diff --git a/cg.c b/cg.c
index dfed495..a2dbd97 100644
--- a/cg.c
+++ b/cg.c
@@ -39,7 +39,6 @@ static enum cg_type check_cgformat(uint8_t *data)
 	if (qnt_checkfmt(data)) {
 		return ALCG_QNT;
 	}
-	WARNING("Unknown CG type");
 	return ALCG_UNKNOWN;
 }
 
@@ -55,6 +54,7 @@ bool cg_get_metrics(int no, struct cg_metrics *dst)
 		qnt_get_metrics(dfile->data, dst);
 		break;
 	default:
+		WARNING("Unknown CG type (CG %d)", no);
 		return false;
 	}
 	return true;
@@ -89,7 +89,7 @@ void cg_free(struct cg *cg)
 bool cg_load(struct cg *cg, int no)
 {
 	struct archive_data *dfile;
-	int type, possibly_unused size = 0;
+	int type;
 
 	if (!(dfile = ald_get(ald[ALDFILE_CG], no))) {
 		WARNING("Failed to load CG %d", no);
@@ -100,32 +100,32 @@ bool cg_load(struct cg *cg, int no)
 	type = check_cgformat(dfile->data);
 
 	// extract cg
-	//  size is only pixel data size
 	switch(type) {
 	case ALCG_QNT:
-		cg->type = ALCG_QNT;
-		cg->s = qnt_extract(dfile->data);
-		cg->pixel_alloc = true;
+		qnt_extract(dfile->data, cg);
 		break;
 	case ALCG_AJP:
-		// TODO
+		WARNING("Unimplemented CG type: AJP");
 		break;
 	case ALCG_PNG:
-		// TODO
+		WARNING("Unimplemented CG type: PNG");
 		break;
 	default:
+		WARNING("Unknown CG type (CG %d)", no);
 		break;
 	}
 
 	// ok to free
 	ald_free_data(dfile);
 
-	return true;
+	return !!cg->s;
 }
 
 void _cg_init(struct cg *cg)
 {
+	cg->type = ALCG_UNKNOWN;
 	cg->pixel_alloc = false;
+	cg->has_alpha = false;
 	cg->s = NULL;
 }
 
diff --git a/cg.h b/cg.h
index 208ec43..7464a66 100644
--- a/cg.h
+++ b/cg.h
@@ -40,7 +40,9 @@ enum cg_type {
 struct cg {
 	enum cg_type type; // cg format type
 	bool pixel_alloc;
+	bool has_alpha;
 	SDL_Surface *s;
+	SDL_Texture *t;
 };
 
 struct cg_metrics {
diff --git a/graphics.h b/graphics.h
index 1390e13..9dfda10 100644
--- a/graphics.h
+++ b/graphics.h
@@ -22,30 +22,19 @@
 #include <stdint.h>
 #include <SDL.h>
 
-typedef struct {
-        uint8_t red[256];
-        uint8_t green[256];
-        uint8_t blue[256];
-} Pallet256;
-
-typedef struct {
-        uint8_t r,g,b;
-        uint32_t pixel;
-} Pallet;
-
 typedef SDL_Point Point;
 
+#define POINT(_x, _y) ((Point){.x=_x, .y=_y})
+
 typedef struct {
-        int width;
-        int height;
+        int w;
+        int h;
 } Dimension;
 
+#define DIM(_w, _h) ((Dimension){.w=_w, .h=_h})
+
 typedef SDL_Rect Rectangle;
 
-typedef struct {
-        int width;
-        int height;
-        int depth;
-} DispInfo;
+#define RECT(_x, _y, _w, _h) ((Rectangle){.x=_x, .y=_y, .w=_w, .h=_h})
 
 #endif /* SYSTEM4_GRAPHICS_H */
diff --git a/qnt.c b/qnt.c
index 47bb463..7455fdc 100644
--- a/qnt.c
+++ b/qnt.c
@@ -39,6 +39,8 @@
 #include "cg.h"
 #include "qnt.h"
 #include "system4.h"
+#include "sdl_private.h"
+#include "sdl_core.h"
 
 /*
   zlib の展開バッファで、幅×高さ×３に、さらにどれくらい余裕をとるか
@@ -249,17 +251,27 @@ bool qnt_get_metrics(uint8_t *data, struct cg_metrics *dst)
  *
  *   return: extracted image data and information
 */
-SDL_Surface *qnt_extract(uint8_t *data)
+void qnt_extract(uint8_t *data, struct cg *cg)
 {
 	struct qnt_header qnt;
 	extract_header(data, &qnt);
 	uint8_t *pixels = malloc(sizeof(uint8_t) * ((qnt.width+10) * (qnt.height+10) * 3));
 	extract_pixel(&qnt, pixels, data + qnt.hdr_size);
 
-	if (!qnt.alpha_size)
-		return SDL_CreateRGBSurfaceWithFormatFrom(pixels, qnt.width, qnt.height, 24,
-							  qnt.width * 3, SDL_PIXELFORMAT_RGB24);
+	cg->type = ALCG_QNT;
+	cg->has_alpha = qnt.alpha_size > 0;
 
+	if (!qnt.alpha_size) {
+		// convert RGB -> ARGB
+		SDL_Surface *tmp =  SDL_CreateRGBSurfaceWithFormatFrom(pixels, qnt.width, qnt.height, 24,
+								       qnt.width * 3, SDL_PIXELFORMAT_RGB24);
+		cg->s = SDL_ConvertSurface(tmp, sdl.format, 0);
+		cg->t = sdl_surface_to_texture(cg->s);
+		cg->pixel_alloc = false;
+		SDL_FreeSurface(tmp);
+		free(pixels);
+		return;
+	}
 	// combine color/alpha data
 	uint8_t *alpha = malloc(sizeof(uint8_t) * ((qnt.width+10) * (qnt.height+10)));
 	uint8_t *tmp = malloc((qnt.width+10) * (qnt.height+10) * 4);
@@ -274,6 +286,8 @@ SDL_Surface *qnt_extract(uint8_t *data)
 	free(pixels);
 	pixels = tmp;
 
-	return SDL_CreateRGBSurfaceWithFormatFrom(pixels, qnt.width, qnt.height, 32,
-						  qnt.width * 4, SDL_PIXELFORMAT_ARGB32);
+	cg->s = SDL_CreateRGBSurfaceWithFormatFrom(pixels, qnt.width, qnt.height, 32,
+						   qnt.width * 4, SDL_PIXELFORMAT_ARGB32);
+	cg->t = sdl_surface_to_texture(cg->s);
+	cg->pixel_alloc = true;
 }
diff --git a/qnt.h b/qnt.h
index 54cdb68..c786fce 100644
--- a/qnt.h
+++ b/qnt.h
@@ -45,6 +45,6 @@ struct qnt_header {
 
 bool qnt_checkfmt(uint8_t *data);
 bool qnt_get_metrics(uint8_t *data, struct cg_metrics *dst);
-SDL_Surface *qnt_extract(uint8_t *data);
+void qnt_extract(uint8_t *data, struct cg *cg);
 
 #endif /* __QNT_H__ */
diff --git a/sact.h b/sact.h
index 7f8d425..09e0921 100644
--- a/sact.h
+++ b/sact.h
@@ -34,6 +34,7 @@ struct sact_sprite {
 	struct {
 		struct string *str;
 		SDL_Surface *surf;
+		SDL_Texture *t;
 		Point home;
 		Point pos;
 		int char_space;
diff --git a/sact_graphics.c b/sact_graphics.c
index 703213e..4af967b 100644
--- a/sact_graphics.c
+++ b/sact_graphics.c
@@ -70,17 +70,21 @@ int sact_Init(void)
 int sact_Update(void)
 {
 	handle_events();
+
+	sdl_render_clear();
 	struct sact_sprite *p;
 	TAILQ_FOREACH(p, &sprite_list, entry) {
 		if (!p->show)
 			continue;
-		if (!p->cg->s)
-			p->cg->s = sdl_make_rectangle(p->rect.w, p->rect.h, &p->color);
-		sdl_draw_surface(p->cg->s, &p->rect);
-		if (p->text.surf)
-			sdl_draw_surface(p->text.surf, &p->rect);
+		if (!p->cg->s) {
+			p->cg->s = sdl_create_surface(p->rect.w, p->rect.h, &p->color);
+			p->cg->t = sdl_surface_to_texture(p->cg->s);
+		}
+		sdl_render_texture(p->cg->t, &p->rect);
+		if (p->text.t)
+			sdl_render_texture(p->text.t, &p->rect);
 	}
-	sdl_update_screen();
+	sdl_render_present();
 	return 1;
 }
 
@@ -253,7 +257,7 @@ static struct sact_sprite *create_sprite(int sp_no, int width, int height, int r
 		VM_ERROR("Invalid sprite number: %d", sp_no);
 	if (!(sp = sact_get_sprite(sp_no)))
 		sp = alloc_sprite(sp_no);
-	sp->color = (SDL_Color) { .r = r, .g = g, .b = b, .a = a };
+	sp->color = (SDL_Color) { .r = r, .g = g, .b = b, .a = (a >= 0 ? a : 255) };
 	sp->rect.w = width;
 	sp->rect.h = height;
 	if (sp->cg) {
@@ -262,6 +266,7 @@ static struct sact_sprite *create_sprite(int sp_no, int width, int height, int r
 		sp->cg = cg_init();
 		sprite_register(sp);
 	}
+	sp->cg->has_alpha = a >= 0;
 	return sp;
 }
 
@@ -273,7 +278,7 @@ int sact_SP_Create(int sp_no, int width, int height, int r, int g, int b, int a)
 
 int sact_SP_CreatePixelOnly(int sp_no, int width, int height)
 {
-	create_sprite(sp_no, width, height, 0, 0, 0, 255);
+	create_sprite(sp_no, width, height, 0, 0, 0, -1);
 	return 1;
 }
 
@@ -303,46 +308,31 @@ int sact_SP_ExistsAlpha(int sp_no)
 {
 	struct sact_sprite *sp = sact_get_sprite(sp_no);
 	if (!sp) return 0;
-	if (!sp->cg->s) return 1;
-	return !!sp->cg->s->format->Amask;
+	return sp->cg->has_alpha;
 }
 
-#define tm_ColorR(tm)       (tm[0].i)
-#define tm_ColorG(tm)       (tm[1].i)
-#define tm_ColorB(tm)       (tm[2].i)
-#define tm_Size(tm)         (tm[3].i)
-#define tm_Weight(tm)       (tm[4].i)
-#define tm_Face(tm)         (tm[5].i)
-#define tm_ShadowPixelL(tm) (tm[6].i)
-#define tm_ShadowPixelU(tm) (tm[7].i)
-#define tm_ShadowPixelR(tm) (tm[8].i)
-#define tm_ShadowPixelD(tm) (tm[9].i)
-#define tm_ShadowColorR(tm) (tm[10].i)
-#define tm_ShadowColorG(tm) (tm[11].i)
-#define tm_ShadowColorB(tm) (tm[12].i)
-
 static void init_text_metrics(struct text_metrics *tm, union vm_value *_tm)
 {
 	*tm = (struct text_metrics) {
 		.color = {
-			.r = tm_ColorR(_tm),
-			.g = tm_ColorG(_tm),
-			.b = tm_ColorB(_tm),
+			.r = _tm[0].i,
+			.g = _tm[1].i,
+			.b = _tm[2].i,
 			.a = 255
 		},
 		.outline_color = {
-			.r = tm_ShadowColorR(_tm),
-			.g = tm_ShadowColorG(_tm),
-			.b = tm_ShadowColorB(_tm),
+			.r = _tm[10].i,
+			.g = _tm[11].i,
+			.b = _tm[12].i,
 			.a = 255
 		},
-		.size          = tm_Size(_tm),
-		.weight        = tm_Weight(_tm),
-		.face          = tm_Face(_tm),
-		.outline_left  = tm_ShadowPixelL(_tm),
-		.outline_up    = tm_ShadowPixelU(_tm),
-		.outline_right = tm_ShadowPixelR(_tm),
-		.outline_down  = tm_ShadowPixelD(_tm),
+		.size          = _tm[3].i,
+		.weight        = _tm[4].i,
+		.face          = _tm[5].i,
+		.outline_left  = _tm[6].i,
+		.outline_up    = _tm[7].i,
+		.outline_right = _tm[8].i,
+		.outline_down  = _tm[9].i,
 	};
 }
 
@@ -354,11 +344,13 @@ int sact_SP_TextDraw(int sp_no, struct string *text, union vm_value *_tm)
 
 	if (!sp->text.surf) {
 		SDL_Color c = { 0, 0, 0, 0 };
-		sp->text.surf = sdl_make_rectangle(sp->rect.w, sp->rect.h, &c);
+		sp->text.surf = sdl_create_surface(sp->rect.w, sp->rect.h, &c);
+		sp->text.t = sdl_create_texture(sp->rect.w, sp->rect.h);
 	}
 
 	init_text_metrics(&tm, _tm);
 	sp->text.pos.x += sdl_render_text(sp->text.surf, sp->text.pos, text->text, &tm) + sp->text.char_space;
+	sdl_update_texture(sp->text.t, sp->text.surf);
 	return 1;
 }
 
@@ -366,7 +358,9 @@ static void clear_text(struct sact_sprite *sp)
 {
 	if (sp->text.surf) {
 		SDL_FreeSurface(sp->text.surf);
+		SDL_DestroyTexture(sp->text.t);
 		sp->text.surf = NULL;
+		sp->text.t = NULL;
 	}
 }
 
@@ -395,9 +389,11 @@ int sact_SP_TextCopy(int dno, int sno)
 	clear_text(dsp);
 	if (ssp->text.surf) {
 		SDL_Color c = { 0, 0, 0, 0 };
-		Rectangle rect = { .x = 0, .y = 0, .w = dsp->rect.w, .h = dsp->rect.h };
-		dsp->text.surf = sdl_make_rectangle(dsp->rect.w, dsp->rect.h, &c);
+		Rectangle rect = RECT(0, 0, dsp->rect.w, dsp->rect.h);
+		dsp->text.surf = sdl_create_surface(dsp->rect.w, dsp->rect.h, &c);
+		dsp->text.t = sdl_create_texture(dsp->rect.w, dsp->rect.h);
 		SDL_BlitSurface(ssp->text.surf, NULL, dsp->text.surf, &rect);
+		sdl_update_texture(dsp->text.t, dsp->text.surf);
 	}
 	dsp->text.home = ssp->text.home;
 	dsp->text.pos = ssp->text.pos;
@@ -425,269 +421,69 @@ int sact_CG_GetMetrics(int cg_no, union vm_value *cgm)
 // --- DrawGraph.dll ---
 //
 
-struct sact_sprite *DrawGraph_get_sprite(int no)
+struct sact_sprite *get_surface(int no)
 {
 	struct sact_sprite *sp = sact_get_sprite(no);
 	if (!sp)
 		ERROR("Invalid sprite number: %d", no);
 	if (!sp->cg->s)
-		sp->cg->s = sdl_make_rectangle(sp->rect.w, sp->rect.h, &sp->color);
+		sp->cg->s = sdl_create_surface(sp->rect.w, sp->rect.h, &sp->color);
+	if (!sp->cg->t)
+		sp->cg->t = sdl_surface_to_texture(sp->cg->s);
 	return sp;
 }
 
-static void DrawGraph_Blit(SDL_Surface *ds, int dx, int dy, SDL_Surface *ss, int sx, int sy, int w, int h)
-{
-	Rectangle src_rect = { .x = sx, .y = sy, .w = w, .h = h };
-	Rectangle dst_rect = { .x = dx, .y = dy, .w = w, .h = h };
-	SDL_BlitSurface(ss, &src_rect, ds, &dst_rect);
-}
-
 void DrawGraph_Copy(int dno, int dx, int dy, int sno, int sx, int sy, int w, int h)
 {
-	SDL_BlendMode mode;
-	SDL_Surface *ds = DrawGraph_get_sprite(dno)->cg->s;
-	SDL_Surface *ss = DrawGraph_get_sprite(sno)->cg->s;
-
-	SDL_GetSurfaceBlendMode(ss, &mode);
-	SDL_SetSurfaceBlendMode(ss, SDL_BLENDMODE_NONE);
-
-	DrawGraph_Blit(ds, dx, dy, ss, sx, sy, w, h);
-
-	SDL_SetSurfaceBlendMode(ss, mode);
+	sdl_copy(get_surface(dno)->cg, dx, dy, get_surface(sno)->cg, sx, sy, w, h);
 }
 
 void DrawGraph_CopyBright(int dno, int dx, int dy, int sno, int sx, int sy, int w, int h, int rate)
 {
-	SDL_BlendMode mode;
-	SDL_Surface *ds = DrawGraph_get_sprite(dno)->cg->s;
-	SDL_Surface *ss = DrawGraph_get_sprite(sno)->cg->s;
-
-	SDL_GetSurfaceBlendMode(ss, &mode);
-	SDL_SetSurfaceBlendMode(ss, SDL_BLENDMODE_NONE);
-	SDL_SetSurfaceColorMod(ss, rate, rate, rate);
-
-	DrawGraph_Blit(ds, dx, dy, ss, sx, sy, w, h);
-
-	SDL_SetSurfaceColorMod(ss, 255, 255, 255);
-	SDL_SetSurfaceBlendMode(ss, mode);
+	sdl_copy_bright(get_surface(dno)->cg, dx, dy, get_surface(sno)->cg, sx, sy, w, h, rate);
 }
 
-// Clip src/dst rectangles in preparation for a copy.
-static void clip_rects(SDL_Surface *ds, int *dx, int *dy, SDL_Surface *ss, int *sx, int *sy, int *w, int *h)
-{
-	if (*sx < 0) {
-		*dx -= *sx;
-		*w += *sx;
-		*sx = 0;
-	}
-	if (*sy < 0) {
-		*dy -= *sy;
-		*h += *sy;
-		*sy = 0;
-	}
-	if (*dx < 0) {
-		*sx -= *dx;
-		*w += *dx;
-		*dx = 0;
-	}
-	if (*dy < 0) {
-		*sy -= *dy;
-		*w += *dy;
-		*dy = 0;
-	}
-	*w = min(*w, min(ds->w - *dx, ss->w - *sx));
-	*h = min(*h, min(ds->h - *dy, ss->h - *sy));
-}
-
-static inline uint32_t *get_pixel(SDL_Surface *s, int x, int y)
-{
-	return (uint32_t*)(((uint8_t*)s->pixels) + s->pitch*y + s->format->BytesPerPixel*x);
-}
-
-static inline void next_pixel(SDL_Surface *s, uint32_t **p)
-{
-	*p = (uint32_t*)((uint8_t*)*p + s->format->BytesPerPixel);
-}
-
-// iterator for copy operations
-#define copy_for_each_pixel(ds, dx, dy, ss, sx, sy, w, h, dp, sp, expr)	\
-	do {								\
-		clip_rects(ds, &dx, &dy, ss, &sx, &sy, &w, &h);		\
-		SDL_LockSurface(ds);					\
-		SDL_LockSurface(ss);					\
-		for (int _row = 0; _row < h; _row++) {			\
-			uint32_t *dp = get_pixel(ds, dx, _row+dy);	\
-			uint32_t *sp = get_pixel(ss, sx, _row+sy);	\
-			for (int _col = 0; _col < w; _col++, next_pixel(ds, &dp), next_pixel(ss, &sp)) \
-				expr;					\
-		}							\
-		SDL_UnlockSurface(ss);					\
-		SDL_UnlockSurface(ds);					\
-	} while (0)
-
-#define fill_for_each_pixel(s, x, y, w, h, p, expr)			\
-	do {								\
-		SDL_LockSurface(s);					\
-		for (int _row = 0; _row < h; _row++) {			\
-			uint32_t *p = get_pixel(s, x, _row+y);		\
-			for (int _col = 0; _col < w; _col++, next_pixel(s, &p)) \
-				expr;					\
-		}							\
-		SDL_UnlockSurface(s);					\
-	} while(0);
-
 void DrawGraph_CopyAMap(int dno, int dx, int dy, int sno, int sx, int sy, int w, int h)
 {
-	SDL_Surface *ds = DrawGraph_get_sprite(dno)->cg->s;
-	SDL_Surface *ss = DrawGraph_get_sprite(sno)->cg->s;
-
-	if (!ds->format->Amask || !ss->format->Amask)
-		return;
-
-	copy_for_each_pixel(ds, dx, dy, ss, sx, sy, w, h, dp, sp, {
-		uint32_t a = (*sp & ss->format->Amask) >> ss->format->Ashift;
-		*dp &= ~ds->format->Amask;
-		*dp |= (a << ds->format->Ashift);
-	});
+	sdl_copy_amap(get_surface(dno)->cg, dx, dy, get_surface(sno)->cg, sx, sy, w, h);
 }
 
 void DrawGraph_CopySprite(int dno, int dx, int dy, int sno, int sx, int sy, int w, int h, int r, int g, int b)
 {
-	SDL_BlendMode mode;
-	SDL_Surface *ds = DrawGraph_get_sprite(dno)->cg->s;
-	SDL_Surface *ss = DrawGraph_get_sprite(sno)->cg->s;
-
-	SDL_GetSurfaceBlendMode(ss, &mode);
-	SDL_SetSurfaceBlendMode(ss, SDL_BLENDMODE_NONE);
-	SDL_SetColorKey(ss, SDL_TRUE, SDL_MapRGB(ss->format, r, g, b));
-
-	DrawGraph_Blit(ds, dx, dy, ss, sx, sy, w, h);
-
-	SDL_SetColorKey(ss, SDL_FALSE, 0);
-	SDL_SetSurfaceBlendMode(ss, mode);
+	sdl_copy_sprite(get_surface(dno)->cg, dx, dy, get_surface(sno)->cg, sx, sy, w, h, r, g, b);
 }
 
 void DrawGraph_CopyUseAMapUnder(int dno, int dx, int dy, int sno, int sx, int sy, int w, int h, int a_threshold)
 {
-	SDL_Surface *ds = DrawGraph_get_sprite(dno)->cg->s;
-	SDL_Surface *ss = DrawGraph_get_sprite(sno)->cg->s;
-
-	if (!ss->format->Amask)
-		return;
-
-	uint8_t r, g, b, a;
-	copy_for_each_pixel(ds, dx, dy, ss, sx, sy, w, h, dp, sp, {
-		SDL_GetRGBA(*sp, ss->format, &r, &g, &b, &a);
-		if (a <= a_threshold) {
-			*dp &= ~(ds->format->Rmask | ds->format->Gmask | ds->format->Bmask);
-			*dp |= (uint32_t)r << ds->format->Rshift;
-			*dp |= (uint32_t)g << ds->format->Gshift;
-			*dp |= (uint32_t)b << ds->format->Bshift;
-		}
-	});
+	sdl_copy_use_amap_under(get_surface(dno)->cg, dx, dy, get_surface(sno)->cg, sx, sy, w, h, a_threshold);
 }
 
 void DrawGraph_CopyUseAMapBorder(int dno, int dx, int dy, int sno, int sx, int sy, int w, int h, int a_threshold)
 {
-	SDL_Surface *ds = DrawGraph_get_sprite(dno)->cg->s;
-	SDL_Surface *ss = DrawGraph_get_sprite(sno)->cg->s;
-
-	if (!ss->format->Amask)
-		return;
-
-	uint8_t r, g, b, a;
-	copy_for_each_pixel(ds, dx, dy, ss, sx, sy, w, h, dp, sp, {
-			SDL_GetRGBA(*sp, ss->format, &r, &g, &b, &a);
-			if (a >= a_threshold) {
-				*dp &= ~(ds->format->Rmask | ds->format->Gmask | ds->format->Bmask);
-				*dp |= (uint32_t)r << ds->format->Rshift;
-				*dp |= (uint32_t)g << ds->format->Gshift;
-				*dp |= (uint32_t)b << ds->format->Bshift;
-			}
-		});
+	sdl_copy_use_amap_border(get_surface(dno)->cg, dx, dy, get_surface(sno)->cg, sx, sy, w, h, a_threshold);
 }
 
 void DrawGraph_CopyAMapMax(int dno, int dx, int dy, int sno, int sx, int sy, int w, int h)
 {
-	SDL_Surface *ds = DrawGraph_get_sprite(dno)->cg->s;
-	SDL_Surface *ss = DrawGraph_get_sprite(sno)->cg->s;
-
-	if (!ss->format->Amask || !ds->format->Amask)
-		return;
-
-	copy_for_each_pixel(ds, dx, dy, ss, sx, sy, w, h, dp, sp, {
-		uint32_t d_a = (*dp & ds->format->Amask) >> ds->format->Ashift;
-		uint32_t s_a = (*sp & ss->format->Amask) >> ss->format->Ashift;
-		if (s_a > d_a) {
-			*dp &= ~ds->format->Amask;
-			*dp |= s_a << ds->format->Ashift;
-		}
-	});
+	sdl_copy_amap_max(get_surface(dno)->cg, dx, dy, get_surface(sno)->cg, sx, sy, w, h);
 }
 
 void DrawGraph_CopyAMapMin(int dno, int dx, int dy, int sno, int sx, int sy, int w, int h)
 {
-	SDL_Surface *ds = DrawGraph_get_sprite(dno)->cg->s;
-	SDL_Surface *ss = DrawGraph_get_sprite(sno)->cg->s;
-
-	if (!ss->format->Amask || !ds->format->Amask)
-		return;
-
-	copy_for_each_pixel(ds, dx, dy, ss, sx, sy, w, h, dp, sp, {
-		uint32_t d_a = (*dp & ds->format->Amask) >> ds->format->Ashift;
-		uint32_t s_a = (*sp & ss->format->Amask) >> ss->format->Ashift;
-		if (s_a < d_a) {
-			*dp &= ~ds->format->Amask;
-			*dp |= s_a << ds->format->Ashift;
-		}
-	});
-}
-
-static void blend_pixels(SDL_Color *dst, SDL_Color src)
-{
-	uint32_t alpha = src.a + 1;
-	uint32_t inv_alpha = 256 - src.a;
-	dst->r = (uint8_t)((alpha * src.r + inv_alpha * dst->r) >> 8);
-	dst->g = (uint8_t)((alpha * src.g + inv_alpha * dst->g) >> 8);
-	dst->b = (uint8_t)((alpha * src.b + inv_alpha * dst->b) >> 8);
+	sdl_copy_amap_min(get_surface(dno)->cg, dx, dy, get_surface(sno)->cg, sx, sy, w, h);
 }
 
 void DrawGraph_Fill(int sp_no, int x, int y, int w, int h, int r, int g, int b)
 {
-	SDL_Surface *s = DrawGraph_get_sprite(sp_no)->cg->s;
-
-	fill_for_each_pixel(s, x, y, w, h, p, {
-		*p &= ~(s->format->Rmask | s->format->Gmask | s->format->Bmask);
-		*p |= (uint32_t)r << s->format->Rshift;
-		*p |= (uint32_t)g << s->format->Gshift;
-		*p |= (uint32_t)b << s->format->Bshift;
-	});
+	sdl_fill(get_surface(sp_no)->cg, x, y, w, h, r, g, b);
 }
 
-// XXX: Despite being called a fill operation, this function actually performs blending.
 void DrawGraph_FillAlphaColor(int sp_no, int x, int y, int w, int h, int r, int g, int b, int a)
 {
-	SDL_Surface *s = DrawGraph_get_sprite(sp_no)->cg->s;
-
-	SDL_Color dst;
-	SDL_Color src = { .r = r, .g = g, .b = b, .a = a };
-	fill_for_each_pixel(s, x, y, w, h, p, {
-		SDL_GetRGBA(*p, s->format, &dst.r, &dst.g, &dst.b, &dst.a);
-		blend_pixels(&dst, src);
-		*p &= ~(s->format->Rmask | s->format->Gmask | s->format->Bmask | s->format->Amask);
-		*p |= (uint32_t)dst.r << s->format->Rshift;
-		*p |= (uint32_t)dst.g << s->format->Gshift;
-		*p |= (uint32_t)dst.b << s->format->Bshift;
-		*p |= (uint32_t)dst.a << s->format->Ashift;
-	});
+	sdl_fill_alpha_color(get_surface(sp_no)->cg, x, y, w, h, r, g, b, a);
 }
 
 void DrawGraph_FillAMap(int sp_no, int x, int y, int w, int h, int a)
 {
-	SDL_Surface *s = DrawGraph_get_sprite(sp_no)->cg->s;
-
-	fill_for_each_pixel(s, x, y, w, h, p, {
-		*p &= ~s->format->Amask;
-		*p |= (uint32_t)a << s->format->Ashift;
-	});
+	sdl_fill_amap(get_surface(sp_no)->cg, x, y, w, h, a);
 }
diff --git a/sdl_core.h b/sdl_core.h
index f8e6075..c6d1b7f 100644
--- a/sdl_core.h
+++ b/sdl_core.h
@@ -28,12 +28,32 @@ struct cg;
 int sdl_initialize(void);
 void sdl_remove(void);
 
-void sdl_set_window_size(int x, int y, int w, int h);
+void sdl_set_window_size(int w, int h);
 void sdl_fullscreen(bool on);
 
-void sdl_update_screen(void);
-void sdl_draw_surface(SDL_Surface *s, Rectangle *dst);
-SDL_Surface *sdl_make_rectangle(int w, int h, SDL_Color *color);
+// surface/texture creation
+SDL_Texture *sdl_create_texture(int w, int h);
+void sdl_update_texture(SDL_Texture *t, SDL_Surface *s);
+SDL_Texture *sdl_surface_to_texture(SDL_Surface *s);
+SDL_Surface *sdl_create_surface(int w, int h, SDL_Color *color);
+
+// rendering
+void sdl_render_clear(void);
+void sdl_render_present(void);
+void sdl_render_texture(SDL_Texture *t, Rectangle *r);
+
+// drawing
+void sdl_copy(struct cg *dst, int dx, int dy, struct cg *src, int sx, int sy, int w, int h);
+void sdl_copy_bright(struct cg *dst, int dx, int dy, struct cg *src, int sx, int sy, int w, int h, int rate);
+void sdl_copy_amap(struct cg *dst, int dx, int dy, struct cg *src, int sx, int sy, int w, int h);
+void sdl_copy_sprite(struct cg *dst, int dx, int dy, struct cg *src, int sx, int sy, int w, int h, int r, int g, int b);
+void sdl_copy_use_amap_under(struct cg *dst, int dx, int dy, struct cg *src, int sx, int sy, int w, int h, int a_threshold);
+void sdl_copy_use_amap_border(struct cg *dst, int dx, int dy, struct cg *src, int sx, int sy, int w, int h, int a_threshold);
+void sdl_copy_amap_max(struct cg *dst, int dx, int dy, struct cg *src, int sx, int sy, int w, int h);
+void sdl_copy_amap_min(struct cg *dst, int dx, int dy, struct cg *src, int sx, int sy, int w, int h);
+void sdl_fill(struct cg *dst, int x, int y, int w, int h, int r, int g, int b);
+void sdl_fill_alpha_color(struct cg *dst, int x, int y, int w, int h, int r, int g, int b, int a);
+void sdl_fill_amap(struct cg *dst, int x, int y, int w, int h, int a);
 
 enum font_weight {
 	FW_NORMAL = 400,
diff --git a/sdl_draw.c b/sdl_draw.c
index 40a10c1..0a4c48e 100644
--- a/sdl_draw.c
+++ b/sdl_draw.c
@@ -1,5 +1,4 @@
-/* Copyright (C) 2000- Fumihiko Murata <fmurata@p1.tcnet.ne.jp>
- *               2019 Nunuhara Cabbage <nunuhara@haniwa.technology>
+/* 2019 Nunuhara Cabbage <nunuhara@haniwa.technology>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -23,55 +22,276 @@
 #include "sdl_private.h"
 #include "cg.h"
 
-bool sdl_dirty = false;
+// FIXME: these can be constants (but depend on endianness)
+#define R_MASK (sdl.format->Rmask)
+#define G_MASK (sdl.format->Gmask)
+#define B_MASK (sdl.format->Bmask)
+#define A_MASK (sdl.format->Amask)
 
-void sdl_update_screen(void)
+#define R_SHIFT (sdl.format->Rshift)
+#define G_SHIFT (sdl.format->Gshift)
+#define B_SHIFT (sdl.format->Bshift)
+#define A_SHIFT (sdl.format->Ashift)
+
+#define PIXEL_R(p) ((p & R_MASK) >> R_SHIFT)
+#define PIXEL_G(p) ((p & G_MASK) >> G_SHIFT)
+#define PIXEL_B(p) ((p & B_MASK) >> B_SHIFT)
+#define PIXEL_A(p) ((p & A_MASK) >> A_SHIFT)
+
+static inline void PIXEL_SET_R(uint32_t *p, uint8_t r)
 {
-	if (!sdl.dirty)
+	*p = (*p & ~R_MASK) | (r << R_SHIFT);
+}
+
+static inline void PIXEL_SET_G(uint32_t *p, uint8_t g)
+{
+	*p = (*p & ~G_MASK) | (g << G_SHIFT);
+}
+
+static inline void PIXEL_SET_B(uint32_t *p, uint8_t b)
+{
+	*p = (*p & ~B_MASK) | (b << B_SHIFT);
+}
+
+static inline void PIXEL_SET_A(uint32_t *p, uint8_t a)
+{
+	*p = (*p & ~A_MASK) | (a << A_SHIFT);
+}
+
+static inline void PIXEL_SET_RGB(uint32_t *p, uint8_t r, uint8_t g, uint8_t b)
+{
+	*p = (*p & A_MASK) | (r << R_SHIFT) | (g << G_SHIFT) | (b << B_SHIFT);
+}
+
+static inline void PIXEL_SET_RGBA(uint32_t *p, uint8_t r, uint8_t g, uint8_t b, uint8_t a)
+{
+	*p = (r << R_SHIFT) | (g << G_SHIFT) | (b << B_SHIFT) | (a << A_SHIFT);
+}
+
+// Clip src/dst rectangles in preparation for a copy.
+static void copy_clip_rects(int dw, int dh, int *dx, int *dy, int sw, int sh, int *sx, int *sy, int *w, int *h)
+{
+	if (*sx < 0) {
+		*dx -= *sx;
+		*w += *sx;
+		*sx = 0;
+	}
+	if (*sy < 0) {
+		*dy -= *sy;
+		*h += *sy;
+		*sy = 0;
+	}
+	if (*dx < 0) {
+		*sx -= *dx;
+		*w += *dx;
+		*dx = 0;
+	}
+	if (*dy < 0) {
+		*sy -= *dy;
+		*w += *dy;
+		*dy = 0;
+	}
+	*w = min(*w, min(dw - *dx, sw - *sx));
+	*h = min(*h, min(dh - *dy, sh - *sy));
+}
+
+static void fill_clip_rect(int *dx, int *dy, int dw, int dh, int *w, int *h)
+{
+	if (*dx > dw || *dy > dh) {
+		*dx = *dy = *w = *h = 0;
 		return;
-	SDL_UpdateTexture(sdl.texture, NULL, sdl.display->pixels, sdl.display->pitch);
-	SDL_RenderClear(sdl.renderer);
-	SDL_RenderCopy(sdl.renderer, sdl.texture, NULL, NULL);
-	SDL_RenderPresent(sdl.renderer);
-	sdl.dirty = false;
+	}
+
+	if (*dx < 0) {
+		*w += *dx;
+		*dx = 0;
+	}
+	if (*dy < 0) {
+		*h += *dy;
+		*dy = 0;
+	}
+	*w = min(*w, dw - *dx);
+	*h = min(*h, dh - *dy);
 }
 
-SDL_Surface *sdl_make_rectangle(int w, int h, SDL_Color *color)
+static inline uint32_t *get_pixel(SDL_Surface *s, int x, int y)
 {
-	Rectangle rect = { .x = 0, .y = 0, .w = w, .h = w };
-	SDL_Surface *s = SDL_CreateRGBSurfaceWithFormat(0, w, h, 32, SDL_PIXELFORMAT_ARGB32);
-	uint32_t c = SDL_MapRGBA(s->format, color->r, color->g, color->b, color->a);
-	SDL_FillRect(s, &rect, c);
-	return s;
+	return (uint32_t*)(((uint8_t*)s->pixels) + s->pitch*y + s->format->BytesPerPixel*x);
 }
 
-void sdl_draw_rectangle(Rectangle *_rect, int pixels, uint8_t r, uint8_t g, uint8_t b)
+// iterator for copy operations
+// FIXME: texture should be marked as dirty and updated later to avoid unnecessary copying
+#define copy_for_each_pixel(dcg, dx, dy, scg, sx, sy, w, h, dp, sp, expr) \
+	do {								\
+		copy_clip_rects(dcg->s->w, dcg->s->h, &dx, &dy, scg->s->w, scg->s->h, &sx, &sy, &w, &h); \
+		SDL_LockSurface(dcg->s);				\
+		SDL_LockSurface(scg->s);				\
+		for (int _row = 0; _row < h; _row++) {			\
+			uint32_t *dp = get_pixel(dcg->s, dx, _row+dy);	\
+			uint32_t *sp = get_pixel(scg->s, sx, _row+sy);	\
+			for (int _col = 0; _col < w; _col++, dp++, sp++) \
+				expr;					\
+		}							\
+		SDL_UpdateTexture(dcg->t, NULL, dcg->s->pixels, dcg->s->pitch); \
+		SDL_UnlockSurface(scg->s);				\
+		SDL_UnlockSurface(dcg->s);				\
+	} while (0)
+
+// iterator for fill operations
+#define fill_for_each_pixel(cg, x, y, w, h, p, expr)			\
+	do {								\
+		fill_clip_rect(&x, &y, cg->s->w, cg->s->h, &w, &h);	\
+		SDL_LockSurface(cg->s);					\
+		for (int _row = 0; _row < h; _row++) {			\
+			uint32_t *p = get_pixel(cg->s, x, _row+y);	\
+			for (int _col = 0; _col < w; _col++, p++)	\
+				expr;					\
+		}							\
+		SDL_UpdateTexture(cg->t, NULL, cg->s->pixels, cg->s->pitch); \
+		SDL_UnlockSurface(cg->s);				\
+	} while(0);
+
+static void sdl_blit(SDL_Surface *ds, int dx, int dy, SDL_Surface *ss, int sx, int sy, int w, int h)
 {
-	SDL_Rect  rect[4];
-
-	// top
-	rect[0] = *_rect;
-	rect[0].h = pixels;
-	// bot
-	rect[1] = *_rect;
-	rect[1].y += _rect->h - pixels;
-	rect[1].h = pixels;
-	// left
-	rect[2] = *_rect;
-	rect[2].w = pixels;
-	// right
-	rect[3] = *_rect;
-	rect[3].x += _rect->w - pixels;
-	rect[3].w = pixels;
-
-	uint32_t c = SDL_MapRGB(sdl.display->format, r, g, b);
-	SDL_FillRects(sdl.display, rect, 4, c);
-	sdl.dirty = true;
+	Rectangle src_rect = RECT(sx, sy, w, h);
+	Rectangle dst_rect = RECT(dx, dy, w, h);
+	SDL_BlitSurface(ss, &src_rect, ds, &dst_rect);
 }
 
-void sdl_draw_surface(SDL_Surface *s, Rectangle *dst)
+void sdl_copy(struct cg *dst, int dx, int dy, struct cg *src, int sx, int sy, int w, int h)
 {
-	Rectangle src = { .x = 0, .y = 0, .w = s->w, .h = s->h };
-	SDL_BlitSurface(s, &src, sdl.display, dst);
-	sdl.dirty = true;
+	SDL_BlendMode mode;
+	SDL_GetSurfaceBlendMode(src->s, &mode);
+	SDL_SetSurfaceBlendMode(src->s, SDL_BLENDMODE_NONE);
+	sdl_blit(dst->s, dx, dy, src->s, sx, sy, w, h);
+
+	SDL_SetSurfaceBlendMode(src->s, mode);
+}
+
+void sdl_copy_bright(struct cg *dst, int dx, int dy, struct cg *src, int sx, int sy, int w, int h, int rate)
+{
+	SDL_BlendMode mode;
+	SDL_GetSurfaceBlendMode(src->s, &mode);
+	SDL_SetSurfaceBlendMode(src->s, SDL_BLENDMODE_NONE);
+	SDL_SetSurfaceColorMod(src->s, rate, rate, rate);
+
+	sdl_blit(dst->s, dx, dy, src->s, sx, sy, w, h);
+
+	SDL_SetSurfaceColorMod(src->s, 255, 255, 255);
+	SDL_SetSurfaceBlendMode(src->s, mode);
+}
+
+void sdl_copy_amap(struct cg *dst, int dx, int dy, struct cg *src, int sx, int sy, int w, int h)
+{
+	if (!dst->has_alpha || !src->has_alpha)
+		return;
+
+	copy_for_each_pixel(dst, dx, dy, src, sx, sy, w, h, dp, sp, {
+		PIXEL_SET_A(dp, PIXEL_A(*sp));
+	});
+}
+
+void sdl_copy_sprite(struct cg *dst, int dx, int dy, struct cg *src, int sx, int sy, int w, int h, int r, int g, int b)
+{
+	SDL_BlendMode mode;
+
+	SDL_GetSurfaceBlendMode(src->s, &mode);
+	SDL_SetSurfaceBlendMode(src->s, SDL_BLENDMODE_NONE);
+	SDL_SetColorKey(src->s, SDL_TRUE, SDL_MapRGB(sdl.format, r, g, b));
+
+	sdl_blit(dst->s, dx, dy, src->s, sx, sy, w, h);
+
+	SDL_SetColorKey(src->s, SDL_FALSE, 0);
+	SDL_SetSurfaceBlendMode(src->s, mode);
+}
+
+void sdl_copy_use_amap_under(struct cg *dst, int dx, int dy, struct cg *src, int sx, int sy, int w, int h, int a_threshold)
+{
+	if (!src->has_alpha)
+		return;
+
+	uint8_t r, g, b, a;
+	copy_for_each_pixel(dst, dx, dy, src, sx, sy, w, h, dp, sp, {
+		SDL_GetRGBA(*sp, sdl.format, &r, &g, &b, &a);
+		if (a <= a_threshold) {
+			PIXEL_SET_RGB(dp, r, g, b);
+		}
+	});
+}
+
+void sdl_copy_use_amap_border(struct cg *dst, int dx, int dy, struct cg *src, int sx, int sy, int w, int h, int a_threshold)
+{
+	if (!src->has_alpha)
+		return;
+
+	uint8_t r, g, b, a;
+	copy_for_each_pixel(dst, dx, dy, src, sx, sy, w, h, dp, sp, {
+		SDL_GetRGBA(*sp, sdl.format, &r, &g, &b, &a);
+		if (a >= a_threshold) {
+			PIXEL_SET_RGB(dp, r, g, b);
+		}
+	});
+}
+
+void sdl_copy_amap_max(struct cg *dst, int dx, int dy, struct cg *src, int sx, int sy, int w, int h)
+{
+	if (!src->has_alpha || !dst->has_alpha)
+		return;
+
+	copy_for_each_pixel(dst, dx, dy, src, sx, sy, w, h, dp, sp, {
+		uint32_t d_a = (*dp & sdl.format->Amask) >> sdl.format->Ashift;
+		uint32_t s_a = (*sp & sdl.format->Amask) >> sdl.format->Ashift;
+		if (s_a > d_a) {
+			PIXEL_SET_A(dp, s_a);
+		}
+	});
+}
+
+void sdl_copy_amap_min(struct cg *dst, int dx, int dy, struct cg *src, int sx, int sy, int w, int h)
+{
+	if (!src->has_alpha || !dst->has_alpha)
+		return;
+
+	copy_for_each_pixel(dst, dx, dy, src, sx, sy, w, h, dp, sp, {
+		uint32_t d_a = (*dp & A_MASK) >> A_SHIFT;
+		uint32_t s_a = (*sp & A_MASK) >> A_SHIFT;
+		if (s_a < d_a) {
+			PIXEL_SET_A(dp, s_a);
+		}
+	});
+}
+
+static void blend_pixels(SDL_Color *dst, SDL_Color src)
+{
+	uint32_t alpha = src.a + 1;
+	uint32_t inv_alpha = 256 - src.a;
+	dst->r = (uint8_t)((alpha * src.r + inv_alpha * dst->r) >> 8);
+	dst->g = (uint8_t)((alpha * src.g + inv_alpha * dst->g) >> 8);
+	dst->b = (uint8_t)((alpha * src.b + inv_alpha * dst->b) >> 8);
+}
+
+void sdl_fill(struct cg *dst, int x, int y, int w, int h, int r, int g, int b)
+{
+	fill_for_each_pixel(dst, x, y, w, h, p, {
+		PIXEL_SET_RGBA(p, r, g, b, PIXEL_A(*p));
+	});
+}
+
+// XXX: Despite being called a fill operation, this function actually performs blending.
+void sdl_fill_alpha_color(struct cg *cg, int x, int y, int w, int h, int r, int g, int b, int a)
+{
+	SDL_Color dst;
+	SDL_Color src = { .r = r, .g = g, .b = b, .a = a };
+	fill_for_each_pixel(cg, x, y, w, h, p, {
+		SDL_GetRGBA(*p, sdl.format, &dst.r, &dst.g, &dst.b, &dst.a);
+		blend_pixels(&dst, src);
+		PIXEL_SET_RGBA(p, dst.r, dst.g, dst.b, dst.a);
+	});
+}
+
+void sdl_fill_amap(struct cg *dst, int x, int y, int w, int h, int a)
+{
+	fill_for_each_pixel(dst, x, y, w, h, p, {
+		PIXEL_SET_A(p, a);
+	});
 }
diff --git a/sdl_private.h b/sdl_private.h
index bf3f3a6..eb4057f 100644
--- a/sdl_private.h
+++ b/sdl_private.h
@@ -29,19 +29,12 @@
 struct sdl_private_data {
 	SDL_Window *window;
 	SDL_Renderer *renderer;
-	SDL_Texture *texture;
-	SDL_Surface *display; /* toplevel surface */
-	SDL_Surface *dib; /* offscreen surface */
-	SDL_Color col[256]; /* color pallet */
-	unsigned long white; /* white pixel */
-	//agsurface_t *cimg;
-	SDL_Rect view;
+	SDL_PixelFormat *format;
+	int w, h;
 	//FONT *font;
 	bool dirty;
 	bool ms_active; /* mouse is active */
 	bool fs_on;
-	int winoffset_x; /* draw offset in Window x */
-	int winoffset_y; /*                       y */
 };
 
 struct sdl_private_data sdl;
diff --git a/sdl_video.c b/sdl_video.c
index 064ab73..dd0faf7 100644
--- a/sdl_video.c
+++ b/sdl_video.c
@@ -21,31 +21,24 @@
 #include "sdl_core.h"
 #include "sdl_private.h"
 
+#define PIXEL_FORMAT SDL_PIXELFORMAT_ARGB32
+
 int sdl_initialize(void)
 {
 	memset(&sdl, 0, sizeof(struct sdl_private_data));
 
 	// make toplevel window
 	SDL_Init(SDL_INIT_VIDEO);
+	sdl.format = SDL_AllocFormat(PIXEL_FORMAT);
 	sdl.window = SDL_CreateWindow("XSystem4",
 				      SDL_WINDOWPOS_UNDEFINED,
 				      SDL_WINDOWPOS_UNDEFINED,
 				      config.view_width,
 				      config.view_height,
 				      SDL_WINDOW_RESIZABLE);
+
 	sdl.renderer = SDL_CreateRenderer(sdl.window, -1, 0);
-
-	// offscreen pixmap
-	//makeDIB(config.view_width, config.view_height, SYS4_DEFAULT_DEPTH);
-
-	// init cursor
-	//sdl_cursor_init();
-
-	sdl_set_window_size(0, 0, config.view_width, config.view_height);
-
-	//sdl_shadow_init();
-
-	//joy_open();
+	sdl_set_window_size(config.view_width, config.view_height);
 	return 0;
 }
 
@@ -54,9 +47,7 @@ void sdl_remove(void)
 	if (!sdl.window)
 		return;
 
-	//SDL_FreeSurface(sdl.dib);
 	SDL_DestroyRenderer(sdl.renderer);
-	//joy_close();
 	SDL_Quit();
 }
 
@@ -71,24 +62,64 @@ void sdl_fullscreen(bool on)
 	}
 }
 
-void sdl_set_window_size(int x, int y, int w, int h)
+void sdl_set_window_size(int w, int h)
 {
-	sdl.view.x = x;
-	sdl.view.y = y;
-
-	if (w == sdl.view.w && h == sdl.view.h)
+	if (w == sdl.w && h == sdl.h)
 		return;
 
-	sdl.view.w = w;
-	sdl.view.h = h;
+	sdl.w = w;
+	sdl.h = h;
 
 	SDL_SetWindowSize(sdl.window, w, h);
 	SDL_RenderSetLogicalSize(sdl.renderer, w, h);
-	if (sdl.display)
-		SDL_FreeSurface(sdl.display);
-	if (sdl.texture)
-		SDL_DestroyTexture(sdl.texture);
-	sdl.display = SDL_CreateRGBSurface(0, w, h, 32, 0xFF00, 0xFF0000, 0xFF000000, 0xFF);
-	sdl.texture = SDL_CreateTexture(sdl.renderer, sdl.display->format->format,
-					SDL_TEXTUREACCESS_STATIC, w, h);
+}
+
+SDL_Texture *sdl_create_texture(int w, int h)
+{
+	SDL_Texture *t = SDL_CreateTexture(sdl.renderer, PIXEL_FORMAT, SDL_TEXTUREACCESS_STATIC, w, h);
+	SDL_SetTextureBlendMode(t, SDL_BLENDMODE_BLEND);
+	return t;
+}
+
+SDL_Surface *sdl_create_surface(int w, int h, SDL_Color *color)
+{
+	Rectangle rect = { .x = 0, .y = 0, .w = w, .h = w };
+	SDL_Surface *s = SDL_CreateRGBSurfaceWithFormat(0, w, h, 32, SDL_PIXELFORMAT_ARGB32);
+	if (color) {
+		uint32_t c = SDL_MapRGBA(s->format, color->r, color->g, color->b, color->a);
+		SDL_FillRect(s, &rect, c);
+	}
+	return s;
+}
+
+void sdl_update_texture(SDL_Texture *t, SDL_Surface *s)
+{
+	if (SDL_MUSTLOCK(s))
+		SDL_LockSurface(s);
+	SDL_UpdateTexture(t, NULL, s->pixels, s->pitch);
+	if (SDL_MUSTLOCK(s))
+		SDL_UnlockSurface(s);
+}
+
+SDL_Texture *sdl_surface_to_texture(SDL_Surface *s)
+{
+	SDL_Texture *t = SDL_CreateTexture(sdl.renderer, PIXEL_FORMAT, SDL_TEXTUREACCESS_STATIC, s->w, s->h);
+	SDL_SetTextureBlendMode(t, SDL_BLENDMODE_BLEND);
+	SDL_UpdateTexture(t, NULL, s->pixels, s->pitch);
+	return t;
+}
+
+void sdl_render_clear(void)
+{
+	SDL_RenderClear(sdl.renderer);
+}
+
+void sdl_render_present(void)
+{
+	SDL_RenderPresent(sdl.renderer);
+}
+
+void sdl_render_texture(SDL_Texture *t, Rectangle *r)
+{
+	SDL_RenderCopy(sdl.renderer, t, NULL, r);
 }