Added the :save() method to textures, Added support for some image formats

The new image formats are loaded with stb_image, and the textures are saved with stb_image_write.
https://github.com/nothings/stb
You can now load GIFs (not animated), PSD, TGA, HDR, PIC and PNM.
The texture loading still uses sfil for JPEG, PNG, and BMP. You can force the use of stbi by loading with
the "type" argument in texture.load() set to 242 (or anything 5<x<250, but 242 is a good value).
The :save() formats are PNG and BMP only.

Makefile

@@ -67,7 +67,8 @@ LIBDIRS	:= $(CTRULIB) $(PORTLIBS) \
 			$(CURDIR)/libs/3ds_portlibs/build \
 			$(CURDIR)/libs/sf2dlib/libsf2d \
 			$(CURDIR)/libs/sftdlib/libsftd \
-			$(CURDIR)/libs/sfillib/libsfil
+			$(CURDIR)/libs/sfillib/libsfil \
+			$(CURDIR)/libs/stb
 
 #---------------------------------------------------------------------------------
 # no real need to edit anything past this point unless you need to add additional

source/gfx.c

@@ -558,6 +558,10 @@ static const struct luaL_Reg target_methods[] = {
 	{ NULL, NULL }
 };
 
+/***
+Constants
+@section constants
+*/
 // Constants
 struct { char *name; int value; } gfx_constants[] = {
 	/***

source/texture.c

@@ -12,6 +12,12 @@ The `gfx.texture` module.
 #include <stdlib.h>
 #include <string.h>
 
+#define STB_IMAGE_IMPLEMENTATION
+#include <stb_image.h>
+#define STB_IMAGE_WRITE_IMPLEMENTATION
+#include <stb_image_write.h>
+#include <png.h>
+
 #include "texture.h"
 
 int getType(const char *name) {
@@ -58,9 +64,15 @@ static int texture_load(lua_State *L) {
 	} else if (type==2) { //BMP
 		texture->texture = sfil_load_BMP_file(path, place); //appears to be broken right now.
 	} else {
-		lua_pushnil(L);
-		lua_pushstring(L, "Bad type");
-		return 2;
+		int w, h;
+		char* data = (char*)stbi_load(path, &w, &h, NULL, 4);
+		if (data == NULL) {
+			lua_pushnil(L);
+			lua_pushstring(L, "Can't open file");
+			return 2;
+		}
+		texture->texture = sf2d_create_texture_mem_RGBA8(data, w, h, TEXFMT_RGBA8, place);
+		free(data);
 	}
 	
 	if (texture->texture == NULL) {
@@ -246,7 +258,7 @@ Set the blend color of the texture.
 @tparam number color new blend color
 */
 static int texture_setBlendColor(lua_State *L) {
-  texture_userdata *texture = luaL_checkudata(L, 1, "LTexture");
+	texture_userdata *texture = luaL_checkudata(L, 1, "LTexture");
 	u32 color = luaL_checkinteger(L, 2);
 	
 	texture->blendColor = color;
@@ -254,6 +266,87 @@ static int texture_setBlendColor(lua_State *L) {
 	return 0;
 }
 
+/***
+Save a texture to a file.
+@function :save
+@tparam string filename path to the file to save the texture to
+@tparam[opt=TYPE_PNG] number type type of the image to save. Can be TYPE_PNG or TYPE_BMP
+@treturn[1] boolean true on success
+@treturn[2] nil
+@treturn[2] string error message
+*/
+static int texture_save(lua_State *L) {
+	texture_userdata *texture = luaL_checkudata(L, 1, "LTexture");
+	const char* path = luaL_checkstring(L, 2);
+	u8 type = luaL_optinteger(L, 3, 0);
+
+	u32* buff = malloc(texture->texture->width * texture->texture->height * 4);
+	if (buff == NULL) {
+		lua_pushnil(L);
+		lua_pushstring(L, "Failed to allocate buffer");
+		return 2;
+	}
+	for (int y=0;y<texture->texture->height;y++) {
+		for (int x=0;x<texture->texture->width;x++) {
+			buff[x+(y*texture->texture->width)] = __builtin_bswap32(sf2d_get_pixel(texture->texture, x, y));
+		}
+	}
+
+	int result = 0;
+	if (type == 0) { // PNG
+		FILE* file = fopen(path, "wb");
+		if (file == NULL) {
+			free(buff);
+			lua_pushnil(L);
+			lua_pushstring(L, "Can open file");
+			return 2;
+		}
+		png_structp png = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
+		png_infop infos = png_create_info_struct(png);
+		setjmp(png_jmpbuf(png));
+		png_init_io(png, file);
+
+		png_set_IHDR(png, infos, texture->texture->width, texture->texture->height, 8, PNG_COLOR_TYPE_RGB_ALPHA, PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
+		png_write_info(png, infos);
+
+		png_bytep row = malloc(4 * texture->texture->width * sizeof(png_byte));
+
+		for(int y=0;y<texture->texture->height;y++) {
+			for (int x=0;x<texture->texture->width;x++) {
+				((u32*)row)[x] = buff[x+(y*texture->texture->width)];
+			}
+			png_write_row(png, row);
+		}
+
+		png_write_end(png, NULL);
+
+		fclose(file);
+		png_free_data(png, infos, PNG_FREE_ALL, -1);
+		png_destroy_write_struct(&png, &infos);
+		free(row);
+
+		result = 1;
+
+	} else if (type == 2) { // BMP
+		result = stbi_write_bmp(path, texture->texture->width, texture->texture->height, 4, buff);
+	} else {
+		free(buff);
+		lua_pushnil(L);
+		lua_pushstring(L, "Not a valid type");
+		return 2;
+	}
+	free(buff);
+
+	if (result == 0) {
+		lua_pushnil(L);
+		lua_pushstring(L, "Failed to save the texture");
+		return 2;
+	}
+
+	lua_pushboolean(L, true);
+	return 1;
+}
+
 // object
 static const struct luaL_Reg texture_methods[] = {
 	{ "draw",          texture_draw          },
@@ -264,6 +357,7 @@ static const struct luaL_Reg texture_methods[] = {
 	{ "getPixel",      texture_getPixel      },
 	{ "setPixel",      texture_setPixel      },
 	{ "setBlendColor", texture_setBlendColor },
+	{ "save",          texture_save          },
 	{ "__gc",          texture_unload        },
 	{NULL, NULL}
 };