• Announcements

    • khawk

      Download the Game Design and Indie Game Marketing Freebook   07/19/17

      GameDev.net and CRC Press have teamed up to bring a free ebook of content curated from top titles published by CRC Press. The freebook, Practices of Game Design & Indie Game Marketing, includes chapters from The Art of Game Design: A Book of Lenses, A Practical Guide to Indie Game Marketing, and An Architectural Approach to Level Design. The GameDev.net FreeBook is relevant to game designers, developers, and those interested in learning more about the challenges in game development. We know game development can be a tough discipline and business, so we picked several chapters from CRC Press titles that we thought would be of interest to you, the GameDev.net audience, in your journey to design, develop, and market your next game. The free ebook is available through CRC Press by clicking here. The Curated Books The Art of Game Design: A Book of Lenses, Second Edition, by Jesse Schell Presents 100+ sets of questions, or different lenses, for viewing a game’s design, encompassing diverse fields such as psychology, architecture, music, film, software engineering, theme park design, mathematics, anthropology, and more. Written by one of the world's top game designers, this book describes the deepest and most fundamental principles of game design, demonstrating how tactics used in board, card, and athletic games also work in video games. It provides practical instruction on creating world-class games that will be played again and again. View it here. A Practical Guide to Indie Game Marketing, by Joel Dreskin Marketing is an essential but too frequently overlooked or minimized component of the release plan for indie games. A Practical Guide to Indie Game Marketing provides you with the tools needed to build visibility and sell your indie games. With special focus on those developers with small budgets and limited staff and resources, this book is packed with tangible recommendations and techniques that you can put to use immediately. As a seasoned professional of the indie game arena, author Joel Dreskin gives you insight into practical, real-world experiences of marketing numerous successful games and also provides stories of the failures. View it here. An Architectural Approach to Level Design This is one of the first books to integrate architectural and spatial design theory with the field of level design. The book presents architectural techniques and theories for level designers to use in their own work. It connects architecture and level design in different ways that address the practical elements of how designers construct space and the experiential elements of how and why humans interact with this space. Throughout the text, readers learn skills for spatial layout, evoking emotion through gamespaces, and creating better levels through architectural theory. View it here. Learn more and download the ebook by clicking here. Did you know? GameDev.net and CRC Press also recently teamed up to bring GDNet+ Members up to a 20% discount on all CRC Press books. Learn more about this and other benefits here.
  • entries
    50
  • comments
    92
  • views
    65420

Resuming development

Sign in to follow this  
Followers 0
ManTis

701 views

I have finally returned to developing my C64 skills. I've set up a computer dedicated to that purpose, and now am able to play around with it. Currently following C64 programmer's reference guide 3 - programming graphics. I'm at the beginning, which is setting up charset. Unfortunately, the booklet with which I'm working is so old, I can barely read through some parts - the source scan mostly. Which means I have to write most of the code I'm copying couple times, so that funky things stop appearing.

Current part of the code should copy bit-by-bit charset from ROM into RAM, and make screen display chars from that. Effectively, nothing should happen visually ( it should use same charset as that in ROM ), but it seems I'm one off somewhere, which result in funky caesar-ciphred ( with offset 1 ) screen display biggrin.png :

gallery_66033_391_13951.png

The only question I have to anyone out there is:

poke 52,48 : poke 56,48 : clr

reserves memory for my charset. What exactly is happening here? According to http://sta.c64.org/cbm64mem.html it sets pointer to beginning of string variable area and pointer to end of BASIC area to 48. Why would that reserve memory? How much memory is reserved? I don't like doing something 'because it works'. I'd prefer to know why ;).

Well, back to coding. See you soon!

##################################################

Update: thanks to Ben, it's clear now:

17:13 <@benryves> mantis: I'm no expert, but if the string table is the last thing in BASIC memory then moving it down would allow you to use the space between the old value and the new value as scratch RAM without worrying about the BASIC interpreter overwriting it. BBC BASIC makes things slightly clearer by calling that variable HIMEM and letting you refer to it directly (so HIMEM=HIMEM-100 reserves 100 bytes).
17:23 <@benryves> mantis: The 6502 is little-endian. If we assume that the string variable area is the same as the "end of BASIC" (&A000) then that becomes &3000. Which seems odd (reserving 12KB?) :|

The 0x3000 is where I'm storing the charset in RAM. And now it all makes sense.

0
Sign in to follow this  
Followers 0


0 Comments


There are no comments to display.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now