ui: Use SDL to determine resource/preference base paths

ui/Makefile.objs

@@ -25,19 +25,20 @@ endif
 
 # Override with xemu UI
 sdl.mo-objs := \
-	xemu.o \
-	xemu-hud.o \
-	xemu-custom-widgets.o \
-	xemu-input.o \
-	xemu-monitor.o \
-	xemu-settings.o \
-	xemu-shaders.o \
 	imgui/imgui.o \
 	imgui/imgui_demo.o \
 	imgui/imgui_draw.o \
 	imgui/imgui_widgets.o \
 	imgui/examples/imgui_impl_opengl3.o \
-	imgui/examples/imgui_impl_sdl.o
+	imgui/examples/imgui_impl_sdl.o \
+	xemu.o \
+	xemu-custom-widgets.o \
+	xemu-data.o \
+	xemu-hud.o \
+	xemu-input.o \
+	xemu-monitor.o \
+	xemu-settings.o \
+	xemu-shaders.o \
 
 ui/xemu-shaders.o: ui/shader/xemu-logo-frag.h
 

ui/xemu-custom-widgets.c

@@ -24,6 +24,7 @@
 
 #include "xemu-shaders.h"
 #include "xemu-custom-widgets.h"
+#include "xemu-data.h"
 
 static struct decal_shader *s = NULL;
 static struct decal_shader *s_logo = NULL;
@@ -66,9 +67,9 @@ void initialize_custom_ui_rendering(void)
     glGetIntegerv(GL_VIEWPORT, vp);
 
     glActiveTexture(GL_TEXTURE0);
-    g_ui_tex = load_texture_from_file("data/controller-mask.png");
+    g_ui_tex = load_texture_from_file(xemu_get_resource_path("controller-mask.png"));
     s = create_decal_shader(SHADER_TYPE_MASK);
-    g_logo_tex = load_texture_from_file("data/logo-sdf.png");
+    g_logo_tex = load_texture_from_file(xemu_get_resource_path("logo-sdf.png"));
     s_logo = create_decal_shader(SHADER_TYPE_LOGO);
     controller_fbo = create_fbo(512, 512);
     logo_fbo = create_fbo(512, 512);

ui/xemu-data.c

@@ -0,0 +1,72 @@
+/*
+ * xemu Data File and Path Helpers
+ *
+ * Copyright (C) 2020 Matt Borgerson
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <SDL2/SDL.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <assert.h>
+
+#include "xemu-data.h"
+
+static int path_exists(const char *path)
+{
+	FILE *fd = fopen(path, "rb");
+	if (fd == NULL) return 0;
+	fclose(fd);
+	return 1;
+}
+
+const char *xemu_get_resource_path(const char *filename)
+{
+	// Allocate an arbitrarily long buffer for resource path storage FIXME: This
+	// could be done better with a growing printf. Keep it simple for now.
+	const size_t resource_path_buffer_len = 1024;
+	static char *sdl_base_path = NULL;
+	static char *resource_path = NULL;
+
+	if (!sdl_base_path) {
+		sdl_base_path = SDL_GetBasePath();
+	}
+
+	if (!resource_path) {
+		resource_path = malloc(resource_path_buffer_len);
+		assert(resource_path != NULL);
+	}
+
+	// Try whichever location SDL deems appropriate
+	snprintf(resource_path, resource_path_buffer_len, "%sdata/%s",
+		sdl_base_path, filename);
+
+	if (path_exists(resource_path)) {
+		return resource_path;
+	}
+
+	// Try parent directory if launched from source root
+	snprintf(resource_path, resource_path_buffer_len, "%s../data/%s",
+		sdl_base_path, filename);
+
+	if (path_exists(resource_path)) {
+		return resource_path;
+	}
+
+	// Path not found or file not readable
+	assert(0);
+	return NULL;
+}

ui/xemu-data.h

@@ -0,0 +1,34 @@
+/*
+ * xemu Data File and Path Helpers
+ *
+ * Copyright (C) 2020 Matt Borgerson
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef XEMU_DATA
+#define XEMU_DATA
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+// Note: Not thread safe. Returns a pointer to an internally allocated buffer.
+const char *xemu_get_resource_path(const char *filename);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif

ui/xemu-hud.cc

@@ -29,6 +29,7 @@
 #include "xemu-custom-widgets.h"
 #include "xemu-monitor.h"
 #include "xemu-version.h"
+#include "xemu-data.h"
 
 #include "imgui/imgui.h"
 #include "imgui/examples/imgui_impl_sdl.h"
@@ -111,7 +112,7 @@ void xemu_hud_init(SDL_Window* window, void* sdl_gl_context)
     io.IniFilename = NULL;
 
     // Load fonts
-    io.Fonts->AddFontFromFileTTF("./data/Roboto-Medium.ttf", 16);
+    io.Fonts->AddFontFromFileTTF(xemu_get_resource_path("Roboto-Medium.ttf"), 16);
     fixed_width_font = io.Fonts->AddFontDefault();
 
     // Setup Platform/Renderer bindings

ui/xemu-settings.c

@@ -166,29 +166,25 @@ const char *xemu_settings_get_path(void)
 		return settings_path;
 	}
 
-	// Note: Ideally SDL_GetPrefPath should be used here to determine where the
-	// settings file should be stored. However, until xemu gains a proper
-	// installer, assume it will be run in "portable mode" such that everything
-	// needed to run is all in the same directory, or specified explicitly by
-	// the user via config file.
-#if 0
 	char *base = SDL_GetPrefPath("xemu", "xemu");
-#else
-	// char *base = SDL_GetBasePath();
-	// if (base == NULL) {
-	// 	base = strdup("./");
-	// }
-	char *base = strdup("./");
-#endif
 	assert(base != NULL);
 	size_t base_len = strlen(base);
+
 	size_t filename_len = strlen(filename);
-	size_t len = base_len + filename_len + 1;
-	char *path = malloc(len);
+	size_t final_len = base_len + filename_len;
+	final_len += 1; // Terminating null byte
+
+	char *path = malloc(final_len);
+	assert(path != NULL);
+
+	// Copy base part
 	memcpy(path, base, base_len);
 	free(base);
+
+	// Copy filename part
 	memcpy(path+base_len, filename, strlen(filename));
-	path[len-1] = '\0';
+	path[final_len-1] = '\0';
+
 	settings_path = path;
 
 	fprintf(stderr, "%s: config path: %s\n", __func__, settings_path);