paletted conversion

1 files changed, 101 insertions, 10 deletions

diff --git a/pximg.c b/pximg.c
index 64ab30d..ba0f019 100644
--- a/pximg.c
+++ b/pximg.c
@@ -3,28 +3,40 @@
 #define STB_IMAGE_IMPLEMENTATION
 #include "stb_image.h"
 
-int main(int argc, char **argv) {
-	int img_w, img_h, img_col_chans;
-	uint8_t *img_data;
+static int grayscale(char **argv);
+static int indexed(char **argv);
 
-	if (argc != 3) {
-		fprintf(stderr, "usage: %s image.png name\n", argv[0]);
+int
+main(int argc, char **argv) {
+	if (argc != 3 && argc != 4) {
+		fprintf(stderr, "usage: %s image.png name [palette.png]\n",
+		        argv[0]);
 		return 1;
 	}
 
-	img_data = stbi_load(argv[1], &img_w, &img_h, &img_col_chans, 0);
+	if (argc == 3)
+		return grayscale(argv);
+	return indexed(argv);
+}
+
+static int
+grayscale(char **argv)
+{
+	int img_w, img_h, img_col_chans;
+	uint8_t *const img_data =
+	    stbi_load(argv[2], &img_w, &img_h, &img_col_chans, 1);
 
 	if (img_data == NULL) {
-		fputs("error: failed to load image\n", stderr);
+		fprintf(stderr, "error: failed to load image\n");
 		return 1;
 	}
 	if (img_col_chans != 1) {
-		fputs("error: image isn't grayscale\n", stderr);
+		fprintf(stderr, "error: image isn't grayscale\n");
 		stbi_image_free(img_data);
 		return 1;
 	}
 	if (img_h * img_w == 0) {
-		fputs("error: image size is 0\n", stderr);
+		fprintf(stderr, "error: image size is 0\n");
 		stbi_image_free(img_data);
 		return 1;
 	}
@@ -32,7 +44,86 @@ int main(int argc, char **argv) {
 	printf("#include \"px.h\"\nconst PxSpr %s={%d,%d,(uint8_t[]){",
 	       argv[2], img_w, img_h);
 	for (int i = 0; i < img_w * img_h; i++)
-		printf("%#x,", (unsigned)img_data[i]);
+		printf("%u,", (unsigned)img_data[i]);
+	printf("}};\n");
+
+	stbi_image_free(img_data);
+	return 0;
+}
+
+static int
+indexed(char **argv)
+{
+	/* read palette */
+	int pal_w, pal_h, pal_col_chans;
+	uint8_t *const pal_data =
+	    stbi_load(argv[3], &pal_w, &pal_h, &pal_col_chans, 3);
+
+	if (pal_data == NULL) {
+		fprintf(stderr, "error: failed to load palette\n");
+		return 1;
+	}
+	if (pal_col_chans != 3) {
+		fprintf(stderr, "error: palette isn't RGB\n");
+		stbi_image_free(pal_data);
+		return 1;
+	}
+	if (pal_w * pal_h == 0) {
+		fprintf(stderr, "error: palette size is 0\n");
+		stbi_image_free(pal_data);
+		return 1;
+	}
+	if (pal_w * pal_h >= 256) {
+		fprintf(stderr, "error: palette size is greater than 255\n");
+		stbi_image_free(pal_data);
+		return 1;
+	}
+
+	/* store unpacked palette */
+	const int pal_size = pal_w * pal_h;
+	uint8_t pal[256 * 3] = {0};
+	for (int i = 0; i < pal_size * 3; i++)
+		pal[i] = pal_data[i];
+	stbi_image_free(pal_data);
+
+	/* read image */
+	int img_w, img_h, img_col_chans;
+	uint8_t *const img_data =
+	    stbi_load(argv[1], &img_w, &img_h, &img_col_chans, 3);
+
+	if (img_data == NULL) {
+		fprintf(stderr, "error: failed to load image\n");
+		return 1;
+	}
+	if (pal_col_chans != 3) {
+		fprintf(stderr, "error: image isn't RBG\n");
+		stbi_image_free(img_data);
+		return 1;
+	}
+	if (img_h * img_w == 0) {
+		fprintf(stderr, "error: image size is 0\n");
+		stbi_image_free(img_data);
+		return 1;
+	}
+
+	printf("#include \"px.h\"\nconst PxSpr %s={%d,%d,(uint8_t[]){",
+	       argv[2], img_w, img_h);
+	for (int i = 0; i < img_w * img_h; i++) {
+		int col = -1;
+		for (int k = 0; k < pal_size; k++)
+			if (memcmp(pal + k * 3, img_data + i * 3, 3) == 0) {
+				col = k;
+				break;
+			}
+		if (col == -1) {
+			fprintf(stderr,
+			        "color at pixel %d:%d not found in palette\n",
+			        i % img_w, i / img_w);
+			stbi_image_free(img_data);
+			return 1;
+		}
+		printf("%d,", col);
+	}
 	printf("}};\n");
 
 	stbi_image_free(img_data);