******************************************************************************** * oo oo * * \( )/ Bullfrog Demo \( )/ * * ^ ^^ ^ Movement ^ ^^ ^ * ******************************************************************************** ;LEVEL equ 0 ;Current Level 0 or 1 GRAVITY equ 2 ;Speed at which gravity affects man MAX_SPEED equ 16 ;maximum speed of man JUMP equ 20 ACEL equ 3 ;speed of accleration for man MAN_LEFT_START equ 4*4 ;start frame number for man running left MAN_LEFT_FINISH equ 1*4 ;end frame number for man running left MAN_STATIONARY equ 5*4 ;frame for man standing still MAN_RIGHT_START equ 6*4 ;start frame number for man running right MAN_RIGHT_FINISH equ 9*4 ;end frame number for man running right LEFT_FOOT equ 3 ;mans left foot RIGHT_FOOT equ 10 ;mans right foot ******************************************************************************** _move_all tst.w _pressed_fire ;are we in the middle of a jump bne.s .no_fire ;yes so dont check for jump tst.w _fire ;is the fire button pressed beq.s .no_fire ;no so dont jump move.w #-JUMP,man_vy ;yes it was, jump into y-velocity move.w #1,_pressed_fire ;and set jump flag .no_fire jsr _man_x ;move the man left and right jsr _man_y ;move the man up and down jsr _man_anim ;animate the man. jsr _map_collision ;has the man hit a block rts ;return ******************************************************************************** *Move man left and right with joystick *Uses the variables man_x - mans x position on screen * man_vx - mans current x velocity * _dx_joy - reads the joystick x. -1 if left, 1 if right. _man_x move.w man_vx,d0 ;move the value in man_vx into d0 move.w #0,d2 tst.w _pressed_fire ;are we jumping bne.s .jumping move.w _dx_joy,d2 ;move joystick value to d2 mulu #ACEL,d2 ;multiply it by accleration add.w d2,d0 cmp.w #MAX_SPEED+1,d0 ;is the value in d0 is ble.s .lessthanx ;less than or equal to the maximum speed move.w #MAX_SPEED+1,d0 ;if it isnt then change it back to max speed .lessthanx cmp.w #-MAX_SPEED-1,d0 ;see if value in d0 is bge.s .greaterthanx ;greater than or equal to the maximum speed move.w #-MAX_SPEED-1,d0 ;if not then replace with max speed .greaterthanx .jumping move.w man_x,d1 ;where the man is add.w d0,d1 ;add his velocity bgt.s .not_left_side ;if greater than 0 not at edge of screen move.w #0,d0 ;otherwise stop momentum move.w #0,d1 ;and place us at edge of screen .not_left_side cmp.w #304*4,d1 ;at the right hand edge of screen? blt.s .not_right_side ;no. good. move.w #0,d0 ;otherwise stop momentum move.w #304*4,d1 ;place at edge of screen .not_right_side tst.w _dx_joy ;have we actual changed velocity bne.s .no_reduction ;yes, then dont slow down tst.w d0 ;which way are we going beq.s .no_reduction ;we are not moving blt.s .going_left ;going left .going_right ;where going right sub.w #2,d0 ;reduce speed .going_left add.w #1,d0 ;reduce speed .no_reduction ;finished move.w d0,man_vx ;store new momentum move.w d1,man_x ;store the new value in man_x rts ;return ******************************************************************************** _man_y move.w #1,_pressed_fire ;set falling/jump flag move.w man_y,d0 ;get man y position move.w man_vy,d1 ;get man y velocity add.w #GRAVITY,d1 ;add gravity to it cmp.w #MAX_SPEED,d1 ;see if we have gone over max speed ble.s .below_max_speed ;no then jump past this bit move.w #MAX_SPEED,d1 ;yes, place max speed into d1 .below_max_speed add.w d1,d0 ;change position by speed move.w d0,man_y ;store new position move.w d1,man_vy ;store new speed rts ;return ******************************************************************************** *Animation of man. _man_anim move.w man_frame,d0 ;pick up current frame of man tst.w man_vx ;see if man is stationary beq.s .stationary_man ;he is so goto that code blt.s .man_move_left ;is he going left add.w #1,d0 ;no so add 1 to animation frame cmp.w #MAN_RIGHT_FINISH,d0 ;see if we have got to the end blt.s .finished_anim ;if not then we have finished move.w #MAN_RIGHT_START,d0 ;otherwise replace with start anim bra.s .finished_anim ;again we have finished .man_move_left ;OK so we are going left sub.w #1,d0 ;subtract 1 from animation frame cmp.w #MAN_LEFT_FINISH,d0 ;have we got to end of animation bgt.s .finished_anim ;no then we have finished move.w #MAN_LEFT_START,d0 ;yes, so restart animation bra.s .finished_anim ;again we have finished .stationary_man ;the man is not moving move.w #MAN_STATIONARY,d0 ;so lets put the animation frame in .finished_anim ;finished changing things move.w d0,man_frame ;so put back current frame rts ;and return. ******************************************************************************** _map_collision move.w man_x,d0 ;mans x position move.w man_y,d1 ;mans y position lea _map_data,a0 ;point at map data asr.w #FOUR,d0 ;hi res co-ord move.w d0,d4 ;take a copy of current x add.w #LEFT_FOOT,d0 ;his feet size asr.w #SIXTEEN,d0 ;block coord asr.w #FOUR,d1 ;hi res co-ord add.w #24,d1 ;find bottom of man asr.w #FOUR,d1 ;scale down btst #0,d1 ;is this an odd number bne.s .no_collision ;yes, then no collide btst #1,d1 ;is the second bit set bne.s .no_collision ;yes, then no collide asr.w #FOUR,d1 ;scale y position rest of way down move.w d1,d3 ;copy of current y mulu #20,d1 ;offset into map data adda.l d1,a0 ;move to start of line adda.l d0,a0 ;move to column tst.b (a0) ;is this a block or not bne.s .collision ;yes then goto collide ;that was his left foot, now do ;his right foot lea _map_data,a0 ;point at data adda.l d1,a0 ;move to start row add.w #RIGHT_FOOT,d4 ;change x by size of foot asr.w #SIXTEEN,d4 ;and scale down to grid adda.l d4,a0 ;move into data tst.b (a0) ;is this a block beq.s .no_collision ;no then finished here .collision clr.w _pressed_fire ;clear falling flag as on a block move.w #-1,man_vy ;stop mans speed asl.w #SIXTEEN,d3 ;and recalculate his y position sub.w #24,d3 ;so that he is standing asl.w #FOUR,d3 ;on top of the block move.w d3,man_y ;store his new y position .no_collision rts ;finished ******************************************************************************** ;;;