Write conversion methods, palette still tbd

src/reskit/tileset.rs

@@ -1,14 +1,81 @@
 use crate::reskit::utility;
-use image::GenericImageView;
+use std::process::exit;
+use std::fs::File;
+use std::io::Write;
+use image::{ GenericImageView, DynamicImage };
+
+fn color_to_palette( r: u16, g: u16, b: u16, palette: &mut [u16; 16] ) -> u32 {
+	let final_val =
+		( ( r & 0x00F0 ) >> 4 ) |
+		( g & 0x00F0 ) |
+		( ( b & 0x00F0 ) << 4 );
+
+	// Does the color already exist?
+	for i in 0..palette.len() {
+		if palette[ i ] == final_val {
+			return i as u32;
+		}
+	}
+
+	// Place the colour in the next open slot
+	for i in 1..palette.len() {
+		if palette[ i ] == 0 {
+			palette[ i ] = final_val;
+			return i as u32;
+		}
+	}
+
+	utility::print_error( "image contains greater than 15 colours, exiting..." );
+	exit( 3 );
+}
+
+fn get_pixel( image: &DynamicImage, palette: &mut [u16; 16], x: u32, y: u32 ) -> u32 {
+	let ( max_x, max_y ) = image.dimensions();
+
+	if x >= max_x || y >= max_y {
+		return 0;
+	}
+
+	let pixel = image.get_pixel( x, y );
+	color_to_palette( pixel[ 0 ].into(), pixel[ 1 ].into(), pixel[ 2 ].into(), palette )
+}
 
 pub fn generate( image_filename: &str, output_filename: &str ) {
 	let img = image::open( image_filename );
 	if let Ok( img ) = img {
-		// Image must be multiple of 8 in both dimensions
-		let x = img.dimensions().0;
-		let y = img.dimensions().1;
+		let ( mut max_x, mut max_y ) = img.dimensions();
+		if max_x % 8 != 0 { max_x = ( 8 * ( max_x / 8 ) ) + ( 8 - ( max_x % 8 ) ); }
+		if max_y % 8 != 0 {	max_y = ( 8 * ( max_y / 8 ) ) + ( 8 - ( max_y % 8 ) ); }
 
+		let mut palette: [u16; 16] = [ 0; 16 ];
+		let mut body: Vec< u8 > = Vec::new();
+
+		for y in ( 0..max_y ).step_by( 8 ) {
+            for x in ( 0..max_x ).step_by( 8 ) {
+				for cell_y in 0..8 {
+					let mut series: u32 = 0;
+
+					for cell_x in 0..8 {
+						let nibble = get_pixel( &img, &mut palette, cell_x + x, cell_y + y ) << ( 7 - cell_x );
+						series = series | nibble;
+					}
+
+					let bytes = series.to_be_bytes();
+					for i in 0..4 {
+						body.push( bytes[ i ] );
+					}
+				}
+			}
+		}
+
+		let output_try = File::create( output_filename );
+		if let Ok( mut output_file ) = output_try {
+			output_file.write( &body ).unwrap();
+			utility::print_good( format!( "converted file {}", image_filename ).as_str() );
 		} else {
-
+			utility::print_error( format!( "could not open filename for output {}", output_filename ).as_str() );
+		}
+	} else {
+		utility::print_error( format!( "could not open filename {}", image_filename ).as_str() );
 	}
 }

src/reskit/utility.rs

@@ -1,3 +1,7 @@
-pub fn print_error( error_msg: &'static str ) {
+pub fn print_error( error_msg: &str ) {
 	red!( "fatal: " ); println!( "{}", error_msg );
 }
+
+pub fn print_good( message: &str ) {
+	green!( "success: " ); println!( "{}", message );
+}