dynamically show list of available roms

src/main-scene.zig

@@ -12,16 +12,17 @@ const assert = std.debug.assert;
 const Allocator = std.mem.Allocator;
 const StringList = std.ArrayList([]const u8);
 
-const example_roms = roms.listROMs();
+const rom_list = roms.listROMs();
 
 allocator: Allocator,
 
 chip: *ChipContext,
 raylib_chip: *RaylibChip,
 chip_sound: rl.Sound,
-rom: ?ROM = null,
 
 is_gui_open: bool = true,
+selected_rom_index: i32 = 3,
+rom_list_scroll_index: i32 = 0,
 
 pub fn genSinWave(wave: *rl.Wave, frequency: f32) void {
     assert(wave.sampleSize == 16); // Only 16 bits are supported
@@ -68,7 +69,7 @@ pub fn init(allocator: Allocator) !Self {
         .chip_sound = chip_sound,
     };
 
-    self.set_rom(example_roms[3]);
+    self.set_rom(3);
 
     return self;
 }
@@ -81,8 +82,9 @@ pub fn deinit(self: *Self) void {
     self.allocator.destroy(self.chip);
 }
 
-pub fn set_rom(self: *Self, rom: ROM) void {
+pub fn set_rom(self: *Self, index: i32) void {
-    self.rom = rom;
+    self.selected_rom_index = index;
+    const rom = rom_list[@intCast(index)];
     self.chip.reset();
     self.chip.set_memory(0x200, rom.data);
 }
@@ -115,10 +117,67 @@ pub fn draw(self: *Self) void {
         render_height
     );
 
-    self.draw_gui();
+    self.drawGui(self.allocator) catch @panic("GUI OOM");
 }
 
-pub fn draw_gui(self: *Self) void {
+fn GuiListView(
+    allocator: Allocator,
+    bounds: rl.Rectangle,
+    items: []const []const u8,
+    scroll_index: *i32,
+    active: *i32,
+) !i32 {
+    var needed_size: usize = 0;
+    needed_size += items.len-1; // N-1 character are needed for the separators
+    for (items) |item| {
+        needed_size += item.len;
+    }
+
+    var str_buffer = try allocator.allocSentinel(u8, needed_size, 0);
+    defer allocator.free(str_buffer);
+
+    var idx: usize = 0;
+    for (0.., items) |i, item| {
+        @memcpy(str_buffer[idx..(idx+item.len)], item);
+        idx += item.len;
+
+        if (i != items.len-1) {
+            str_buffer[idx] = ';';
+            idx += 1;
+        }
+    }
+
+    return gui.GuiListView(bounds, str_buffer, scroll_index, active);
+}
+
+fn GuiListViewMinWidth(allocator: Allocator, height: i32, items: []const []const u8) !i32 {
+    const border_width    = gui.GuiGetStyle(.DEFAULT , @intFromEnum(gui.GuiControlProperty.BORDER_WIDTH));
+    const item_spacing    = gui.GuiGetStyle(.LISTVIEW, @intFromEnum(gui.GuiListViewProperty.LIST_ITEMS_SPACING));
+    const item_height     = gui.GuiGetStyle(.LISTVIEW, @intFromEnum(gui.GuiListViewProperty.LIST_ITEMS_HEIGHT));
+    const font_size       = gui.GuiGetStyle(.DEFAULT , @intFromEnum(gui.GuiDefaultProperty.TEXT_SIZE));
+    const scrollbar_width = gui.GuiGetStyle(.LISTVIEW, @intFromEnum(gui.GuiListViewProperty.SCROLLBAR_WIDTH));
+
+    var max_item_width: i32 = 0;
+    for (items) |item| {
+        const item_z = try allocator.dupeZ(u8, item);
+        defer allocator.free(item_z);
+        const item_width = rl.MeasureText(item_z, font_size);
+
+        max_item_width = @max(max_item_width, item_width);
+    }
+
+    const item_count: i32 = @intCast(items.len);
+    const need_scrollbar = ((item_height + item_spacing)*item_count > height);
+
+    var min_width = max_item_width + 2*item_spacing + border_width;
+    if (need_scrollbar) {
+        min_width += scrollbar_width;
+    }
+
+    return min_width;
+}
+
+pub fn drawGui(self: *Self, allocator: Allocator) !void {
     if (rl.IsKeyPressed(.KEY_TAB)) {
         self.is_gui_open = !self.is_gui_open;
     }
@@ -137,12 +196,34 @@ pub fn draw_gui(self: *Self) void {
     const window_width: f32 = 300;
     const window_height: f32 = 100;
     const window = rl.Rectangle{
-        .x = (screen_width-window_width)/2,
+        .x = @trunc((screen_width-window_width)/2),
-        .y = (screen_height-window_height)/2,
+        .y = @trunc((screen_height-window_height)/2),
         .width = window_width,
         .height = window_height
     };
     if (gui.GuiWindowBox(window, "CHIP-8 Settings") == 1) {
         self.is_gui_open = false;
     }
+
+    rl.rlPushMatrix();
+    rl.rlTranslatef(window.x, window.y, 0);
+
+    const rom_list_names = try allocator.alloc([]const u8, rom_list.len);
+    defer allocator.free(rom_list_names);
+
+    for (0.., rom_list) |i, rom| {
+        rom_list_names[i] = rom.name;
+    }
+
+    const list_height = 100;
+    const list_width = try GuiListViewMinWidth(allocator, list_height, rom_list_names) + 20;
+    _ = try GuiListView(
+        allocator,
+        .{.x=10,.y=24, .width=@floatFromInt(list_width), .height=list_height},
+        rom_list_names,
+        &self.rom_list_scroll_index,
+        &self.selected_rom_index
+    );
+
+    rl.rlPopMatrix();
 }

src/main.zig

@@ -31,11 +31,6 @@ pub fn main() anyerror!void {
     var scene = try MainScene.init(allocator);
     defer scene.deinit();
 
-    const font_size = 24;
-    const font_ttf_default_numchars = 95; // TTF font generation default charset: 95 glyphs (ASCII 32..126)
-    const font = rl.LoadFontEx("src/assets/fonts/generic-mono.otf", font_size, null, font_ttf_default_numchars);
-    defer rl.UnloadFont(font);
-
     while (!rl.WindowShouldClose()) {
         var dt = rl.GetFrameTime();
         scene.update(dt);

src/roms.zig

@@ -1,3 +1,4 @@
+const std = @import("std");
 const options = @import("options");
 const rom_count = options.roms.len;
 
@@ -10,8 +11,12 @@ pub fn listROMs() [options.roms.len]ROM {
     var roms: [options.roms.len]ROM = undefined;
 
     for (0.., options.roms) |i, file| {
+        const extension = std.mem.lastIndexOfScalar(u8, file, '.') orelse file.len;
+        const slash = std.mem.lastIndexOfScalar(u8, file, '/') orelse -1;
+
+        const name = file[(slash+1)..extension];
         roms[i] = ROM{
-            .name = file,
+            .name = name,
             .data = @embedFile(file)
         };
     }