use SDL_RWops to read png textures

src/resource/texture.c

@@ -52,36 +52,30 @@ Texture* prefix_get_tex(const char *name, const char *prefix) {
 	return tex;
 }
 
-static SDL_Surface* load_png(const char *filename) {
+static SDL_Surface* load_png_p(const char *filename, SDL_RWops *rwops) {
 #define PNGFAIL(msg) { warnx("load_png(): couldn't load '%s': %s", filename, msg); return NULL; }
-
-	FILE *fp = fopen(filename, "rb");
-
-	if(!fp) {
-		PNGFAIL("fopen() failed")
+	if(!rwops) {
+		PNGFAIL(SDL_GetError())
 	}
 
 	png_structp png_ptr;
 	if(!(png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL))) {
-		fclose(fp);
 		PNGFAIL("png_create_read_struct() failed")
 	}
 
 	png_infop info_ptr;
 	if(!(info_ptr = png_create_info_struct(png_ptr))) {
-		fclose(fp);
 		png_destroy_read_struct(&png_ptr, NULL, NULL);
 		PNGFAIL("png_create_info_struct() failed")
 	}
 
 	png_infop end_info;
 	if(!(end_info = png_create_info_struct(png_ptr))) {
-		fclose(fp);
 		png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
 		PNGFAIL("png_create_info_struct() failed")
 	}
 
-	png_init_io(png_ptr, fp);
+	png_init_rwops(png_ptr, rwops);
 	png_read_info(png_ptr, info_ptr);
 
 	int colortype = png_get_color_type(png_ptr,info_ptr);
@@ -95,19 +89,19 @@ static SDL_Surface* load_png(const char *filename) {
 		png_set_filler(png_ptr, 0xff, PNG_FILLER_AFTER);
 
 	png_read_update_info(png_ptr, info_ptr);
-	
+
 	int width = png_get_image_width(png_ptr, info_ptr);
 	int height = png_get_image_height(png_ptr, info_ptr);
 	int depth = png_get_bit_depth(png_ptr, info_ptr);
 
-	
+
 	png_bytep row_pointers[height];
 
 	Uint32 *pixels = malloc(sizeof(Uint32)*width*height);
 
 	for(int i = 0; i < height; i++)
 		row_pointers[i] = (png_bytep)(pixels+i*width);
-	
+
 	png_read_image(png_ptr, row_pointers);
 	png_read_end(png_ptr, end_info);
 
@@ -129,17 +123,22 @@ static SDL_Surface* load_png(const char *filename) {
 	SDL_Surface *res = SDL_CreateRGBSurfaceFrom(pixels, width, height, depth*4, 0, rmask, gmask, bmask, amask);
 
 	if(!res) {
-		fclose(fp);
 		PNGFAIL(SDL_GetError())
 	}
 
-	fclose(fp);
 	png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
 
 	return res;
 #undef PNGFAIL
 }
 
+static SDL_Surface* load_png(const char *filename) {
+	SDL_RWops *rwops = SDL_RWFromFile(filename, "r");
+	SDL_Surface *surf = load_png_p(filename, rwops);
+	SDL_RWclose(rwops);
+	return surf;
+}
+
 void load_sdl_surf(SDL_Surface *surface, Texture *texture) {
 	glGenTextures(1, &texture->gltex);
 	glBindTexture(GL_TEXTURE_2D, texture->gltex);

src/util.c

@@ -351,6 +351,25 @@ Hashtable* parse_keyvalue_file(const char *filename, size_t tablesize) {
     return ht;
 }
 
+static void png_rwops_write_data(png_structp png_ptr, png_bytep data, png_size_t length) {
+    SDL_RWops *out = png_get_io_ptr(png_ptr);
+    SDL_RWwrite(out, data, length, 1);
+}
+
+static void png_rwops_flush_data(png_structp png_ptr) {
+    // no flush operation in SDL_RWops
+}
+
+static void png_rwops_read_data(png_structp png_ptr, png_bytep data, png_size_t length) {
+    SDL_RWops *out = png_get_io_ptr(png_ptr);
+    SDL_RWread(out, data, length, 1);
+}
+
+void png_init_rwops(png_structp png, SDL_RWops *rwops) {
+    png_set_write_fn(png, rwops, png_rwops_write_data, png_rwops_flush_data);
+    png_set_read_fn(png, rwops, png_rwops_read_data);
+}
+
 //
 // misc utils
 //

src/util.h

@@ -6,6 +6,7 @@
 #include <string.h>
 #include <stdio.h>
 #include <zlib.h> // compiling under mingw may fail without this...
+#include <png.h>
 #include <SDL.h>
 #include "hashtable.h"
 
@@ -96,6 +97,7 @@ bool parse_keyvalue_stream_cb(SDL_RWops *strm, KVCallback callback, void *data);
 bool parse_keyvalue_file_cb(const char *filename, KVCallback callback, void *data);
 Hashtable* parse_keyvalue_stream(SDL_RWops *strm, size_t tablesize);
 Hashtable* parse_keyvalue_file(const char *filename, size_t tablesize);
+void png_init_rwops(png_structp png, SDL_RWops *rwops);
 
 //
 // misc utils

src/video.c

@@ -221,15 +221,6 @@ void video_setmode(int w, int h, bool fs, bool resizable) {
 	_video_setmode(w, h, flags, false);
 }
 
-static void png_rwops_write_data(png_structp png_ptr, png_bytep data, png_size_t length) {
-	SDL_RWops *out = png_get_io_ptr(png_ptr);
-	SDL_RWwrite(out, data, length, 1);
-}
-
-static void png_rwops_flush_data(png_structp png_ptr) {
-	// no flush operation in SDL_RWops
-}
-
 void video_take_screenshot(void) {
 	SDL_RWops *out;
 	char *data;
@@ -282,7 +273,7 @@ void video_take_screenshot(void) {
 		memcpy(row_pointers[y], data + rw*3*(h-1-y), w*3);
 	}
 
-	png_set_write_fn(png_ptr, out, png_rwops_write_data, png_rwops_flush_data);
+	png_init_rwops(png_ptr, out);
 	png_set_rows(png_ptr, info_ptr, row_pointers);
 	png_write_png(png_ptr, info_ptr, PNG_TRANSFORM_IDENTITY, NULL);