From 108d27c2b9b61b698edb17d17aba9859031b49d7 Mon Sep 17 00:00:00 2001
From: Nihilazo <nico@itwont.work>
Date: Sun, 2 May 2021 19:34:46 +0100
Subject: [PATCH] draw pattern on screen

---
 main.usm | 81 +++++++++++++++++++++++++++++++++++++++++++++++---------
 1 file changed, 69 insertions(+), 12 deletions(-)

diff --git a/main.usm b/main.usm
index 8d8b488..7cb310c 100644
--- a/main.usm
+++ b/main.usm
@@ -2,6 +2,8 @@
 
 ( macros )
 %RTN { JMP2r } ( return from a subroutine )
+%LOB { SWP POP } ( get low byte of short as byte )
+%HIB { POP } ( get high byte of short as byte )
 
 ( data structure access macros )
 %NOTE { NOP } ( get the note of a pattern line addr )
@@ -34,7 +36,8 @@
 
 |0000
 
-@State [ &position $2 &pattern-addr $2 &tick $1 &speed $1 ]
+@Playback [ &position $2 &pattern-addr $2 &tick $1 &speed $1 ]
+@Draw [ &row $1 &col $1 ]
 
 ( program )
 
@@ -46,9 +49,9 @@
 #000f .System/b DEO2
 
 ( speed - how many ticks we play a note every )
-#10 .State/speed POK
+#10 .Playback/speed POK
 
-;pattern .State/pattern-addr POK2
+;pattern .Playback/pattern-addr POK2
 
 ( display/audio init )
 ;on-frame .Screen/vector DEO2
@@ -58,21 +61,64 @@
 BRK
 
 @on-frame ( -> )
-	.State/tick PEK .State/speed PEK NEQ ,&inc JNZ ( if the tick != speed, skip to inc )
+	;draw JSR2
+	.Playback/tick PEK .Playback/speed PEK NEQ ,&inc JNZ ( if the tick != speed, skip to inc )
 	;on-step JSR2 ( otherwise, run the on-step routine )
-	#00 .State/tick POK ( reset the tick )
+	#00 .Playback/tick POK ( reset the tick )
 	,&end JMP ( jump to end )
 	&inc
-	#01 .State/tick PEK ADD .State/tick POK ( tick up 1 )
+	#01 .Playback/tick PEK ADD .Playback/tick POK ( tick up 1 )
 	&end
 	BRK
 
+@draw-nibble ( nibble ) 
+	#08 MUL #00 SWP ;font_hex ADD2 .Screen/addr DEO2 ( locate nibble in the hex font )
+	#21 .Screen/color DEO ( display it )
+	.Screen/x DEI2 #0008 ADD2 .Screen/x DEO2 ( move right a sprite )
+	RTN
+	
+( draw-byte draws a byte as hex on the screen )
+@draw-byte ( byte )
+	DUP #04 SFT ( high digit ) ;draw-nibble JSR2
+	#0f AND ( low digit ) ;draw-nibble JSR2
+	RTN
+
+( draw-pattern-line draws a single line in a pattern )
+@draw-pattern-line ( addr )
+	#00 .Draw/col POK
+	&loop
+		DUP2 GET ;draw-byte JSR2
+		.Screen/x DEI2 #0004 ADD2 .Screen/x DEO2 ( add spacing between digits )
+		#0001 ADD2 ( get the next byte in the pattern )
+		#01 .Draw/col PEK ADD .Draw/col POK
+		.Draw/col PEK PTN_WIDTH LOB NEQ ,&loop JNZ
+	POP2 ( remove final address from stack )
+	RTN
+
+( draw-pattern draws a pattern )
+@draw-pattern ( addr )
+	#00 .Draw/row POK
+	&loop
+		#0010 .Screen/x DEO2
+		DUP2 ;draw-pattern-line JSR2
+		.Screen/y DEI2 #000b ADD2 .Screen/y DEO2 ( add spacing between rows )
+		PTN_WIDTH ADD2 ( get the next byte in the pattern )
+		#01 .Draw/row PEK ADD .Draw/row POK
+		.Draw/row PEK PTN_LEN LOB NEQ ,&loop JNZ
+	POP2 ( remove final address from stack )
+	RTN
+	
+@draw
+	#0010 .Screen/x DEO2
+	#0010 .Screen/y DEO2
+	.Playback/pattern-addr PEK2 ;draw-pattern JSR2
+	RTN
+	
 @on-step ( whenever a pattern step should be played )
-	PTN_WIDTH PTN_LEN MUL2 .State/position PEK2 NEQ2 ,&continue JNZ ( if we're at the end of the pattern, reset the counter )
-	#ff .Console/byte DEO
-	#0000 .State/position POK2
+	PTN_WIDTH PTN_LEN MUL2 .Playback/position PEK2 NEQ2 ,&continue JNZ ( if we're at the end of the pattern, reset the counter )
+	#0000 .Playback/position POK2
 	&continue
-	.State/position PEK2 .State/pattern-addr PEK2 ADD2 ( put pattern line address on the stack )
+	.Playback/position PEK2 .Playback/pattern-addr PEK2 ADD2 ( put pattern line address on the stack )
 	DUP2 VOL GET .Audio0/volume DEO ( ln -- ) ( put the address of the pattern line on the stack )
 	NOTE GET  ( get the current note )
 	DUP #00 EQU ,&rest JNZ ( if the note is 00, aka empty, skip playing it )
@@ -81,16 +127,27 @@ BRK
 	
 	&rest POP ( if the note is a 00, jump here. POP to clean up the stack )
 	&end
-	PTN_WIDTH .State/position PEK2 ADD2 .State/position POK2 
+	PTN_WIDTH .Playback/position PEK2 ADD2 .Playback/position POK2 
 	
 	 RTN 
 
 @wave [ a8 58 ]
 
+@font_hex ( 0-F )
+[
+	003c 464a 5262 3c00 0018 0808 0808 1c00
+	003c 4202 3c40 7e00 003c 421c 0242 3c00
+	000c 1424 447e 0400 007e 407c 0242 3c00
+	003c 407c 4242 3c00 007e 0204 0810 1000
+	003c 423c 4242 3c00 003c 4242 3e02 3c00
+	003c 4242 7e42 4200 007c 427c 4242 7c00
+	003c 4240 4042 3c00 007c 4242 4242 7c00
+	007e 4078 4040 7e00 007e 4078 4040 4000
+]
 
 ( pattern format - each note has 3 bytes. Pitch, instrument, volume. patterns are 0x10 long.
   an ff in the note column of the pattern will kill the existing note without starting a new one (this is the tracker "box" note) )
-	
+
 @pattern [
 	3c 00 66
 	ff 00 66