set/get pixel

src/sdl-instead/graphics.c

@@ -582,6 +582,57 @@ img_t gfx_display_alpha(img_t src)
 	return res;
 }
 
+int gfx_get_pixel(img_t src, int x, int y,  color_t *color)
+{
+	Uint8 r, g, b, a;
+	Uint32 col;
+	Uint32 *ptr;
+	SDL_Surface *img = Surf(src);
+	if (!img)
+		return -1;
+
+	if (x >= img->w || y >= img->h || x < 0 || y < 0)
+		return -1;
+
+	if (SDL_LockSurface(img))
+		return -1;
+	ptr = (Uint32*)img->pixels;
+	ptr += y * img->w + x;
+	col = *ptr;
+	SDL_UnlockSurface(img);	
+	if (color)
+		SDL_GetRGBA(col, img->format, &r, &g, &b, &a);
+
+	if (color) {
+		color->r = r;
+		color->g = g;
+		color->b = b;
+		color->a = a;
+	}
+	return 0;
+}
+
+int gfx_set_pixel(img_t src, int x, int y,  color_t color)
+{
+	Uint32 col;
+	Uint32 *ptr;
+	SDL_Surface *img = Surf(src);
+	if (!img)
+		return -1;
+
+	if (x >= img->w || y >= img->h || x < 0 || y < 0)
+		return -1;
+
+	if (SDL_LockSurface(img))
+		return -1;
+	ptr = (Uint32*)img->pixels;
+	ptr += y * img->w + x;
+	col = SDL_MapRGBA(img->format, color.r, color.g, color.b, color.a);
+	*ptr = col;
+	SDL_UnlockSurface(img);
+	return 0;
+}
+
 img_t gfx_alpha_img(img_t src, int alpha)
 {
 	Uint32 *ptr;

src/sdl-instead/graphics.h

@@ -26,6 +26,7 @@ typedef struct {
 	int r;
 	int g;
 	int b;
+	int a;
 } color_t;
 
 #define ALIGN_LEFT 	1
@@ -99,6 +100,8 @@ extern void	gfx_change_screen(img_t src, int steps);
 extern int	gfx_fading(void);
 extern void	gfx_img_fill(img_t img, int x, int y, int w, int h, color_t col);
 extern void	gfx_fill(int x, int y, int w, int h, color_t col);
+extern int	gfx_get_pixel(img_t src, int x, int y,  color_t *color);
+extern int	gfx_set_pixel(img_t src, int x, int y,  color_t color);
 
 extern fnt_t 	fnt_load(const char *fname, int size);
 extern void 	fnt_free(fnt_t);

src/sdl-instead/instead.c

@@ -1196,7 +1196,7 @@ static int luaB_fill_sprite(lua_State *L) {
 	int y = luaL_optnumber(L, 3, 0);
 	int w = luaL_optnumber(L, 4, -1);
 	int h = luaL_optnumber(L, 5, -1);
-	const char *color = luaL_optstring(L, 6, 0);
+	const char *color = luaL_optstring(L, 6, NULL);
 	int xoff = 0, yoff = 0;
 	color_t  col = { .r = game_theme.bgcol.r, .g = game_theme.bgcol.g, .b = game_theme.bgcol.b };
 	if (!dst)
@@ -1232,6 +1232,55 @@ static int luaB_fill_sprite(lua_State *L) {
 	return 1;
 }
 
+static int luaB_pixel_sprite(lua_State *L) {
+	img_t d;
+	float v;
+	int rc;
+	color_t  col = { .r = game_theme.bgcol.r, .g = game_theme.bgcol.g, .b = game_theme.bgcol.b, .a = 255 };
+	const char *dst = luaL_optstring(L, 1, NULL);
+	int x = luaL_optnumber(L, 2, 0);
+	int y = luaL_optnumber(L, 3, 0);
+	const char *color = luaL_optstring(L, 4, NULL);
+	int alpha = luaL_optnumber(L, 5, 255);
+	int xoff = 0, yoff = 0;
+
+	if (!dst)
+		return 0;
+
+	d = grab_sprite(dst, &xoff, &yoff);
+
+	if (color)
+		gfx_parse_color(color, &col);
+
+	if (!d)
+		return 0;
+
+	v = game_theme.scale;
+
+	if (v != 1.0f) {
+		x *= v;
+		y *= v;
+	}
+	if (color) {
+		game_pict_modify(d);
+		gfx_clip(game_theme.xoff, game_theme.yoff, game_theme.w - 2*game_theme.xoff, game_theme.h - 2*game_theme.yoff);
+		col.a = alpha;
+		rc = gfx_set_pixel(d, x + xoff, y + yoff, col);
+		gfx_noclip();
+	} else {
+		rc = gfx_get_pixel(d, x + xoff, y + yoff, &col);
+	}
+
+	if (rc)
+		return 0;
+
+	lua_pushnumber(L, col.r);
+	lua_pushnumber(L, col.g);
+	lua_pushnumber(L, col.b);
+	lua_pushnumber(L, col.a);
+	return 4;
+}
+
 static int _free_sprite(const char *key)
 {
 	_spr_t *sp;
@@ -1391,6 +1440,7 @@ static const luaL_Reg base_funcs[] = {
 	{"sprite_scale", luaB_scale_sprite},
 	{"sprite_rotate", luaB_rotate_sprite},
 	{"sprite_text_size", luaB_text_size},
+	{"sprite_pixel", luaB_pixel_sprite},
 	{NULL, NULL}
 };
 

stead/sprites.lua

@@ -12,6 +12,7 @@ stead.sprite_text_size = sprite_text_size
 stead.sprite_draw = sprite_draw
 stead.sprite_copy = sprite_copy
 stead.sprite_fill = sprite_fill
+stead.sprite_pixel = sprite_pixel
 stead.sprite_load = sprite_load
 stead.sprite_free = sprite_free
 stead.sprite_size = sprite_size
@@ -81,6 +82,9 @@ sprite = {
 		end 
 		return stead.sprite_fill(d, x, y, w, h, col);
 	end;
+	pixel = function(d, x, y, col)
+		return stead.sprite_pixel(d, x, y, col)
+	end;
 	load = function(fname)
 		return stead.sprite_load(fname);
 	end;