From c09a85ef9da7c1608b9d78c41975b4fdbbadf3e4 Mon Sep 17 00:00:00 2001
From: "Juan J. Martinez" <jjm@usebox.net>
Date: Mon, 22 May 2023 07:13:54 +0100
Subject: Use a bitmap font

---
 game/assets/font.png | Bin 0 -> 6627 bytes
 game/main.asm        |  79 ++++++++----------------------------------
 game/text.asm        |  95 +++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 109 insertions(+), 65 deletions(-)
 create mode 100644 game/assets/font.png
 create mode 100644 game/text.asm

diff --git a/game/assets/font.png b/game/assets/font.png
new file mode 100644
index 0000000..4b0fbf0
Binary files /dev/null and b/game/assets/font.png differ
diff --git a/game/main.asm b/game/main.asm
index 365e381..5be96a6 100644
--- a/game/main.asm
+++ b/game/main.asm
@@ -8,12 +8,6 @@
 ; Menu entry point
 ;
 menu:
-    ; reset the blink flag
-    ld x, <blink
-    ld a, >blink
-    ld y, 0
-    ld [a : x], y
-
     call clear_screen
 
 menu_loop:
@@ -31,7 +25,6 @@ menu_loop:
     bnz
     jmp menu_loop
 
-
 ;
 ; Gameplay entry point
 ;
@@ -102,12 +95,6 @@ fill_loop:
     jmp fill_loop
     ret
 
-;
-; Controls the blink of the "press start" text
-;
-blink:
-    .db 0
-
 ;
 ; Draws the menu
 ;
@@ -145,59 +132,15 @@ menu_draw:
     ld y, 3
     port b, y
 
-    ; settings mode
-    ld y, 128
-    port b, y
-
-    ; setup
-    inc b
-
-    ld x, <blink
-    ld a, >blink
-    ld y, [a : x]
-    inc y
-    and y, 31
-    ld [a : x], y
-    cmp y, 10
-    bnc
-    jmp menu_draw_start
-
-    ; addr: black to erase sprite
-    ld y, 0
-    port b, y
-    ld y, 0xa0
-    port b, y
-    jmp menu_continue_start
-
-menu_draw_start:
-    ; addr: press start sprite
-    ld y, <press
-    port b, y
-    ld y, >press
-    port b, y
-
-menu_continue_start:
-    ; x
-    ld y, 36
-    port b, y
-
-    ; y
-    ld y, 80
-    port b, y
-
-    ld y, 56
-    port b, y
-    ld y, 8
-    port b, y
-
-    ; blit
-    dec b
-    ; write, transparent
-    ld y, 3
-    port b, y
+    ld x, <press_start
+    ld a, >press_start
+    ld b, 40
+    ld y, 84
+    call put_text
 
     ; settings mode
     ld y, 128
+    ld b, 0xb0
     port b, y
 
     ; setup
@@ -250,6 +193,7 @@ init:
 int_handler:
     iret
 
+.include "text.asm"
 .include "random.asm"
 .include "starfield.asm"
 .include "entities.asm"
@@ -331,7 +275,12 @@ stars:
 ; menu data
 title:
     .incpng "assets/title.png"
-press:
-    .incpng "assets/press.png"
+font:
+    .incpng "assets/font.png"
 usebox:
     .incpng "assets/usebox.png"
+
+; texts
+press_start:
+    .str "PRESS START!"
+    .db 0
diff --git a/game/text.asm b/game/text.asm
new file mode 100644
index 0000000..06a40b3
--- /dev/null
+++ b/game/text.asm
@@ -0,0 +1,95 @@
+;
+; Bitmap font
+;
+
+;
+; Write text on screen
+;
+; Expects a 4x8 font on "font" label.
+;
+; in: a : x: text to write
+;     b, y : (x, y) dst coords
+put_text:
+    push y
+    push b
+
+put_text_loop:
+    ld y, [a : x]
+    cmp y, 0
+    bz
+    jmp put_text_exit
+
+    sub y, 32
+
+    push a
+    push x
+
+    rol y, 5
+    ld x, y
+    and x, 31
+    and y, 224
+
+    ld a, >font
+    add a, x
+
+    ld x, <font
+    add x, y
+    bo
+    inc a
+
+    call put_text_c
+
+    pop x
+    pop a
+
+    inc x
+    bo
+    inc a
+
+    pop b
+    add b, 4
+    push b
+
+    jmp put_text_loop
+
+put_text_exit:
+    pop b
+    pop y
+    ret
+
+put_text_c:
+    ; settings mode
+    ld y, 128
+    ld b, 0xb0
+    port b, y
+
+    ; setup
+    inc b
+
+    ; addr: char sprite
+    ld y, x
+    port b, y
+    ld y, a
+    port b, y
+
+    ; x
+    ld y, [sp + 4]
+    port b, y
+
+    ; y
+    ld y, [sp + 5]
+    port b, y
+
+    ; w
+    ld y, 4
+    port b, y
+    ; h
+    ld y, 8
+    port b, y
+
+    ; blit
+    dec b
+    ; write, transparent
+    ld y, 3
+    port b, y
+    ret
-- 
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