rename: bouncing ball

18-project-bouncing-ball/02-add-a-buffer/main.go

@@ -0,0 +1,66 @@
+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+package main
+
+import (
+	"fmt"
+)
+
+func main() {
+	const (
+		width  = 50
+		height = 10
+
+		cellEmpty = ' '
+		cellBall  = '⚾'
+	)
+
+	var cell rune // current cell (for caching)
+
+	// create the board
+	board := make([][]bool, width)
+	for row := range board {
+		board[row] = make([]bool, height)
+	}
+
+	// create a drawing buffer
+	buf := make([]rune, 0, width*height)
+
+	// draw a smiley
+	board[12][2] = true
+	board[16][2] = true
+	board[14][4] = true
+	board[10][6] = true
+	board[18][6] = true
+	board[12][7] = true
+	board[14][7] = true
+	board[16][7] = true
+
+	// use the loop for measuring the performance difference
+	for i := 0; i < 1000; i++ {
+		// rewind the buffer so that the program reuses it
+		buf = buf[:0]
+
+		// draw the board into the buffer
+		for y := range board[0] {
+			for x := range board {
+				cell = cellEmpty
+				if board[x][y] {
+					cell = cellBall
+				}
+				// fmt.Print(string(cell), " ")
+				buf = append(buf, cell, ' ')
+			}
+			// fmt.Println()
+			buf = append(buf, '\n')
+		}
+
+		// print the buffer
+		fmt.Print(string(buf))
+	}
+}