started on collision detection between objects

galactic-armada/src/main/states/gameplay/objects/enemies.asm

@@ -5,7 +5,7 @@ include "src/main/includes/constants.inc"
 SECTION "Enemies", ROM0
 ; ANCHOR_END: enemies-start
 
-; ANCHOR: enemies-update
+; ANCHOR: enemies-update1
 UpdateEnemy::
 
     ; get the start of our object back in hl
@@ -37,6 +37,9 @@ UpdateEnemy::
     cp a, 10
     jp nc, DeactivateEnemy
 
+; ANCHOR_END: enemies-update1
+; ANCHOR: enemies-update2
+
     push hl
 
     ; Check for collision for current enemy
@@ -52,14 +55,16 @@ UpdateEnemy::
     cp a, ENEMY_COLLISION_DAMAGED
     jp z, DamageEnemy
     ret
-; ANCHOR_END: enemies-update
+; ANCHOR_END: enemies-update2
 
 ; ANCHOR: enemies-damage
 DamageEnemy:
-
+    
+    ; Save our pointers
     push hl
-    ; Decrease the enemies health byte
     push de
+
+    ; Move to the health byte
     ld de, object_healthByte
     add hl, de
     ld a, [hl]
@@ -81,7 +86,7 @@ DamageEnemy:
     pop de
 
     ; Set as damaged for 128 frames
-    ld a, 128
+    ld a, 32
     ld [hl], a
 
     ; Move to the next

galactic-armada/src/main/states/gameplay/objects/collision/object-object-collision.asm → galactic-armada/src/main/states/gameplay/objects/object-collision.asm

@@ -1,115 +1,120 @@
-
-; ANCHOR: enemy-bullet-collision-start
-include "src/main/includes/hardware.inc"
-include "src/main/includes/constants.inc"
-include "src/main/includes/hardware.inc"
-
-
-SECTION "ObjectObjectCollisionVariables", WRAM0
-wSizeY:: db
-wSizeX:: db
-wCheckByte: db
-
-SECTION "ObjectObjectCollision", ROM0
-
-CheckCollisionWithObjectsInHL_andDE::
-
-    ; SAve original values for y axis
-    push de
-    push hl
-
-XAxis:
-
-    ; Save which byte we are checking
-    ld a, object_xLowByte
-    ld [wCheckByte], a
-
-    ; Save if the minimum distance
-    ld a, [wSizeX]
-    ld [wSize], a
-
-    call CheckObjectBytesOfObjects_InDE_AndHL
-
-    ; Restore original vaues just in case
-    pop hl
-    pop de
-
-    jp nz, YAxis
-
-    ld a,0
-    and a
-    ret
-
-YAxis:
-
-    ; Save which byte we are checking
-    ld a, object_yLowByte
-    ld [wCheckByte], a
-
-    ; Save if the minimum distance
-    ld a, [wSizeY]
-    ld [wSize], a
-
-    call CheckObjectBytesOfObjects_InDE_AndHL
-
-    ; Normal return with the z/c flags as-is
-    ret
-
-
-CheckObjectBytesOfObjects_InDE_AndHL::
-
-    ; put de in hl so we can get the x bytes (for the de object) in bc and descale just to c
-
-    push hl
-    
-    ; Offset de by the check byte
-    ld a, [wCheckByte]
-    add a,e
-    ld e,a
-
-    ; copy the low byte to c
-    ld a, [de]
-    ld c, a
-
-    ; move to the high byte
-    inc de
-
-    ; copy the high byte to b
-    ld a, [de]
-    ld b, a
-
-    ; Descale
-    REPT 4
-    srl b
-    rr c
-    ENDR
-
-    ld a, c
-    ld [wObject1Value], a
-
-    pop hl
-
-    ; get the bytes (for the hl object) in bc and descale just to c
-    ld a, [wCheckByte]
-    add a, l
-    ld l, a
-
-    ; move to the high byte
-    ld a, [hli]
-    ld c, a
-
-    ; copy the high byte to b
-    ld a, [hl]
-    ld b, a
-
-    ; Descale
-    REPT 4
-    srl b
-    rr c
-    ENDR
-
-    ld a, c
-    ld [wObject2Value], a
-
-    call CheckObjectPositionDifference
-    ret
+
+; ANCHOR: object-collision-start
+include "src/main/includes/hardware.inc"
+include "src/main/includes/constants.inc"
+include "src/main/includes/hardware.inc"
+
+
+SECTION "ObjectObjectCollisionVariables", WRAM0
+wSizeY:: db
+wSizeX:: db
+wCheckByte: db
+
+SECTION "ObjectObjectCollision", ROM0
+
+; ANCHOR_END: object-collision-start
+; ANCHOR: object-collision-x
+
+CheckCollisionWithObjectsInHL_andDE::
+
+    ; SAve original values for y axis
+    push de
+    push hl
+XAxis:
+
+    ; Save which byte we are checking
+    ld a, object_xLowByte
+    ld [wCheckByte], a
+
+    ; Save if the minimum distance
+    ld a, [wSizeX]
+    ld [wSize], a
+
+    call CheckObjectBytesOfObjects_InDE_AndHL
+
+    ; Restore original vaues just in case
+    pop hl
+    pop de
+
+    jp nz, YAxis
+
+    ld a,0
+    and a
+    ret
+; ANCHOR_END: object-collision-x
+; ANCHOR: object-collision-y
+YAxis:
+
+    ; Save which byte we are checking
+    ld a, object_yLowByte
+    ld [wCheckByte], a
+
+    ; Save if the minimum distance
+    ld a, [wSizeY]
+    ld [wSize], a
+
+    call CheckObjectBytesOfObjects_InDE_AndHL
+
+    ; Normal return with the z/c flags as-is
+    ret
+; ANCHOR_END: object-collision-y
+
+; ANCHOR: object-collision-check-bytes
+CheckObjectBytesOfObjects_InDE_AndHL::
+
+    ; put de in hl so we can get the x bytes (for the de object) in bc and descale just to c
+
+    push hl
+    
+    ; Offset de by the check byte
+    ld a, [wCheckByte]
+    add a,e
+    ld e,a
+
+    ; copy the low byte to c
+    ld a, [de]
+    ld c, a
+
+    ; move to the high byte
+    inc de
+
+    ; copy the high byte to b
+    ld a, [de]
+    ld b, a
+
+    ; Descale
+    REPT 4
+    srl b
+    rr c
+    ENDR
+
+    ld a, c
+    ld [wObject1Value], a
+
+    pop hl
+
+    ; get the bytes (for the hl object) in bc and descale just to c
+    ld a, [wCheckByte]
+    add a, l
+    ld l, a
+
+    ; move to the high byte
+    ld a, [hli]
+    ld c, a
+
+    ; copy the high byte to b
+    ld a, [hl]
+    ld b, a
+
+    ; Descale
+    REPT 4
+    srl b
+    rr c
+    ENDR
+
+    ld a, c
+    ld [wObject2Value], a
+
+    call CheckObjectPositionDifference
+    ret
+; ANCHOR_END: object-collision-check-bytes

src/SUMMARY.md

@@ -42,22 +42,22 @@
   - [Drawing Text](part3/drawing-text.md)
   - [Included Utilities](part3/utilities.md)
   - [Compilation](part3/compilation.md)
+  - [Collision Detection](part3/collision.md)
 - [Game State Management](part3/game-state-management.md)
 - [Title Screen](part3/title-screen.md)
 - [Story Screen](part3/story-screen.md)
 - [Gameplay](part3/gameplay.md)
   - [Object Pools](part3/object-pools.md)
+  - [Object Collision Detection](part3/object-collisions.md)
   - [Scrolling Background](part3/scrolling-background.md)
   - [Heads-Up Interface](part3/heads-up-interface.md)
   - [The Player](part3/the-player.md)
   - [Bullets](part3/bullets.md)
   - [Enemies](part3/enemies.md)
-  - [Collision Detection](part3/collision.md)
-  - [Enemy Collisions](part3/collision.md)
+  - [Spawning Enemies](part3/enemy-spawning.md)
+  - [Enemy Collisions](part3/enemy-collision.md)
 - [Conclusion](part3/conclusion.md)
 
-
-
 [Where to go next](next.md)
 [Resources](resources.md)
 [Thanks](thanks.md)