@@ -27,6 +27,7 @@ file(GLOB GBA_CHEATS_SRC ${CMAKE_SOURCE_DIR}/src/gba/cheats/*.c)
 file(GLOB GBA_RR_SRC ${CMAKE_SOURCE_DIR}/src/gba/rr/*.c)
 file(GLOB GBA_SV_SRC ${CMAKE_SOURCE_DIR}/src/gba/supervisor/*.c)
 file(GLOB UTIL_SRC ${CMAKE_SOURCE_DIR}/src/util/*.[cSs])
+file(GLOB GUI_SRC ${CMAKE_SOURCE_DIR}/src/util/gui/*.c)
 file(GLOB RENDERER_SRC ${CMAKE_SOURCE_DIR}/src/gba/renderers/*.c)
 file(GLOB SIO_SRC ${CMAKE_SOURCE_DIR}/src/gba/sio/lockstep.c)
 file(GLOB THIRD_PARTY_SRC ${CMAKE_SOURCE_DIR}/src/third-party/inih/*.c)
@@ -355,6 +356,7 @@ ${GBA_SV_SRC}
 	${DEBUGGER_SRC}
 	${RENDERER_SRC}
 	${SIO_SRC}
+	${GUI_SRC}
 	${UTIL_SRC}
 	${VFS_SRC}
 	${OS_SRC}

@@ -1,8 +1,10 @@
 file(GLOB PLATFORM_SRC ${CMAKE_SOURCE_DIR}/src/platform/psp2/*.c)
 
-set(PLATFORM_LIBRARY -lvita2d -lSceCtrl_stub -lSceRtc_stub -lSceGxm_stub -lSceDisplay_stub -lSceAudio_stub -lm_stub)
+execute_process(COMMAND ${DEVKITARM}/bin/arm-none-eabi-objcopy -I binary -O elf32-littlearm -B arm font.png ${CMAKE_BINARY_DIR}/font.o WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}/res)
 
-add_executable(${BINARY_NAME}.elf ${PLATFORM_SRC})
+set(PLATFORM_LIBRARY -lvita2d -lSceCtrl_stub -lSceRtc_stub -lSceGxm_stub -lSceDisplay_stub -lSceAudio_stub -lpng -lz -lm_stub)
+
+add_executable(${BINARY_NAME}.elf ${PLATFORM_SRC} ${CMAKE_BINARY_DIR}/font.o)
 target_link_libraries(${BINARY_NAME}.elf ${BINARY_NAME} ${PLATFORM_LIBRARY})
 set_target_properties(${BINARY_NAME}.elf PROPERTIES OUTPUT_NAME ${BINARY_NAME}.elf)
 add_custom_command(TARGET ${BINARY_NAME}.elf POST_BUILD COMMAND ${FIXUP} -q -S ${BINARY_NAME}.elf ${BINARY_NAME}.velf MAIN_DEPENDENCY ${BINARY_NAME}.elf)

@@ -0,0 +1,60 @@
+/* Copyright (c) 2013-2015 Jeffrey Pfau
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#include "util/gui/font.h"
+
+#include <vita2d.h>
+
+#define GLYPH_HEIGHT 11
+#define GLYPH_WIDTH 14
+#define FONT_TRACKING 10
+#define CELL_HEIGHT 16
+#define CELL_WIDTH 16
+
+extern const uint8_t _binary_font_png_start[];
+
+struct GUIFont {
+	vita2d_texture* tex;
+};
+
+struct GUIFont* GUIFontCreate(void) {
+	struct GUIFont* font = malloc(sizeof(struct GUIFont));
+	if (!font) {
+		return 0;
+	}
+	font->tex = vita2d_load_PNG_buffer(_binary_font_png_start);
+	return font;
+}
+
+void GUIFontDestroy(struct GUIFont* font) {
+	vita2d_free_texture(font->tex);
+	free(font);
+}
+
+int GUIFontHeight(const struct GUIFont* font) {
+	UNUSED(font);
+	return GLYPH_HEIGHT;
+}
+
+void GUIFontPrintf(const struct GUIFont* font, int x, int y, enum GUITextAlignment align, uint32_t color, const char* text, ...) {
+	UNUSED(align); // TODO
+	char buffer[256];
+	va_list args;
+	va_start(args, text);
+	int len = vsnprintf(buffer, sizeof(buffer), text, args);
+	va_end(args);
+	int i;
+	for (i = 0; i < len; ++i) {
+		char c = buffer[i];
+		if (c > 0x7F) {
+			c = 0;
+		}
+		vita2d_draw_texture_tint_part(font->tex, x, y - GLYPH_HEIGHT,
+			                          (c & 15) * CELL_WIDTH + ((CELL_WIDTH - GLYPH_WIDTH) >> 1),
+			                          (c >> 4) * CELL_HEIGHT + ((CELL_HEIGHT - GLYPH_HEIGHT) >> 1),
+			                          GLYPH_WIDTH, GLYPH_HEIGHT, color);
+		x += FONT_TRACKING;
+	}
+}

@@ -5,18 +5,82 @@ * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 #include "psp2-context.h"
 
+#include "util/gui.h"
+#include "util/gui/font.h"
+#include "util/gui/file-select.h"
+
+#include <psp2/ctrl.h>
 #include <psp2/kernel/processmgr.h>
 #include <psp2/moduleinfo.h>
 
+#include <vita2d.h>
+
 PSP2_MODULE_INFO(0, 0, "mGBA");
 
+static void _drawStart(void) {
+	vita2d_start_drawing();
+	vita2d_clear_screen();
+}
+
+static void _drawEnd(void) {
+	vita2d_end_drawing();
+	vita2d_swap_buffers();
+}
+
+static int _pollInput(void) {
+	SceCtrlData pad;
+	sceCtrlPeekBufferPositive(0, &pad, 1);
+	int input = 0;
+	if (pad.buttons & PSP2_CTRL_TRIANGLE) {
+		input |= 1 << GUI_INPUT_CANCEL;
+	}
+	if (pad.buttons & PSP2_CTRL_CIRCLE) {
+		input |= 1 << GUI_INPUT_BACK;
+	}
+	if (pad.buttons & PSP2_CTRL_CROSS) {
+		input |= 1 << GUI_INPUT_SELECT;
+	}
+
+	if (pad.buttons & PSP2_CTRL_UP) {
+		input |= 1 << GUI_INPUT_UP;
+	}
+	if (pad.buttons & PSP2_CTRL_DOWN) {
+		input |= 1 << GUI_INPUT_DOWN;
+	}
+	if (pad.buttons & PSP2_CTRL_LEFT) {
+		input |= 1 << GUI_INPUT_LEFT;
+	}
+	if (pad.buttons & PSP2_CTRL_RIGHT) {
+		input |= 1 << GUI_INPUT_RIGHT;
+	}
+	return input;
+}
+
 int main() {
 	printf("%s initializing", projectName);
+
+	vita2d_init();
+	struct GUIFont* font = GUIFontCreate();
 	GBAPSP2Setup();
-	GBAPSP2LoadROM("cache0:/VitaDefilerClient/Documents/GBA/rom.gba");
-	GBAPSP2Runloop();
-	GBAPSP2UnloadROM();
+	struct GUIParams params = {
+		PSP2_HORIZONTAL_PIXELS, PSP2_VERTICAL_PIXELS,
+		font, _drawStart, _drawEnd, _pollInput
+	};
+
+	while (true) {
+		char path[256];
+		if (!selectFile(&params, "cache0:", path, sizeof(path), "gba")) {
+			break;
+		}
+		GBAPSP2LoadROM(path);
+		GBAPSP2Runloop();
+		GBAPSP2UnloadROM();
+	}
+
 	GBAPSP2Teardown();
+
+	GUIFontDestroy(font);
+	vita2d_fini();
 
 	sceKernelExitProcess(0);
 	return 0;

@@ -0,0 +1,14 @@
+/* Copyright (c) 2013-2015 Jeffrey Pfau
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#ifndef PSP2_COMMON_H
+#define PSP2_COMMON_H
+ 
+#include "util/common.h"
+
+#define PSP2_HORIZONTAL_PIXELS 960
+#define PSP2_VERTICAL_PIXELS 544
+
+#endif

@@ -39,8 +39,6 @@ static Thread audioThread;
 
 static bool fullscreen = false;
 
-#define PSP2_HORIZONTAL_PIXELS 960
-#define PSP2_VERTICAL_PIXELS 544
 #define PSP2_INPUT 0x50535032
 #define PSP2_SAMPLES 64
 #define PSP2_AUDIO_BUFFER_SIZE (PSP2_SAMPLES * 19)
@@ -100,7 +98,6 @@ GBAInputBindAxis(&inputMap, PSP2_INPUT, 0, &desc);
 	desc = (struct GBAAxis) { GBA_KEY_RIGHT, GBA_KEY_LEFT, 192, 64 };
 	GBAInputBindAxis(&inputMap, PSP2_INPUT, 1, &desc);
 
-	vita2d_init();
 	tex = vita2d_create_empty_texture_format(256, 256, SCE_GXM_TEXTURE_FORMAT_X8U8U8U8_1BGR);
 
 	renderer.outputBuffer = vita2d_texture_get_datap(tex);
@@ -251,7 +248,6 @@ void GBAPSP2Teardown(void) {
 	GBAInputMapDeinit(&inputMap);
 
 	vita2d_free_texture(tex);
-	vita2d_fini();
 }
 
 void GBAPSP2Draw(void) {

@@ -6,7 +6,7 @@ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 #ifndef PSP2_CONTEXT_H
 #define PSP2_CONTEXT_H
 
-#include "util/common.h"
+#include "psp2-common.h"
 
 void GBAPSP2Setup(void);
 void GBAPSP2Teardown(void);

@@ -0,0 +1,35 @@
+/* Copyright (c) 2013-2015 Jeffrey Pfau
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#ifndef GUI_H
+#define GUI_H
+
+#include "util/common.h"
+
+struct GUIFont;
+
+enum GUIInput {
+	GUI_INPUT_NONE = -1,
+	GUI_INPUT_SELECT = 0,
+	GUI_INPUT_BACK,
+	GUI_INPUT_CANCEL,
+
+	GUI_INPUT_UP,
+	GUI_INPUT_DOWN,
+	GUI_INPUT_LEFT,
+	GUI_INPUT_RIGHT,
+};
+
+struct GUIParams {
+	int width;
+	int height;
+	const struct GUIFont* font;
+
+	void (*drawStart)(void);
+	void (*drawEnd)(void);
+	int (*pollInput)(void);
+};
+
+#endif

@@ -0,0 +1,121 @@
+/* Copyright (c) 2013-2015 Jeffrey Pfau
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#include "file-select.h"
+
+#include "util/gui/font.h"
+#include "util/vector.h"
+#include "util/vfs.h"
+
+DECLARE_VECTOR(FileList, char*);
+DEFINE_VECTOR(FileList, char*);
+
+void _cleanFiles(struct FileList* currentFiles) {
+	size_t size = FileListSize(currentFiles);
+	size_t i;
+	for (i = 0; i < size; ++i) {
+		free(*FileListGetPointer(currentFiles, i));
+	}
+	FileListClear(currentFiles);
+}
+
+void _upDirectory(char* currentPath) {
+	char* end = strrchr(currentPath, '/');
+	if (!end) {
+		return;
+	}
+	end[0] = '\0';
+	if (end[1]) {
+		return;
+	}
+	// TODO: What if there was a trailing slash?
+}
+
+bool _refreshDirectory(const char* currentPath, struct FileList* currentFiles) {
+	_cleanFiles(currentFiles);
+
+	struct VDir* dir = VDirOpen(currentPath);
+	if (!dir) {
+		return false;
+	}
+	struct VDirEntry* de;
+	while ((de = dir->listNext(dir))) {
+		if (de->name(de)[0] == '.') {
+			continue;
+		}
+		*FileListAppend(currentFiles) = strdup(de->name(de));
+	}
+	dir->close(dir);
+	return true;
+}
+
+bool selectFile(const struct GUIParams* params, const char* basePath, char* outPath, size_t outLen, const char* suffix) {
+	char currentPath[256];
+	strncpy(currentPath, basePath, sizeof(currentPath));
+	int oldInput = -1;
+	size_t fileIndex = 0;
+
+	struct FileList currentFiles;
+	FileListInit(&currentFiles, 0);
+	_refreshDirectory(currentPath, &currentFiles);
+
+	while (true) {
+		int input = params->pollInput();
+		int newInput = input & (oldInput ^ input);
+		oldInput = input;
+
+		if (newInput & (1 << GUI_INPUT_UP) && fileIndex > 0) {
+			--fileIndex;
+		}
+		if (newInput & (1 << GUI_INPUT_DOWN) && fileIndex < FileListSize(&currentFiles) - 1) {
+			++fileIndex;
+		}
+		if (newInput & (1 << GUI_INPUT_CANCEL)) {
+			_cleanFiles(&currentFiles);
+			FileListDeinit(&currentFiles);
+			return false;
+		}
+		if (newInput & (1 << GUI_INPUT_SELECT)) {
+			snprintf(currentPath, sizeof(currentPath), "%s%c%s", currentPath, '/', *FileListGetPointer(&currentFiles, fileIndex));
+			if (!_refreshDirectory(currentPath, &currentFiles)) {
+				strncpy(outPath, currentPath, outLen);
+				return true;
+			}
+			fileIndex = 0;
+		}
+		if (newInput & (1 << GUI_INPUT_BACK)) {
+			if (strncmp(currentPath, basePath, sizeof(currentPath)) == 0) {
+				_cleanFiles(&currentFiles);
+				FileListDeinit(&currentFiles);
+				return false;
+			}
+			_upDirectory(currentPath);
+			_refreshDirectory(currentPath, &currentFiles);
+			fileIndex = 0;
+		}
+
+		params->drawStart();
+		int y = GUIFontHeight(params->font);
+		GUIFontPrintf(params->font, 0, y, GUI_TEXT_LEFT, 0xFFFFFFFF, "Current directory: %s", currentPath);
+		y += 2 * GUIFontHeight(params->font);
+		size_t i;
+		for (i = 0; i < FileListSize(&currentFiles); ++i) {
+			int color = 0xE0A0A0A0;
+			char bullet = ' ';
+			if (i == fileIndex) {
+				color = 0xFFFFFFFF;
+				bullet = '>';
+			}
+			GUIFontPrintf(params->font, 0, y, GUI_TEXT_LEFT, color, "%c %s", bullet, *FileListGetPointer(&currentFiles, i));
+			y += GUIFontHeight(params->font);
+			if (y + GUIFontHeight(params->font) > params->height) {
+				break;
+			}
+		}
+		y += GUIFontHeight(params->font) * 2;
+
+		params->drawEnd();
+	}
+}

@@ -0,0 +1,13 @@
+/* Copyright (c) 2013-2015 Jeffrey Pfau
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#ifndef GUI_FILE_CHOOSER_H
+#define GUI_FILE_CHOOSER_H
+
+#include "util/gui.h"
+
+bool selectFile(const struct GUIParams*, const char* basePath, char* outPath, size_t outLen, const char* suffix);
+
+#endif

@@ -0,0 +1,25 @@
+/* Copyright (c) 2013-2015 Jeffrey Pfau
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#ifndef GUI_FONT_H
+#define GUI_FONT_H
+
+#include "util/common.h"
+
+struct GUIFont;
+struct GUIFont* GUIFontCreate(void);
+void GUIFontDestroy(struct GUIFont*);
+
+enum GUITextAlignment {
+	GUI_TEXT_LEFT = 0,
+	GUI_TEXT_CENTER,
+	GUI_TEXT_RIGHT
+};
+
+int GUIFontHeight(const struct GUIFont*);
+
+void GUIFontPrintf(const struct GUIFont*, int x, int y, enum GUITextAlignment, uint32_t color, const char* text, ...);
+
+#endif