@@ -20,15 +20,23 @@ static Uint8 blending[5][16] = {

 	{1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 0, 1, 1, 1, 1, 0}};

 void

-ppu_pixel(Ppu *p, Uint8 layer, Uint16 x, Uint16 y, Uint8 color)

+ppu_pixel(Ppu *p, Uint8 *layer, Uint16 x, Uint16 y, Uint8 color)

 {

-	Uint8 *pixel = &p->pixels[y * p->width + x], shift = layer * 2;

-	if(x < p->width && y < p->height)

-		*pixel = (*pixel & ~(0x3 << shift)) | (color << shift);

+	int row = (y % 8) + ((x / 8 + y / 8 * p->width / 8) * 16), col = x % 8;

+	if(x >= p->width || y >= p->height)

+		return;

+	if(color == 0 || color == 2)

+		layer[row] &= ~(1UL << (7 - col));

+	else

+		layer[row] |= 1UL << (7 - col);

+	if(color == 0 || color == 1)

+		layer[row + 8] &= ~(1UL << (7 - col));

+	else

+		layer[row + 8] |= 1UL << (7 - col);

 }

 void

-ppu_1bpp(Ppu *p, Uint8 layer, Uint16 x, Uint16 y, Uint8 *sprite, Uint8 color, Uint8 flipx, Uint8 flipy)

+ppu_1bpp(Ppu *p, Uint8 *layer, Uint16 x, Uint16 y, Uint8 *sprite, Uint8 color, Uint8 flipx, Uint8 flipy)

 {

 	Uint16 v, h;

 	for(v = 0; v < 8; v++)

@@ -44,7 +52,7 @@ ppu_1bpp(Ppu *p, Uint8 layer, Uint16 x, Uint16 y, Uint8 *sprite, Uint8 color, Ui

 }

 void

-ppu_2bpp(Ppu *p, Uint8 layer, Uint16 x, Uint16 y, Uint8 *sprite, Uint8 color, Uint8 flipx, Uint8 flipy)

+ppu_2bpp(Ppu *p, Uint8 *layer, Uint16 x, Uint16 y, Uint8 *sprite, Uint8 color, Uint8 flipx, Uint8 flipy)

 {

 	Uint16 v, h;

 	for(v = 0; v < 8; v++)

@@ -68,5 +76,7 @@ ppu_init(Ppu *p, Uint8 hor, Uint8 ver)

 {

 	p->width = 8 * hor;

 	p->height = 8 * ver;

+	p->bg = malloc(p->width / 4 * p->height * sizeof(Uint8));

+	p->fg = malloc(p->width / 4 * p->height * sizeof(Uint8));

 	return 1;

 }

@@ -19,10 +19,10 @@ typedef unsigned int Uint32;

 typedef struct Ppu {

 	Uint16 width, height;

-	Uint8 *pixels;

+	Uint8 *pixels, *bg, *fg;

 } Ppu;

 int ppu_init(Ppu *p, Uint8 hor, Uint8 ver);

-void ppu_pixel(Ppu *p, Uint8 layer, Uint16 x, Uint16 y, Uint8 color);

-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_pixel(Ppu *p, Uint8 *layer, Uint16 x, Uint16 y, Uint8 color);

+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);

@@ -25,14 +25,18 @@ WITH REGARD TO THIS SOFTWARE.

 #define POLYPHONY 4

 #define BENCH 0

-static SDL_AudioDeviceID audio_id;

 static SDL_Window *gWindow;

-static SDL_Surface *winSurface, *idxSurface, *rgbaSurface;

+static SDL_Surface *gSurface;

+static SDL_Texture *gTexture;

+static SDL_Renderer *gRenderer;

+static SDL_AudioDeviceID audio_id;

 static SDL_Rect gRect;

+

+/* devices */

 static Ppu ppu;

 static Apu apu[POLYPHONY];

 static Device *devsystem, *devscreen, *devmouse, *devctrl, *devaudio0, *devconsole;

-static Uint32 stdin_event, audio0_event;

+static Uint32 *ppu_screen, stdin_event, audio0_event, palette[4];

 static Uint8 zoom = 1, reqdraw = 0;

@@ -86,71 +90,79 @@ inspect(Ppu *p, Uint8 *stack, Uint8 wptr, Uint8 rptr, Uint8 *memory)

 	Uint8 i, x, y, b;

 	for(i = 0; i < 0x20; ++i) { /* stack */

 		x = ((i % 8) * 3 + 1) * 8, y = (i / 8 + 1) * 8, b = stack[i];

-		ppu_1bpp(p, 1, x, y, font[(b >> 4) & 0xf], 1 + (wptr == i) * 0x7, 0, 0);

-		ppu_1bpp(p, 1, x + 8, y, font[b & 0xf], 1 + (wptr == i) * 0x7, 0, 0);

+		ppu_1bpp(p, ppu.fg, x, y, font[(b >> 4) & 0xf], 1 + (wptr == i) * 0x7, 0, 0);

+		ppu_1bpp(p, ppu.fg, x + 8, y, font[b & 0xf], 1 + (wptr == i) * 0x7, 0, 0);

 	}

 	/* return pointer */

-	ppu_1bpp(p, 1, 0x8, y + 0x10, font[(rptr >> 4) & 0xf], 0x2, 0, 0);

-	ppu_1bpp(p, 1, 0x10, y + 0x10, font[rptr & 0xf], 0x2, 0, 0);

+	ppu_1bpp(p, ppu.fg, 0x8, y + 0x10, font[(rptr >> 4) & 0xf], 0x2, 0, 0);

+	ppu_1bpp(p, ppu.fg, 0x10, y + 0x10, font[rptr & 0xf], 0x2, 0, 0);

 	for(i = 0; i < 0x20; ++i) { /* memory */

 		x = ((i % 8) * 3 + 1) * 8, y = 0x38 + (i / 8 + 1) * 8, b = memory[i];

-		ppu_1bpp(p, 1, x, y, font[(b >> 4) & 0xf], 3, 0, 0);

-		ppu_1bpp(p, 1, x + 8, y, font[b & 0xf], 3, 0, 0);

+		ppu_1bpp(p, ppu.fg, x, y, font[(b >> 4) & 0xf], 3, 0, 0);

+		ppu_1bpp(p, ppu.fg, x + 8, y, font[b & 0xf], 3, 0, 0);

 	}

 	for(x = 0; x < 0x10; ++x) { /* guides */

-		ppu_pixel(p, 1, x, p->height / 2, 2);

-		ppu_pixel(p, 1, p->width - x, p->height / 2, 2);

-		ppu_pixel(p, 1, p->width / 2, p->height - x, 2);

-		ppu_pixel(p, 1, p->width / 2, x, 2);

-		ppu_pixel(p, 1, p->width / 2 - 0x10 / 2 + x, p->height / 2, 2);

-		ppu_pixel(p, 1, p->width / 2, p->height / 2 - 0x10 / 2 + x, 2);

+		ppu_pixel(p, ppu.fg, x, p->height / 2, 2);

+		ppu_pixel(p, ppu.fg, p->width - x, p->height / 2, 2);

+		ppu_pixel(p, ppu.fg, p->width / 2, p->height - x, 2);

+		ppu_pixel(p, ppu.fg, p->width / 2, x, 2);

+		ppu_pixel(p, ppu.fg, p->width / 2 - 0x10 / 2 + x, p->height / 2, 2);

+		ppu_pixel(p, ppu.fg, p->width / 2, p->height / 2 - 0x10 / 2 + x, 2);

+	}

+}

+

+static Uint8

+get_pixel(int x, int y)

+{

+	int ch1, ch2, r = (y % 8) + ((x / 8 + y / 8 * ppu.width / 8) * 16);

+	ch1 = (ppu.fg[r] >> (7 - x % 8)) & 1;

+	ch2 = (ppu.fg[r + 8] >> (7 - x % 8)) & 1;

+	if(!ch1 && !ch2) {

+		ch1 = (ppu.bg[r] >> (7 - x % 8)) & 1;

+		ch2 = (ppu.bg[r + 8] >> (7 - x % 8)) & 1;

 	}

+	return ch1 + (ch2 << 1);

 }

 static void

 redraw(Uxn *u)

 {

+	Uint16 x, y;

 	if(devsystem->dat[0xe])

 		inspect(&ppu, u->wst.dat, u->wst.ptr, u->rst.ptr, u->ram.dat);

-	if(rgbaSurface == NULL)

-		SDL_BlitScaled(idxSurface, NULL, winSurface, &gRect);

-	else if(zoom == 1)

-		SDL_BlitSurface(idxSurface, NULL, winSurface, &gRect);

-	else {

-		SDL_BlitSurface(idxSurface, NULL, rgbaSurface, NULL);

-		SDL_BlitScaled(rgbaSurface, NULL, winSurface, &gRect);

-	}

-	SDL_UpdateWindowSurface(gWindow);

+	for(y = 0; y < ppu.height; ++y)

+		for(x = 0; x < ppu.width; ++x)

+			ppu_screen[x + y * ppu.width] = palette[get_pixel(x, y)];

+	SDL_UpdateTexture(gTexture, &gRect, ppu_screen, ppu.width * sizeof(Uint32));

+	SDL_RenderClear(gRenderer);

+	SDL_RenderCopy(gRenderer, gTexture, NULL, NULL);

+	SDL_RenderPresent(gRenderer);

 	reqdraw = 0;

 }

 static void

-toggledebug(Uxn *u)

+toggle_debug(Uxn *u)

 {

 	devsystem->dat[0xe] = !devsystem->dat[0xe];

 	redraw(u);

 }

 static void

-togglezoom(Uxn *u)

+toggle_zoom(Uxn *u)

 {

 	zoom = zoom == 3 ? 1 : zoom + 1;

 	SDL_SetWindowSize(gWindow, (ppu.width + PAD * 2) * zoom, (ppu.height + PAD * 2) * zoom);

-	winSurface = SDL_GetWindowSurface(gWindow);

-	gRect.x = zoom * PAD;

-	gRect.y = zoom * PAD;

-	gRect.w = zoom * ppu.width;

-	gRect.h = zoom * ppu.height;

+	gSurface = SDL_GetWindowSurface(gWindow);

 	redraw(u);

 }

 static void

-screencapture(void)

+capture_screen(void)

 {

 	time_t t = time(NULL);

 	char fname[64];

 	strftime(fname, sizeof(fname), "screenshot-%Y%m%d-%H%M%S.bmp", localtime(&t));

-	SDL_SaveBMP(winSurface, fname);

+	SDL_SaveBMP(gSurface, fname);

 	fprintf(stderr, "Saved %s\n", fname);

 }

@@ -158,9 +170,11 @@ static void

 quit(void)

 {

 	SDL_UnlockAudioDevice(audio_id);

-	SDL_FreeSurface(winSurface);

-	SDL_FreeSurface(idxSurface);

-	if(rgbaSurface) SDL_FreeSurface(rgbaSurface);

+	SDL_FreeSurface(gSurface);

+	SDL_DestroyTexture(gTexture);

+	gTexture = NULL;

+	SDL_DestroyRenderer(gRenderer);

+	gRenderer = NULL;

 	SDL_DestroyWindow(gWindow);

 	SDL_Quit();

 	exit(0);

@@ -191,27 +205,25 @@ init(void)

 	gWindow = SDL_CreateWindow("Uxn", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, (ppu.width + PAD * 2) * zoom, (ppu.height + PAD * 2) * zoom, SDL_WINDOW_SHOWN);

 	if(gWindow == NULL)

 		return error("sdl_window", SDL_GetError());

-	winSurface = SDL_GetWindowSurface(gWindow);

-	if(winSurface == NULL)

+	gSurface = SDL_GetWindowSurface(gWindow);

+	if(gSurface == NULL)

 		return error("sdl_surface win", SDL_GetError());

-	idxSurface = SDL_CreateRGBSurfaceWithFormat(0, ppu.width, ppu.height, 8, SDL_PIXELFORMAT_INDEX8);

-	if(idxSurface == NULL || SDL_SetSurfaceBlendMode(idxSurface, SDL_BLENDMODE_NONE))

-		return error("sdl_surface idx", SDL_GetError());

-	if(SDL_MUSTLOCK(idxSurface) == SDL_TRUE)

-		return error("sdl_surface idx", "demands locking");

-	gRect.x = zoom * PAD;

-	gRect.y = zoom * PAD;

-	gRect.w = zoom * ppu.width;

-	gRect.h = 2 * ppu.height; /* force non-1:1 scaling for BlitScaled test */

-	if(SDL_BlitScaled(idxSurface, NULL, winSurface, &gRect) < 0) {

-		rgbaSurface = SDL_CreateRGBSurfaceWithFormat(0, ppu.width, ppu.height, 32, SDL_PIXELFORMAT_RGB24);

-		if(rgbaSurface == NULL || SDL_SetSurfaceBlendMode(rgbaSurface, SDL_BLENDMODE_NONE))

-			return error("sdl_surface rgba", SDL_GetError());

-	}

-	gRect.h = zoom * ppu.height;

-	ppu.pixels = idxSurface->pixels;

+	gRenderer = SDL_CreateRenderer(gWindow, -1, 0);

+	if(gRenderer == NULL)

+		return error("sdl_renderer", SDL_GetError());

+	SDL_RenderSetLogicalSize(gRenderer, ppu.width + PAD * 2, ppu.height + PAD * 2);

+	gTexture = SDL_CreateTexture(gRenderer, SDL_PIXELFORMAT_ARGB8888, SDL_TEXTUREACCESS_STATIC, ppu.width + PAD * 2, ppu.height + PAD * 2);

+	if(gTexture == NULL || SDL_SetTextureBlendMode(gTexture, SDL_BLENDMODE_NONE))

+		return error("sdl_texture", SDL_GetError());

+	SDL_UpdateTexture(gTexture, NULL, ppu_screen, 4);

+	if(!(ppu_screen = malloc(ppu.width * ppu.height * sizeof(Uint32))))

+		return 0;

 	SDL_StartTextInput();

 	SDL_ShowCursor(SDL_DISABLE);

+	gRect.x = PAD;

+	gRect.y = PAD;

+	gRect.w = ppu.width;

+	gRect.h = ppu.height;

 	return 1;

 }

@@ -219,8 +231,8 @@ static void

 domouse(SDL_Event *event)

 {

 	Uint8 flag = 0x00;

-	Uint16 x = clamp(event->motion.x / zoom - PAD, 0, ppu.width - 1);

-	Uint16 y = clamp(event->motion.y / zoom - PAD, 0, ppu.height - 1);

+	Uint16 x = clamp(event->motion.x - PAD, 0, ppu.width - 1);

+	Uint16 y = clamp(event->motion.y - PAD, 0, ppu.height - 1);

 	poke16(devmouse->dat, 0x2, x);

 	poke16(devmouse->dat, 0x4, y);

 	switch(event->button.button) {

@@ -253,9 +265,9 @@ doctrl(Uxn *u, SDL_Event *event, int z)

 	case SDLK_DOWN: flag = 0x20; break;

 	case SDLK_LEFT: flag = 0x40; break;

 	case SDLK_RIGHT: flag = 0x80; break;

-	case SDLK_F1: if(z) togglezoom(u); break;

-	case SDLK_F2: if(z) toggledebug(u); break;

-	case SDLK_F3: if(z) screencapture(); break;

+	case SDLK_F1: if(z) toggle_zoom(u); break;

+	case SDLK_F2: if(z) toggle_debug(u); break;

+	case SDLK_F3: if(z) capture_screen(); break;

 	}

 	/* clang-format on */

 	if(z) {

@@ -268,22 +280,17 @@ doctrl(Uxn *u, SDL_Event *event, int z)

 		devctrl->dat[2] &= ~flag;

 }

-static void

-docolors(Device *d)

+void

+update_palette(Uint8 *addr)

 {

-	SDL_Color pal[16];

 	int i;

 	for(i = 0; i < 4; ++i) {

-		pal[i].r = ((d->dat[0x8 + i / 2] >> (!(i % 2) << 2)) & 0x0f) * 0x11;

-		pal[i].g = ((d->dat[0xa + i / 2] >> (!(i % 2) << 2)) & 0x0f) * 0x11;

-		pal[i].b = ((d->dat[0xc + i / 2] >> (!(i % 2) << 2)) & 0x0f) * 0x11;

-	}

-	for(i = 4; i < 16; ++i) {

-		pal[i].r = pal[i / 4].r;

-		pal[i].g = pal[i / 4].g;

-		pal[i].b = pal[i / 4].b;

+		Uint8

+			r = (*(addr + i / 2) >> (!(i % 2) << 2)) & 0x0f,

+			g = (*(addr + 2 + i / 2) >> (!(i % 2) << 2)) & 0x0f,

+			b = (*(addr + 4 + i / 2) >> (!(i % 2) << 2)) & 0x0f;

+		palette[i] = 0xff000000 | (r << 20) | (r << 16) | (g << 12) | (g << 8) | (b << 4) | b;

 	}

-	SDL_SetPaletteColors(idxSurface->format->palette, pal, 0, 16);

 	reqdraw = 1;

 }

@@ -303,7 +310,8 @@ system_talk(Device *d, Uint8 b0, Uint8 w)

 		case 0x3: d->u->rst.ptr = d->dat[0x3]; break;

 		case 0xf: return 0;

 		}

-		if(b0 > 0x7 && b0 < 0xe) docolors(d);

+		if(b0 > 0x7 && b0 < 0xe)

+			update_palette(&d->dat[0x8]);

 	}

 	return 1;

 }

@@ -323,7 +331,7 @@ screen_talk(Device *d, Uint8 b0, Uint8 w)

 		Uint16 x = peek16(d->dat, 0x8);

 		Uint16 y = peek16(d->dat, 0xa);

 		Uint8 layer = d->dat[0xe] & 0x40;

-		ppu_pixel(&ppu, !!layer, x, y, d->dat[0xe] & 0x3);

+		ppu_pixel(&ppu, layer ? ppu.fg : ppu.bg, x, y, d->dat[0xe] & 0x3);

 		if(d->dat[0x6] & 0x01) poke16(d->dat, 0x8, x + 1); /* auto x+1 */

 		if(d->dat[0x6] & 0x02) poke16(d->dat, 0xa, y + 1); /* auto y+1 */

 		reqdraw = 1;

@@ -333,10 +341,10 @@ screen_talk(Device *d, Uint8 b0, Uint8 w)

 		Uint8 layer = d->dat[0xf] & 0x40;

 		Uint8 *addr = &d->mem[peek16(d->dat, 0xc)];

 		if(d->dat[0xf] & 0x80) {

-			ppu_2bpp(&ppu, !!layer, x, y, addr, d->dat[0xf] & 0xf, d->dat[0xf] & 0x10, d->dat[0xf] & 0x20);

+			ppu_2bpp(&ppu, layer ? ppu.fg : ppu.bg, x, y, addr, d->dat[0xf] & 0xf, d->dat[0xf] & 0x10, d->dat[0xf] & 0x20);

 			if(d->dat[0x6] & 0x04) poke16(d->dat, 0xc, peek16(d->dat, 0xc) + 16); /* auto addr+16 */

 		} else {

-			ppu_1bpp(&ppu, !!layer, x, y, addr, d->dat[0xf] & 0xf, d->dat[0xf] & 0x10, d->dat[0xf] & 0x20);

+			ppu_1bpp(&ppu, layer ? ppu.fg : ppu.bg, x, y, addr, d->dat[0xf] & 0xf, d->dat[0xf] & 0x10, d->dat[0xf] & 0x20);

 			if(d->dat[0x6] & 0x04) poke16(d->dat, 0xc, peek16(d->dat, 0xc) + 8); /* auto addr+8 */

 		}

 		if(d->dat[0x6] & 0x01) poke16(d->dat, 0x8, x + 8); /* auto x+8 */

@@ -488,7 +496,7 @@ run(Uxn *u)

 				if(event.window.event == SDL_WINDOWEVENT_EXPOSED)

 					redraw(u);

 				else if(event.window.event == SDL_WINDOWEVENT_RESIZED)

-					winSurface = SDL_GetWindowSurface(gWindow);

+					gSurface = SDL_GetWindowSurface(gWindow);

 				break;

 			default:

 				if(event.type == stdin_event) {