! A game of colored balls. ! ! Every time you bounce a ball off a wall of the same color, the red ! score-line at the bottom of the screen will advance by a little. ! Every time you bounce a ball off a different-colored wall, the ! score-line will retreat. To win, advance the score line all the way ! to the right edge of the screen. ! ! This game demonstrates the use of the Developer's Toolkit animation ! routines. It uses only Sprite-type objects. There are two tricky ! things to watch for when reading this program. First, we use sprites ! for one paddle and up to three balls. Since the balls must be ! able to change color independently, we use sprites 1, 3 and 5 (which ! don't share colors with each other). This leaves no independent ! sprite for the paddle (since 6 and 7 are unavailable, as usual). So ! we use sprite 2 for the paddle, but use only colors 1 and 2 in the ! paddle image. Then we change only color 3 to change the color of the ! balls. This way, the image of the paddle won't change color when we ! change the color of the ball that shares colors with it. Whew! ! ! The other trick is that the left border (object 1) is in color 1 and ! the right border (object 2) is in color 2. So we save time by using ! object numbers as color numbers when testing for collisions with ! identically-colored walls. ! LIBRARY "libs/animate*","libs/amiga*" DECLARE DEF makesprite DIM balls(0:7) ! table of ball object numbers DIM colors(0:7) ! matching table of current ball colors SET mode "low4" RANDOMIZE LET screenwidth = 320*32-1 ! animation uses thirty-seconds of a pixel LET screenheight = 200*32-1 SET window 0,screenwidth,screenheight,0 ! so do we SET color mix (0) 1,1,1 ! background SET color mix (1) 0,1,0 ! left wall SET color mix (2) .5,0,1 ! right wall SET color mix (3) 1,0,0 ! score line LET ballwidth = 10*32 ! parameters for object sizes LET ballheight = 6*32 LET paddlewidth = 10*32 LET halfpaddlewidth = paddlewidth/2 LET paddleheight = 20*32 LET xmin = 6*32 ! borders for animation LET xmax = 314*32 LET ymin = 5*32 LET ymax = 195*32 CALL initanimation ! initialize animation routines CALL makestrings(ball$,paddle$) ! make BOX KEEP strings ball$ and paddle$ CALL makepaddle(paddle) ! make paddle object LET nextball = 1 CALL addball ! add the first ball -- sprite 1, color 1 SET color 1 BOX AREA 0,xmin,0,ymax ! draw left wall SET color 2 BOX AREA xmax,screenwidth,0,ymax ! draw right wall CALL setborder(xmin,xmax,ymin,ymax) ! set collision border CALL changescore(128*32) ! initial score (nearly halfway there) DO CALL animate_all(-1,vs1,vs2) ! animate until there's a collision IF vs1 = paddle then LET vs1 = vs2 ! make vs1 the ball object FOR i = 1 to 5 step 2 ! get number of this ball IF balls(i) = vs1 then EXIT FOR NEXT i CALL getob_vel(vs1,dx,dy) ! get current x,y velocities SELECT CASE vs2 ! branch on what we hit CASE 1,2 ! left or right wall IF colors(i) <> vs2 then ! compare color# with border object# CALL changescore(-300) ! bad hit ELSE CALL changescore(50) ! good hit END IF IF rnd<.2 then CALL changecolor(i,vs1) ! flip color sometimes LET dx = -dx ! bounce off wall CASE 3,4 ! top or bottom wall LET dy = -dy ! bounce off wall CASE else ! paddle CALL getob_loc(vs1,x,y) ! get location too CALL getob_loc(paddle,px,py) ! and location of paddle IF x-px > halfpaddlewidth then ! ball closest to right side LET x = px+paddlewidth+1 ! pop ball to right of paddle LET dx = abs(dx) ! x velocity will be positive ELSE ! ball closest to left side LET x = px-ballwidth-33 ! pop ball to left of paddle LET dx = -abs(dx) ! x velocity will be negative END IF IF y <= ymin+1 then ! make sure we're not above top border LET y = ymin+1 ELSE if y >= ymax-ballheight-33 then ! or below bottom border LET y = ymax-ballheight-33 END IF LET dy = -dy ! nothing tricky -- it's hard enough CALL setob_loc(vs1,x,y) ! pop ball to new location END SELECT CALL setob_vel(vs1,dx,dy) ! set adjusted velocity LET count = count + 1 ! count collisions IF (count>100 and nextball=3) or (count>300 and nextball=5) then CALL addball ! add another ball END IF LOOP until key input CALL endanimation SUB changescore(delta) IF delta>0 then SET color 3 else SET color 0 BOX AREA score,score+delta,ymax,screenheight ! change score LET score = score + delta ! remember new score IF score < 0 then CALL youlose ! lost IF score > screenwidth then CALL youwin ! won END SUB SUB changecolor(i,sprite) IF colors(i) = 2 then ! flip color from 2 to 1 CALL setsprite_color(sprite,3,0,1,0) LET colors(i) = 1 ELSE ! flip color from 1 to 2 CALL setsprite_color(sprite,3,.5,0,1) LET colors(i) = 2 END IF END SUB SUB addball LET colors(nextball) = 2 ! we'll flip to make balls start out color 1 LET balls(nextball) = makesprite(ball$,nextball,10*32,100*32) CALL changecolor(nextball,balls(nextball)) ! set color 1 CALL setob_mask(balls(nextball),1,2) ! hits border, paddle CALL setob_vel(balls(nextball),32+int(16*rnd),16+int(16*rnd)) CALL setsprite_color(balls(nextball),2,1,0,0) ! set border color LET nextball = nextball+2 ! 1 to 3, 3 to 5, 5 to more-than-5 END SUB SUB makepaddle(paddle) LET paddle = makesprite(paddle$,2,155*32,185*32) CALL setob_mask(paddle,2,0) ! hits balls only CALL setob_mouse(paddle,0,1) ! tracks mouse in y-axis only CALL setsprite_color(paddle,2,1,0,0) ! border color same as sprites END SUB SUB makestrings(ball$,paddle$) SET color 1 ! color 1, paddle only BOX AREA 0,paddlewidth,0,paddleheight SET color 2 ! color 2, shared by balls and paddle BOX LINES 0,paddlewidth,0,paddleheight BOX KEEP 0,paddlewidth,0,paddleheight in paddle$ BOX CLEAR 0,paddlewidth,0,paddleheight BOX CIRCLE 0,ballwidth,0,ballheight SET color 3 ! color 3, balls only FLOOD ballwidth/2,ballheight/2 BOX KEEP 0,ballwidth,0,ballheight in ball$ BOX CLEAR 0,ballwidth,0,ballheight END SUB SUB youlose PAUSE 3 CALL endanimation CLEAR SET color 2 PLOT TEXT, at 100*32,100*32: "Sorry, you lose." STOP END SUB SUB youwin PAUSE 3 CALL endanimation CLEAR SET color 2 PLOT TEXT, at 65*32,100*32: "Congratulations, you win." STOP END SUB END