process = fork();
 	if (child_process < 0) {
 		fprintf(stderr, "ERROR: process couldn't fork");
 		return EXIT_FAILURE;
-	} else if (child_process == 0)
+	} else if (child_process == 0) {
 		/* child process, start the tile picker */
-		return tile_picker_main(argc, argv);
-	else
+		return tile_picker_main(argc, argv, shared_data);
+	} else {
 		/* main process, start the editing area */
-		return editing_area_main(argc, argv);
+		editing_area_main(argc, argv, shared_data);
+		return EXIT_SUCCESS;
+	}
+}
+
+static void *create_shared_memory(size_t size)
+{
+	/* shared memory will be read & write */
+	int protection = PROT_READ | PROT_WRITE;
+	/* anonymous and shared, only child process will be able to
+	 * access it */
+	int visibility = MAP_SHARED | MAP_ANONYMOUS;
+	return mmap(NULL, size, protection, visibility, -1, 0);
 }

src/tile_picker/main.c

@@ -2,22 +2,24 @@
 /* Copyright (C) 2021 KikooDX */
 
 #include "conf.h"
+#include "shared_data.h"
 #include "tile_picker/draw.h"
 #include <raylib.h>
 #include <stdlib.h>
 
-int tile_picker_main(int argc, char **argv)
+int tile_picker_main(int argc, char **argv,
+                     struct SharedData *shared_data)
 {
 	/* initialize raylib */
 	InitWindow(picker_window_width, picker_window_height,
 	           "SLE secondary window");
-	SetTargetFPS(target_fps);
+	SetTargetFPS(picker_target_fps);
 	/* load textures */
 	const Texture2D tileset = LoadTexture(argv[1]);
 
-	/* only process if tileset is well loaded */
+	/* only proceed if tileset is well loaded */
 	if (tileset.width > 0) {
-		while (!WindowShouldClose()) {
+		while (!shared_data->end_child) {
 			/* draw */
 			BeginDrawing();
 
@@ -30,6 +32,7 @@ int tile_picker_main(int argc, char **argv)
 
 	/* unload textures */
 	UnloadTexture(tileset);
+
 	CloseWindow();
 
 	return EXIT_SUCCESS;