From f75da270f738fdb49e1789840427fcb42ddc7aa8 Mon Sep 17 00:00:00 2001
From: Vince Weaver <vincent.weaver@maine.edu>
Date: Tue, 2 May 2017 10:56:59 -0400
Subject: [PATCH] gr-sim: make it a library

---
 gr-sim/Makefile  | 12 ++++++----
 gr-sim/gr-sim.c  | 57 +++++++++++++++++++++++++++++++++---------------
 gr-sim/gr-sim.h  |  8 +++++++
 gr-sim/rainbow.c | 38 ++++++++++++++++++++++++++++++++
 4 files changed, 94 insertions(+), 21 deletions(-)
 create mode 100644 gr-sim/gr-sim.h
 create mode 100644 gr-sim/rainbow.c

diff --git a/gr-sim/Makefile b/gr-sim/Makefile
index 91c84c9a..0d30ab55 100644
--- a/gr-sim/Makefile
+++ b/gr-sim/Makefile
@@ -5,15 +5,19 @@ LFLAGS =
 SDL_LIBS= `sdl-config --libs`
 SDL_INCLUDE= `sdl-config --cflags`
 
-all:	gr-sim
+all:	rainbow
+
+rainbow:	rainbow.o gr-sim.o
+	$(CC) $(LFLAGS) $(SDL_LIBS) -o rainbow rainbow.o gr-sim.o
+
+rainbow.o:	rainbow.c
+	$(CC) $(CFLAGS) -c rainbow.c
 
-gr-sim:	gr-sim.o
-	$(CC) $(LFLAGS) $(SDL_LIBS) -o gr-sim gr-sim.o
 
 gr-sim.o:	gr-sim.c
 	$(CC) $(CFLAGS) $(SDL_INCLUDE) -c gr-sim.c
 
 clean:	
-	rm -f *~ *.o gr-sim
+	rm -f *~ *.o gr-sim rainbow
 
 
diff --git a/gr-sim/gr-sim.c b/gr-sim/gr-sim.c
index 33c02c45..1a241871 100644
--- a/gr-sim/gr-sim.c
+++ b/gr-sim/gr-sim.c
@@ -4,6 +4,8 @@
 
 #include <SDL.h>
 
+#include "gr-sim.h"
+
 #define XSIZE		40
 #define YSIZE		48
 
@@ -15,7 +17,13 @@ static int ysize=YSIZE*PIXEL_Y_SCALE;
 
 static unsigned char framebuffer[XSIZE][YSIZE];
 
-static int get_input(void) {
+/* 128kB of RAM */
+unsigned char ram[128*1024];
+
+
+static SDL_Surface *sdl_screen=NULL;
+
+int grsim_input(void) {
 
 	SDL_Event event;
 	int keypressed;
@@ -71,12 +79,12 @@ static unsigned int color[16]={
 	0xffffff,	/* 15 white */
 };
 
-static int gr_to_screen(SDL_Surface *screen) {
+int grsim_update(void) {
 
 	int x,y,i,j;
 	unsigned int *t_pointer;
 
-	t_pointer=((Uint32 *)screen->pixels);
+	t_pointer=((Uint32 *)sdl_screen->pixels);
 
 	for(y=0;y<YSIZE;y++) {
 		for(j=0;j<PIXEL_Y_SCALE;j++) {
@@ -89,19 +97,15 @@ static int gr_to_screen(SDL_Surface *screen) {
 		}
 	}
 
-	SDL_UpdateRect(screen, 0, 0, xsize, ysize);
+	SDL_UpdateRect(sdl_screen, 0, 0, xsize, ysize);
 
 	return 0;
 }
 
 
-int main(int argc, char **argv) {
-
-	SDL_Surface *sdl_screen=NULL;
+int grsim_init(void) {
 
 	int mode;
-	int ch;
-
 	int x,y;
 
 	mode=SDL_SWSURFACE|SDL_HWPALETTE|SDL_HWSURFACE;
@@ -127,18 +131,37 @@ int main(int argc, char **argv) {
 	/* Init screen */
 	for(y=0;y<YSIZE;y++) for(x=0;x<XSIZE;x++) framebuffer[x][y]=0;
 
-	/* Put rainbow on screen */
-	for(y=0;y<40;y++) for(x=0;x<XSIZE;x++) framebuffer[x][y]=y%16;
+	return 0;
+}
 
-	while(1) {
-		gr_to_screen(sdl_screen);
+static int current_color=0;
 
-		ch=get_input();
-		if (ch=='q') break;
+int color_equals(int new_color) {
+	current_color=new_color;
+	return 0;
+}
 
-		usleep(100000);
+int plot(int x, int y) {
+	framebuffer[x][y]=current_color;
+	return 0;
+}
 
-	}
+int hlin(int x1, int x2, int at) {
+
+	int i;
+
+	for(i=x1;i<x2;i++) plot(i,at);
 
 	return 0;
 }
+
+int vlin(int y1, int y2, int at) {
+
+	int i;
+
+	for(i=y1;i<y2;i++) plot(at,i);
+
+	return 0;
+}
+
+
diff --git a/gr-sim/gr-sim.h b/gr-sim/gr-sim.h
new file mode 100644
index 00000000..5f3d2c51
--- /dev/null
+++ b/gr-sim/gr-sim.h
@@ -0,0 +1,8 @@
+extern unsigned char ram[128*1024];
+int grsim_input(void);
+int grsim_update(void);
+int grsim_init(void);
+int color_equals(int new_color);
+int plot(int x, int y);
+int hlin(int x1, int x2, int at);
+int vlin(int y1, int y2, int at);
diff --git a/gr-sim/rainbow.c b/gr-sim/rainbow.c
new file mode 100644
index 00000000..8ca395ae
--- /dev/null
+++ b/gr-sim/rainbow.c
@@ -0,0 +1,38 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include "gr-sim.h"
+
+int main(int argc, char **argv) {
+
+	int x,y,ch;
+
+	grsim_init();
+
+	/* Put rainbow on screen */
+	for(y=0;y<40;y++) for(x=0;x<40;x++) {
+		color_equals(y%16);
+		plot(x,y);
+	}
+
+	color_equals(15);
+	vlin(0,40,20);
+
+	color_equals(0);
+	hlin(0,40,20);
+
+
+	while(1) {
+		grsim_update();
+
+		ch=grsim_input();
+
+		if (ch=='q') break;
+
+		usleep(100000);
+
+	}
+
+	return 0;
+}