fixed the render bug

README.md

@@ -2,11 +2,9 @@
 
 A practise project to learn about emulation, implements CHIP-8 in golang.
 
-Note: Current implementation has major bug in rendering, which makes it unusable. Currently in process of hunting and solving.
-
 ## Screenshots
 
-**__TODO__**
+![Hello Chip8](https://raw.githubusercontent.com/SKatiyar/go-chip8/master/screenshot.png)
 
 ## Installing
 
@@ -39,6 +37,16 @@ Modifier sets the logical size to pixel. Default resolution supported by `CHIP8`
 go run main.go 10 roms/filter.ch8
 ```
 
+## Key Bindings
+
+```
+Chip8 keypad         Keyboard mapping
+1 | 2 | 3 | C        1 | 2 | 3 | 4
+4 | 5 | 6 | D   =>   Q | W | E | R
+7 | 8 | 9 | E   =>   A | S | D | F
+A | 0 | B | F        Z | X | C | V
+```
+
 ## Sources
 
 - [How to write an emulator chip-8 interpreter](http://www.multigesture.net/articles/how-to-write-an-emulator-chip-8-interpreter/)

emulator/emulator.go

@@ -26,7 +26,7 @@ var fontSet = []uint8{
 }
 
 type Chip8 struct {
-	display [64 * 32]uint8 // display size
+	display [32][64]uint8 // display size
 
 	memory [4096]uint8 // memory size 4k
 	vx     [16]uint8   // cpu registers V0-VF
@@ -59,7 +59,7 @@ func Init() Chip8 {
 	return instance
 }
 
-func (c *Chip8) Buffer() [2048]uint8 {
+func (c *Chip8) Buffer() [32][64]uint8 {
 	return c.display
 }
 
@@ -89,7 +89,9 @@ func (c *Chip8) Cycle() {
 		switch c.oc & 0x000F {
 		case 0x0000: // 0x00E0 Clears screen
 			for i := 0; i < len(c.display); i++ {
-				c.display[i] = 0x0
+				for j := 0; j < len(c.display[i]); j++ {
+					c.display[i][j] = 0x0
+				}
 			}
 			c.shouldDraw = true
 			c.pc = c.pc + 2
@@ -204,10 +206,10 @@ func (c *Chip8) Cycle() {
 			pixel := c.memory[c.iv+j]
 			for i = 0; i < 8; i++ {
 				if (pixel & (0x80 >> i)) != 0 {
-					if c.display[x+uint8(i)+((y+uint8(j))*64)] == 1 {
+					if c.display[(y + uint8(j))][x+uint8(i)] == 1 {
 						c.vx[0xF] = 1
 					}
-					c.display[x+uint8(i)+((y+uint8(j))*64)] ^= 1
+					c.display[(y + uint8(j))][x+uint8(i)] ^= 1
 				}
 			}
 		}

main.go

@@ -73,10 +73,10 @@ func main() {
 
 			// Get the display buffer and render
 			vector := c8.Buffer()
-			for j := 0; j < 32; j++ {
-				for i := 0; i < 64; i++ {
+			for j := 0; j < len(vector); j++ {
+				for i := 0; i < len(vector[j]); i++ {
 					// Values of pixel are stored in 1D array of size 64 * 32
-					if vector[(j*64)+i] != 0 {
+					if vector[j][i] != 0 {
 						canvas.SetDrawColor(255, 255, 0, 255)
 					} else {
 						canvas.SetDrawColor(255, 0, 0, 255)