From 0e1839f48ada69b81f5879449d0e0fe435f851c5 Mon Sep 17 00:00:00 2001
From: Miquel Sabaté Solà <msabate@suse.com>
Date: Thu, 23 Nov 2023 09:38:46 +0100
Subject: space: Improve comments and documentation
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Signed-off-by: Miquel Sabaté Solà <msabate@suse.com>
---
 space/README.md           | 10 ++++++++++
 space/src/space.s         | 10 +++++++---
 space/src/states/player.s |  2 +-
 3 files changed, 18 insertions(+), 4 deletions(-)
 create mode 100644 space/README.md

(limited to 'space')

diff --git a/space/README.md b/space/README.md
new file mode 100644
index 0000000..8a0b451
--- /dev/null
+++ b/space/README.md
@@ -0,0 +1,10 @@
+## Space
+
+This is an evolution from the `basics/sprite.s` and `basics/input.s` examples.
+That is, we are no longer just showing a sprite, but we also allow the player to
+move it and shoot bullets according to the player's input.
+
+The movement is done by taking into consideration subpixels. For this, I have
+taken most of the code/idea from [NES
+Hacker](https://github.com/NesHacker/PlatformerMovement). Thus, this part is
+mostly attributed to him.
diff --git a/space/src/space.s b/space/src/space.s
index f2c5dbe..c6d431f 100644
--- a/space/src/space.s
+++ b/space/src/space.s
@@ -5,7 +5,7 @@
 ;;     - The movement is done through subpixels for a smoother experience.
 ;;     - The ship's sprites are updated accordingly: resting, acceleration, full
 ;;       speed.
-;;   - The ship can shoot
+;;   - The ship can shoot bullets.
 ;;
 ;; The subpixel movement is largely based on:
 ;; https://github.com/NesHacker/PlatformerMovement.
@@ -45,8 +45,8 @@
 .include "vectors/irq.s"
 
 ;;;
-;; This is our main subroutine, the reset procedure will call at the very end of
-;; initializing the hardware.
+;; This is our main subroutine, the reset procedure will call it at the very end
+;; of initializing the hardware.
 ;;;
 .proc main
     ;; Before starting the game loop proper we initialize all our assets: load
@@ -69,6 +69,10 @@
     sta PPU::MASK
 
 @main_game_loop:
+    ;; The main game loop leverages the logic to different subroutines. In
+    ;; short: first of all update the values on the joypad, then update the
+    ;; player's movement and sprites, and finally update the bullets'
+    ;; creation/movement.
     jsr Joypad::read
     jsr Player::Movement::update
     jsr Player::Sprite::update
diff --git a/space/src/states/player.s b/space/src/states/player.s
index 29c1585..e03f54c 100644
--- a/space/src/states/player.s
+++ b/space/src/states/player.s
@@ -1,7 +1,7 @@
 ;;;
 ;; Player state: movement, animation, etc. The following memory addresses are
 ;; reserved for the player:
-;;   -> $30-$3F: internal data.
+;;   -> $30-$38: internal data.
 ;;   -> $0200-$0207: OAM data.
 ;;;
 .scope Player
-- 
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