From a49ae0411818f2845287c8a7d13018f121825dfb Mon Sep 17 00:00:00 2001
From: Vince Weaver <vincent.weaver@maine.edu>
Date: Wed, 6 Dec 2023 23:31:08 -0500
Subject: [PATCH] gr: twister: working on some twister code

---
 graphics/gr/twister/Makefile    | 32 ++++++++++++++++++++++++++++++++
 graphics/gr/twister/hello.bas   |  2 ++
 graphics/gr/twister/twister.bas | 22 ++++++++++++++++++++++
 3 files changed, 56 insertions(+)
 create mode 100644 graphics/gr/twister/Makefile
 create mode 100644 graphics/gr/twister/hello.bas
 create mode 100644 graphics/gr/twister/twister.bas

diff --git a/graphics/gr/twister/Makefile b/graphics/gr/twister/Makefile
new file mode 100644
index 00000000..8c65a871
--- /dev/null
+++ b/graphics/gr/twister/Makefile
@@ -0,0 +1,32 @@
+include ../../../Makefile.inc
+
+DOS33 = ../../../utils/dos33fs-utils/dos33
+PNG2GR = ../../../utils/gr-utils/png2gr
+PNG2RLE = ../../../utils/gr-utils/png2rle
+TOKENIZE = ../../../utils/asoft_basic-utils/tokenize_asoft
+LINKERSCRIPTS = ../../../linker_scripts
+EMPTY_DISK = ../../../empty_disk
+
+all:	twister.dsk
+
+twister.dsk:	$(DOS33) HELLO TWISTER.BAS
+	cp $(EMPTY_DISK)/empty.dsk twister.dsk
+	$(DOS33) -y twister.dsk SAVE A HELLO
+	$(DOS33) -y twister.dsk SAVE A TWISTER.BAS
+
+###
+
+HELLO:	hello.bas
+	$(TOKENIZE) < hello.bas > HELLO
+
+###
+
+TWISTER.BAS:	twister.bas
+	$(TOKENIZE) < twister.bas > TWISTER.BAS
+
+
+###
+
+clean:	
+	rm -f *~ *.o HELLO TWISTER.BAS *.lst
+
diff --git a/graphics/gr/twister/hello.bas b/graphics/gr/twister/hello.bas
new file mode 100644
index 00000000..133a44bb
--- /dev/null
+++ b/graphics/gr/twister/hello.bas
@@ -0,0 +1,2 @@
+5 HOME
+10 PRINT CHR$(4);"CATALOG"
diff --git a/graphics/gr/twister/twister.bas b/graphics/gr/twister/twister.bas
new file mode 100644
index 00000000..5695cb25
--- /dev/null
+++ b/graphics/gr/twister/twister.bas
@@ -0,0 +1,22 @@
+10 REM TWISTER-DEMO
+15 REM https://8bitshack.org/post/twister/
+20 HGR
+30 FOR A2 = 1 TO 360 STEP 3
+40 AM = 120+COS(A2*0.0174533)*100
+50 AN = -3.141593+SIN(A2*0.0174533)*3.141593
+60 FOR Y = 1 TO 159 STEP 2
+65 FV = Y/AM+AN
+70 X1 = 35*SIN(FV)
+80 X2 = 35*SIN(FV+1.570796)
+90 REM X3 = 140+35*SIN(FV+3.141593)
+95 X3 = -X1
+100 REM X4 = 140+35*SIN(FV+4.712389)
+105 X4 = -X2
+108 HCOLOR = 0: HPLOT 105,Y TO 175,Y
+110 IF X1 < X2 THEN HCOLOR = 1: HPLOT 140+X1,Y TO 140+X2,Y: GOTO 130
+120 IF X3 < X4 THEN HCOLOR = 1: HPLOT 140+X3,Y TO 140+X4,Y
+130 IF X2 < X3 THEN HCOLOR = 2: HPLOT 140+X2,Y TO 140+X3,Y: GOTO 150
+140 IF X4 < X1 THEN HCOLOR = 2: HPLOT 140+X4,Y TO 140+X1,Y
+150 NEXT Y
+160 NEXT A2
+170 GOTO 30