Merge pull request #1191 from ThomasdenH/develop

Add dithering to sprite importer

src/cmdline.c

@@ -60,6 +60,7 @@ int cmdline_run(const char **argv, int argc)
 		OPT_HELP(),
 		OPT_BOOLEAN('v', "version", &version, "show version information and exit"),
 		OPT_BOOLEAN(0, "verbose", &verbose, "log verbose messages"),
+		OPT_INTEGER('m', "mode", &sprite_mode, "the type of sprite conversion. 0 = default, 1 = simple closest pixel match, 2 = dithering"),
 		OPT_END()
 	};
 

src/cmdline.h

@@ -26,6 +26,8 @@
 /** The exit code for OpenRCT2 when it exits. */
 extern int gExitCode;
 
+int sprite_mode;
+
 int cmdline_run(const char **argv, int argc);
 int cmdline_for_sprite(const char **argv, int argc);
 

src/cmdline_sprite.c

@@ -3,6 +3,10 @@
 #include "drawing/drawing.h"
 #include "util/util.h"
 
+#define MODE_DEFAULT 0
+#define MODE_CLOSEST 1
+#define MODE_DITHERING 2
+
 typedef struct {
 	uint32 num_entries;
 	uint32 total_size;
@@ -171,17 +175,56 @@ bool sprite_file_export(int spriteIndex, const char *outPath)
 	}
 }
 
-int get_palette_index(uint32 colour)
-{
-	uint8 *rgba = (uint8*)(&colour);
-	
-	if (rgba[3] < 128)
+bool is_transparent_pixel(sint16 *colour){
+	return colour[3] < 128;
+}
+
+// Returns true if pixel index is an index not used for remapping
+bool is_changable_pixel(int palette_index) {
+	if (palette_index == -1)
+		return true;
+	if (palette_index == 0)
+		return false;
+	if (palette_index >= 203 && palette_index < 214)
+		return false;
+	if (palette_index == 226)
+		return false;
+	if (palette_index >= 227 && palette_index < 229)
+		return false;
+	if (palette_index >= 243)
+		return false;
+	return true;
+}
+
+int get_closest_palette_index(sint16 *colour){
+	uint32 smallest_error = -1;
+	int best_match = -1;
+
+	for (int x = 0; x < 256; x++){
+		if (is_changable_pixel(x)){
+			uint32 error =
+				((sint16)(spriteFilePalette[x].r) - colour[0]) * ((sint16)(spriteFilePalette[x].r) - colour[0]) +
+				((sint16)(spriteFilePalette[x].g) - colour[1]) * ((sint16)(spriteFilePalette[x].g) - colour[1]) +
+				((sint16)(spriteFilePalette[x].b) - colour[2]) * ((sint16)(spriteFilePalette[x].b) - colour[2]);
+
+			if (smallest_error == -1 || smallest_error > error){
+				best_match = x;
+				smallest_error = error;
+			}
+		}
+	}
+	return best_match;
+}
+
+int get_palette_index(sint16 *colour)
+{	
+	if (is_transparent_pixel(colour))
 		return -1;
 
 	for (int i = 0; i < 256; i++) {
-		if (spriteFilePalette[i].r != rgba[0]) continue;
-		if (spriteFilePalette[i].g != rgba[1]) continue;
-		if (spriteFilePalette[i].b != rgba[2]) continue;
+		if ((sint16)(spriteFilePalette[i].r) != colour[0]) continue;
+		if ((sint16)(spriteFilePalette[i].g) != colour[1]) continue;
+		if ((sint16)(spriteFilePalette[i].b) != colour[2]) continue;
 		return i;
 	}
 
@@ -193,7 +236,7 @@ typedef struct {
 	uint8 offset_x;
 } rle_code;
 
-bool sprite_file_import(const char *path, rct_g1_element *outElement, uint8 **outBuffer, int *outBufferLength)
+bool sprite_file_import(const char *path, rct_g1_element *outElement, uint8 **outBuffer, int *outBufferLength, int mode)
 {
 	unsigned char *pixels;
 	unsigned int width, height;
@@ -215,7 +258,13 @@ bool sprite_file_import(const char *path, rct_g1_element *outElement, uint8 **ou
 
 	uint8 *buffer = malloc((height * 2) + (width * height * 16));
 	uint16 *yOffsets = (uint16*)buffer;
-	uint8 *src = pixels;
+
+	// A larger range is needed for proper dithering
+	sint16 *src = malloc(height * width * 4 * 2);
+	for (uint32 x = 0; x < height * width * 4; x++){
+		src[x] = (sint16) pixels[x];
+	}
+
 	uint8 *dst = buffer + (height * 2);
 	
 	for (unsigned int y = 0; y < height; y++) {
@@ -230,7 +279,56 @@ bool sprite_file_import(const char *path, rct_g1_element *outElement, uint8 **ou
 		int pixels = 0;
 		bool pushRun = false;
 		for (unsigned int x = 0; x < width; x++) {
-			int paletteIndex = get_palette_index(*((uint32*)src));
+			int paletteIndex = get_palette_index(src);
+
+			if (mode == MODE_CLOSEST || mode == MODE_DITHERING)
+				if (paletteIndex == -1 && !is_transparent_pixel(src))
+					paletteIndex = get_closest_palette_index(src);
+			
+
+			if (mode == MODE_DITHERING)
+				if (!is_transparent_pixel(src) && is_changable_pixel(get_palette_index(src))){
+					sint16 dr = src[0] - (sint16)(spriteFilePalette[paletteIndex].r);
+					sint16 dg = src[1] - (sint16)(spriteFilePalette[paletteIndex].g);
+					sint16 db = src[2] - (sint16)(spriteFilePalette[paletteIndex].b);
+
+					if (x + 1 < width){
+						if (!is_transparent_pixel(src + 4) && is_changable_pixel(get_palette_index(src + 4))){
+							// Right
+							src[4] += dr * 7 / 16;
+							src[5] += dg * 7 / 16;
+							src[6] += db * 7 / 16;
+						}
+					}
+
+					if (y + 1 < height){
+						if (x > 0){
+							if (!is_transparent_pixel(src + 4 * (width - 1)) && is_changable_pixel(get_palette_index(src + 4 * (width - 1)))){
+								// Bottom left
+								src[4 * (width - 1)] += dr * 3 / 16;
+								src[4 * (width - 1) + 1] += dg * 3 / 16;
+								src[4 * (width - 1) + 2] += db * 3 / 16;
+							}
+						}
+
+						// Bottom
+						if (!is_transparent_pixel(src + 4 * width) && is_changable_pixel(get_palette_index(src + 4 * width))){
+							src[4 * width] += dr * 5 / 16;
+							src[4 * width + 1] += dg * 5 / 16;
+							src[4 * width + 2] += db * 5 / 16;
+						}
+
+						if (x + 1 < width){
+							if (!is_transparent_pixel(src + 4 * (width - 1)) && is_changable_pixel(get_palette_index(src + 4 * (width + 1)))){
+								// Bottom right
+								src[4 * (width + 1)] += dr * 1 / 16;
+								src[4 * (width + 1) + 1] += dg * 1 / 16;
+								src[4 * (width + 1) + 2] += db * 1 / 16;
+							}
+						}
+					}
+				}
+
 			src += 4;
 			if (paletteIndex == -1) {
 				if (pixels != 0) {
@@ -391,7 +489,7 @@ int cmdline_for_sprite(const char **argv, int argc)
 		rct_g1_element spriteElement;
 		uint8 *buffer;
 		int bufferLength;
-		if (!sprite_file_import(imagePath, &spriteElement, &buffer, &bufferLength))
+		if (!sprite_file_import(imagePath, &spriteElement, &buffer, &bufferLength, sprite_mode))
 			return -1;
 
 		if (!sprite_file_open(spriteFilePath)) {
@@ -445,7 +543,7 @@ int cmdline_for_sprite(const char **argv, int argc)
 				rct_g1_element spriteElement;
 				uint8 *buffer;
 				int bufferLength;
-				if (!sprite_file_import(imagePath, &spriteElement, &buffer, &bufferLength)) {
+				if (!sprite_file_import(imagePath, &spriteElement, &buffer, &bufferLength, sprite_mode)) {
 					fprintf(stderr, "Could not import image file: %s\nCanceling\n", imagePath);
 					return -1;
 				}
@@ -488,6 +586,8 @@ int cmdline_for_sprite(const char **argv, int argc)
 	}
 }
 
+
+
 static rct_sprite_file_palette_entry _standardPalette[256] = {
 	// 0 (unused)
 	{ 0, 0, 0, 255 },