BOING

Author: omiq

examples/boing.bas

@@ -0,0 +1,80 @@
+#OPTION petscii
+
+REM ================================
+REM   BOING!
+REM   Amiga Boing Ball Tribute
+REM   for RGC-BASIC
+REM ================================
+REM
+REM Uses SCREEN 1 bitmap for the grid
+REM and a PNG sprite sheet for the ball.
+REM
+REM Requires: boing_sheet.png (768x64
+REM sprite sheet, 12 frames of 64x64)
+
+REM Switch to 320x200 bitmap mode
+SCREEN 1
+COLOR 1
+BACKGROUND 6
+
+REM Load the ball sprite sheet
+REM 12 frames, each 64x64 pixels
+LOADSPRITE 1, "boing_sheet.png", 64, 64
+LOADSPRITE 2, "boing_shadow.png"
+SPRITEMODULATE 2, 150, 255, 255, 255
+SPRITEVISIBLE 1, 1
+SPRITEVISIBLE 2, 1
+
+
+REM Draw the grid background
+GOSUB DrawGrid
+
+REM Ball position, velocity, sprite frame index (BF — avoid name FRAME; clashes with SPRITEFRAME in some editors)
+REM One line keeps numbered-line IDEs from inserting an unnumbered "FRAME = 1" (that breaks parsing).
+BX = 40 : BY = 10 : VX = 2 : VY = 2 : BF = 1
+
+REM ~10 animation fps: 60 jiffies/s / 10 = 6 jiffies per sprite frame (TI = wall clock in canvas/basic-gfx)
+JIFFIES_PER_FRAME = 6
+LAST = TI
+
+REM === Main Loop ===
+DO
+
+  DRAWSPRITE 2, BX+8, BY+8, 1
+  REM Draw ball at current rotation frame
+  DRAWSPRITETILE 1, BX, BY, BF, 2
+
+  
+
+  SLEEP 1
+
+  REM Update position every frame (movement speed unchanged)
+  BX = BX + VX
+  BY = BY + VY
+
+  REM Advance rotation on TI — independent of movement
+  IF TI - LAST >= JIFFIES_PER_FRAME THEN
+    LAST = TI
+    BF = BF + 1
+    IF BF > 12 THEN BF = 1
+  END IF
+
+  REM Bounce off edges
+  IF BX < 0 OR BX > 256 THEN VX = -VX
+  IF BY < 0 OR BY > 130 THEN VY = -VY
+
+LOOP
+
+REM ----- Draw grid with LINE -----
+DrawGrid:
+  REM Vertical lines
+  FOR X = 20 TO 300 STEP 20
+    LINE X, 0 TO X, 199
+  NEXT X
+
+  REM Horizontal lines
+  FOR Y = 14 TO 199 STEP 14
+    LINE 0, Y TO 319, Y
+  NEXT Y
+RETURN
+