Commodore Amiga - Page 8

Chapter 3 PLAYFIELD HARDWARE ..................................................................... 27
Introduction .......................................................................................................... ,.................. 27
ABOUT THIS CIIAPTER
............................................................................................ 28
PLAYFIELD FEATURES
............................................................................................ 28
Forming a Basic Playfield ............................................................................................ 33
HEIGHT AND WIDTH
OF THE PLAYFIELD .................................................. 34
BIT-PLANES AND COLOR ....................................................................................... 34
SELECTING RESOLUTION
...................................................................................... 38
ALLOCATING MEMORY
FOR BIT-PLANES .................................................. 41
CODING
THE BIT-PLANES FOR CORRECT COLORING ...................... 44
DEFINING
THE SIZE OF THE DISPLAY WINDOW................................... 46
TELLING
THE SYSTEM HOW TO FETCH AND DISPLAY
DATA
................................................................................................................................... 49
DISPLAYING AND REDISPLAYING THE PLAYFIELD ............................. 52
ENABLING THE COLOR DISPLAY
..................................................................... 52
SUMMARY
......................................................................................................................... 53
EXAMPLES
OF FORMING BASIC PLAYFIELDS .......................................... 55
Forming a Dual-playfield Display .......................................................................... 58
Bit-Plane Assignment in Dual-playfield Mode ............................................. 60
COLOR REGISTERS IN DUAL-PLAYFIELD MODE .................................... 62
DUAL-PLAYFIELD PRIORITY AND CONTROL
........................................... 64
ACTIVATING DUAL-PLAYFIELD MODE
......................................................... 64
SUMMARY
......................................................................................................................... 65
Bit-planes and Display Windows of All Sizes ............................................... 65
WHEN THE BIG PICTURE IS LARGER THAN
THE DISPLAY
WINDOW
........................................................................................................................... 65
MAXIMUM DISPLAY WINDOW SIZE
................................................................. 72
Moving (Scrolling) Playfields ..................................................................................... 73
VERTICAL SCROLLING ............................................................................................ 73
HORIZONTAL SCROLLING
..................................................................................... 74
SUMMARY ......................................................................................................................... 78
Advanced Topics ................................................................................................................. 79
INTERACTIONS- PLAYFIELDS AND OTHER OBJECTS .................... 79
HOLD-AND-MODIFY MODE
.................................................................................... 79
FORMING A DISPLAY WITH SEVERAL DIFFERENT
PLA YFIELDS .................................................................................................................... 82
USING AN EXTERNAL VIDEO SOURCE
......................................................... 82
SUMMARY
OF PLAYFIELD REGISTERS ......................................................... 83
Summary of Color Selection ....................................................................................... 86
COLOR REGISTER CONTENTS ........................................................................... 86
SOME SAMPLE COLOR REGISTER CONTENTS ........................................ 86
COLOR SELEOTION IN LOW-RESOLUTION MODE ................................ 87
COLOR SELEOTION IN HOLD-AND-MODIFY MODE
............................... 89
COLOR SELEOTION IN HIGH-RESOLUTION MODE
................................ 89
-x-