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SSC Vectors

SSC is an abbreviation of Screen Specific Code and is a block of up to around 16,100 bytes of memory from $C000 to $FEFF.

Each Outside Screen in Wurlde has specific code to control specific screen graphics and effects.

The Main window contains the Windmill screen and the SSC memory will hold this HIRES screen, Collision Map, graphics and code to rotate the veins on the windmill, shimmer the stars in the sky and control any incidental creatures on the screen (incidental meaning that they do not directly affect the Hero).

The SSC Memory or module always has a 32 byte header that always resides between C000 to C01F

LocationVector Address
C000JMP ScreenInit Code
C003JMP ScreenRun Code
C006JMP Collision Detected
C009JMP Action Vector
C018Screen Prose Vector
C01AScreen Name Vector
C01CScreen Rules
C01DLocation ID
C01ERecognised Action Keys
C01FCollision Type
C020Collision Table vector(C02C)
C022Screen Inlay vector
C024Entering text vector
C026Interaction Header vector
C028Character List Vector
C02ACharacter Info Vector
C02CCeiling Table
C054Floor Table
C07CCollisions Table

C0A4 (onwards) always contains the Screen Inlay which always contain embedded codes for Sky and Land contours. The Screen Inlay is always 40×119.

The Vectors at $C000,C003 and C006 can be directly JSR'd to since they contain the JMP op-code in each call address.

ScreenInit is called immediately after the block is loaded.

ScreenRun is called during the main Game loop

Each Bit of the Screen Rules Byte defines a rule that applies to the screen.

B0Disable Hero Control until this flag is cleared (controlled through levelrun)
B1Disable Hero Jump (Standing jump, standing jump left/right, running jumps)
B2Exit Left to logical Screen Left
B3Exit Right to logical Screen Right
B7Sync to 25Hz

Recognised Action

B0Call ProcAction when Action key pressed
B1Call ProcAction when Inventory key pressed
B2Call ProcAction when Item Drop key pressed
B3Call ProcAction when Item Pickup key pressed
B4Call ProcAction when Up key pressed

Screen Prose contains the text that will be displayed in the textbox and should be a description of the location. Dimensions are 35×7. A line terminator is “%” and the passage terminator always “]”. Codes below 32 trigger Object names Codes between 128 and 143 trigger Group names Codes between 144 and 175 trigger Character names Codes between 176 and 207 trigger Keywords Codes between 208 and 223 trigger Location names Codes above 223 trigger general texts

Screen Name is Short Name of location. Dimensions are 13×1.

oric/wurlde/ssc_vectors.txt · Last modified: 2008/10/05 20:14 by twilighte