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The latest version of the book is P1.0, released almost 2 years ago. If you've bought a PDF of the book and would like to upgrade it to this version (for free), visit your home page.

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If you've found a new error, please submit it.

  • Typo
  • Tech. error
  • Suggestion
  • Maybe next edition
  • Not a problem
  • Reported in: P1.0 (30-Apr-17)
#81489
PDF page: 11
The sentence "Who wants to give screens full of painfully handwritten code?", while perfectly fine English, doesn't seem to go with the previous sente...more...
  • Reported in: P1.0 (02-Jan-16)
#79514
Paper page: 12
For anyone using Gosu 0.10.0 or later, there is no longer a requirement to install libogg or libvorbis, i.e. only sdl2 needs to be installed using hom...more...
  • Reported in: P1.0 (02-Jan-16)
#79515
Paper page: 13
Regarding the note on running ruby programs from within Sublime Text, this can be a bit buggy if the computer contains several versions of ruby (e.g. ...more...
  • Reported in: P1.0 (02-Jan-16)
#79512
Paper page: 33
Example code near the top is missing a line from the previous example, specifically the @font.draw() method call to display the score has been replace...more...
  • Reported in: P1.0 (03-Jan-16)
#79525
Paper page: 46
The third sentence in the second paragraph incorrectly reads, "One method of the SectorFive class, accelerate()...". This method actually belongs in t...more...
  • Reported in: B2.0 (31-Jul-15)
#78696
PDF page: 59
The footnote that reads "You can see all the methods of the Array class by looking in the Ruby documentation at -link-" should probably point to the R...more...
  • Reported in: P1.0 (10-Apr-16)
#80211
PDF page: 65
The second paragraph says: "... the Bullet class uses the Gosu.offet_x() ..." It should be: "... the Bullet class uses the Gosu.offset_x() ..."--E...more...
  • Reported in: P1.0 (06-May-17)
#81524
PDF page: 65
I don't think running the project (ie, "ruby sector_five.rb") will show any bullet.rb errors until after the next section, when you require it in the ...more...
  • Reported in: P1.0 (11-Jan-16)
#79606
Paper page: 72
In the Explosion class diagram, one of the instance variables in incorrectly written as "@image_number". In the code and descriptive paragraphs the sa...more...
  • Reported in: P1.0 (17-Apr-16)
#80239
Paper page: 106
The diagram with the large '3' text has incorrect code written next to it to determine the top left corner x value, where it says "text+width/2" it sh...more...
  • Reported in: P1.0 (30-Apr-17)
#81490
Paper page: 125
Each time the book says to "test", it would be helpful if there was a version of the game's code at that particular moment for the reader to reference...more...
  • Reported in: P1.0 (17-Apr-16)
#80240
Paper page: 128
The code segment on this page is missing the marker on the line "attr_reader :space" to say that this is a new piece of code. Also, this same line of ...more...
  • Reported in: P1.0 (24-Jan-16)
#79694
Paper page: 131+
On the enlarged boulder image, one of the vertices marked does not match the x and y co-ordinates provided for it. The affected vertex is the top left...more...
  • Reported in: P1.0 (18-Apr-16)
#80241
Paper page: 142/3
There are 8 sprites in the Chip sprite sheet. The last paragraph on page 142 says to rotate through 7 images, and the draw method of the Chip class on...more...
  • Reported in: P1.0 (29-Apr-17)
#81486
Paper page: 145
On pages 145 the book describes the #check_footing method. The book never tells the reader to implement the #check_footing method within the Escape#u...more...
  • Reported in: P1.0 (18-Apr-16)
#80242
Paper page: 146
Within the jump method definition, the second nested conditional which checks the @action instance variable is checking equality to an incorrect symbo...more...
  • Reported in: P1.0 (18-Apr-16)
#80244
Paper page: 154
The new lines of code make a call to the x method of the Chip class "@player.x". This requires that the Chip class makes the x method available e.g. b...more...
  • Reported in: P1.0 (18-Apr-16)
#80245
Paper page: 161-9
The markup of which lines of code are new gets a bit messed up for 10 pages in the escape2.rb code snippets: - p161: "require_relative 'camera'" shou...more...
  • Reported in: P1.0 (18-Apr-16)
#80246
Paper page: 170
The paragraph beginning with, "Finally, you write", contains the sentence, "Note that you read just the camera..." which I believe should be "readjust...more...