From 33af076cfc59a6232cd9230e4467149b68bb5128 Mon Sep 17 00:00:00 2001
From: uz <uz@b7a2c559-68d2-44c3-8de9-860c34a00d81>
Date: Mon, 26 Oct 2009 19:28:11 +0000
Subject: [PATCH] Lynx TGI driver update by Karri Kaksonen. Adds collision
 detection.

git-svn-id: svn://svn.cc65.org/cc65/trunk@4393 b7a2c559-68d2-44c3-8de9-860c34a00d81
---
 doc/lynx.sgml                 | 13 +++++++++++--
 include/lynx.h                |  1 +
 libsrc/lynx/lynx-160-102-16.s | 26 ++++++++++++++++++++++++++
 3 files changed, 38 insertions(+), 2 deletions(-)

diff --git a/doc/lynx.sgml b/doc/lynx.sgml
index fa2a9dc51..856b909ec 100644
--- a/doc/lynx.sgml
+++ b/doc/lynx.sgml
@@ -46,7 +46,7 @@ that shows how to create a complete bootable Lynx cart.
 <sect>Memory layout<p>
 
 cc65 generated programs with the default setup run with the I/O area and the
-kernal enabled, which gives a usable memory range of &dollar;400 - &dollar;C038.
+kernal enabled, which gives a usable memory range of &dollar;400 - &dollar;C037.
 
 Special locations:
 
@@ -62,12 +62,17 @@ Special locations:
   '?' for all keys down at the same time.
 
   <tag/Stack/
-  The C runtime stack is located at &dollar;C037 and growing downwards.
+  The C runtime stack is located at &dollar;C037 (or &dollar;A057 if collision
+  detection is enabled) and growing downwards.
 
   <tag/Heap/
   The C heap is located at the end of the program and grows towards the C
   runtime stack.
 
+  <tag/Screen/
+  The collision detection screen is at &dollar;A058 if it is enabled. The
+  double buffered screens are at &dollar;C038 and &dollar;E018.
+
 </descrip><p>
 
 
@@ -145,6 +150,10 @@ To update displays you can call tgi_updatedisplay() or tgi_ioctl(4, 1) it
 will wait for the next VBL interrupt and set the draw buffer to the
 view buffer. The draw buffer is also changed to (drawbuffer xor 1).
 
+You can also enable or disable collision detection by a call to
+tgi_setcollisiondetection(active) or tgi_ioctl(5, active). The collision
+result is located before the sprite structure by default in this driver.
+
 <sect1>Extended memory drivers<p>
 
 No extended memory drivers are currently available for the Lynx.
diff --git a/include/lynx.h b/include/lynx.h
index c51d4cbf1..303260e33 100644
--- a/include/lynx.h
+++ b/include/lynx.h
@@ -109,6 +109,7 @@ void __fastcall__ lynx_eeprom_erase (unsigned char cell);
 #define tgi_setframerate(rate) tgi_ioctl(3, (unsigned)(rate))
 #define tgi_busy() tgi_ioctl(4, 0)
 #define tgi_updatedisplay() tgi_ioctl(4, 1)
+#define tgi_setcollisiondetection(active) tgi_ioctl(5, (unsigned)(active))
 
 /* End of lynx.h */
 #endif
diff --git a/libsrc/lynx/lynx-160-102-16.s b/libsrc/lynx/lynx-160-102-16.s
index 864ab554f..83e0c10af 100644
--- a/libsrc/lynx/lynx-160-102-16.s
+++ b/libsrc/lynx/lynx-160-102-16.s
@@ -199,6 +199,16 @@ INIT:
 ; Enable interrupts for VBL
 	lda	#$80
 	tsb	VTIMCTLA
+; Set up collision buffer to $A058
+	lda	#$58
+	sta	COLLBASL
+	lda	#$A0
+	sta	COLLBASH
+; Put collision index before sprite data
+	lda	#$FE
+	sta	COLLOFFL
+	lda	#$FF
+	sta	COLLOFFH
 ; Done, reset the error code
         lda     #TGI_ERR_OK
         sta     ERROR
@@ -245,6 +255,8 @@ GETERROR:
 ;
 ; To update displays you can call tgi_ioctl(4, 1) it will wait for the
 ; next VBL interrupt and swap draw and view buffers.
+;
+; Activate or deactivate collision detection by calling tgi_ioctl(5, 0/1).
 
 CONTROL:
         pha			; Almost all control routines succeed
@@ -252,6 +264,20 @@ CONTROL:
 	sta	ERROR
 	pla
 
+	cmp	#5
+	bne	ControlSwap
+	lda	ptr1
+	bne	@L0
+	lda	__sprsys
+	ora	#$20
+	bra	@L1
+@L0:	lda	__sprsys
+	and	#$df
+@L1:	sta	__sprsys
+	sta	SPRSYS
+	rts
+
+ControlSwap:
 	cmp	#4
 	bne	ControlFramerate
 
-- 
2.39.5