add 3d model for emulator

.gitmodules

@@ -1,3 +1,6 @@
 [submodule "libs/raylib-zig"]
 	path = libs/raylib-zig
 	url = git@github.com:Not-Nik/raylib-zig.git
+[submodule "libs/raylib"]
+	path = libs/raylib
+	url = https://github.com/ryupold/raylib.zig

build.zig

@@ -1,5 +1,6 @@
 const std = @import("std");
-const rl = @import("libs/raylib-zig/build.zig");
+// const rl = @import("libs/raylib-zig/build.zig");
+const raylib = @import("libs/raylib/build.zig");
 
 pub fn build(b: *std.Build) !void {
     const target = b.standardTargetOptions(.{});
@@ -31,9 +32,11 @@ pub fn build(b: *std.Build) !void {
 
     const exe = b.addExecutable(.{ .name = "chip8-zig", .root_source_file = .{ .path = "src/main.zig" }, .optimize = optimize, .target = target });
 
-    rl.link(b, exe, target, optimize);
-    exe.addModule("raylib", rl.getModule(b, "libs/raylib-zig"));
-    exe.addModule("raylib-math", rl.math.getModule(b, "libs/raylib-zig"));
+    raylib.addTo(b, exe, target, optimize);
+
+    // rl.link(b, exe, target, optimize);
+    // exe.addModule("raylib", rl.getModule(b, "libs/raylib-zig"));
+    // exe.addModule("raylib-math", rl.math.getModule(b, "libs/raylib-zig"));
 
     const run_cmd = b.addRunArtifact(exe);
     const run_step = b.step("run", "Run chip8-zig");

build.zig.zon

@@ -1,5 +1,5 @@
 .{
-    .name = "zig-raylib",
+    .name = "chip8-zig",
     .version = "0.1.0",
     .dependencies = .{
         .raylib = .{

libs/raylib

@@ -0,0 +1 @@
+Subproject commit 642458242078d4e3299ea31c9a6c415c65a4e907

src/assets/models/emulator.mtl

@@ -0,0 +1,42 @@
+# Blender 3.5.1 MTL File: 'emulator.blend'
+# www.blender.org
+
+newmtl Behind_buttons
+Ns 0.000000
+Ka 1.000000 1.000000 1.000000
+Kd 0.001734 0.004824 0.007141
+Ks 0.500000 0.500000 0.500000
+Ke 0.000000 0.000000 0.000000
+Ni 1.550000
+d 1.000000
+illum 2
+
+newmtl Button
+Ns 250.000000
+Ka 1.000000 1.000000 1.000000
+Ks 0.500000 0.500000 0.500000
+Ke 0.000000 0.000000 0.000000
+Ni 1.450000
+d 1.000000
+illum 2
+map_Kd Buttons texture.png
+
+newmtl Case
+Ns 298.057037
+Ka 1.000000 1.000000 1.000000
+Kd 0.057402 0.087001 0.228570
+Ks 0.500000 0.500000 0.500000
+Ke 0.000000 0.000000 0.000000
+Ni 1.450000
+d 1.000000
+illum 2
+
+newmtl Screen
+Ns 250.000000
+Ka 1.000000 1.000000 1.000000
+Kd 0.010867 0.020340 0.012183
+Ks 0.500000 0.500000 0.500000
+Ke 0.000000 0.000000 0.000000
+Ni 1.450000
+d 1.000000
+illum 2

src/chip.zig

@@ -50,13 +50,15 @@ pub fn init(allocator: *const Allocator) !Self {
     const display_width = 64;
     const display_height = 32;
     const memory_size = 4096;
+    const memory = try allocator.alloc(u8, memory_size);
+    @memset(memory, 0);
 
     var self = Self {
         .allocator = allocator,
         .display = try allocator.alloc(bool, display_width * display_height),
         .display_width = display_width,
         .display_height = display_height,
-        .memory = try allocator.alloc(u8, memory_size),
+        .memory = memory,
         .stack = [1]u16{0} ** 16,
         .V = [1]u8{0} ** 16,
         .I = 0,
@@ -388,12 +390,11 @@ pub fn run_instruction(self: *Self, inst: u16) !void {
             self.V[x] = (self.V[x] >> 1);
 
         } else if (inst & 0x000F == 0x7) { // 8xy7 - SUBN Vx, Vy
-            const Vx = get_inst_x(inst);
-            const Vy = get_inst_y(inst);
-            const sub: i16 = self.V[Vy] - self.V[Vx];
-            const not_borrow = @intFromBool(sub > 0);
-            self.V[Vx] = @intCast(sub & 0x00FF);
-            self.V[0xF] = not_borrow;
+            const x = get_inst_x(inst);
+            const y = get_inst_y(inst);
+            const result = @subWithOverflow(self.V[y], self.V[x]);
+            self.V[x] = result[0];
+            self.V[0xF] = (1 - result[1]);
 
         } else if (inst & 0x000F == 0xE) { // 8xyE - Vx SHR 1
             const Vx = get_inst_x(inst);

src/main.zig

@@ -1,11 +1,21 @@
 const rl = @import("raylib");
 const std = @import("std");
 
+const print = std.debug.print;
+const Allocator = std.mem.Allocator;
 const ChipContext = @import("chip.zig");
 const RaylibChip = @import("raylib-chip.zig");
+const UI = @import("ui.zig").UI;
+
+const MemoryView = @import("memory-view.zig").MemoryView;
+const Range = @import("memory-view.zig").Range;
 
 const assert = std.debug.assert;
 
+const Tab = enum {
+    MemoryView
+};
+
 pub fn gen_sin_wave(wave: *rl.Wave, frequency: f32) void {
     assert(wave.sampleSize == 16); // Only 16 bits are supported
 
@@ -25,6 +35,120 @@ fn megabytes(amount: usize) usize {
     return amount * 1024 * 1024;
 }
 
+const Light = struct {
+    const LightType = enum(i32) {
+        DIRECTIONAL = 0,
+        POINT = 1,
+    };
+
+    type: LightType,
+    enabled: bool,
+    position: rl.Vector3,
+    target: rl.Vector3,
+    color: rl.Color,
+    attenuation: f32 = 0.0,
+
+    enabledLoc: i32,
+    typeLoc: i32,
+    positionLoc: i32,
+    targetLoc: i32,
+    colorLoc: i32,
+    attenuationLoc: i32 = 0,
+
+    fn create(light_type: LightType, postion: rl.Vector3, target: rl.Vector3, color: rl.Color, shader: rl.Shader) Light {
+        var light = Light{
+            .type = light_type,
+            .enabled = true,
+            .position = postion,
+            .target = target,
+            .color = color,
+            .enabledLoc = rl.GetShaderLocation(shader, "lights[0].enabled"),
+            .typeLoc = rl.GetShaderLocation(shader, "lights[0].type"),
+            .positionLoc = rl.GetShaderLocation(shader, "lights[0].position"),
+            .targetLoc = rl.GetShaderLocation(shader, "lights[0].target"),
+            .colorLoc = rl.GetShaderLocation(shader, "lights[0].color"),
+        };
+        light.update_values(shader);
+        return light;
+    }
+
+    fn update_values(light: *Light, shader: rl.Shader) void {
+        const enabled: i32 = @intFromBool(light.enabled);
+        rl.SetShaderValue(shader, light.enabledLoc, &enabled, rl.ShaderUniformDataType.SHADER_UNIFORM_INT);
+
+        const lightType: i32 = @intFromEnum(light.type);
+        rl.SetShaderValue(shader, light.typeLoc, &lightType, rl.ShaderUniformDataType.SHADER_UNIFORM_INT);
+
+        const position = [3]f32{ light.position.x, light.position.y, light.position.z };
+        rl.SetShaderValue(shader, light.positionLoc, &position, rl.ShaderUniformDataType.SHADER_UNIFORM_VEC3);
+
+        const target = [3]f32{ light.target.x, light.target.y, light.target.z };
+        rl.SetShaderValue(shader, light.targetLoc, &target, rl.ShaderUniformDataType.SHADER_UNIFORM_VEC3);
+
+        const color = [4]f32{
+            @as(f32, @floatFromInt(light.color.r)) / 255.0,
+            @as(f32, @floatFromInt(light.color.g)) / 255.0,
+            @as(f32, @floatFromInt(light.color.b)) / 255.0,
+            @as(f32, @floatFromInt(light.color.a)) / 255.0,
+        };
+        rl.SetShaderValue(shader, light.colorLoc, &color, rl.ShaderUniformDataType.SHADER_UNIFORM_VEC4);
+    }
+};
+
+fn get_camera_projection(camera: *const rl.Camera3D) rl.Matrix {
+    const screen_width: f32 = @floatFromInt(rl.GetScreenWidth());
+    const screen_height: f32 = @floatFromInt(rl.GetScreenHeight());
+
+    if (camera.projection == .CAMERA_PERSPECTIVE) {
+        return rl.MatrixPerspective(camera.fovy*rl.DEG2RAD, screen_width/screen_height, rl.RL_CULL_DISTANCE_NEAR, rl.RL_CULL_DISTANCE_FAR);
+    } else if (camera.projection == .CAMERA_ORTHOGRAPHIC) {
+        const aspect = screen_width/screen_height;
+        const top = camera.fovy/2.0;
+        const right = top*aspect;
+
+        return rl.MatrixOrtho(-right, right, -top, top, rl.RL_CULL_DISTANCE_NEAR, rl.RL_CULL_DISTANCE_FAR);
+    } else {
+        unreachable;
+    }
+}
+
+fn get_screen_direction_from_camera(mat_proj: *const rl.Matrix, mat_view: *const rl.Matrix, point: rl.Vector2) rl.Vector3 {
+    const screen_width: f32 = @floatFromInt(rl.GetScreenWidth());
+    const screen_height: f32 = @floatFromInt(rl.GetScreenHeight());
+
+    const ndc_x = (2.0*point.x) / screen_width - 1.0;
+    const ndc_y = 1.0 - (2.0*point.y) / screen_height;
+
+    var near_point = rl.Vector3Unproject(.{ .x = ndc_x, .y = ndc_y, .z = 0.0 }, mat_proj.*, mat_view.*);
+    var far_point  = rl.Vector3Unproject(.{ .x = ndc_x, .y = ndc_y, .z = 1.0 }, mat_proj.*, mat_view.*);
+
+    return rl.Vector3Subtract(far_point, near_point).normalize();
+}
+
+fn get_preffered_distance_to_box(camera: *const rl.Camera3D, box: rl.BoundingBox) f32 {
+    const screen_width: f32 = @floatFromInt(rl.GetScreenWidth());
+    const screen_height: f32 = @floatFromInt(rl.GetScreenHeight());
+    const margin = @min(screen_width, screen_height)*0.1;
+
+    const box_size = box.max.sub(box.min);
+
+    const max_model_scale = @min((screen_width-2*margin)/box_size.x, (screen_height-2*margin)/box_size.y);
+    // const model_screen_width = box_size.x * max_model_scale;
+    const model_screen_height = box_size.y * max_model_scale;
+
+    const mat_proj = get_camera_projection(camera);
+    const mat_view = rl.MatrixIdentity(); // rl.MatrixLookAt(camera.position, camera.target, camera.up);
+
+    const screen_middle = rl.Vector2{ .x = screen_width/2, .y = screen_height/2 };
+    const box_top_middle = screen_middle.add(.{ .y = -model_screen_height/2 });
+
+    const middle_dir = get_screen_direction_from_camera(&mat_proj, &mat_view, screen_middle);
+    const top_middle_dir = get_screen_direction_from_camera(&mat_proj, &mat_view, box_top_middle);
+    const angle = top_middle_dir.angleBetween(middle_dir);
+    const distance = 1/@tan(angle) * (box_size.y/2) + box_size.z/4;
+    return distance;
+}
+
 pub fn main() anyerror!void {
     var program_memory = try std.heap.page_allocator.alloc(u8, megabytes(2));
     var fba = std.heap.FixedBufferAllocator.init(program_memory);
@@ -33,25 +157,28 @@ pub fn main() anyerror!void {
     var chip = try ChipContext.init(&allocator);
     defer chip.deinit();
 
-    chip.set_memory(0x200, @embedFile("ROMs/morse_demo.ch8"));
-
-    {
-        // const file = try std.fs.cwd().openFile("ROMs/morse_demo.ch8", .{ .mode = .read_only });
-        // defer file.close();
-        // try chip.set_memory_from_file(0x200, file);
-    }
+    chip.set_memory(0x200, @embedFile("ROMs/br8kout.ch8"));
+    // const file = try std.fs.cwd().openFile("ROMs/morse_demo.ch8", .{ .mode = .read_only });
+    // defer file.close();
+    // try chip.set_memory_from_file(0x200, file);
 
     const pixel_size = 20;
-    const screen_width: i32 = @as(i32, chip.display_width) * pixel_size;
-    const screen_height: i32 = @as(i32, chip.display_height) * pixel_size;
+    const initial_screen_width: i32 = @as(i32, chip.display_width) * pixel_size;
+    const initial_screen_height: i32 = @as(i32, chip.display_height) * pixel_size;
 
-    rl.initWindow(screen_width, screen_height, "CHIP-8");
-    defer rl.closeWindow();
+    rl.SetConfigFlags(rl.ConfigFlags{ .FLAG_WINDOW_RESIZABLE = true });
+    rl.InitWindow(initial_screen_width, initial_screen_height, "CHIP-8");
+    defer rl.CloseWindow();
 
-    rl.initAudioDevice();
-    defer rl.closeAudioDevice();
+    rl.InitAudioDevice();
+    defer rl.CloseAudioDevice();
 
-    rl.setTargetFPS(60);
+    rl.SetTargetFPS(60);
+
+    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/fonts/generic-mono.otf", font_size, null, font_ttf_default_numchars);
+    defer rl.UnloadFont(font);
 
     const sample_rate = 44100;
     var data = try allocator.alloc(i16, sample_rate);
@@ -64,24 +191,227 @@ pub fn main() anyerror!void {
         .data = @ptrCast(data.ptr),
     };
     gen_sin_wave(&chip_wave, 440);
-    var chip_sound = rl.loadSoundFromWave(chip_wave);
-    defer rl.unloadSound(chip_sound);
-    rl.setSoundVolume(chip_sound, 0.2);
+    var chip_sound = rl.LoadSoundFromWave(chip_wave);
+    defer rl.UnloadSound(chip_sound);
+    rl.SetSoundVolume(chip_sound, 0.2);
 
     var raylib_chip = RaylibChip.init(&chip, &chip_sound);
+    // var raylib_chip = RaylibChip.init(&chip, null);
     raylib_chip.tick_speed = 500;
     raylib_chip.timer_speed = 60;
 
-    while (!rl.windowShouldClose()) {
-        var dt = rl.getFrameTime();
+    var edit_mode = false;
+    var tab: Tab = .MemoryView;
+
+    // var temp_mem = [1]u8{0xAA} ** (16*80 + 10);
+    // var memory_view = MemoryView.init(&temp_mem, &font, 32);
+    // var memory_view = MemoryView.init(chip.memory, &font, font_size, &allocator);
+    // var selected_memory = Range{};
+    // var ui = UI.init();
+
+    var camera = rl.Camera3D{
+        .position = rl.Vector3.new(0.0, 0, 0.0),
+        .target = rl.Vector3.new(0.0, 0.0, 0.0),
+        .up = rl.Vector3.new(0.0, 1.0, 0.0),
+        .fovy = 45.0,
+        .projection = rl.CameraProjection.CAMERA_PERSPECTIVE,
+    };
+
+    var model = rl.LoadModel("src/assets/models/emulator.obj");
+    var model_bbox = rl.GetModelBoundingBox(model);
+
+    var model_position = rl.Vector3{ };
+    var model_size = model_bbox.max.sub(model_bbox.min);
+
+    const shader = rl.LoadShader("src/shaders/lighting.vs", "src/shaders/lighting.fs");
+    shader.locs.?[@intFromEnum(rl.ShaderLocationIndex.SHADER_LOC_VECTOR_VIEW)] = rl.GetShaderLocation(shader, "viewPos");
+    const ambientLoc = rl.GetShaderLocation(shader, "ambient");
+    rl.SetShaderValue(shader, ambientLoc, &[4]f32{ 0.2, 0.2, 0.2, 1.0 }, rl.ShaderUniformDataType.SHADER_UNIFORM_VEC4);
+
+    for (0..@intCast(model.materialCount)) |i| {
+        model.materials.?[i].shader = shader;
+    }
+
+    var light = Light.create(Light.LightType.DIRECTIONAL, rl.Vector3.new(0.2, 0, -0.2), rl.Vector3.zero(), rl.WHITE, shader);
+
+    std.debug.print("dimensions {}", .{model_size});
+
+    var camera_turn_vel = rl.Vector3Zero();
+    var camera_target_orientation: ?rl.Vector3 = null;
+    var previous_click_time: f64 = 0.0;
+
+    // rl.DisableCursor();
+    while (!rl.WindowShouldClose()) {
+        var dt = rl.GetFrameTime();
         raylib_chip.update(dt);
 
-        {
-            rl.beginDrawing();
-            defer rl.endDrawing();
-
-            rl.clearBackground(rl.Color.white);
-            raylib_chip.render(0, 0, screen_width, screen_height);
+        if (rl.IsKeyPressed(rl.KeyboardKey.KEY_TAB)) {
+            edit_mode = !edit_mode;
         }
+
+        if (edit_mode) {
+            if (rl.IsKeyPressed(rl.KeyboardKey.KEY_ONE)) {
+                tab = .MemoryView;
+            }
+        }
+
+        const mouse_delta = rl.GetMouseDelta();
+
+        if (rl.IsWindowResized()) {
+            const distance = get_preffered_distance_to_box(&camera, model_bbox);
+            const direction = camera.position.sub(model_position).normalize();
+            camera.position = model_position.add(direction.scale(distance));
+        }
+
+        if (rl.Vector3Equals(camera.position, rl.Vector3Zero()) == 1) {
+            const distance = get_preffered_distance_to_box(&camera, model_bbox);
+            camera.target = model_position;
+            camera.position = model_position.sub(rl.Vector3.new(0, 0, 1).scale(distance));
+        }
+
+        var camera_turn_acc = rl.Vector3Zero();
+        if (rl.IsMouseButtonDown(rl.MouseButton.MOUSE_BUTTON_LEFT)) {
+            if (@fabs(mouse_delta.x) > 5) {
+                const rotation_speed = 2; // Radians/second
+                camera_turn_acc.x = -rotation_speed*mouse_delta.x;
+            }
+            if (@fabs(mouse_delta.x) < 5) {
+                camera_turn_vel = camera_turn_vel.scale(0.90); // Holding drag
+            }
+        }
+
+        if (rl.IsMouseButtonPressed(rl.MouseButton.MOUSE_BUTTON_LEFT)) {
+            camera_target_orientation = null;
+
+            const now = rl.GetTime();
+            const duration_between_clicks = now - previous_click_time;
+            if (duration_between_clicks < 0.3) {
+                const ray = rl.GetMouseRay(rl.GetMousePosition(), camera);
+                const collision = rl.GetRayCollisionBox(ray, model_bbox);
+                if (collision.hit) {
+                    const front_face_normal = rl.Vector3.new(0, 0, -1);
+                    const back_face_normal = rl.Vector3.new(0, 0, 1);
+                    if (rl.Vector3Equals(collision.normal, front_face_normal) == 1) {
+                        camera_target_orientation = front_face_normal;
+                    } else if (rl.Vector3Equals(collision.normal, back_face_normal) == 1) {
+                        camera_target_orientation = back_face_normal;
+                    }
+                }
+            }
+            previous_click_time = now;
+        }
+
+        if (camera_target_orientation) |target| {
+            const current_direction = camera.position.sub(model_position).normalize();
+            const current_angle = std.math.atan2(f32, current_direction.z, current_direction.x);
+            const target_angle = std.math.atan2(f32, target.z, target.x);
+            const diff_angle = std.math.pi - @mod((target_angle - current_angle) + 3*std.math.pi, 2*std.math.pi);
+            if (@fabs(diff_angle) < 0.001) {
+                camera_turn_vel.x = 0;
+                camera_target_orientation = null;
+            } else {
+                camera_turn_vel.x = diff_angle*3;
+            }
+        }
+
+        camera_turn_vel = camera_turn_vel.scale(0.95); // Ambient drag
+        camera_turn_vel = camera_turn_vel.add(camera_turn_acc.scale(dt));
+
+        const camera_min_vel = 0;
+        if (camera_turn_vel.length() > camera_min_vel) {
+            const rotation = rl.MatrixRotate(camera.up.normalize(), camera_turn_vel.x*dt);
+            var view = rl.Vector3Subtract(camera.position, camera.target);
+            view = rl.Vector3Transform(view, rotation);
+            camera.position = rl.Vector3Add(camera.target, view);
+        }
+
+        // {
+        //     var matProj = rl.MatrixIdentity();
+        //     // projection = CAMERA_PERSPECTIVE
+        //     matProj = rl.MatrixPerspective(camera.fovy*rl.DEG2RAD, (screen_width/screen_height), rl.RL_CULL_DISTANCE_NEAR, rl.RL_CULL_DISTANCE_FAR);
+        //
+        //     var matView = rl.MatrixLookAt(camera.position, camera.target, camera.up);
+        //     // Convert world position vector to quaternion
+        //     var worldPos = rl.Vector4{ .x = position.x, .y = position.y, .z = position.z, .w = 1.0 };
+        //
+        //     std.debug.print("worldPos {}\n", .{worldPos});
+        //     // Transform world position to view
+        //     worldPos = rl.QuaternionTransform(worldPos, matView);
+        //
+        //     // Transform result to projection (clip space position)
+        //     worldPos = rl.QuaternionTransform(worldPos, matProj);
+        //
+        //     // Calculate normalized device coordinates (inverted y)
+        //     var ndcPos = rl.Vector3.new( worldPos.x/worldPos.w, -worldPos.y/worldPos.w, worldPos.z/worldPos.w );
+        //
+        //     // Calculate 2d screen position vector
+        //     screen_position = rl.Vector2{ .x = (ndcPos.x + 1.0)/2.0*screen_width, .y = (ndcPos.y + 1.0)/2.0*screen_height };
+        // }
+
+        // const target_screen_position = rl.Vector2{ .x = screen_width/2, .y = screen_height*0.1 };
+        // {
+        //     var matProj = get_camera_projection(&camera);
+        //     var matView = rl.MatrixLookAt(camera.position, camera.target, camera.up);
+        //
+        //     const ndc_x = (2.0*target_screen_position.x) / screen_width - 1.0;
+        //     const ndc_y = 1.0 - (2.0*target_screen_position.y) / screen_height;
+        //
+        //     var near_point = rl.Vector3Unproject(.{ .x = ndc_x, .y = ndc_y, .z = 0.0 }, matProj, matView);
+        //     var far_point  = rl.Vector3Unproject(.{ .x = ndc_x, .y = ndc_y, .z = 1.0 }, matProj, matView);
+        //
+        //     var direction = rl.Vector3Subtract(far_point, near_point).normalize();
+        //
+        //     var origin: rl.Vector3 = undefined;
+        //     if (camera.projection == .CAMERA_PERSPECTIVE) {
+        //         origin = camera.position;
+        //     } else {
+        //         origin = rl.Vector3Unproject(.{ .x = ndc_x, .y = ndc_y, .z = -1.0 }, matProj, matView);
+        //     }
+        //
+        //     var world_pos = origin.add(direction.scale(3));
+        //
+        //     model_position = world_pos;
+        // }
+
+        const cameraPos = [3]f32{ camera.position.x, camera.position.y, camera.position.z };
+        rl.SetShaderValue(shader, shader.locs.?[@intFromEnum(rl.ShaderLocationIndex.SHADER_LOC_VECTOR_VIEW)], &cameraPos, rl.ShaderUniformDataType.SHADER_UNIFORM_VEC3);
+        light.update_values(shader);
+
+        rl.BeginDrawing();
+            rl.ClearBackground(.{ .r = 33, .g = 33, .b = 33, .a = 255 });
+
+
+            rl.BeginMode3D(camera);
+                rl.DrawModel(model, model_position, 1.0, rl.WHITE);
+
+                // rl.rlPushMatrix();
+                //     rl.rlSetLineWidth(2);
+                //     rl.rlTranslatef(model_position.x, model_position.y, model_position.z);
+                //     rl.DrawBoundingBox(model_bbox, rl.GREEN);
+                // rl.rlPopMatrix();
+            rl.EndMode3D();
+
+       rl.EndDrawing();
+
+        // if (!edit_mode) {
+        //     rl.ClearBackground(rl.DARKGRAY);
+        //
+        //     const scale_x = @divFloor(screen_width, chip.display_width);
+        //     const scale_y = @divFloor(screen_height, chip.display_height);
+        //     const min_scale = @min(scale_x, scale_y);
+        //
+        //     const display_width = chip.display_width * min_scale;
+        //     const display_height = chip.display_height * min_scale;
+        //     const display_x = @divFloor(screen_width - display_width, 2);
+        //     const display_y = @divFloor(screen_height - display_height, 2);
+        //     raylib_chip.render(display_x, display_y, display_width, display_height);
+        // } else {
+        //     rl.ClearBackground(rl.RAYWHITE);
+        //     ui.update();
+        //
+        //     if (tab == .MemoryView) {
+        //         try memory_view.show(&ui, 0, 0, @floatFromInt(screen_width), @floatFromInt(screen_height), &selected_memory);
+        //     }
+        // }
     }
 }

src/memory-view.zig

@@ -0,0 +1,340 @@
+const rl = @import("raylib");
+const std = @import("std");
+const UILib = @import("ui.zig");
+
+const Allocator = std.mem.Allocator;
+const assert = std.debug.assert;
+const UI = UILib.UI;
+const HorizontalLayout = UILib.HorizontalLayout;
+
+fn nibble_to_char(nibble: u4) u8 {
+    if (0 <= nibble and nibble <= 9) {
+        return '0' + @as(u8, nibble);
+    } else {
+        return 'A' + @as(u8, nibble - 10);
+    }
+}
+
+fn hex_to_strz(str: [:0]u8, number: u32) void {
+    var i: i32 = @intCast(str.len-1);
+    var leftover = number;
+    while (leftover > 0 and i >= 0): (leftover >>= 4) {
+        const nibble: u4 = @intCast(leftover & 0b1111);
+        str[@intCast(i)] = nibble_to_char(nibble);
+        i -= 1;
+    }
+
+    while (i >= 0): (i -= 1) {
+        str[@intCast(i)] = '0';
+    }
+}
+
+fn clamp(value: f32, min: f32, max: f32) f32 {
+    return @min(@max(value, min), max);
+}
+
+pub const Range = struct { start: u32 = 0, end: u32 = 0 };
+
+pub const MemoryView = struct {
+    const Highlight = struct {
+        range: Range,
+        color: rl.Color
+    };
+
+    font: *const rl.Font,
+    font_size: f32,
+
+    base_address: u32,
+    memory: []u8,
+    scroll: f32 = 0,
+
+    scrolling: bool = false,
+    selecting: bool = false,
+    editing: bool = false,
+
+    editing_byte: u32 = 0,
+    selection_pivot: u32 = 0,
+    allocator: *const Allocator,
+
+    grey_out_zeros: bool = true,
+
+    text_color: rl.Color = rl.BLACK,
+    dim_text_color: rl.Color = rl.GRAY,
+
+    row_width: u5 = 16,
+
+    pub fn init(memory: []u8, font: *const rl.Font, font_size: f32, allocator: *const Allocator) MemoryView {
+        return MemoryView{
+            .allocator = allocator,
+            .base_address = 0,
+            .memory = memory,
+            .font = font,
+            .font_size = font_size,
+        };
+    }
+
+    pub fn get_memory_row_count(self: *const MemoryView) f32 {
+        return @ceil(@as(f32, @floatFromInt(self.memory.len)) / @as(f32, @floatFromInt(self.row_width)));
+    }
+
+    pub fn get_visible_row_count(self: *const MemoryView, height: f32) f32 {
+        return @min(height / self.font_size, self.get_memory_row_count());
+    }
+
+    pub fn get_max_scroll(self: *const MemoryView, height: f32) f32 {
+        return @max(self.get_memory_row_count() - self.get_visible_row_count(height), 0);
+    }
+
+    pub fn show(self: *MemoryView, ui: *UI, x: f32, y: f32, width: f32, height: f32, selection: *Range) !void {
+        if (ui.is_mouse_inside(x, y, width, height)) {
+            self.scroll -= rl.GetMouseWheelMove();
+        }
+
+        self.scroll = clamp(self.scroll, 0, self.get_max_scroll(height));
+
+        const from_row: u32 = @intFromFloat(@floor(self.scroll));
+        const to_row: u32 = @intFromFloat(@ceil(self.scroll + self.get_visible_row_count(height)));
+
+        const scroll_offset = @rem(self.scroll, 1) * self.font_size;
+        var layout = HorizontalLayout.init(x, y - scroll_offset, width, height);
+
+        layout.push(try self.show_address_column(ui, layout.next_x(), layout.next_y(), from_row, to_row));
+        layout.push(self.show_hex_column(ui, layout.next_x(), layout.next_y(), selection, from_row, to_row));
+        layout.push(self.show_ascii_column(ui, layout.next_x(), layout.next_y(), selection, from_row, to_row));
+        layout.push(self.show_scrollbar(ui, layout.next_x(), y, height));
+    }
+
+    pub fn show_address_column(self: *MemoryView, ui: *UI, x: f32, y: f32, from_row: u32, to_row: u32) !f32 {
+        const font = self.font.*;
+        const font_size = self.font_size;
+        const margin = font_size/2;
+
+        const memory_size_f32: f32 = @floatFromInt(self.memory.len);
+        const memory_size_log10: u32 = @intFromFloat(@floor(@log2(memory_size_f32)/2));
+        const address_column_max_chars: u32 = memory_size_log10 + 1;
+        const row_count = (to_row - from_row);
+
+        var label_buf = try self.allocator.allocSentinel(u8, address_column_max_chars, 0);
+        defer self.allocator.free(label_buf);
+
+        hex_to_strz(label_buf, 0);
+        const column_width = rl.MeasureTextEx(font, label_buf, font_size, 0).x + 2*margin;
+
+        ui.pushTransformT(.{ .ox = x, .oy = y });
+            for (0..row_count) |i| {
+                const row = from_row + @as(u32, @intCast(i));
+                const row_address = self.base_address + row*self.row_width;
+                hex_to_strz(label_buf, row_address);
+
+                const cell_rect = rl.Rectangle {
+                    .x = 0,
+                    .y = self.font_size * @as(f32, @floatFromInt(i)),
+                    .height = self.font_size,
+                    .width = column_width
+                };
+                if (ui.is_mouse_inside_rect(cell_rect)) {
+                    rl.DrawRectangleRec(cell_rect, rl.RED);
+                }
+
+                const text_pos = rl.Vector2{ .x = cell_rect.x + margin, .y = cell_rect.y };
+                rl.DrawTextEx(font, label_buf, text_pos, font_size, 0, self.text_color);
+            }
+        ui.popTransform();
+
+        return column_width;
+    }
+
+    fn is_in_range(x: u32, from: u32, to: u32) bool {
+        return from <= x and x < to;
+    }
+
+    pub fn show_hex_column(self: *MemoryView, ui: *UI, x: f32, y: f32, selection: *Range, from_row: u32, to_row: u32) f32 {
+        assert(self.row_width <= 16);
+
+        const font = self.font.*;
+        const font_size = self.font_size;
+        const margin = font_size/6;
+
+        var middle_margin: f32 = 0.0;
+        if (self.row_width == 16) {
+            middle_margin = font_size/2;
+        }
+
+        const cell_width = rl.MeasureTextEx(font, "00", font_size, 0).x;
+        const row_count = (to_row - from_row);
+
+        const highlights = [_]Highlight{
+            Highlight{ .range = .{ .start = 16, .end = 17, }, .color = rl.RED },
+            Highlight{ .range = selection.*, .color = rl.RED },
+        };
+
+        ui.pushTransformT(.{ .ox = x, .oy = y });
+            var cell_bufz = [_:0]u8{0} ** 2;
+            for (0..row_count) |i| {
+                const row = from_row + @as(u32, @intCast(i));
+                const row_memory_idx: u32 = @intCast(row*self.row_width);
+
+                var cell_rects: [16]rl.Rectangle = undefined;
+                const to_column = @min(self.memory.len - row*self.row_width, self.row_width);
+                for (0..to_column) |column| {
+                    var cell_rect = rl.Rectangle {
+                        .x = (cell_width + 2*margin) * @as(f32, @floatFromInt(column)),
+                        .y = 0,
+                        .width = cell_width + 2*margin,
+                        .height = self.font_size
+                    };
+
+                    if (column >= self.row_width/2) {
+                        cell_rect.x += middle_margin;
+                    }
+
+                    cell_rects[column] = cell_rect;
+                }
+
+                for (highlights) |highlight| {
+                    const highlight_start = highlight.range.start;
+                    const highlight_end = highlight.range.end;
+                    if (row_memory_idx >= highlight_end) continue;
+                    if (row_memory_idx+self.row_width <= highlight_start) continue;
+
+                    var highlight_from_column: u32 = undefined;
+                    if (row_memory_idx > highlight_start) {
+                        highlight_from_column = 0;
+                    } else {
+                        highlight_from_column = @mod(highlight_start, self.row_width);
+                    }
+
+                    var highlight_to_column: u32 = undefined;
+                    if (row_memory_idx+self.row_width <= highlight_end) {
+                        highlight_to_column = self.row_width-1;
+                    } else {
+                        highlight_to_column = @mod(highlight_end-1, self.row_width);
+                    }
+
+                    const from_cell = cell_rects[highlight_from_column];
+                    const to_cell = cell_rects[highlight_to_column];
+                    rl.DrawRectangleRec(rl.Rectangle{
+                        .x = from_cell.x,
+                        .y = from_cell.y,
+                        .width = (to_cell.x+to_cell.width) - from_cell.x,
+                        .height = (to_cell.y+to_cell.height) - from_cell.y,
+                    }, highlight.color);
+                }
+
+                for (0..to_column) |column| {
+                    const memory_idx: u32 = row_memory_idx + @as(u32, @intCast(column));
+                    if (ui.is_holding_mouse(cell_rects[column], &self.selecting)) {
+                        if (self.selecting) {
+                            self.selection_pivot = memory_idx;
+                            selection.start = memory_idx;
+                            selection.end = memory_idx+1;
+                        }
+                    }
+
+                    if (self.selecting) {
+                        if (ui.is_mouse_inside_rect(cell_rects[column])) {
+                            if (memory_idx > self.selection_pivot) {
+                                selection.start = self.selection_pivot;
+                                selection.end = memory_idx+1;
+                            } else {
+                                selection.start = memory_idx;
+                                selection.end = self.selection_pivot+1;
+                            }
+                        }
+                    }
+
+                    const text_pos = rl.Vector2{ .x = cell_rects[column].x + margin };
+                    const value = self.memory[memory_idx];
+                    hex_to_strz(&cell_bufz, value);
+                    var color = self.text_color;
+                    if (self.grey_out_zeros and value == 0) {
+                        color = self.dim_text_color;
+                    }
+                    rl.DrawTextEx(font, &cell_bufz, text_pos, font_size, 0, color);
+                }
+                ui.translate(0, font_size);
+            }
+        ui.popTransform();
+
+        return (cell_width + 2*margin)*@as(f32, @floatFromInt(self.row_width)) + middle_margin;
+    }
+
+    pub fn show_ascii_column(self: *MemoryView, ui: *UI, x: f32, y: f32, selection: *Range, from_row: u32, to_row: u32) f32 {
+        const font = self.font.*;
+        const font_size = self.font_size;
+        const margin = font_size/2;
+
+        const cell_width = rl.MeasureTextEx(font, ".", font_size, 0).x;
+        const row_count = (to_row - from_row);
+
+        ui.pushTransformT(.{ .ox = x+margin, .oy = y });
+            for (0..row_count) |i| {
+                const row = from_row + @as(u32, @intCast(i));
+
+                const to_column = @min(self.memory.len - row*self.row_width, self.row_width);
+                for (0..to_column) |column| {
+                    const memory_idx: u32 = @intCast(row*self.row_width + column);
+                    const value = self.memory[memory_idx];
+                    var char: u8 = 'A';
+                    if (std.ascii.isPrint(value)) {
+                        char = value;
+                    } else {
+                        char = '.';
+                    }
+
+                    const pos_x = cell_width * @as(f32, @floatFromInt(column));
+                    if (selection.start <= memory_idx and memory_idx < selection.end) {
+                        const cell_rect = rl.Rectangle{
+                            .x = pos_x,
+                            .y = 0,
+                            .height = self.font_size,
+                            .width = cell_width
+                        };
+                        rl.DrawRectangleRec(cell_rect, rl.RED);
+                    }
+
+                    const char_str = [2]u8 { char, 0 };
+                    rl.DrawTextEx(font, char_str[0..1 :0], rl.Vector2{ .x = pos_x }, font_size, 0, self.text_color);
+                }
+
+                ui.translate(0, font_size);
+            }
+        ui.popTransform();
+
+        return cell_width*@as(f32, @floatFromInt(self.row_width)) + 2*margin;
+    }
+
+    pub fn show_scrollbar(self: *MemoryView, ui: *UI, x: f32, y: f32, height: f32) f32 {
+        const max_scroll = self.get_max_scroll(height);
+        if (max_scroll == 0) {
+            return 0;
+        }
+
+        const visible_row_count = self.get_visible_row_count(height);
+        const memory_row_count = self.get_memory_row_count();
+        const visible_percent = visible_row_count / memory_row_count;
+        const scroll_percent = self.scroll / max_scroll;
+        const scrollbar_height = visible_percent * height;
+
+        const scrollbar = rl.Rectangle {
+             .x = x,
+             .y = y + scroll_percent * (height - scrollbar_height),
+             .width = self.font_size,
+             .height = scrollbar_height
+        };
+
+
+        var color = rl.BLACK;
+        _ = ui.is_holding_mouse(scrollbar, &self.scrolling);
+        if (self.scrolling) {
+            const mouse_dy = rl.GetMouseDelta().y;
+            self.scroll += (mouse_dy / (height - scrollbar_height) * max_scroll);
+            self.scroll = clamp(self.scroll, 0, max_scroll);
+            color = rl.DARKGRAY;
+        }
+
+        rl.DrawRectangleRec(scrollbar, color);
+
+        return scrollbar.width;
+    }
+};

src/raylib-chip.zig

@@ -8,16 +8,16 @@ on_color: rl.Color,
 off_color: rl.Color,
 timer_speed: f32,
 tick_speed: f32,
-beep_sound: *rl.Sound,
+beep_sound: ?*rl.Sound,
 
 tick_time: f32,
 timer_time: f32,
 
-pub fn init(chip: *ChipContext, beep_sound: *rl.Sound) Self {
+pub fn init(chip: *ChipContext, beep_sound: ?*rl.Sound) Self {
     return Self{
         .chip = chip,
-        .off_color = rl.Color.black,
-        .on_color = rl.Color.ray_white,
+        .off_color = rl.BLACK,
+        .on_color = rl.RAYWHITE,
         .timer_speed = 60,
         .tick_speed = 500,
         .tick_time = 0,
@@ -28,26 +28,26 @@ pub fn init(chip: *ChipContext, beep_sound: *rl.Sound) Self {
 
 pub fn update_input(self: *Self) void {
     const keys = [16]rl.KeyboardKey{
-        .key_x,
-        .key_one,
-        .key_two,
-        .key_three,
-        .key_q,
-        .key_w,
-        .key_e,
-        .key_a,
-        .key_s,
-        .key_d,
-        .key_z,
-        .key_c,
-        .key_four,
-        .key_r,
-        .key_f,
-        .key_v,
+        .KEY_X,
+        .KEY_ONE,
+        .KEY_TWO,
+        .KEY_THREE,
+        .KEY_Q,
+        .KEY_W,
+        .KEY_E,
+        .KEY_A,
+        .KEY_S,
+        .KEY_D,
+        .KEY_Z,
+        .KEY_C,
+        .KEY_FOUR,
+        .KEY_R,
+        .KEY_F,
+        .KEY_V,
     };
 
     for (0.., keys) |i, key| {
-        self.chip.input[i] = rl.isKeyDown(key);
+        self.chip.input[i] = rl.IsKeyDown(key);
     }
 }
 
@@ -70,14 +70,15 @@ pub fn update(self: *Self, dt: f32) void {
         self.timer_time -= 1/self.timer_speed;
     }
 
-    const beep_sound = self.beep_sound.*;
-    if (self.chip.ST > 0) {
-        if (!rl.isSoundPlaying(beep_sound)) {
-            rl.playSound(beep_sound);
-        }
-    } else {
-        if (rl.isSoundPlaying(beep_sound)) {
-            rl.stopSound(beep_sound);
+    if (self.beep_sound) |beep_sound| {
+        if (self.chip.ST > 0) {
+            if (!rl.IsSoundPlaying(beep_sound.*)) {
+                rl.PlaySound(beep_sound.*);
+            }
+        } else {
+            if (rl.IsSoundPlaying(beep_sound.*)) {
+                rl.StopSound(beep_sound.*);
+            }
         }
     }
 }
@@ -86,14 +87,14 @@ pub fn render(self: *Self, x: i32, y: i32, width: i32, height: i32) void {
     const pixel_width = @divFloor(width, self.chip.display_width);
     const pixel_height = @divFloor(height, self.chip.display_height);
 
-    rl.drawRectangle(0, 0, width, height, self.off_color);
+    rl.DrawRectangle(x, y, width, height, self.off_color);
 
     for (0..self.chip.display_height) |oy| {
         for (0..self.chip.display_width) |ox| {
             if (self.chip.display_get(@intCast(ox), @intCast(oy))) {
                 const ix = x + @as(i32, @intCast(ox)) * pixel_width;
                 const iy = y + @as(i32, @intCast(oy)) * pixel_height;
-                rl.drawRectangle(ix, iy, pixel_width, pixel_height, self.on_color);
+                rl.DrawRectangle(ix, iy, pixel_width, pixel_height, self.on_color);
             }
         }
     }

src/shaders/lighting.fs

@@ -0,0 +1,82 @@
+#version 330
+
+// Input vertex attributes (from vertex shader)
+in vec3 fragPosition;
+in vec2 fragTexCoord;
+//in vec4 fragColor;
+in vec3 fragNormal;
+
+// Input uniform values
+uniform sampler2D texture0;
+uniform vec4 colDiffuse;
+
+// Output fragment color
+out vec4 finalColor;
+
+// NOTE: Add here your custom variables
+
+#define     MAX_LIGHTS              1
+#define     LIGHT_DIRECTIONAL       0
+#define     LIGHT_POINT             1
+
+struct MaterialProperty {
+    vec3 color;
+    int useSampler;
+    sampler2D sampler;
+};
+
+struct Light {
+    int enabled;
+    int type;
+    vec3 position;
+    vec3 target;
+    vec4 color;
+};
+
+// Input lighting values
+uniform Light lights[MAX_LIGHTS];
+uniform vec4 ambient;
+uniform vec3 viewPos;
+
+void main()
+{
+    // Texel color fetching from texture sampler
+    vec4 texelColor = texture(texture0, fragTexCoord);
+    vec3 lightDot = vec3(0.0);
+    vec3 normal = normalize(fragNormal);
+    vec3 viewD = normalize(viewPos - fragPosition);
+    vec3 specular = vec3(0.0);
+
+    // NOTE: Implement here your fragment shader code
+
+    for (int i = 0; i < MAX_LIGHTS; i++)
+    {
+        if (lights[i].enabled == 1)
+        {
+            vec3 light = vec3(0.0);
+
+            if (lights[i].type == LIGHT_DIRECTIONAL)
+            {
+                light = -normalize(lights[i].target - lights[i].position);
+            }
+
+            if (lights[i].type == LIGHT_POINT)
+            {
+                light = normalize(lights[i].position - fragPosition);
+            }
+
+            float NdotL = max(dot(normal, light), 0.0);
+            lightDot += lights[i].color.rgb*NdotL;
+
+            float specCo = 0.0;
+            if (NdotL > 0.0) specCo = pow(max(0.0, dot(viewD, reflect(-(light), normal))), 16.0); // 16 refers to shine
+            specular += specCo;
+        }
+    }
+
+    finalColor = (texelColor*((colDiffuse + vec4(specular, 1.0))*vec4(lightDot, 1.0)));
+    finalColor += texelColor*(ambient/10.0)*colDiffuse;
+
+    // Gamma correction
+    finalColor = pow(finalColor, vec4(1.0/1.9));
+}

src/shaders/lighting.vs

@@ -0,0 +1,32 @@
+#version 330
+
+// Input vertex attributes
+in vec3 vertexPosition;
+in vec2 vertexTexCoord;
+in vec3 vertexNormal;
+in vec4 vertexColor;
+
+// Input uniform values
+uniform mat4 mvp;
+uniform mat4 matModel;
+uniform mat4 matNormal;
+
+// Output vertex attributes (to fragment shader)
+out vec3 fragPosition;
+out vec2 fragTexCoord;
+out vec4 fragColor;
+out vec3 fragNormal;
+
+// NOTE: Add here your custom variables
+
+void main()
+{
+    // Send vertex attributes to fragment shader
+    fragPosition = vec3(matModel*vec4(vertexPosition, 1.0));
+    fragTexCoord = vertexTexCoord;
+    fragColor = vertexColor;
+    fragNormal = normalize(vec3(matNormal*vec4(vertexNormal, 1.0)));
+
+    // Calculate final vertex position
+    gl_Position = mvp*vec4(vertexPosition, 1.0);
+}

src/ui.zig

@@ -0,0 +1,230 @@
+const rl = @import("raylib");
+const assert = @import("std").debug.assert;
+
+pub const UI = struct {
+    const TransformFrame = struct {
+        ox: f32 = 0,
+        oy: f32 = 0,
+        sx: f32 = 1,
+        sy: f32 = 1,
+    };
+
+    frames: [16]TransformFrame,
+    top_frame: u32,
+
+    mouse: rl.Vector2,
+    mouse_delta: rl.Vector2,
+
+    pub fn init() UI {
+        return UI{
+            .frames = [1]TransformFrame{ TransformFrame{} } ** 16,
+            .top_frame = 0,
+            .mouse = rl.Vector2.zero(),
+            .mouse_delta = rl.Vector2.zero(),
+        };
+    }
+
+    pub fn pushTransform(self: *UI) void {
+        assert(self.top_frame < self.frames.len-1);
+
+        rl.rlPushMatrix();
+        self.top_frame += 1;
+        self.frames[self.top_frame] = self.frames[self.top_frame - 1];
+    }
+
+    pub fn pushTransformT(self: *UI, transform: TransformFrame) void {
+        self.pushTransform();
+        self.translate(transform.ox, transform.oy);
+        self.scale(transform.sx, transform.sy);
+    }
+
+    pub fn translate(self: *UI, x: f32, y: f32) void {
+        const top_frame = &self.frames[self.top_frame];
+        top_frame.ox += x * top_frame.sx;
+        top_frame.oy += y * top_frame.sy;
+        rl.rlTranslatef(x, y, 0);
+    }
+
+    pub fn scale(self: *UI, x: f32, y: f32) void {
+        const top_frame = &self.frames[self.top_frame];
+        top_frame.sx *= x;
+        top_frame.sy *= y;
+        rl.rlScalef(x, y, 0);
+    }
+
+    pub fn popTransform(self: *UI) void {
+        rl.rlPopMatrix();
+        self.top_frame -= 1;
+    }
+
+    pub fn update(self: *UI) void {
+        assert(self.top_frame == 0); // Check if 'pushTransform()' and 'popTransform()' are paired
+
+        self.frames[0] = .{};
+        self.mouse = rl.GetMousePosition();
+        self.mouse_delta = rl.GetMouseDelta();
+    }
+
+    /// Screen space -> UI space
+    pub fn apply_transform(self: *UI, vec2: rl.Vector2) rl.Vector2 {
+        const top_frame = &self.frames[self.top_frame];
+        return rl.Vector2{
+            .x = (vec2.x - top_frame.ox) * top_frame.sx,
+            .y = (vec2.y - top_frame.oy) * top_frame.sy
+        };
+    }
+
+    pub fn apply_scale(self: *UI, vec2: rl.Vector2) rl.Vector2 {
+        const top_frame = &self.frames[self.top_frame];
+        return rl.Vector2{
+            .x = vec2.x * top_frame.sx,
+            .y = vec2.y * top_frame.sy,
+        };
+    }
+
+    pub fn get_mouse(self: *UI) rl.Vector2 {
+        return self.apply_transform(self.mouse);
+    }
+
+    pub fn get_mouse_delta(self: *UI) rl.Vector2 {
+        return self.apply_scale(self.mouse_delta);
+    }
+
+    pub fn is_mouse_inside(self: *UI, x: f32, y: f32, width: f32, height: f32) bool {
+        const mouse = self.get_mouse();
+        return (x <= mouse.x and mouse.x < x+width) and (y <= mouse.y and mouse.y < y+height);
+    }
+
+    pub fn is_mouse_inside_rect(self: *UI, rect: rl.Rectangle) bool {
+        return self.is_mouse_inside(rect.x, rect.y, rect.width, rect.height);
+    }
+
+    pub fn is_mouse_down() bool {
+        return rl.IsMouseButtonDown(rl.MouseButton.MOUSE_BUTTON_LEFT);
+    }
+
+    pub fn is_mouse_up() bool {
+        return rl.IsMouseButtonUp(rl.MouseButton.MOUSE_BUTTON_LEFT);
+    }
+
+    pub fn was_secondary_mouse_pressed() bool {
+        return rl.IsMouseButtonPressed(rl.MouseButton.MOUSE_BUTTON_RIGHT);
+    }
+
+    pub fn is_holding_mouse(self: *UI, rect: rl.Rectangle, state: *bool) bool {
+        if (!state.* and UI.is_mouse_down() and self.is_mouse_inside_rect(rect)) {
+            state.* = true;
+            return true;
+        }
+        if (UI.is_mouse_up()) {
+            state.* = false;
+            return true;
+        }
+        return false;
+    }
+};
+
+pub const UIBox = struct {
+    x: f32,
+    y: f32,
+    width: f32,
+    height: f32,
+
+    vert_margin: f32,
+    horz_margin: f32,
+
+    pub fn init(x: f32, y: f32, width: f32, height: f32) UIBox {
+        return UIBox {
+            .x = x,
+            .y = y,
+            .width = width,
+            .height = height,
+            .vert_margin = 0,
+            .horz_margin = 0,
+        };
+    }
+
+    pub fn init_rect(rectangle: rl.Rectangle) UIBox {
+        return UIBox.init(rectangle.x, rectangle.y, rectangle.width, rectangle.height);
+    }
+
+    pub fn body_x(self: *UIBox) f32 {
+        return self.x + self.horz_margin;
+    }
+
+    pub fn body_y(self: *UIBox) f32 {
+        return self.y + self.vert_margin;
+    }
+
+    pub fn body_width(self: *UIBox) f32 {
+        return self.width - 2*self.horz_margin;
+    }
+
+    pub fn body_height(self: *UIBox) f32 {
+        return self.height - 2*self.vert_margin;
+    }
+
+    pub fn body_rect(self: *UIBox) rl.Rectangle {
+        return rl.Rectangle{
+            .x = self.body_x(),
+            .y = self.body_y(),
+            .width = self.body_width(),
+            .height = self.body_height()
+        };
+    }
+
+    pub fn rect(self: *UIBox) rl.Rectangle {
+        return rl.Rectangle{
+            .x = self.x,
+            .y = self.y,
+            .width = self.width,
+            .height = self.height
+        };
+    }
+};
+
+pub const HorizontalLayout = struct {
+    x: f32,
+    y: f32,
+    width: f32,
+    height: f32,
+
+    used_width: f32,
+
+    pub fn init(x: f32, y: f32, width: f32, height: f32) HorizontalLayout {
+        return HorizontalLayout{
+            .x = x,
+            .y = y,
+            .width = width,
+            .height = height,
+            .used_width = 0
+        };
+    }
+
+    pub fn next_x(self: *HorizontalLayout) f32 {
+        return self.x + self.used_width;
+    }
+
+    pub fn next_y(self: *HorizontalLayout) f32 {
+        return self.y;
+    }
+
+    pub fn push_rect(self: *HorizontalLayout, width: f32) rl.Rectangle {
+        const rect = rl.Rectangle{
+            .x = self.next_x(),
+            .y = self.next_y(),
+            .width = width,
+            .height = self.height
+        };
+        self.push(width);
+        return rect;
+    }
+
+    pub fn push(self: *HorizontalLayout, width: f32) void {
+        self.used_width += width;
+    }
+
+    pub fn used_size(self: *HorizontalLayout) rl.Vector2 {
+        return rl.Vector2{ .x = self.used_width, .y = self.height };
+    }
+};