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Diffstat (limited to 'projects/12/Screen.jack')
| -rw-r--r-- | projects/12/Screen.jack | 138 |
1 files changed, 0 insertions, 138 deletions
diff --git a/projects/12/Screen.jack b/projects/12/Screen.jack deleted file mode 100644 index a370ab9..0000000 --- a/projects/12/Screen.jack +++ /dev/null @@ -1,138 +0,0 @@ -// This file is part of www.nand2tetris.org
-// and the book "The Elements of Computing Systems"
-// by Nisan and Schocken, MIT Press.
-// File name: projects/12/Screen.jack
-
-/**
- * A library of functions for displaying graphics on the screen.
- * The Hack physical screen consists of 512 rows (indexed 0..511, top to bottom)
- * of 256 pixels each (indexed 0..255, left to right). The top left pixel on
- * the screen is indexed (0,0).
- */
-class Screen {
- static Array twoToThe;
- static Array screen;
- static boolean color;
-
- /** Initializes the Screen. */
- function void init() {
- var int i, x;
- let x = 1;
- let i = 0;
- let twoToThe = Array.new(16);
- while (i < 16){
- let twoToThe[i] = x;
- let x = x + x;
- let i = i + 1;
- }
- let screen = 16384;
- let color = true;
- return;
- }
-
- /** Erases the entire screen. */
- function void clearScreen() {
- var boolean c;
- let c = color;
- let color = false;
- do Screen.drawRectangle(0, 0, 511, 255);
- let color = c;
- return;
- }
-
- /** Sets the current color, to be used for all subsequent drawXXX commands.
- * Black is represented by true, white by false. */
- function void setColor(boolean b) {
- let color = b;
- return;
- }
-
- /** Draws the (x,y) pixel, using the current color. */
- function void drawPixel(int x, int y) {
- var int addr, t;
- if ((x < 0) | (y < 0) | (x > 511) | (y > 255)) {
- //String.println("drawPixel: coordinates out of range!");
- //Sys.error(2);
- return;
- }
- let t = x / 16;
- let addr = 32 * y + t;
- if (color) {
- let screen[addr] = screen[addr] | twoToThe[x - (t * 16)];
- } else {
- let screen[addr] = screen[addr] & (- (twoToThe[x - (t * 16)] + 1));
- }
- return;
- }
-
- /** Draws a line from pixel (x1,y1) to pixel (x2,y2), using the current color. */
- function void drawLine(int x1, int y1, int x2, int y2) {
- var int dx, dy, x, y, a, b, diff;
- let x = x1;
- let y = y1;
- do Screen.drawPixel(x, y);
- if (x1 = x2) {
- if (y1 = y2) {
- return;
- } else {
- let diff = 1;
- }
- } else {
- if (y1 = y2) {
- let diff = -1;
- } else {
- let diff = 0;
- }
- }
- let dx = x2 - x1;
- let dy = y2 - y1;
- let a = Math.sign(dx);
- let b = Math.sign(dy);
- let dx = Math.abs(dx);
- let dy = Math.abs(dy);
- while (~((x = x2) & (y = y2))) {
- if (diff < 0){
- let x = x + a;
- let diff = diff + dy;
- } else {
- let y = y + b;
- let diff = diff - dx;
- }
- do Screen.drawPixel(x, y);
- }
- return;
- }
-
- /** Draws a filled rectangle whose top left corner is (x1, y1)
- * and bottom right corner is (x2,y2), using the current color. */
- function void drawRectangle(int x1, int y1, int x2, int y2) {
- var int x;
- if ((x1 > x2) | (y1 > y2)) {
- return;
- }
- let x = x1;
- while (~(x > x2)) {
- do Screen.drawLine(x, y1, x, y2);
- let x = x + 1;
- }
- return;
- }
-
- /** Draws a filled circle of radius r<=181 around (x,y), using the current color. */
- function void drawCircle(int x, int y, int r) {
- var int dx, dy, r2;
- if (r > 181) {
- do String.println("drawCircle: radius too big!");
- do Sys.error(2);
- return;
- }
- let dy = -r;
- let r2 = r * r;
- while (~(dy > r)) {
- let dx = Math.sqrt(r2 - (dy * dy));
- do Screen.drawLine(x - dx, y + dy, x + dx, y + dy);
- let dy = dy + 1;
- }
- return;
- }
-}
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