Load default palette from file.

Rather than using hard-coded reference to `doom_palette`.
Part of #2.

src/conv/graphic.c

@@ -43,12 +43,13 @@ static VFILE *RGBABufferToPatch(uint8_t *buffer, size_t rowstep,
                                 struct patch_header *hdr)
 {
 	VFILE *result;
+	const struct palette *pal = PAL_DefaultPalette();
 	struct patch_header swapped_hdr;
 	uint32_t *column_offsets;
 	uint8_t *palettized, *post, alpha;
 	int x, y, post_len;
 
-	palettized = V_PalettizeRGBABuffer(&doom_palette, buffer, rowstep,
+	palettized = V_PalettizeRGBABuffer(pal, buffer, rowstep,
 	                                   hdr->width, hdr->height);
 
 	result = vfopenmem(NULL, 0);
@@ -139,7 +140,8 @@ static VFILE *BufferToRaw(uint8_t *imgbuf, int rowstep,
 	VFILE *result = vfopenmem(NULL, 0);
 
 	palettized = V_PalettizeRGBABuffer(
-		&doom_palette, imgbuf, rowstep, hdr->width, hdr->height);
+		PAL_DefaultPalette(), imgbuf, rowstep,
+		hdr->width, hdr->height);
 	assert(vfwrite(palettized, hdr->width,
 	               hdr->height, result) == hdr->height);
 	free(palettized);
@@ -284,7 +286,8 @@ VFILE *V_ToImageFile(VFILE *input)
 		goto fail;
 	}
 
-	result = V_WritePalettizedPNG(&hdr, imgbuf, &doom_palette, true);
+	result = V_WritePalettizedPNG(&hdr, imgbuf,
+	                              PAL_DefaultPalette(), true);
 
 fail:
 	free(imgbuf);
@@ -313,7 +316,7 @@ VFILE *V_FlatToImageFile(VFILE *input)
 	hdr.height = buf_len / 64;
 	hdr.topoffset = 0;
 	hdr.leftoffset = 0;
-	result = V_WritePalettizedPNG(&hdr, buf, &doom_palette, false);
+	result = V_WritePalettizedPNG(&hdr, buf, PAL_DefaultPalette(), false);
 
 fail:
 	free(buf);
@@ -337,7 +340,7 @@ VFILE *V_FullscreenToImageFile(VFILE *input)
 	hdr.height = FULLSCREEN_H;
 	hdr.topoffset = 0;
 	hdr.leftoffset = 0;
-	result = V_WritePalettizedPNG(&hdr, buf, &doom_palette, false);
+	result = V_WritePalettizedPNG(&hdr, buf, PAL_DefaultPalette(), false);
 	free(buf);
 
 	return result;

src/conv/palette.c

@@ -69,7 +69,7 @@ VFILE *V_ColormapToImageFile(VFILE *input)
 	hdr.height = buf_len / 256;
 	hdr.topoffset = 0;
 	hdr.leftoffset = 0;
-	result = V_WritePalettizedPNG(&hdr, buf, &doom_palette, false);
+	result = V_WritePalettizedPNG(&hdr, buf, PAL_DefaultPalette(), false);
 
 fail:
 	free(buf);
@@ -98,8 +98,8 @@ VFILE *V_ColormapFromImageFile(VFILE *input)
 		goto fail;
 	}
 
-	palettized = V_PalettizeRGBABuffer(&doom_palette, imgbuf, rowstep,
-	                                   hdr.width, hdr.height);
+	palettized = V_PalettizeRGBABuffer(PAL_DefaultPalette(), imgbuf,
+	                                   rowstep, hdr.width, hdr.height);
 	result = vfopenmem(NULL, 0);
 	assert(vfwrite(palettized, hdr.width,
 	               hdr.height, result) == hdr.height);

src/palette/palette.c

@@ -15,6 +15,9 @@
 
 #define PALETTE_SIZE   (256 * 3)
 
+static bool default_palette_loaded = false;
+static struct palette default_palette;
+
 struct palette_set *PAL_FromImageFile(VFILE *input)
 {
 	struct png_context ctx;
@@ -221,6 +224,34 @@ char *PAL_ReadDefaultPointer(void)
 	return buf;
 }
 
+static void LoadDefaultPalette(void)
+{
+	const char *dir = PAL_GetPalettesPath();
+	char *path = DefaultPointerPath(dir);
+	FILE *infile = fopen(path, "rb");
+	VFILE *in;
+	struct palette_set *set;
+
+	assert(infile != NULL);
+	in = vfwrapfile(infile);
+	set = PAL_FromImageFile(in);
+	free(path);
+
+	default_palette = set->palettes[0];
+	PAL_FreePaletteSet(set);
+
+	default_palette_loaded = true;
+}
+
+const struct palette *PAL_DefaultPalette(void)
+{
+	if (!default_palette_loaded) {
+		LoadDefaultPalette();
+	}
+
+	return &default_palette;
+}
+
 static void WriteDoomPalette(const char *path)
 {
 	FILE *fs = fopen(path, "wb");

src/palette/palette.h

@@ -31,3 +31,4 @@ struct palette_set *PAL_UnmarshalPaletteSet(VFILE *input);
 void PAL_FreePaletteSet(struct palette_set *set);
 const char *PAL_GetPalettesPath(void);
 char *PAL_ReadDefaultPointer(void);
+const struct palette *PAL_DefaultPalette(void);