====== VIC Programming ======

On this page you find graphics programming information in general, such as how to set up various graphics modes, how to draw on screen, or how to display and move a sprite. If you are looking for information on how to code certain demo effects, you should look in the [[base:demo_programming|Demo Effects]] section instead.

The general rule of thumb is that //if something is of more general use than just for demo effects, or if it is too simple or restricted to constitute a full demo effect in itself (such as opening the borders or achieving a specific custom screen mode through VIC trickery), you will find it here rather than in the demo coding section.//

There is also some information related to VIC programming in the [[base:game_programming|Game Coding]] section, and there is some information on 3d math in the [[base:6502_6510_maths|maths]] section.

===== Basics =====
  * [[Visible area]] - How much of the overscan area actual monitors actually show
  * [[Pixel aspect ratio]] - To sum it up, it's 0.9365:1 (X:Y) on PAL
  * [[magazines:chacking4#introduction_to_the_vic-ii|Introduction to the VIC]] - by Pasi 'Albert' Ojala (from C= Hacking 4).
  * [[base:memconfig|Memory configuration]] - See the memory configuration section to see how to select VIC bank and where to place sprites etc.
  * [[base:interrupts|Interrupts and timing]] - See the section on interrupts for information on VIC/raster interrupts.
  * [[Built in screen modes]] - written and compiled by Oswald/Resource
  * [[base:spriteintro|Introduction to Sprites]] - written and compiled by Oswald/Resource
===== Using built in screen modes =====
  * [[petscii to screencode|Convert ASCII/PETSCII to screencodes]] by Mace/Secure
  * [[make modified character sets|Applications of modified character sets]]
  * [[Displaying a picture at $2000|Display a multicolor Koala Picture]] by Richard Bayliss
  * [[Calculate VIC settings for showing a koala|Generic koala shower (VIC settings calculator)]] by JTR/DMAgic

===== Sprites =====

See the general section on how to use sprites. It contains basic usage as well as sprite multiplexers and other things, including (some) demo effects with sprites.

  * [[base:sprites|Sprites]] - General section on sprites

===== Drawing on the screen =====

  * [[Various techniques to calculate adresses fast, common screen formats for pixel graphics]]
  * [[Rather small and rather fast screen offset component splitter]] - by JackAsser/Instinct
  * [[Bresenham's line algorithm]] - basic implementation - by Raf/Vulture Design
  * [[Bresenham's line algorithm 2]] - by Hein
  * [[Lines]] (bresenham, collecting pixels into one byte, runlength slice) - by Bitbreaker FIXME (slope and sing the SID / CIA for slopes still missing)
  * [[Filling the vectors]] - by Bitbreaker
  * [[Dots and Plots]] - by TWW/CTR
  * [[Bresenham Circle Routine]] - Implementation by Scout
  * [[Circle Routine]] - by Verz
  * [[Draw RAM to screen or color memory]] - by malcontent
  * [[4x4 mode and circle routine]] - by malcontent

=====  VICII Hardware tricks =====
This section is more about the workings of the VIC chip than about certain demo effects which are //based// on these VIC tricks.

==== Border ====

  * Opening upper and lower borders
    * [[Removing the top/bottom border|Short code]] - by HCL/Booze Design
    * [[Opening the top/bottom borders|Opening the borders]] - by Richard Bayliss
    * [[magazines:chacking6#opening_the_borders|The long story]] - by Pasi 'Albert' Ojala (C= Hacking #6)
    * [[Opening up the borders - a further explanation]] - by TheHighlander
    * [[base:upper_lower_borders|Opening borders and other things]] - by Karmic/HVSC
  * [[Sprites in bottom sideborder]] - by Groepaz/Hitmen
  * [[Removing the sideborders]] - by HCL/Booze Design
  * [[Displaying graphics using $3fff]]  

==== Screen ====

=== Vertical Movement ===

  * [[FLD]] - Flexible Line Distance - by HCL/Booze Design
  * [[Linecrunch]] - Vertical Screen Positioning
  * [[Double Screen Vertical Scroller]] - Using simple copy method with double buffer
  * [[Smooth Linecrunch]] - by Karmic/HVSC/HF

=== Horizontal Movement ===

  * [[Horizontal Screen Positioning (HSP)|HSP]] -  Horizontal Screen Positioning (aka Wanker aka DMA-Delay/VSP - Variable Screen Positioning).

=== Useful Combinations ===

  * [[AGSP (Any Given Screen Position)|AGSP]] - Any Given Screen Position (VSP and LineCrunch combined)
  * [[Double Screen Horizontal Scroller|Double Screen Horizontal Scroller]] - Using VSP to display a double bitmap picture (80x25 chars)

=== Vertical Tweaks ===

  * [[Introduction to vertical tweaks]]
  * [[FLD]] - Flexible Line Distance - by HCL/Booze Design
  * [[FPD]] - Flexible Pixel Distance
  * [[FPS]] - Flexible Pixel Size (like FPD but stretching pixels)
  * [[FPP]] - Flexible Pixel Position
    * [[FPP-last-line|FPP]] - by repeating the last line
    * [[FPP-first-line|FPP]] - by repeating the first line
  * [[Repeating char-lines]] - by HCL/Booze Design

NOTE: The names of above vertical movements are legacy and not always explicative. 'Line' in FLD refers to a char-line of 8 pixels hight. 'Pixel' in FPD etc refers to a single line of graphics.

==== Sprites ====

This section about sprites..

=== Vertical Tweaks ===

  * [[Stretching sprites]] - using $d017.
  * [[Sprite FPD]]
  * [[Sprite FPP]]
  * [[Sprite-crunching]]
=== Sprite Tweaks in general ===

* [[9th Sprite]] code and explanation
=====  Custom Graphics Modes =====

This section is for custom graphics modes only, as contrasted to the built in graphics modes with official hardware support, such as hires, multicolor, etc.

=== Non-tweaked modes ===

  * [[SH]] - Super Hires
  * [[Drazlace]]
    *[[Drazlace displayer|Display Drazlace picture]] - by HCL

=== Tweaked modes ===

  * [[FLI]] -  Flexible Line Interlace
    * [[magazines:chacking4#fli_-_more_color_to_the_screen|FLI]] -  More color to the screen - by Pasi Ojala (C=Hacking #4).
    * [[FLI displayer]] - by Graham
    * [[40 Bytes FLI displayer|FLI displayer]] - by Crossbow (only 40 bytes long)
  * [[Hires FLI]] -  High Resolution FLI
  * [[IFLI]] - Interlaced FLI
  * ([[AFLI]] - Advanced FLI)
  * [[UFLI]] - Underlayer FLI
  * [[SHFLI]] - Super Hires FLI
  * [[SHIFLI]] - Super Hires Interlace FLI
  * [[XFLI]] - EndOfNameSpace :) FLI

=== Others ===

  * [[Junk Modes]] - low resolution modes with charsets
  * [[4x4 FLI chunky mode]]

====  Editors for the Custom Graphics Modes ====
See the general section on:

  * [[GFX Editors and Converters]]

===== Color info =====

  * [[VIC-II Color Cheatsheet]] - by Groepaz
  * [[Commodore VIC-II Color Analysis]] - by Pepto
  * {{ :base:colfade_v2.pdf | Color fade (color ramps)}} - by Veto

===== Graphics file formats =====

  * [[c64 grafix files specs list v0.03|C64 Graphics File Format Specs]] - by Groepaz

There is also a nice collection of file format info at AAY64:

  * [[http://unusedino.de/ec64/technical/aay/c64/frmmain.htm]] - Graphics file formats
===== Various VIC related =====
  * [[https://ist.uwaterloo.ca/~schepers/MJK/ascii/VIC-Article.txt|VIC-Article]] - The mighty... By Christian Bauer. (external link)
  * [[http://unusedino.de/ec64/technical/aay/c64/vicmain.htm|VIC register reference at AAY64]] - Very handy online reference. By Ninja/The Dreams
  * [[Detect VIC Type]] - by Crossbow
  * [[Detect PAL/NTSC]] - Various routines
  * [[base:ntsc_pal_differences|NTSC/PAL Differences]] - article from Domination #13 written by Decomp/Style