Save images as PNG (can be a bit slow).

common.mk

@@ -30,7 +30,7 @@ vpath %.h $(SEARCHPATH)
 
 DEPS += defs.h structs.h
 
-_OBJS += atlas.o atlasTest.o aquaBlob.o
+_OBJS += atlas.o aquaBlob.o
 _OBJS += battery.o blaze.o bob.o boss.o blobBoss.o bullet.o
 _OBJS += camera.o cannon.o cardReader.o cell.o cherry.o combat.o controls.o consumable.o
 _OBJS += debris.o destructable.o door.o draw.o
@@ -47,10 +47,10 @@ _OBJS += objectives.o options.o
 _OBJS += particles.o player.o plasmaBlob.o plasmaDroid.o pistolBlob.o pistolDroid.o postMission.o powerPoint.o powerPool.o pressurePlate.o pushBlock.o
 _OBJS += quadtree.o
 _OBJS += radar.o
-_OBJS += shotgunBlob.o shotgunDroid.o sound.o spreadGunBlob.o spreadGunDroid.o sprites.o stats.o structures.o
+_OBJS += savepng.o shotgunBlob.o shotgunDroid.o sound.o spreadGunBlob.o spreadGunDroid.o sprites.o stats.o structures.o
 _OBJS += tankCommander.o tankTrack.o teeka.o teleporter.o text.o textures.o title.o transition.o triggers.o trophies.o
 _OBJS += unit.o util.o
-_OBJS += weapons.o weaponPickup.o widgets.o world.o worldLoader.o worldSaver.o
+_OBJS += weapons.o weaponPickup.o widgets.o world.o worldLoader.o worldSaver.o worldTest.o
 
 OBJS = $(patsubst %,$(OUT)/%,$(_OBJS))
 

makefile

@@ -25,7 +25,7 @@ CXXFLAGS += -Wall -Wempty-body -ansi -pedantic -Werror -Wstrict-prototypes -Werr
 CXXFLAGS += -g -lefence
 CXXFLAGS += -fms-extensions -std=gnu11
 
-LDFLAGS += `sdl2-config --libs` -lSDL2_mixer -lSDL2_image -lSDL2_ttf -lm -lz
+LDFLAGS += `sdl2-config --libs` -lSDL2_mixer -lSDL2_image -lSDL2_ttf -lm -lz -lpng
 
 SHARED_FILES = CHANGELOG LICENSE README.md data gfx manual music sound icons
 DIST_FILES = $(SHARED_FILES) locale $(PROG)

src/system/draw.c

@@ -266,15 +266,15 @@ void saveScreenshot(char *name)
 	
 	if (name != NULL)
 	{
-		sprintf(filename, "%s/%s.bmp", app.saveDir, name);
+		sprintf(filename, "%s/%s.png", app.saveDir, name);
 	}
 	else
 	{
-		sprintf(filename, "%s/%d.bmp", dev.screenshotFolder, SDL_GetTicks());
+		sprintf(filename, "%s/%d.png", dev.screenshotFolder, SDL_GetTicks());
 	}
 	
 	screenshot = SDL_CreateRGBSurface(0, SCREEN_WIDTH, SCREEN_HEIGHT, 32, 0x00ff0000, 0x0000ff00, 0x000000ff, 0xff000000);
 	SDL_RenderReadPixels(app.renderer, NULL, SDL_PIXELFORMAT_ARGB8888, screenshot->pixels, screenshot->pitch);
-	SDL_SaveBMP(screenshot, filename);
+	SDL_SavePNG(screenshot, filename);
 	SDL_FreeSurface(screenshot);
 }

src/system/draw.h

@@ -19,6 +19,7 @@ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */
 
 #include "../common.h"
+#include "savepng.h"
 
 extern void drawText(int x, int y, int size, int align, SDL_Color c, const char *format, ...);
 

src/system/savepng.c

@@ -0,0 +1,154 @@
+/*
+ * SDL_SavePNG -- libpng-based SDL_Surface writer.
+ *
+ * This code is free software, available under zlib/libpng license.
+ * http://www.libpng.org/pub/png/src/libpng-LICENSE.txt
+ */
+#include <SDL.h>
+#include <png.h>
+
+#define SUCCESS 0
+#define ERROR -1
+
+#define USE_ROW_POINTERS
+
+#if SDL_BYTEORDER == SDL_BIG_ENDIAN
+#define rmask 0xFF000000
+#define gmask 0x00FF0000
+#define bmask 0x0000FF00
+#define amask 0x000000FF
+#else
+#define rmask 0x000000FF
+#define gmask 0x0000FF00
+#define bmask 0x00FF0000
+#define amask 0xFF000000
+#endif
+
+/* libpng callbacks */ 
+static void png_error_SDL(png_structp ctx, png_const_charp str)
+{
+	SDL_SetError("libpng: %s\n", str);
+}
+static void png_write_SDL(png_structp png_ptr, png_bytep data, png_size_t length)
+{
+	SDL_RWops *rw = (SDL_RWops*)png_get_io_ptr(png_ptr);
+	SDL_RWwrite(rw, data, sizeof(png_byte), length);
+}
+
+SDL_Surface *SDL_PNGFormatAlpha(SDL_Surface *src) 
+{
+	SDL_Surface *surf;
+	SDL_Rect rect = { 0 };
+
+	/* NO-OP for images < 32bpp and 32bpp images that already have Alpha channel */ 
+	if (src->format->BitsPerPixel <= 24 || src->format->Amask) {
+		src->refcount++;
+		return src;
+	}
+
+	/* Convert 32bpp alpha-less image to 24bpp alpha-less image */
+	rect.w = src->w;
+	rect.h = src->h;
+	surf = SDL_CreateRGBSurface(src->flags, src->w, src->h, 24,
+		src->format->Rmask, src->format->Gmask, src->format->Bmask, 0);
+	SDL_LowerBlit(src, &rect, surf, &rect);
+
+	return surf;
+}
+
+int SDL_SavePNG_RW(SDL_Surface *surface, SDL_RWops *dst, int freedst) 
+{
+	png_structp png_ptr;
+	png_infop info_ptr;
+	png_colorp pal_ptr;
+	SDL_Palette *pal;
+	int i, colortype;
+#ifdef USE_ROW_POINTERS
+	png_bytep *row_pointers;
+#endif
+	/* Initialize and do basic error checking */
+	if (!dst)
+	{
+		SDL_SetError("Argument 2 to SDL_SavePNG_RW can't be NULL, expecting SDL_RWops*\n");
+		return (ERROR);
+	}
+	if (!surface)
+	{
+		SDL_SetError("Argument 1 to SDL_SavePNG_RW can't be NULL, expecting SDL_Surface*\n");
+		if (freedst) SDL_RWclose(dst);
+		return (ERROR);
+	}
+	png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, png_error_SDL, NULL); /* err_ptr, err_fn, warn_fn */
+	if (!png_ptr) 
+	{
+		SDL_SetError("Unable to png_create_write_struct on %s\n", PNG_LIBPNG_VER_STRING);
+		if (freedst) SDL_RWclose(dst);
+		return (ERROR);
+	}
+	info_ptr = png_create_info_struct(png_ptr);
+	if (!info_ptr)
+	{
+		SDL_SetError("Unable to png_create_info_struct\n");
+		png_destroy_write_struct(&png_ptr, NULL);
+		if (freedst) SDL_RWclose(dst);
+		return (ERROR);
+	}
+	if (setjmp(png_jmpbuf(png_ptr)))	/* All other errors, see also "png_error_SDL" */
+	{
+		png_destroy_write_struct(&png_ptr, &info_ptr);
+		if (freedst) SDL_RWclose(dst);
+		return (ERROR);
+	}
+
+	/* Setup our RWops writer */
+	png_set_write_fn(png_ptr, dst, png_write_SDL, NULL); /* w_ptr, write_fn, flush_fn */
+
+	/* Prepare chunks */
+	colortype = PNG_COLOR_MASK_COLOR;
+	if (surface->format->BytesPerPixel > 0
+	&&  surface->format->BytesPerPixel <= 8
+	&& (pal = surface->format->palette))
+	{
+		colortype |= PNG_COLOR_MASK_PALETTE;
+		pal_ptr = (png_colorp)malloc(pal->ncolors * sizeof(png_color));
+		for (i = 0; i < pal->ncolors; i++) {
+			pal_ptr[i].red   = pal->colors[i].r;
+			pal_ptr[i].green = pal->colors[i].g;
+			pal_ptr[i].blue  = pal->colors[i].b;
+		}
+		png_set_PLTE(png_ptr, info_ptr, pal_ptr, pal->ncolors);
+		free(pal_ptr);
+	}
+	else if (surface->format->BytesPerPixel > 3 || surface->format->Amask)
+		colortype |= PNG_COLOR_MASK_ALPHA;
+
+	png_set_IHDR(png_ptr, info_ptr, surface->w, surface->h, 8, colortype,
+		PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
+
+//	png_set_packing(png_ptr);
+
+	/* Allow BGR surfaces */
+	if (surface->format->Rmask == bmask
+	&& surface->format->Gmask == gmask
+	&& surface->format->Bmask == rmask)
+		png_set_bgr(png_ptr);
+
+	/* Write everything */
+	png_write_info(png_ptr, info_ptr);
+#ifdef USE_ROW_POINTERS
+	row_pointers = (png_bytep*) malloc(sizeof(png_bytep)*surface->h);
+	for (i = 0; i < surface->h; i++)
+		row_pointers[i] = (png_bytep)(Uint8*)surface->pixels + i * surface->pitch;
+	png_write_image(png_ptr, row_pointers);
+	free(row_pointers);
+#else
+	for (i = 0; i < surface->h; i++)
+		png_write_row(png_ptr, (png_bytep)(Uint8*)surface->pixels + i * surface->pitch);
+#endif
+	png_write_end(png_ptr, info_ptr);
+
+	/* Done */
+	png_destroy_write_struct(&png_ptr, &info_ptr);
+	if (freedst) SDL_RWclose(dst);
+	return (SUCCESS);
+}

src/system/savepng.h

@@ -0,0 +1,45 @@
+#ifndef _SDL_SAVEPNG
+#define _SDL_SAVEPNG
+/*
+ * SDL_SavePNG -- libpng-based SDL_Surface writer.
+ *
+ * This code is free software, available under zlib/libpng license.
+ * http://www.libpng.org/pub/png/src/libpng-LICENSE.txt
+ */
+#include <SDL_video.h>
+
+#ifdef __cplusplus
+extern "C" { /* This helps CPP projects that include this header */
+#endif
+
+/*
+ * Save an SDL_Surface as a PNG file.
+ *
+ * Returns 0 success or -1 on failure, the error message is then retrievable
+ * via SDL_GetError().
+ */
+#define SDL_SavePNG(surface, file) \
+	SDL_SavePNG_RW(surface, SDL_RWFromFile(file, "wb"), 1)
+
+/*
+ * Save an SDL_Surface as a PNG file, using writable RWops.
+ * 
+ * surface - the SDL_Surface structure containing the image to be saved
+ * dst - a data stream to save to
+ * freedst - non-zero to close the stream after being written
+ *
+ * Returns 0 success or -1 on failure, the error message is then retrievable
+ * via SDL_GetError().
+ */
+extern int SDL_SavePNG_RW(SDL_Surface *surface, SDL_RWops *rw, int freedst);
+
+/*
+ * Return new SDL_Surface with a format suitable for PNG output.
+ */
+extern SDL_Surface *SDL_PNGFormatAlpha(SDL_Surface *src);
+
+#ifdef __cplusplus
+} /* extern "C" */
+#endif
+
+#endif