Added some default game roms

Updated the components to start with a gui_ prefix, changed the layout
idea that each component is responsible for their own bounding box and
inner content.

.ignore

@@ -1 +1,2 @@
 external/
+assets/

src/simulator/gui.odin

@@ -3,29 +3,36 @@ package simulator
 import emu "../machine"
 import rl "vendor:raylib"
 
-// Initial window size
+// @ Window
 WINDOW_WIDTH  :: 1920
 WINDOW_HEIGHT :: 1080
 
-// @TODO: If this grows lets move it into its own file
-// ─── Layout constants ───────────────────────────────────────────────────
-SIDEBAR_PERCENT     :: 0.20
-DISPLAY_PERCENT     :: 0.30
-CONTROL_BAR_H 		:: f32(50)
-STATUS_BAR_H  		:: f32(30)
-PANEL_PADDING		:: 10
-PANEL_HEADER		:: 24
+// @ Layout proportions
+// Sidebar takes 20% of screen width on each side; display takes the rest.
+// The center column splits vertically: 40% display, 60% debug panel.
+SIDEBAR_PERCENT		:: f32(0.20)
+DISPLAY_V_RATIO		:: f32(0.40)
+// @ Fixed heights
+CONTROL_BAR_H		:: f32(50)
+STATUS_BAR_H		:: f32(30)
+// @ Layout constants
+PADDING_X			:: f32(10)
+PADDING_Y			:: f32(8)
+PANEL_HEADER		:: f32(24)
+// @ Buttons
 BUTTON_HEIGHT		:: 30
 BUTTON_WIDTH		:: 120
+// @ Fonts
 BIG_FONT_SIZE		:: 20
 KEYPAD_FONT_SIZE	:: 18
 
 Layout :: struct {
 	control_bar  : rl.Rectangle,
-	left_panel   : rl.Rectangle,
+	file_loader  : rl.Rectangle,
+	keypad       : rl.Rectangle,
 	display		 : rl.Rectangle,
 	bottom_panel : rl.Rectangle,
-	right_panel  : rl.Rectangle,
+	cpu			 : rl.Rectangle,
 	status_bar   : rl.Rectangle,
 }
 
@@ -46,7 +53,7 @@ run_gui :: proc(sim: ^Simulator) {
     rl.GuiLoadStyle("./assets/raygui_styles/style_dark.rgs")
 
     rl.GuiSetFont(font)
-    rl.GuiSetStyle(.DEFAULT, cast(i32)rl.GuiDefaultProperty.TEXT_SIZE, 18)
+    rl.GuiSetStyle(.DEFAULT, i32(rl.GuiDefaultProperty.TEXT_SIZE), 18)
 
 	// Draw each of the components in its own window within the main window
 	for !rl.WindowShouldClose() {
@@ -79,9 +86,26 @@ run_gui :: proc(sim: ^Simulator) {
 			}
 		}
 
+		// Top
+		// ------------------------------------------
 		gui_control_bar(layout.control_bar, sim)
-		gui_left_panel(layout.left_panel, sim)
+
+		// Left
+		// ------------------------------------------
+		gui_file_loader(layout.file_loader, sim)
+		gui_key_pad(layout.keypad, sim.machine.keypad, sim.font)
+
+		// Center
+		// ------------------------------------------
 		gui_screen(layout.display, sim)
+
+		// Right
+		// ------------------------------------------
+		gui_cpu(layout.cpu, sim)
+
+		// Bottom
+		// ------------------------------------------
+		gui_bottom_tabs(layout.bottom_panel, sim)
 		gui_status_bar(layout.status_bar, sim)
 
 		rl.EndDrawing()
@@ -95,64 +119,74 @@ run_gui :: proc(sim: ^Simulator) {
 
 // @TODO: If this grows lets move it into its own file
 calc_layout :: proc(screen_width: f32, screen_height: f32) -> Layout {
-	top_h    := CONTROL_BAR_H
-	bottom_h := STATUS_BAR_H
-	content_h := screen_height - top_h - bottom_h
-	content_y := top_h
+	// Control bar is a fixed height frozen at top of gui, all items start below it.
+	y_pos			   := CONTROL_BAR_H
+	x_pos			   := f32(0)
 
-	sidebar_w := screen_width * SIDEBAR_PERCENT
+	// Usable gui vertical space
+	visible_height	   := screen_height - CONTROL_BAR_H - STATUS_BAR_H
+	sidebar_width	   := screen_width * SIDEBAR_PERCENT
+	display_width	   := screen_width - (sidebar_width * 2) - sidebar_width
+	display_height	   := visible_height * DISPLAY_V_RATIO
 
-	screen_h_ratio := 0.40
-	bottom_panel_h := content_h * f32(1.0 - screen_h_ratio)
-	screen_h := content_h * f32(screen_h_ratio)
-	memory_h := content_h - screen_h
-
-	center_x := sidebar_w
-	center_w := screen_width - sidebar_w * 2
+	x_center		   := sidebar_width
+	y_center		   := screen_width - sidebar_width * 2
 
 	return Layout {
+		// Left Area
 		control_bar = rl.Rectangle{
 			x = 0,
 			y = 0,
 			width = screen_width,
-			height = top_h,
+			height = CONTROL_BAR_H,
 		},
-
-		left_panel = rl.Rectangle{
+		file_loader = rl.Rectangle{
 			x = 0,
-			y = top_h,
-			width = sidebar_w,
-			height = content_h,
+			y = y_pos,
+			width = sidebar_width,
+			height = visible_height / 3
+		},
+		keypad = rl.Rectangle{
+			x = 0,
+			y = (y_pos + visible_height - visible_height / 2),
+			width = sidebar_width,
+			height = visible_height / 2
 		},
 
-		// CHIP-8 screen (top center)
+		// ------------------------------------------
+		// Center Area
 		display = rl.Rectangle{
-			x = center_x,
-			y = top_h,
-			width = center_w,
-			height = screen_h,
+			x = sidebar_width,
+			y = y_pos,
+			width = display_width,
+			height = display_height,
 		},
 
-		// MEMORY / DEBUG panel (bottom center)
+		// ------------------------------------------
+		// Bottom Area
 		bottom_panel = rl.Rectangle{
-			x = center_x,
-			y = top_h + screen_h,
-			width = center_w,
-			height = memory_h,
+			x = sidebar_width,
+			y = y_pos + display_height,
+			width = screen_width - sidebar_width,
+			height = visible_height - display_height,
 		},
 
-		right_panel = rl.Rectangle{
-			x = screen_width - sidebar_w,
-			y = top_h,
-			width = sidebar_w,
-			height = content_h,
+		// ------------------------------------------
+		// Right Area
+		cpu = rl.Rectangle {
+			x = sidebar_width + display_width,
+			y = y_pos,
+			width = sidebar_width * 2,
+			height = display_height
 		},
 
+		// ------------------------------------------
+		// Bottom Area
 		status_bar = rl.Rectangle{
-			x = 0,
-			y = screen_height - bottom_h,
+			x = x_pos,
+			y = y_pos + visible_height,
 			width = screen_width,
-			height = bottom_h,
+			height = STATUS_BAR_H,
 		},
 	}
 }

src/simulator/gui_bottom_tabs.odin

@@ -0,0 +1,34 @@
+package simulator
+
+import rl "vendor:raylib"
+
+gui_bottom_tabs :: proc(rect: rl.Rectangle, sim: ^Simulator) {
+	rl.DrawRectangleLinesEx(rect, 1, rl.GRAY)
+
+	// Setup tab bar
+	tabs := [?]cstring{ "Memory", "Disassembly", "Log" }
+
+	tab_bar_rect := rl.Rectangle{
+		rect.x,
+		rect.y,
+		rect.width,
+		BUTTON_HEIGHT + PADDING_Y
+	}
+
+	// inside draw loop:
+	rl.GuiTabBar(tab_bar_rect, &tabs[0], i32(len(tabs)), &sim.active_tab)
+
+	bounds := rl.Rectangle {
+		x = rect.x + PADDING_X,
+		y = rect.y + PADDING_Y + tab_bar_rect.height,
+		width = rect.width - (PADDING_X * 2),
+		height = rect.height - (PADDING_Y * 2) - tab_bar_rect.height,
+	}
+
+	switch sim.active_tab {
+		case 0: // draw registers panel
+			gui_tab_memory(bounds, sim)
+		case 1: // draw memory panel
+		case 2: // draw display panel
+	}
+}

src/simulator/gui_control_bar.odin

@@ -3,15 +3,16 @@ package simulator
 import "core:log"
 import rl "vendor:raylib"
 
-PADDING :: 10
-
 gui_control_bar :: proc(rect: rl.Rectangle, sim: ^Simulator) {
 	rl.DrawRectangleLinesEx(rect, 1, rl.DARKGRAY)
 
-	// Cursor moves for every btn call places them left to right with padding
-	cursor : f32 = rect.x + PANEL_PADDING
+	rl.DrawTextEx(sim.font, "Octal Cookie Chip 8 Sim ", {rect.x + PADDING_X, rect.y + 12}, 25, 1, rl.WHITE)
+	text_size := rl.MeasureTextEx(sim.font, "Octal Cookie Chip 8 Sim ", 25, 1)
 
-	if btn(&cursor, rect, BUTTON_HEIGHT, BUTTON_WIDTH, PANEL_PADDING, "RUN") {
+	// Cursor moves for every btn call places them left to right with padding
+	cursor : f32 = text_size.x + 5 + rect.x + PADDING_X
+
+	if btn(&cursor, rect, BUTTON_HEIGHT, BUTTON_WIDTH, PADDING_X, "RUN") {
 		if sim.rom_loaded {
 			sim.paused = false
 			sim.running = true
@@ -20,14 +21,18 @@ gui_control_bar :: proc(rect: rl.Rectangle, sim: ^Simulator) {
 		}
 	}
 
-	if btn(&cursor, rect, BUTTON_HEIGHT, BUTTON_WIDTH, PANEL_PADDING, "PAUSE") {
+	if btn(&cursor, rect, BUTTON_HEIGHT, BUTTON_WIDTH, PADDING_X, "PAUSE") {
 		sim.paused = true
 		sim.running = false
 	}
+
+	if btn(&cursor, rect, BUTTON_HEIGHT, BUTTON_WIDTH, PADDING_X, "RESET") {
+
+	}
 }
 
 btn :: proc(cursor: ^f32, rect: rl.Rectangle, h, w, gap: f32, label: cstring) -> bool {
-	r := rl.Rectangle{cursor^, rect.y + PADDING, w, h}
+	r := rl.Rectangle{cursor^, rect.y + PADDING_X, w, h}
 	cursor^ += w + gap
 	return rl.GuiButton(r, label)
 }

src/simulator/gui_cpu.odin

@@ -0,0 +1,104 @@
+package simulator
+
+import rl "vendor:raylib"
+
+CPU_SECTION_H :: 100  // enough for 3 rows of labels
+REG_CELL_H :: 40  // fixed, won't grow with the panel
+
+gui_cpu :: proc(rect: rl.Rectangle, sim: ^Simulator) {
+	rl.DrawRectangleLinesEx(rect, 1, rl.GRAY)
+
+	bounds := rl.Rectangle {
+		x = rect.x + PADDING_X,
+		y = rect.y + PADDING_Y,
+		width = rect.width - (PADDING_X * 2),
+		height = rect.height - (PADDING_Y * 2),
+	}
+	rl.GuiPanel(bounds, "CPU / Registers")
+
+	cpu_rect := rl.Rectangle {
+		x      = bounds.x + PADDING_X,
+		y      = bounds.y + PADDING_Y + PANEL_HEADER,
+		width  = bounds.width - (PADDING_X * 2),
+		height = CPU_SECTION_H - (PADDING_Y * 2),
+	}
+
+	// Grid constants
+	COLS   :: 2
+	ROWS   :: 3
+	LRATIO :: f32(0.6)
+
+	cell_w := cpu_rect.width / COLS
+	cell_h := cpu_rect.height / ROWS
+
+	labels := [5]string{ "Progam Counter", "Increment pointer", "Stack Pointer", "Delay Timer", "Sound Timer" }
+	values := [5]u16{
+		sim.machine.pc,
+		sim.machine.i,
+		u16(sim.machine.sp),
+		u16(sim.machine.delay_timer),
+		u16(sim.machine.sound_timer),
+	}
+
+	for index in 0..<5 {
+		col := index % COLS
+		row := index / COLS
+
+        cell_x := cpu_rect.x + f32(col) * cell_w
+        cell_y := cpu_rect.y + f32(row) * cell_h
+
+        label_rect := rl.Rectangle{cell_x + 20, cell_y, cell_w,cell_h}
+        box_rect   := rl.Rectangle{cell_x + cell_w * LRATIO, cell_y, cell_w * (1 - LRATIO), cell_h}
+
+        rl.GuiLabel(label_rect, rl.TextFormat("%s", labels[index]))
+        rl.DrawRectangleLinesEx(box_rect, 1, rl.DARKGRAY)
+
+		// Right-aligned value
+		value_text := rl.TextFormat("0x%04X", values[index])
+		text_w     := rl.MeasureText(value_text, 18)
+		value_x    := box_rect.x + box_rect.width - f32(text_w) - 4
+		rl.GuiLabel({value_x, box_rect.y, box_rect.width, box_rect.height}, value_text)
+	}
+
+
+	register_bounds := rl.Rectangle {
+		x      = bounds.x,
+		y      = bounds.y + PANEL_HEADER + PADDING_Y + CPU_SECTION_H,
+		width  = bounds.width,
+		height = bounds.height - PANEL_HEADER - PADDING_Y - CPU_SECTION_H,
+	}
+	rl.GuiPanel(register_bounds, "Registers")
+
+	register_rect := rl.Rectangle {
+		x = register_bounds.x + PADDING_X,
+		y = register_bounds.y + PADDING_Y + PANEL_HEADER,
+		width = register_bounds.width - (PADDING_X * 2),
+		height = register_bounds.height - (PADDING_Y * 2) - PANEL_HEADER,
+	}
+
+	// V registers grid (V0–VF, 16 registers)
+	REG_COLS   :: 4
+	REG_ROWS   :: 4
+
+	reg_cell_w := register_rect.width  / REG_COLS
+
+	for index in 0..<16 {
+		col := index % REG_COLS
+		row := index / REG_COLS
+
+		cell_x := register_rect.x + f32(col) * reg_cell_w
+		cell_y := register_rect.y + f32(row) * REG_CELL_H
+
+		label_rect := rl.Rectangle{cell_x + 20, cell_y, reg_cell_w, REG_CELL_H}
+		box_rect   := rl.Rectangle{cell_x + reg_cell_w * LRATIO, cell_y, reg_cell_w * (1 - LRATIO), REG_CELL_H}
+
+		rl.GuiLabel(label_rect, rl.TextFormat("V%X", index))
+		rl.DrawRectangleLinesEx(box_rect, 1, rl.DARKGRAY)
+
+		// Right-aligned value
+		value_text := rl.TextFormat("0x%02X", sim.machine.v[index])
+		text_w     := rl.MeasureText(value_text, 18)
+		value_x    := box_rect.x + box_rect.width - f32(text_w) - 4
+		rl.GuiLabel({value_x, box_rect.y, box_rect.width, box_rect.height}, value_text)
+	}
+}

src/simulator/gui_file_loader.odin

@@ -0,0 +1,77 @@
+package simulator
+
+import "core:log"
+import rl "vendor:raylib"
+
+import emu "../machine"
+import tfd "../../external/tinyfiledialogs"
+
+gui_file_loader :: proc(rect: rl.Rectangle, sim: ^Simulator) {
+	rl.DrawRectangleLinesEx(rect, 1, rl.GRAY)
+
+	bounds := rl.Rectangle {
+		x = rect.x + PADDING_X,
+		y = rect.y + PADDING_Y,
+		width = rect.width - (PADDING_X * 2),
+		height = rect.height - (PADDING_Y * 2),
+	}
+	rl.GuiPanel(bounds, "Rom / File")
+
+	// drop-zone occupies the panel's content area, minus space for the button
+	drop_zone := rl.Rectangle {
+		bounds.x + PADDING_X,
+		bounds.y + PADDING_Y,
+		bounds.width - (PADDING_X * 2),
+		bounds.height - ((PADDING_Y * 2) + (BUTTON_HEIGHT + PADDING_Y))
+	}
+
+	// centered drop-zone text
+	text: cstring = "Drop a CHIP-8 ROM here"
+	text_width := rl.MeasureText(text, BIG_FONT_SIZE)
+	text_x := drop_zone.x + (drop_zone.width - f32(text_width)) / 2
+	text_y := drop_zone.y + (drop_zone.height - f32(BIG_FONT_SIZE)) / 2
+	rl.DrawTextEx(sim.font, text, {text_x, text_y}, BIG_FONT_SIZE, 1, rl.WHITE)
+
+	// open rom button below drop-zone
+	btn_rect := rl.Rectangle {
+		drop_zone.x,
+		drop_zone.y + drop_zone.height + PADDING_Y,
+		drop_zone.width,
+		BUTTON_HEIGHT,
+	}
+
+	if rl.GuiButton(btn_rect, "Open ROM") {
+		ret := tfd.openFileDialog("Open File Dialog", nil, 0, nil, nil, 0,)
+		rom_path := string(ret)
+		if rom_path == "" do return
+
+		// reset machine state
+		emu.reset_machine(sim.machine)
+
+		// load new rom
+		err := emu.load_rom(sim.machine, rom_path)
+		if err != nil {
+			// @TODO: update status bar here
+			panic("failed to load rom!")
+		}
+
+		sim.rom_loaded = true
+	}
+
+	// Handle file drop
+	if rl.IsFileDropped() {
+		dropped_file := rl.LoadDroppedFiles()
+		if dropped_file.count > 0 {
+			mouse := rl.GetMousePosition()
+
+			if rl.CheckCollisionPointRec(mouse, drop_zone) {
+				path_str := string(dropped_file.paths[0])
+				log.info("file dropped: ", path_str)
+				// @TODO: Stop sim, reset mem etc, load new rom
+			} else {
+				log.info("File dropped outside drop zone, ignoring")
+			}
+		}
+		rl.UnloadDroppedFiles(dropped_file)
+	}
+}

src/simulator/gui_key_pad.odin

@@ -0,0 +1,65 @@
+package simulator
+
+import "core:strings"
+import rl "vendor:raylib"
+
+
+gui_key_pad :: proc(rect: rl.Rectangle, display: [16]bool, font: rl.Font) {
+	rl.DrawRectangleLinesEx(rect, 1, rl.GRAY)
+
+	bounds := rl.Rectangle {
+		x = rect.x + PADDING_X,
+		y = rect.y + PADDING_Y,
+		width = rect.width - (PADDING_X * 2),
+		height = rect.height - (PADDING_Y * 2),
+	}
+	rl.GuiPanel(bounds, "Input / Keypad")
+
+	content := rl.Rectangle {
+		bounds.x,
+		bounds.y + PANEL_HEADER,
+		bounds.width,
+		bounds.height - PANEL_HEADER,
+	}
+
+	Key :: struct {
+		label: string,
+		index: int,
+	}
+
+	keys := [16]Key {
+		{"1", 1}, {"2", 2}, {"3", 3}, {"C", 12},
+		{"4", 4}, {"5", 5}, {"6", 6}, {"D", 13},
+		{"7", 7}, {"8", 8}, {"9", 9}, {"E", 14},
+		{"A", 10}, {"0", 0}, {"B", 11}, {"F", 15},
+	}
+
+	btn_width := content.width / 4
+	btn_height := content.height / 4
+
+	for val, idx in keys {
+		str := strings.clone_to_cstring(val.label)
+		defer delete(str)
+
+		ri := idx / 4
+		ci := idx % 4
+		irect := rl.Rectangle {
+			x      = content.x + btn_width * f32(ci),
+			y      = content.y + btn_height * f32(ri),
+			width  = btn_width,
+			height = btn_height,
+		}
+
+		if display[val.index] { rl.DrawRectangleRec(irect, rl.BLACK) }
+
+		rl.DrawRectangleLinesEx(irect, 1, rl.GRAY)
+		rl.DrawTextEx(
+			font,
+			str,
+			rl.Vector2{irect.x + btn_width / 2, irect.y + btn_height / 2},
+			KEYPAD_FONT_SIZE,
+			1,
+			rl.WHITE,
+		)
+	}
+}

src/simulator/gui_screen.odin

@@ -3,6 +3,14 @@ package simulator
 import rl "vendor:raylib"
 
 gui_screen :: proc(rect: rl.Rectangle, sim: ^Simulator) {
+	bounds := rl.Rectangle {
+		x = rect.x + PADDING_X,
+		y = rect.y + PADDING_Y,
+		width = rect.width - (PADDING_X * 2),
+		height = rect.height - (PADDING_Y * 2),
+	}
+	rl.GuiPanel(bounds, nil)
+
 	s := sim.machine
 
 	// 2 : 1
@@ -12,14 +20,14 @@ gui_screen :: proc(rect: rl.Rectangle, sim: ^Simulator) {
 
 	// create viewport for the ratio
 	view := rect
-	avail_space := rect.width / rect.height
+	avail_space := bounds.width / bounds.height
 
 	if avail_space > aspect_ratio {
-		view.width = rect.height * aspect_ratio
-		view.x = rect.x + (rect.width - view.width) * 0.5
+		view.width = bounds.height * aspect_ratio
+		view.x = bounds.x + (bounds.width - view.width) * 0.5
 	} else {
-		view.height = rect.width / aspect_ratio
-		view.y = rect.y + (rect.height - view.height) * 0.5
+		view.height = bounds.width / aspect_ratio
+		view.y = bounds.y + (bounds.height - view.height) * 0.5
 	}
 
 	// get scale
@@ -32,9 +40,7 @@ gui_screen :: proc(rect: rl.Rectangle, sim: ^Simulator) {
 	// center frame
 	x := i32(view.x + (view.width - f32(draw_w)) * 0.5)
 	y := i32(view.y + (view.height - f32(draw_h)) * 0.5)
-
 	rl.DrawRectangleLinesEx(rect, 1, rl.DARKGRAY)
-	rl.DrawRectangleLinesEx(view, 2, rl.WHITE)
 
 	if !sim.rom_loaded {
 		// centered drop-zone text

src/simulator/gui_status_bar.odin

@@ -3,12 +3,14 @@ package simulator
 import "core:fmt"
 import rl "vendor:raylib"
 
+StatusIconShape :: enum { CIRCLE, SQUARE }
+
 // @TODO: render status bar text
 gui_status_bar :: proc(rect: rl.Rectangle, sim: ^Simulator) {
     // Left to right text draws
     rl.DrawRectangleLinesEx(rect, 1, rl.DARKGRAY)
 
-    cursor: f32 = rect.x + PADDING
+    cursor: f32 = rect.x + PADDING_X
     cy := rect.y + rect.height * 0.5
 
     if sim.running && !sim.paused {
@@ -23,7 +25,7 @@ gui_status_bar :: proc(rect: rl.Rectangle, sim: ^Simulator) {
     // FPS set far right
     fps_text := fmt.ctprintf("FPS: %d", rl.GetFPS())
     fps_width := rl.MeasureTextEx(sim.font, fps_text, f32(sim.font.baseSize), 1).x
-    fps_x := rect.x + rect.width - PADDING - fps_width
+    fps_x := rect.x + rect.width - PADDING_X - fps_width
 
     rl.DrawTextEx(
         sim.font,
@@ -35,8 +37,6 @@ gui_status_bar :: proc(rect: rl.Rectangle, sim: ^Simulator) {
     )
 }
 
-StatusIconShape :: enum { CIRCLE, SQUARE }
-
 status_icon :: proc(cursor: ^f32, cy: f32, color: rl.Color, shape: StatusIconShape, label: cstring, font: rl.Font) {
     size: f32 = 10
     ix := cursor^ + size * 0.5
@@ -48,15 +48,15 @@ status_icon :: proc(cursor: ^f32, cy: f32, color: rl.Color, shape: StatusIconSha
 
     cursor^ += size + 6
     rl.DrawTextEx(font, label, {cursor^, cy - f32(font.baseSize) * 0.5}, f32(font.baseSize), 1, rl.RAYWHITE)
-    cursor^ += rl.MeasureTextEx(font, label, f32(font.baseSize), 1).x + PADDING
+    cursor^ += rl.MeasureTextEx(font, label, f32(font.baseSize), 1).x + PADDING_X
 }
 
 status_divider :: proc(cursor: ^f32, cy: f32) {
     rl.DrawLineV({cursor^, cy - 8}, {cursor^, cy + 8}, rl.DARKGRAY)
-    cursor^ += PADDING
+    cursor^ += PADDING_X
 }
 
 status_text :: proc(cursor: ^f32, cy: f32, text: cstring, font: rl.Font) {
     rl.DrawTextEx(font, text, {cursor^, cy - f32(font.baseSize) * 0.5}, f32(font.baseSize), 1, rl.RAYWHITE)
-    cursor^ += rl.MeasureTextEx(font, text, f32(font.baseSize), 1).x + PADDING
+    cursor^ += rl.MeasureTextEx(font, text, f32(font.baseSize), 1).x + PADDING_X
 }

src/simulator/gui_tab_memory.odin

@@ -0,0 +1,126 @@
+package simulator
+
+import "core:fmt"
+import "core:strings"
+import rl "vendor:raylib"
+
+MEM_INDICATOR_W   :: 14
+MEM_ADDRESS_W     :: 72
+MEM_ROW_H         :: 20
+MEM_HEADER_H      :: 24
+MEM_BYTES_PER_ROW :: 16
+MEM_TOTAL_ROWS    :: 256
+MEM_FONT_ROWS     :: 5
+MEM_ROM_START     :: 512
+MEM_VIRTUAL_ROWS  :: MEM_FONT_ROWS + 1 + (256 - 32)
+
+MEM_COL_LABELS := [16]string{"0","1","2","3","4","5","6","7","8","9","A","B","C","D","E","F"}
+
+byte_col_w :: proc(rect: rl.Rectangle) -> f32 {
+    used := f32(MEM_INDICATOR_W + MEM_ADDRESS_W + 12)
+    return (rect.width - used) / 16
+}
+
+gui_tab_memory :: proc(rect: rl.Rectangle, sim: ^Simulator) {
+    rl.DrawRectangleRec(rect, rl.DARKGRAY)
+
+    // Header background
+    rl.DrawRectangle(i32(rect.x), i32(rect.y), i32(rect.width), MEM_HEADER_H, rl.BLACK)
+
+    // Header: Address label
+    rl.DrawTextEx(sim.font, "Address", {rect.x + MEM_INDICATOR_W, rect.y + 4}, 16, 1, rl.GRAY)
+
+    // Header: column labels 0-F
+    col_w := byte_col_w(rect)
+    for col in 0..<16 {
+        x     := rect.x + MEM_INDICATOR_W + MEM_ADDRESS_W + f32(col) * col_w
+        label := strings.clone_to_cstring(MEM_COL_LABELS[col], context.temp_allocator)
+        rl.DrawTextEx(sim.font, label, {x, rect.y + 4}, 16, 1, rl.GRAY)
+    }
+
+    // Header separator
+    rl.DrawLine(
+        i32(rect.x), i32(rect.y + MEM_HEADER_H),
+        i32(rect.x + rect.width), i32(rect.y + MEM_HEADER_H),
+        rl.GRAY,
+    )
+
+    // Scroll panel area (below header)
+    panel_rect := rl.Rectangle{
+        rect.x,
+        rect.y + MEM_HEADER_H,
+        rect.width,
+        rect.height - MEM_HEADER_H,
+    }
+
+    content_rect := rl.Rectangle{
+        0, 0,
+        rect.width - 12,
+        f32(MEM_VIRTUAL_ROWS) * MEM_ROW_H,
+    }
+
+    view : rl.Rectangle
+    rl.GuiScrollPanel(panel_rect, nil, content_rect, &sim.mem_scroll, &view)
+
+    rl.BeginScissorMode(i32(view.x), i32(view.y), i32(view.width), i32(view.height))
+
+    draw_row := 0
+
+    // --- Font rows (0x000 - 0x04F) ---
+    for row in 0..<MEM_FONT_ROWS {
+        addr  := row * MEM_BYTES_PER_ROW
+        row_y := panel_rect.y + f32(draw_row) * MEM_ROW_H + sim.mem_scroll.y
+        draw_memory_row(rect, sim, draw_row, addr, row_y)
+        draw_row += 1
+    }
+
+    // --- Divider ---
+    divider_y := panel_rect.y + f32(draw_row) * MEM_ROW_H + sim.mem_scroll.y
+    rl.DrawRectangle(i32(rect.x), i32(divider_y), i32(rect.width), MEM_ROW_H, rl.ColorAlpha(rl.BLACK, 0.4))
+    rl.DrawTextEx(
+        sim.font,
+        "---- reserved (0x0050 - 0x01FF) ----",
+        {rect.x + MEM_INDICATOR_W, divider_y + 2},
+        16, 1, rl.DARKGRAY,
+    )
+    draw_row += 1
+
+    // --- ROM rows (0x200 onwards) ---
+    for i := 0; MEM_ROM_START + i * MEM_BYTES_PER_ROW < 4096; i += 1 {
+        addr  := MEM_ROM_START + i * MEM_BYTES_PER_ROW
+        row_y := panel_rect.y + f32(draw_row) * MEM_ROW_H + sim.mem_scroll.y
+        draw_memory_row(rect, sim, draw_row, addr, row_y)
+        draw_row += 1
+    }
+
+    rl.EndScissorMode()
+}
+
+draw_memory_row :: proc(rect: rl.Rectangle, sim: ^Simulator, visual_row: int, addr: int, row_y: f32) {
+    col_w := byte_col_w(rect)
+
+    if visual_row % 2 == 0 {
+        rl.DrawRectangle(i32(rect.x), i32(row_y), i32(rect.width), MEM_ROW_H, rl.ColorAlpha(rl.BLACK, 0.2))
+    }
+
+    addr_str := fmt.tprintf("%04X", addr)
+    rl.DrawTextEx(
+        sim.font,
+        strings.clone_to_cstring(addr_str, context.temp_allocator),
+        {rect.x + MEM_INDICATOR_W, row_y + 2},
+        16, 1, rl.RAYWHITE,
+    )
+
+    for col in 0..<16 {
+        byte_val := sim.machine.memory[addr + col]
+        byte_str := fmt.tprintf("%02X", byte_val)
+        x        := rect.x + MEM_INDICATOR_W + MEM_ADDRESS_W + f32(col) * col_w
+        color    := rl.RAYWHITE if byte_val != 0 else rl.GRAY
+        rl.DrawTextEx(
+            sim.font,
+            strings.clone_to_cstring(byte_str, context.temp_allocator),
+            {x, row_y + 2},
+            16, 1, color,
+        )
+    }
+}

src/simulator/left_panel.odin

@@ -1,155 +0,0 @@
-package simulator
-
-import "core:log"
-import "core:strings"
-import rl "vendor:raylib"
-
-import emu "../machine"
-import tfd "../../external/tinyfiledialogs"
-
-gui_left_panel :: proc(rect: rl.Rectangle, sim: ^Simulator) {
-	// ── Top panel and components ──
-	top_panel := rl.Rectangle {
-		rect.x,
-		rect.y,
-		rect.width,
-		rect.height / 2,
-	}
-	rl.DrawRectangleLinesEx(top_panel, 1, rl.DARKGRAY)
-
-	// Dropzone/file loader
-	file_loader_rect := rl.Rectangle {
-		top_panel.x,
-		top_panel.y,
-		top_panel.width,
-		(top_panel.height / 3) - PANEL_HEADER - PANEL_PADDING * 2,
-	}
-	gui_file_loader(file_loader_rect, sim)
-
-	// ── Bottom panel and components ──
-	bottom_panel := rl.Rectangle {
-		rect.x,
-		rect.y + top_panel.height,
-		rect.width,
-		rect.height / 2,
-	}
-	rl.DrawRectangleLinesEx(bottom_panel, 1, rl.GREEN)
-	gui_key_pad(bottom_panel, sim.machine.keypad, sim.font)
-}
-
-gui_file_loader :: proc(rect: rl.Rectangle, sim: ^Simulator) {
-	rl.GuiPanel(rect, "Rom / File")
-
-	// drop-zone occupies the panel's content area, minus space for the button
-	drop_zone := rl.Rectangle {
-		rect.x + PANEL_PADDING,
-		rect.y + PANEL_HEADER + PANEL_PADDING,
-		rect.width - PANEL_PADDING * 2,
-		rect.height - PANEL_HEADER - PANEL_PADDING * 2 - BUTTON_HEIGHT - PANEL_PADDING,
-	}
-	rl.DrawRectangleLinesEx(drop_zone, 1, rl.GREEN)
-
-	// centered drop-zone text
-	text: cstring = "Drop a CHIP-8 ROM here"
-	text_width := rl.MeasureText(text, BIG_FONT_SIZE)
-	text_x := drop_zone.x + (drop_zone.width - f32(text_width)) / 2
-	text_y := drop_zone.y + (drop_zone.height - f32(BIG_FONT_SIZE)) / 2
-	rl.DrawTextEx(sim.font, text, {text_x, text_y}, BIG_FONT_SIZE, 1, rl.WHITE)
-
-	// open rom button below drop-zone
-	btn_rect := rl.Rectangle {
-		drop_zone.x,
-		drop_zone.y + drop_zone.height + PANEL_PADDING,
-		BUTTON_WIDTH,
-		BUTTON_HEIGHT,
-	}
-
-	if rl.GuiButton(btn_rect, "Open ROM") {
-		ret := tfd.openFileDialog("Open File Dialog", nil, 0, nil, nil, 0,)
-		rom_path := string(ret)
-		if rom_path == "" do return
-
-		// reset machine state
-		emu.reset_machine(sim.machine)
-
-		// load new rom
-		err := emu.load_rom(sim.machine, rom_path)
-		if err != nil {
-			// @TODO: update status bar here
-			panic("failed to load rom!")
-		}
-
-		sim.rom_loaded = true
-		sim.running = true
-		sim.paused = false
-	}
-
-	// Handle file drop
-	if rl.IsFileDropped() {
-		dropped_file := rl.LoadDroppedFiles()
-		if dropped_file.count > 0 {
-			mouse := rl.GetMousePosition()
-
-			if rl.CheckCollisionPointRec(mouse, drop_zone) {
-				path_str := string(dropped_file.paths[0])
-				log.info("file dropped: ", path_str)
-				// @TODO: Stop sim, reset mem etc, load new rom
-			} else {
-				log.info("File dropped outside drop zone, ignoring")
-			}
-		}
-		rl.UnloadDroppedFiles(dropped_file)
-	}
-}
-
-gui_key_pad :: proc(rect: rl.Rectangle, display: [16]bool, font: rl.Font) {
-	rl.GuiPanel(rect, "Input / Keypad")
-
-	content := rl.Rectangle {
-		rect.x + PANEL_PADDING,
-		rect.y + PANEL_HEADER + PANEL_PADDING,
-		rect.width - PANEL_PADDING * 2,
-		rect.height - PANEL_HEADER - PANEL_PADDING * 2,
-	}
-
-	Key :: struct {
-		label: string,
-		index: int,
-	}
-
-	keys := [16]Key {
-		{"1", 1}, {"2", 2}, {"3", 3}, {"C", 12},
-		{"4", 4}, {"5", 5}, {"6", 6}, {"D", 13},
-		{"7", 7}, {"8", 8}, {"9", 9}, {"E", 14},
-		{"A", 10}, {"0", 0}, {"B", 11}, {"F", 15},
-	}
-
-	btn_width := content.width / 4
-	btn_height := content.height / 4
-
-	for val, idx in keys {
-		str := strings.clone_to_cstring(val.label)
-		defer delete(str)
-
-		ri := idx / 4
-		ci := idx % 4
-		irect := rl.Rectangle {
-			x      = content.x + btn_width * f32(ci),
-			y      = content.y + btn_height * f32(ri),
-			width  = btn_width,
-			height = btn_height,
-		}
-
-		if display[val.index] { rl.DrawRectangleRec(irect, rl.BLACK) }
-
-		rl.DrawRectangleLinesEx(irect, 1, rl.GRAY)
-		rl.DrawTextEx(
-			font,
-			str,
-			rl.Vector2{irect.x + btn_width / 2, irect.y + btn_height / 2},
-			KEYPAD_FONT_SIZE,
-			1,
-			rl.WHITE,
-		)
-	}
-}

src/simulator/right_panel.odin

@@ -1,8 +0,0 @@
-package simulator
-
-import m "../machine"
-import rl "vendor:raylib"
-
-gui_right_panel :: proc(rect: rl.Rectangle, s: ^m.System) {
-	rl.DrawRectangleLinesEx(rect, 1, rl.DARKGRAY)
-}

src/simulator/simulator.odin

@@ -4,12 +4,16 @@ import emu "../machine"
 import rl "vendor:raylib"
 
 Simulator :: struct {
+	// Emulator
 	machine: ^emu.System,
 	rom_loaded: bool,
 	running: bool,
 	paused: bool,
 	cycles_per_second: int,
+	// GUI
 	font: rl.Font,
+	active_tab: i32,
+	mem_scroll : rl.Vector2,
 }
 
 // Requires an initilized emulatore System Struct