First pass on terrain craters

Also refactored collision/physics functions for improved appearance

GSCats.xcodeproj/project.pbxproj

@@ -16,6 +16,7 @@
 		706DF1641F2D39F700AA6680 /* loader.s */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.asm; path = loader.s; sourceTree = "<group>"; };
 		706DF1651F2D4A8100AA6680 /* terrain.s */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.asm; path = terrain.s; sourceTree = "<group>"; };
 		7088096D1F2ECE8D00D4C950 /* GenerateRenderSpans.py */ = {isa = PBXFileReference; lastKnownFileType = text.script.python; path = GenerateRenderSpans.py; sourceTree = "<group>"; };
+		709175C01F60D263008FAFAB /* GenerateCircles.py */ = {isa = PBXFileReference; lastKnownFileType = text.script.python; path = GenerateCircles.py; sourceTree = "<group>"; };
 		7099E3841F41022100182A82 /* gameobject.s */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.asm; path = gameobject.s; sourceTree = "<group>"; };
 		7099E3851F4107B100182A82 /* GenerateVRAMYOffset.py */ = {isa = PBXFileReference; lastKnownFileType = text.script.python; path = GenerateVRAMYOffset.py; sourceTree = "<group>"; };
 		70A80FB01F43D7F200BD34C9 /* gamemanager.s */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.asm; path = gamemanager.s; sourceTree = "<group>"; };
@@ -53,6 +54,7 @@
 				7059502B1F37A0BE00BBE90F /* GenerateVRAMTable.py */,
 				7099E3851F4107B100182A82 /* GenerateVRAMYOffset.py */,
 				700F21E01F4A3A5500D7007D /* GenerateTrigTables.py */,
+				709175C01F60D263008FAFAB /* GenerateCircles.py */,
 			);
 			sourceTree = "<group>";
 		};

GenerateCircles.py

@@ -0,0 +1,49 @@
+#!/usr/bin/env python3
+
+import sys
+import math
+
+def main(argv):
+	
+	minRadius = 3
+	maxRadius = 10
+	
+	print ("circleTable:\t\t;-Y for each X, in words")
+	
+	for radius in range(0,maxRadius+1):
+		if radius < minRadius:
+			print ("\t.addr 0")
+		else:
+			print ("\t.addr circleTable%d" % radius)
+	
+	print()
+
+	for radius in range(minRadius,maxRadius+1):
+		
+		print ("circleTable%d:" % radius)
+		print ("\t.word ",end="")
+		
+		skipMinus1 = 0
+		for p in range(0,radius):
+			x = radius-p
+			y = (int)(math.sqrt(radius*radius - x*x))
+			if p==radius-1:			# A fudge to make circles close better
+				y = radius
+			y*=-4		# Because X=words and we need -Y
+			print (y, end=",")
+
+		skipMinus1 = 0
+		for p in range(0,radius):
+			x = p+1
+			y = (int)(math.sqrt(radius*radius - x*x))
+			if p==0:				# A fudge to make circles close better
+				y = radius
+			
+			y*=-4		# Because X=words and we need -Y
+			if p==radius-1:
+				print(y)
+			else:
+				print (y, end=",")
+
+if __name__ == "__main__":
+	main(sys.argv[1:])

equates.s

@@ -19,4 +19,5 @@ PARAML1			= $08
 SCRATCH0		= $19
 SCRATCH1		= $1a
 SCRATCHL		= $19		; 16-bit version of scratch
+SCRATCHL2		= $67		; Second 16-bit scratch
 PARAM24			= $67		; 24-bit param (This is almost certainly messing up AppleSoft, but meh)

gamemanager.s

@@ -22,6 +22,21 @@ beginGameplay:
 
 	; Generate, compile, and clip terrain
 	jsr generateTerrain
+
+;	lda #40
+;	sta PARAML0
+;	lda #30
+;	sta PARAML1
+;	ldy #12
+;	jsr craterTerrain
+
+;	lda #74
+;	sta PARAML0
+;	lda #30
+;	sta PARAML1
+;	ldy #16
+;	jsr craterTerrain
+
 	jsr compileTerrain
 	jsr clipTerrain
 
@@ -83,8 +98,9 @@ gameplayLoopFire:
 gameplayLoopProjectiles:
 	sta KBDSTROBE
 	jsr unrenderProjectiles
-	jsr updateProjectiles
+	jsr updateProjectilePhysics
 	jsr renderProjectiles
+	jsr updateProjectileCollisions
 
 	lda turnRequested
 	beq gameplayLoopVictoryCondition

projectile.s

@@ -30,10 +30,11 @@ GRAVITY = $ffff	; 8.8 fixed point
 
 projectileTypes:		; Byte offsets into projectile type data structure
 	.word 50		; Damage
-	.word 0,0,0	; Padding
+	.word 12		; Crater radius
+	.word 0,0		; Padding
 
 PT_DAMAGE = 0
-
+PT_RADIUS = 2
 
 
 .macro PROJECTILEPTR_Y
@@ -133,17 +134,18 @@ fireProjectile:
 
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-; updateProjectiles
+; updateProjectilePhysics
 ;
 ; Trashes SCRATCHL
 ;
-updateProjectiles:
+updateProjectilePhysics:
 	SAVE_AY
-	lda projectileData+GO_POSX
-	bpl updateProjectilesActive
-	jmp updateProjectilesDone
 
-updateProjectilesActive:
+	lda projectileData+GO_POSX
+	bpl updateProjectilePhysicsActive
+	jmp updateProjectilePhysicsDone
+
+updateProjectilePhysicsActive:
 	; Integrate gravity over velocity
 	lda projectileData+JD_VY
 	clc
@@ -171,15 +173,11 @@ updateProjectilesActive:
 	lsr
 	lsr
 	sta projectileData+GO_POSX
-	bmi updateProjectilesOffWorld
+	bmi updateProjectilePhysicsDelete
 	cmp #TERRAINWIDTH-GAMEOBJECTWIDTH-1
-	bpl updateProjectilesOffWorld
+	bpl updateProjectilePhysicsDelete
-	bra updateProjectilesContinue
 
-updateProjectilesOffWorld:
+updateProjectilePhysicsContinue:
-	jmp updateProjectilesDelete
-
-updateProjectilesContinue:
 	; Integrate Y velocity over position
 	lda projectileData+JD_VY
 	; Convert 8.8 to 12.4
@@ -202,13 +200,31 @@ updateProjectilesContinue:
 	lsr
 	sta projectileData+GO_POSY
 	cmp #GAMEOBJECTHEIGHT
-	bmi updateProjectilesDelete
+	bmi updateProjectilePhysicsDelete
 	cmp #201
-	bpl updateProjectilesDelete
+	bpl updateProjectilePhysicsDelete
+
+updateProjectilePhysicsDone:
+	RESTORE_AY
+	rts
+
+updateProjectilePhysicsDelete:
+	jsr endProjectile
+	bra updateProjectilePhysicsDone
+
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; updateProjectileCollisions
+;
+; Trashes SCRATCHL
+;
+updateProjectileCollisions:
+	SAVE_AY
 
 	; Check for player collisions
 	ldy #0
 	lda projectileData+GO_POSX
+	bmi updateProjectileCollisionsDone	; Projectile not active
 	sta rectParams
 	lda projectileData+GO_POSY
 	sta rectParams+2
@@ -217,17 +233,17 @@ updateProjectilesContinue:
 	lda #GAMEOBJECTHEIGHT
 	sta rectParams+6
 
-updateProjectilesPlayerLoop:
+updateProjectileCollisionsPlayerLoop:
 	iny
 	cpy #NUMPLAYERS
-	beq updateProjectilesPlayerDone
+	beq updateProjectileCollisionsPlayerDone
 	cpy currentPlayer
-	beq updateProjectilesPlayerLoop
+	beq updateProjectileCollisionsPlayerLoop
 	jsr playerIntersectRect
 	cmp #0
-	bne updateProjectilesPlayerHit
+	bne updateProjectileCollisionsPlayerHit
 
-updateProjectilesPlayerDone:
+updateProjectileCollisionsPlayerDone:
 
 	; Check for terrain collisions
 	lda projectileData+GO_POSX
@@ -241,27 +257,36 @@ updateProjectilesPlayerDone:
 
 	jsr intersectRectTerrain
 	cmp #0
-	bne updateProjectilesTerrainHit
+	bne updateProjectileCollisionsTerrainHit
 
-updateProjectilesDone:
+updateProjectileCollisionsDone:
 	RESTORE_AY
 	rts
 
-updateProjectilesDelete:
+updateProjectileCollisionsPlayerHit:
+	jsr processPlayerImpact
+	jsr endProjectile
+	bra updateProjectileCollisionsDone
+
+updateProjectileCollisionsTerrainHit:
+	jsr processTerrainImpact
+	jsr endProjectile
+	bra updateProjectileCollisionsDone
+
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; endProjectile
+;
+; Trashes A and Y
+;
+endProjectile:
 	ldy #0
 	jsr deleteProjectile
 	lda #1
 	sta turnRequested
 	lda #-1
 	sta projectileActive
-	bra updateProjectilesDone
+	rts
-
-updateProjectilesPlayerHit:
-	jsr processPlayerImpact
-	bra updateProjectilesDelete
-
-updateProjectilesTerrainHit:
-	bra updateProjectilesDelete
 
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
@@ -348,3 +373,34 @@ processPlayerImpactDeath:
 	lda currentPlayer
 	sta gameOver
 	rts
+
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; processTerrainImpact
+;
+; Trashes A,Y
+;
+processTerrainImpact:
+	ldy #0		; Assume projectile 0
+	PROJECTILEPTR_Y
+	lda projectileData+GO_POSX,y
+	clc
+	adc #GAMEOBJECTWIDTH/2
+	sta PARAML0
+	lda projectileData+GO_POSY,y
+	sec
+	sbc #GAMEOBJECTHEIGHT
+	sta PARAML1
+
+	lda projectileData+JD_TYPE,y
+	tay
+	PROJECTILETYPEPTR_Y
+
+	lda projectileTypes+PT_RADIUS,y
+	tay
+
+	jsr craterTerrain
+	jsr compileTerrain
+	jsr clipTerrain
+
+	rts

tables.s

@@ -152,3 +152,32 @@ vramYOffset:
 	.word $6400,$64a0,$6540,$65e0,$6680,$6720,$67c0,$6860,$6900,$69a0,$6a40,$6ae0,$6b80,$6c20,$6cc0,$6d60,$6e00,$6ea0,$6f40,$6fe0
 	.word $7080,$7120,$71c0,$7260,$7300,$73a0,$7440,$74e0,$7580,$7620,$76c0,$7760,$7800,$78a0,$7940,$79e0,$7a80,$7b20,$7bc0,$7c60
 
+circleTable:		;-Y for each X, in words
+	.addr 0
+	.addr 0
+	.addr 0
+	.addr circleTable3
+	.addr circleTable4
+	.addr circleTable5
+	.addr circleTable6
+	.addr circleTable7
+	.addr circleTable8
+	.addr circleTable9
+	.addr circleTable10
+
+circleTable3:
+	.word 0,-8,-12,-12,-8,0
+circleTable4:
+	.word 0,-8,-12,-16,-16,-12,-8,0
+circleTable5:
+	.word 0,-12,-16,-16,-20,-20,-16,-16,-12,0
+circleTable6:
+	.word 0,-12,-16,-20,-20,-24,-24,-20,-20,-16,-12,0
+circleTable7:
+	.word 0,-12,-16,-20,-24,-24,-28,-28,-24,-24,-20,-16,-12,0
+circleTable8:
+	.word 0,-12,-20,-24,-24,-28,-28,-32,-32,-28,-28,-24,-24,-20,-12,0
+circleTable9:
+	.word 0,-16,-20,-24,-28,-32,-32,-32,-36,-36,-32,-32,-32,-28,-24,-20,-16,0
+circleTable10:
+	.word 0,-16,-24,-28,-32,-32,-36,-36,-36,-40,-40,-36,-36,-36,-32,-32,-28,-24,-16,0

terrain.s

@@ -47,6 +47,60 @@ renderRowComplete:
 	rts
 
 
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; craterTerrain
+;
+; PARAML0 = X pos of center in pixels from logical left terrain edge
+; PARAML1 = Y pos of center in pixels from bottom terrain edge
+; Y = Radius of circle, in pixels
+;
+; Trashes SCRATCHL
+craterTerrain:
+	SAVE_AX
+
+	lda #TERRAINWIDTH		; Convert X pos to terrain-right byte count
+	sec
+	sbc PARAML0
+	sty SCRATCHL			; Center width
+	sbc SCRATCHL
+	lsr
+	and #$fffe
+	clc
+	adc #terrainData
+	sta PARAML0
+
+	phy
+	tya						; Look up circle data
+	lsr
+	tay
+	lda circleTable,y
+	sta SCRATCHL
+	ply
+
+craterTerrainLoop:
+	dey
+	dey
+	bmi craterTerrainDone
+
+	lda (SCRATCHL),y		; Fetch circle Y value
+	clc
+	adc PARAML1				; Convert to terrain-space
+	sta SCRATCHL2
+	lda (PARAML0),y
+	cmp SCRATCHL2
+	bmi craterTerrainLoop
+
+	lda SCRATCHL2			; Circle value is lower, so use that
+	sta (PARAML0),y
+	bra craterTerrainLoop
+
+craterTerrainDone:
+	lda #1
+	sta terrainDirty
+
+	RESTORE_AX
+	rts
+
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ; clipTerrain
@@ -272,7 +326,7 @@ generateTerrainLoop:
 
 
 
-; Terrain data, stored as height values 4 pixels wide
+; Terrain data, stored as height values 4 pixels wide (words)
 
 terrainData:
 	.repeat TERRAINWIDTH/4  ; VISIBLETERRAINWIDTH