diff --git a/src/devices/ppu.c b/src/devices/ppu.c
index 59a1b77..6a1b8be 100644
--- a/src/devices/ppu.c
+++ b/src/devices/ppu.c
@@ -38,7 +38,7 @@ static Uint8 font[][8] = {
 	{0x00, 0x7c, 0x82, 0x80, 0xf0, 0x80, 0x80, 0x80}};
 
 void
-ppu_set_size(Ppu *p, Uint16 width, Uint16 height)
+ppu_resize(Ppu *p, Uint16 width, Uint16 height)
 {
 	Uint8 *pixels;
 	if(!(pixels = realloc(p->pixels, width * height / 2)))
@@ -49,11 +49,19 @@ ppu_set_size(Ppu *p, Uint16 width, Uint16 height)
 	p->height = height;
 }
 
+void
+ppu_clear(Ppu *p, Uint8 mask)
+{
+	Uint32 i, size = p->width * p->height / 2;
+	for(i = 0; i < size; ++i)
+		p->pixels[i] &= mask;
+}
+
 Uint8
 ppu_read(Ppu *p, Uint16 x, Uint16 y)
 {
 	if(x < p->width && y < p->height) {
-		Uint32 row = (x + y * p->width) / 0x2;
+		Uint32 row = (x + y * p->width) / 2;
 		Uint8 shift = !(x & 0x1) << 2;
 		Uint8 pix = p->pixels[row] >> shift;
 		if(pix & 0x0c)
@@ -67,7 +75,7 @@ void
 ppu_write(Ppu *p, Uint8 layer, Uint16 x, Uint16 y, Uint8 color)
 {
 	if(x < p->width && y < p->height) {
-		Uint32 row = (x + y * p->width) / 0x2;
+		Uint32 row = (x + y * p->width) / 2;
 		Uint8 shift = (!(x & 0x1) << 2) + (layer << 1);
 		Uint8 pix = p->pixels[row];
 		Uint8 mask = ~(0x3 << shift);
diff --git a/src/devices/ppu.h b/src/devices/ppu.h
index 93a8110..7911317 100644
--- a/src/devices/ppu.h
+++ b/src/devices/ppu.h
@@ -14,6 +14,10 @@ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 WITH REGARD TO THIS SOFTWARE.
 */
 
+#define CLEAR_BG 0xcc
+#define CLEAR_FG 0x33
+#define CLEAR_BOTH 0x00
+
 typedef unsigned char Uint8;
 typedef unsigned short Uint16;
 typedef unsigned int Uint32;
@@ -23,10 +27,10 @@ typedef struct Ppu {
 	Uint16 width, height;
 } Ppu;
 
-void ppu_set_size(Ppu *p, Uint16 width, Uint16 height);
+void ppu_resize(Ppu *p, Uint16 width, Uint16 height);
+void ppu_clear(Ppu *p, Uint8 layer);
 Uint8 ppu_read(Ppu *p, Uint16 x, Uint16 y);
 void ppu_write(Ppu *p, Uint8 layer, Uint16 x, Uint16 y, Uint8 color);
-void ppu_frame(Ppu *p);
 void ppu_1bpp(Ppu *p, Uint8 layer, Uint16 x, Uint16 y, Uint8 *sprite, Uint8 color, Uint8 flipx, Uint8 flipy);
 void ppu_2bpp(Ppu *p, Uint8 layer, Uint16 x, Uint16 y, Uint8 *sprite, Uint8 color, Uint8 flipx, Uint8 flipy);
 void ppu_debug(Ppu *p, Uint8 *stack, Uint8 wptr, Uint8 rptr, Uint8 *memory);
diff --git a/src/uxnemu.c b/src/uxnemu.c
index 8e02448..f237052 100644
--- a/src/uxnemu.c
+++ b/src/uxnemu.c
@@ -127,7 +127,7 @@ set_zoom(Uint8 scale)
 static int
 set_size(Uint16 width, Uint16 height, int is_resize)
 {
-	ppu_set_size(&ppu, width, height);
+	ppu_resize(&ppu, width, height);
 	gRect.x = PAD;
 	gRect.y = PAD;
 	gRect.w = ppu.width;
@@ -487,7 +487,7 @@ doctrl(Uxn *u, SDL_Event *event, int z)
 	case SDLK_LEFT: flag = 0x40; break;
 	case SDLK_RIGHT: flag = 0x80; break;
 	case SDLK_F1: if(z) set_zoom(zoom > 2 ? 1 : zoom + 1); break;
-	case SDLK_F2: if(z) devsystem->dat[0xe] = !devsystem->dat[0xe]; break;
+	case SDLK_F2: if(z) devsystem->dat[0xe] = !devsystem->dat[0xe]; ppu_clear(&ppu, CLEAR_FG); break;
 	case SDLK_F3: if(z) capture_screen(); break;
 	case SDLK_AC_BACK:
 	case SDLK_F4: if(z) restart(u); break;