;;==========================================================================;; ;; Joe Zbiciak's Space Patrol for Intellivision. ;; ;; Copyright 2006, Joe Zbiciak, intvnut AT gmail.com. ;; ;; http://spatula-city.org/~im14u2c/intv/ ;; ;;==========================================================================;; ;;==========================================================================;; ;; UPSPA Updates sprite allocations within each MOB group. ;; ;;==========================================================================;; UPSPA PROC ;;------------------------------------------------------------------;; ;; Recalc GP1ACT, GP2ACT. ;; ;;------------------------------------------------------------------;; MVII #SPAT, R4 ; 8 Point to sprite attribute table MVII #3, R3 ; 8 We reuse this 4 times. ;---- ; 16 ; totally abuse the fact bit 1 is always 0 MVI@ R4, R0 ; 8 ADD@ R4, R0 ; 8 ADD@ R4, R0 ; 8 MVI@ R4, R1 ; 8 ADD@ R4, R1 ; 8 ANDR R3, R0 ; 6 ANDR R3, R1 ; 6 ADDR R0, R1 ; 6 MVO R1, GP1ACT ; 11 ;---- ; 69 MVI@ R4, R0 ; 8 ADD@ R4, R0 ; 8 ADD@ R4, R0 ; 8 MVI@ R4, R1 ; 8 ADD@ R4, R1 ; 8 ADD@ R4, R1 ; 8 ANDR R3, R0 ; 6 ANDR R3, R1 ; 6 ADDR R0, R1 ; 6 AND@ R4, R3 ; 8 ADDR R3, R1 ; 6 MVO R1, GP2ACT ; 11 ;---- ; 91 ; 16 (carried forward) ; 69 (carried forward) ;---- ; 176 ;;------------------------------------------------------------------;; ;; Allocate active objects to actual MOBs. ;; ;; ;; ;; Objects are divided into two groups. Group 1 objects are the ;; ;; "bad guy" objects, and Group 2 objects are the bullets. Each ;; ;; group gets 3 MOBs by default. If one of the groups has fewer ;; ;; than 3 active sprites, then the other group may use the left- ;; ;; over MOBs. ;; ;; ;; ;; The reason we divide up the objects into two groups like this ;; ;; is that we typically have between 1 and 3 creeps (but as many ;; ;; as 5 in rare circumstances). In contrast, we typically have ;; ;; around 3 to 5 bullets in the air, with up to 7 being in flight. ;; ;; The creeps are more susceptible to multiplexing artifacts than ;; ;; the bullets, so we want to give them preference when muxing ;; ;; MOBs. This arrangement ends up working out pretty well. ;; ;; ;; ;; Addendum: If the level marker is onscreen, it steals from ;; ;; Group 2. The level marker always gets a MOB. ;; ;;------------------------------------------------------------------;; @@spa: MVII #3, R0 ; 8 R0 is Group 1's MOB allocation CLRR R3 ; 6 Used for resetting MUX counter CLRR R1 ; 6 CMP LMCNT, R1 ; 10 Is level marker active? BEQ @@no_level_marker ; 9/7 DECR R1 ; 6 ;---- ; 43 ; 176 ;---- ; 219 @@no_level_marker: ADDR R0, R1 ; 6 R1 is Group 2's MOB allocation ; (2 if level marker active, 3 ; otherwise.) MOVR R0, R2 ; 6 SUB GP1ACT, R2 ; 10 3 or more active in Group 1? BMI @@gp1full ; 7/9 Yes -- go straight to Group 2 ADDR R2, R1 ; 6 No -- add extra to Group 2's MOBs MVI GP1ACT, R0 ; 10 Clamp Group 1 to actual # of active MVO R3, GP1CNT ; 10 Reset MUX counter. MVI GP2ACT, R2 ; 10 Get # of active in Group 2 CMPR R2, R1 ; 6 Fewer MOBs than active? BLT @@spadone ; 7/9 Yes -- done allocating MOVR R2, R1 ; 6 No -- Clamp to number of active MVO R3, GP2CNT ; 10 Reset MUX counter. B @@spadone ; 9 Done allocating ;---- ; 103 (only last branch taken) ; 31 (if jumping to gp1full) @@gp1full: MOVR R1, R2 ; 6 SUB GP2ACT, R2 ; 10 More sprites than MOBs in group 2? BMI @@spadone ; 7/9 Yes -- done allocating ADDR R2, R0 ; 6 No -- add extra to Group 1's MOBs MVI GP2ACT, R1 ; 10 Clamp Group 2 to actual # of active MVO R3, GP2CNT ; 10 Reset MUX counter. MVI GP1ACT, R2 ; 10 Get # of active in Group 1 CMPR R2, R0 ; 6 Fewer MOBs than active? BLT @@spadone ; 7/9 Yes -- done allocating MOVR R2, R0 ; 6 No -- Clamp to number of active MVO R3, GP1CNT ; 10 Reset MUX counter. ; B @@spadone ;.... Done allocating ;---- ; 88 (fall thru) ; 31 (carried forward) ;---- ; 119 @@spadone: MVO R0, GP1MOB ; 11 MVO R1, GP2MOB ; 11 JR R5 ; 7 ;---- ; 29 ; 219 (carried forward) ; 119 (carried forward) ; 12 (call overhead) ;---- ; 379 ENDP ;* ======================================================================== *; ;* This program is free software; you can redistribute it and/or modify *; ;* it under the terms of the GNU General Public License as published by *; ;* the Free Software Foundation; either version 2 of the License, or *; ;* (at your option) any later version. *; ;* *; ;* This program is distributed in the hope that it will be useful, *; ;* but WITHOUT ANY WARRANTY; without even the implied warranty of *; ;* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU *; ;* General Public License for more details. *; ;* *; ;* You should have received a copy of the GNU General Public License *; ;* along with this program; if not, write to the Free Software *; ;* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. *; ;* ======================================================================== *; ;* Copyright (c) 2006, Joseph Zbiciak *; ;* ======================================================================== *;