refactor(graphics): add graphics package

core/chip8.go

@@ -42,9 +42,9 @@ func (c8 *Chip8) Update() error {
 func (c8 *Chip8) Draw(screen *ebiten.Image) {
 	screen.Fill(color.NRGBA{23, 20, 33, 1})
 
-	for h := 0; h < cpu.HEIGHT; h++ {
-		for w := 0; w < cpu.WIDTH; w++ {
-			if c8.cpu.Display[h][w] == 0x01 {
+	for h := 0; h < c8.cpu.Graphics.Height; h++ {
+		for w := 0; w < c8.cpu.Graphics.Width; w++ {
+			if c8.cpu.Graphics.GetPixel(h, w) == 0x01 {
 				imgOpts := &ebiten.DrawImageOptions{}
 				imgOpts.GeoM.Translate(float64(w*10), float64(h*10))
 				screen.DrawImage(c8.square, imgOpts)
@@ -74,8 +74,8 @@ func RunChip8(rom []byte, title string) {
 		square:       sqr,
 		cpu:          &c,
 		audioPlayer:  p,
-		screenWidth:  cpu.WIDTH * 10,
-		screenHeight: cpu.HEIGHT * 10,
+		screenWidth:  c.Graphics.Width * 10,
+		screenHeight: c.Graphics.Height * 10,
 	}
 
 	ebiten.SetWindowSize(c8.screenWidth, c8.screenHeight)

core/cpu/cpu.go

@@ -5,6 +5,7 @@ import (
 	"time"
 
 	"github.com/gaoliveira21/chip8/core/font"
+	"github.com/gaoliveira21/chip8/core/graphics"
 	"github.com/gaoliveira21/chip8/core/memory"
 )
 
@@ -19,26 +20,21 @@ const (
 	NNN_BITMASK         = 0x0FFF
 )
 
-// Display
-const (
-	WIDTH  = 0x40
-	HEIGHT = 0x20
-)
-
 type CPU struct {
 	pc         uint16   // Program Counter
 	i          uint16   // I Register
 	v          [16]byte // Variable registers
 	mmu        memory.MMU
-	Display    [HEIGHT][WIDTH]byte
+	Graphics   *graphics.Graphics
 	delayTimer uint8
 	SoundTimer uint8
 	Keys       [16]uint8
 }
 
 func NewCpu() CPU {
 	cpu := CPU{
-		pc: 0x200,
+		pc:       0x200,
+		Graphics: graphics.NewGraphics(),
 	}
 
 	cpu.loadFont()
@@ -169,11 +165,7 @@ func (cpu *CPU) clock() {
 }
 
 func (cpu *CPU) cls() {
-	for i := 0; i < HEIGHT; i++ {
-		for j := 0; j < WIDTH; j++ {
-			cpu.Display[i][j] = 0x00
-		}
-	}
+	cpu.Graphics.Clear()
 }
 
 func (cpu *CPU) ret() {
@@ -316,23 +308,24 @@ func (cpu *CPU) drw(oc *opcode) {
 
 		for j := 0; j < 8; j++ {
 			bit := (pixels >> (7 - j)) & 0x01
+			pixelOnDisplay := cpu.Graphics.GetPixel(int(y), int(xIndex))
 
-			if bit == 0x01 && cpu.Display[y][xIndex] == 0x01 {
+			if bit == 0x01 && pixelOnDisplay == 0x01 {
 				cpu.v[0xF] = 0x01
 			}
 
-			cpu.Display[y][xIndex] ^= bit
+			cpu.Graphics.SetPixel(int(y), int(xIndex), pixelOnDisplay^bit)
 
 			xIndex++
 
-			if xIndex >= WIDTH {
+			if int(xIndex) >= cpu.Graphics.Width {
 				break
 			}
 		}
 
 		y++
 
-		if y >= HEIGHT {
+		if int(y) >= cpu.Graphics.Height {
 			break
 		}
 	}

core/cpu/cpu_test.go

@@ -58,15 +58,15 @@ func TestCLS(t *testing.T) {
 	cpu.mmu.Write(0x200, 0x00)
 	cpu.mmu.Write(0x201, 0xE0)
 
-	cpu.Display[0][0] = 0xFF
-	cpu.Display[0][1] = 0xEF
+	cpu.Graphics.SetPixel(0, 0, 0xFF)
+	cpu.Graphics.SetPixel(0, 1, 0xEF)
 
 	cpu.clock()
 
-	for i := 0; i < HEIGHT; i++ {
-		for j := 0; j < WIDTH; j++ {
-			if cpu.Display[i][j] != 0x00 {
-				t.Errorf("cpu.Display[%d][%d] = 0x%X; expected 0x00", i, j, cpu.Display[i][j])
+	for i := 0; i < cpu.Graphics.Height; i++ {
+		for j := 0; j < cpu.Graphics.Width; j++ {
+			if cpu.Graphics.GetPixel(i, j) != 0x00 {
+				t.Errorf("cpu.Display[%d][%d] = 0x%X; expected 0x00", i, j, cpu.Graphics.GetPixel(i, j))
 			}
 		}
 	}
@@ -687,19 +687,19 @@ func TestDRWNoWrapAndNoCollision(t *testing.T) {
 		t.Errorf("cpu.v[0xF] = 0x%X; expected 0x00", cpu.v[0xF])
 	}
 
-	if cpu.Display[0][3] != 0x01 {
-		t.Errorf("cpu.Display[0][3] = 0x%X; expected 0x01", cpu.Display[0][3])
+	if cpu.Graphics.GetPixel(0, 3) != 0x01 {
+		t.Errorf("cpu.Graphics.GetPixel(0,3) = 0x%X; expected 0x01", cpu.Graphics.GetPixel(0, 3))
 	}
 
-	if cpu.Display[0][7] != 0x01 {
-		t.Errorf("cpu.Display[0][7] = 0x%X; expected 0x01", cpu.Display[0][7])
+	if cpu.Graphics.GetPixel(0, 7) != 0x01 {
+		t.Errorf("cpu.Graphics.GetPixel(0,7) = 0x%X; expected 0x01", cpu.Graphics.GetPixel(0, 7))
 	}
 
-	if cpu.Display[1][0] != 0x01 {
-		t.Errorf("cpu.Display[1][0] = 0x%X; expected 0x01", cpu.Display[1][0])
+	if cpu.Graphics.GetPixel(1, 0) != 0x01 {
+		t.Errorf("cpu.Graphics.GetPixel(1,0) = 0x%X; expected 0x01", cpu.Graphics.GetPixel(1, 0))
 	}
 
-	if cpu.Display[1][4] != 0x01 {
-		t.Errorf("cpu.Display[1][4] = 0x%X; expected 0x01", cpu.Display[1][4])
+	if cpu.Graphics.GetPixel(1, 4) != 0x01 {
+		t.Errorf("cpu.Graphics.GetPixel(1,4) = 0x%X; expected 0x01", cpu.Graphics.GetPixel(1, 4))
 	}
 }

core/graphics/graphics.go

@@ -0,0 +1,33 @@
+package graphics
+
+const width = 0x40
+const height = 0x20
+
+type Graphics struct {
+	display [height][width]byte
+	Width   int
+	Height  int
+}
+
+func NewGraphics() *Graphics {
+	return &Graphics{
+		Width:  width,
+		Height: height,
+	}
+}
+
+func (g *Graphics) Clear() {
+	for i := 0; i < g.Height; i++ {
+		for j := 0; j < g.Width; j++ {
+			g.display[i][j] = 0x00
+		}
+	}
+}
+
+func (g *Graphics) GetPixel(y int, x int) byte {
+	return g.display[y][x]
+}
+
+func (g *Graphics) SetPixel(y int, x int, b byte) {
+	g.display[y][x] = b
+}

core/graphics/graphics_test.go

@@ -0,0 +1,17 @@
+package graphics_test
+
+import (
+	"testing"
+
+	"github.com/gaoliveira21/chip8/core/graphics"
+)
+
+func TestSetAndGetPixel(t *testing.T) {
+	g := graphics.NewGraphics()
+
+	g.SetPixel(0, 0, 0x1)
+
+	if g.GetPixel(0, 0) != 0x1 {
+		t.Errorf("graphics.Display[0][0] = 0x%X; expected 0x01", g.GetPixel(0, 0))
+	}
+}