Add option for using PicCon compatible color conversion in 4 bit pale…

…tte mode
tditlu · Jan 24, 2021 · 4cb06aa · 4cb06aa
1 parent eb581f7
commit 4cb06aa
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Showing 4 changed files with 43 additions and 30 deletions.
diff --git a/README.md b/README.md
@@ -35,6 +35,8 @@ Available options are:
 
 	-a, --attached                                        Attach sprites, only valid for sprite.
 
+	-n, --piccon                                          Use PicCon compatible color conversion for 4 bit palette, only valid with palette output file format.
+
 Examples:
 
 	amigeconv -f bitplanes -d 8 font.png font.raw

diff --git a/src/amigeconv.c b/src/amigeconv.c
@@ -12,8 +12,8 @@
 #include "formats/sprite.h"
 #include "formats/palette.h"
 
-#define AMIGECONV_VERSION "1.0.1"
-#define AMIGECONV_VERSION_DATE "2019-09-01"
+#define AMIGECONV_VERSION "1.0.2"
+#define AMIGECONV_VERSION_DATE "2021-01-24"
 
 typedef enum {
 	PALETTE_UNKNOWN = 0,
@@ -93,14 +93,15 @@ static bool write_palette(
 	image_t *const image,
 	palette_t palette,
 	const unsigned int colors,
-	bool copper
+	bool copper,
+	const bool piccon_compatibility
 ) {
 	buffer_t *buffer;
 	if (palette == PALETTE_PAL4) {
 		if (copper) {
-			buffer = palette_convert_pal4_copper(image, colors);
+			buffer = palette_convert_pal4_copper(image, colors, piccon_compatibility);
 		} else {
-			buffer = palette_convert_pal4(image, colors);
+			buffer = palette_convert_pal4(image, colors, piccon_compatibility);
 		}
 	}
 
@@ -117,7 +118,7 @@ static bool write_palette(
 	}
 
 	if (palette == PALETTE_LOADRGB4) {
-		buffer = palette_convert_pal4(image, colors);
+		buffer = palette_convert_pal4(image, colors, piccon_compatibility);
 	}
 
 	if (palette == PALETTE_LOADRGB32) {
@@ -146,11 +147,12 @@ static void usage() {
 	printf(" -w, --width [16,32,64]                                Width, only valid with sprite output file format.\n");
 	printf(" -t, --controlword                                     Write control word, only valid with sprite output file format.\n");
 	printf(" -a, --attached                                        Attach mode sprite, only valid with sprite output file format.\n");
+	printf(" -n, --piccon                                          Use PicCon compatible color conversion for 4 bit palette, only valid with palette output file format.\n");
 	printf("\n");
 }
 
 int main(int argc, char *argv[]) {
-	bool interleaved = false, copper = false, controlword = false, attached = false;
+	bool interleaved = false, copper = false, controlword = false, attached = false, piccon_compatibility = false;
 	int depth = -1, colors = -1, width = -1;
 	palette_t palette = PALETTE_UNKNOWN;
 	format_t format = FORMAT_UNKNOWN;
@@ -165,6 +167,7 @@ int main(int argc, char *argv[]) {
 		{"width", required_argument, 0, 'w' },
 		{"controlword", no_argument, 0, 't' },
 		{"attached", no_argument, 0, 'a' },
+		{"piccon", no_argument, 0, 'n' },
 		{0, 0, 0, 0}
 	};
 
@@ -239,6 +242,9 @@ int main(int argc, char *argv[]) {
 			case 'a':
 				attached = true;
 				break;
+			case 'n':
+				piccon_compatibility = true;
+				break;
 			default:
 				usage();
 				exit(EXIT_FAILURE);
@@ -387,7 +393,7 @@ int main(int argc, char *argv[]) {
 			goto error;
 		}
 
-		if (!write_palette(outfile, &image, palette, colors, copper)) {
+		if (!write_palette(outfile, &image, palette, colors, copper, piccon_compatibility)) {
 			error = true;
 			printf("Error: Could not write output file \"%s\".\n\n", outfile);
 			goto error;

diff --git a/src/formats/palette.c b/src/formats/palette.c
@@ -1,11 +1,11 @@
 #include <stdlib.h>
-// #include <math.h>
+#include <math.h>
 
 #include "../buffer.h"
 #include "../image.h"
 
 // PAL4 & LOADRGB4 is the same format
-buffer_t *palette_convert_pal4(image_t *const image, const unsigned int colors) {
+buffer_t *palette_convert_pal4(image_t *const image, const unsigned int colors, const bool piccon_compatibility) {
 	if (colors < 1 || colors > 256) { return NULL; }
 
 	unsigned int buffer_size = (((colors * 4) + (4 - 1)) >> 2) * 2;
@@ -18,15 +18,18 @@ buffer_t *palette_convert_pal4(image_t *const image, const unsigned int colors)
 		unsigned char g = buffer_get_byte(image->palette, i + 1);
 		unsigned char b = buffer_get_byte(image->palette, i + 2);
 
-		// Correct conversion
-//		r = round((float)r / 17.0);
-//		g = round((float)g / 17.0);
-//		b = round((float)b / 17.0);
+		if (piccon_compatibility) {
+			// PicCon compatibility
+			r >>= 4;
+			g >>= 4;
+			b >>= 4;
+		} else {
+			// Correct conversion
+			r = round((float)r / 17.0);
+			g = round((float)g / 17.0);
+			b = round((float)b / 17.0);
+		}
 
-		// PicCon compatibility
-		r >>= 4;
-		g >>= 4;
-		b >>= 4;
 
 		buffer_set_byte(buffer, j++, r);
 		buffer_set_byte(buffer, j++, (g << 4) + b);
@@ -35,7 +38,7 @@ buffer_t *palette_convert_pal4(image_t *const image, const unsigned int colors)
 	return buffer;
 }
 
-buffer_t *palette_convert_pal4_copper(image_t *const image, const unsigned int colors) {
+buffer_t *palette_convert_pal4_copper(image_t *const image, const unsigned int colors, const bool piccon_compatibility) {
 	if (colors < 1 || colors > 32) { return NULL; }
 
 	unsigned int buffer_size = (((colors * 4) + (4 - 1)) >> 2) * 4;
@@ -48,15 +51,17 @@ buffer_t *palette_convert_pal4_copper(image_t *const image, const unsigned int c
 		unsigned char g = buffer_get_byte(image->palette, i + 1);
 		unsigned char b = buffer_get_byte(image->palette, i + 2);
 
-		// Correct conversion
-//		r = round((float)r / 17.0);
-//		g = round((float)g / 17.0);
-//		b = round((float)b / 17.0);
-
-		// PicCon compatibility
-		r >>= 4;
-		g >>= 4;
-		b >>= 4;
+		if (piccon_compatibility) {
+			// PicCon compatibility
+			r >>= 4;
+			g >>= 4;
+			b >>= 4;
+		} else {
+			// Correct conversion
+			r = round((float)r / 17.0);
+			g = round((float)g / 17.0);
+			b = round((float)b / 17.0);
+		}
 
 		buffer_set_byte(buffer, j++, (reg >> 8) & 255);
 		buffer_set_byte(buffer, j++, reg & 255);

diff --git a/src/formats/palette.h b/src/formats/palette.h
@@ -3,8 +3,8 @@
 
 #include "../buffer.h"
 
-buffer_t *palette_convert_pal4(image_t *const image, const unsigned int colors);
-buffer_t *palette_convert_pal4_copper(image_t *const image, const unsigned int colors);
+buffer_t *palette_convert_pal4(image_t *const image, const unsigned int colors, const bool piccon_compatibility);
+buffer_t *palette_convert_pal4_copper(image_t *const image, const unsigned int colors, const bool piccon_compatibility);
 buffer_t *palette_convert_pal8(image_t *const image, const unsigned int colors);
 buffer_t *palette_convert_pal8_copper(image_t *const image, const unsigned int colors);
 buffer_t *palette_convert_pal32(image_t *const image, const unsigned int colors);