From 7b1c8dd5bbdfd62f32156464755ef7bd4bb20b15 Mon Sep 17 00:00:00 2001
From: Amy Gale Ruth Bowersox <amy@erbosoft.com>
Date: Fri, 6 Dec 2019 23:26:13 -0700
Subject: [PATCH] implemented frame buffer primitives

---
 src/Makefile      |   2 +-
 src/fbprimitive.c | 113 ++++++++++++++++++++++++++++++++++++++++++++++
 src/fbprimitive.h |  20 ++++++++
 src/main.c        |  19 +++-----
 src/wintype.h     |   1 +
 5 files changed, 142 insertions(+), 13 deletions(-)
 create mode 100644 src/fbprimitive.c
 create mode 100644 src/fbprimitive.h

diff --git a/src/Makefile b/src/Makefile
index 26bfb95..c1558d4 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -1,4 +1,4 @@
-OBJS=main.o sysinput.o fbinit.o log.o gpio.o msg_queue.o time_func.o config.o splash.o
+OBJS=main.o sysinput.o fbinit.o fbprimitive.o log.o gpio.o msg_queue.o time_func.o config.o splash.o
 LIBS=-lbcm2835 -lpthread
 
 upiwin: $(OBJS)
diff --git a/src/fbprimitive.c b/src/fbprimitive.c
new file mode 100644
index 0000000..2292f48
--- /dev/null
+++ b/src/fbprimitive.c
@@ -0,0 +1,113 @@
+#include "wintype.h"
+#include "fbinit.h"
+
+inline static PUINT16 loc_from_coords(INT32 x, INT32 y)
+{
+  return Fb_Ptr + (y * Fb_Info->width) + x;
+}
+
+UINT16 Fb_setpixel(INT32 x, INT32 y, UINT16 color, BOOL xor)
+{
+  UINT16 rc;
+  PUINT16 loc = loc_from_coords(x, y);
+
+  rc = *loc;
+  if (xor)
+    *loc ^= color;
+  else
+    *loc = color;
+  return rc;
+}
+
+void Fb_line(INT32 x1, INT32 y1, INT32 x2, INT32 y2, UINT16 color, BOOL xor)
+{
+  INT32 tmp;
+  INT32 dx = x2 - x1;
+  INT32 dy = y2 - y1;
+
+  if (ABS(dx) < ABS(dy))
+  {
+    if (y1 > y2)
+    {
+      tmp = x1;
+      x1 = x2;
+      x2 = tmp;
+      tmp = y1;
+      y1 = y2;
+      y2 = tmp;
+      dx = -dx;
+      dy = -dy;
+    }
+    x1 <<= 16;
+    dx = (dx << 16) / dy;
+    while (y1 <= y2)
+    {
+      Fb_setpixel(x1 >> 16, y1, color, xor);
+      x1 += dx;
+      y1++;
+    }
+  }
+  else
+  {
+    if (x1 > x2)
+    {
+      tmp = x1;
+      x1 = x2;
+      x2 = tmp;
+      tmp = y1;
+      y1 = y2;
+      y2 = tmp;
+      dx = -dx;
+      dy = -dy;
+    }
+    y1 <<= 16;
+    dy = dx ? (dy << 16) / dx : 0;
+    while (x1 <= x2)
+    {
+      Fb_setpixel(x1, y1 >> 16, color, xor);
+      y1 += dy;
+      x1++;
+    }
+  }
+}
+
+void Fb_rectangle(INT32 x1, INT32 y1, INT32 x2, INT32 y2, UINT16 color, BOOL xor)
+{
+  FB_line(x1, y1, x2, y1, color, xor);
+  FB_line(x2, y1 + 1, x2, y2 - 1, color, xor);
+  FB_line(x1, y2, x2, y2, color, xor);
+  FB_line(x1, y1 + 1, x1, y2 - 1, color, xor);
+}
+
+void Fb_filled_rectangle(INT32 x1, INT32 y1, INT32 x2, INT32 y2, UINT16 color, BOOL xor)
+{
+  INT32 tmp;
+  PUINT16 ps, p;
+
+  if (x1 > x2)
+  {
+    tmp = x1;
+    x1 = x2;
+    x2 = tmp;
+  }
+  if (y1 > y2)
+  {
+    tmp = y1;
+    y1 = y2;
+    y2 = tmp;
+  }
+
+  ps = loc_from_coords(x1, y1);
+  for (; y1 <= y2; y1++)
+  {
+    p = ps;
+    for (tmp = x1; tmp <= x2; tmp++)
+    {
+      if (xor)
+	*p++ ^= color;
+      else
+	*p++ = color;
+    }
+    ps += Fb_Info->width;
+  }
+}
diff --git a/src/fbprimitive.h b/src/fbprimitive.h
new file mode 100644
index 0000000..fddd6c8
--- /dev/null
+++ b/src/fbprimitive.h
@@ -0,0 +1,20 @@
+#ifndef __FBPRIMITIVE_H_INCLUDED
+#define __FBPRIMITIVE_H_INCLUDED
+
+#include "wintype.h"
+
+#define FBPRIMCLR_BLACK   0x0000
+#define FBPRIMCLR_RED     0xF800
+#define FBPRIMCLR_GREEN   0x07E0
+#define FBPRIMCLR_BLUE    0x001F
+#define FBPRIMCLR_YELLOW  0xFFE0
+#define FBPRIMCLR_CYAN    0x07FF
+#define FBPRIMCLR_MAGENTA 0xF81F
+#define FBPRIMCLR_WHITE   0xFFFF
+
+extern UINT16 Fb_setpixel(INT32 x, INT32 y, UINT16 color, BOOL xor);
+extern void Fb_line(INT32 x1, INT32 y1, INT32 x2, INT32 y2, UINT16 color, BOOL xor);
+extern void Fb_rectangle(INT32 x1, INT32 y1, INT32 x2, INT32 y2, UINT16 color, BOOL xor);
+extern void Fb_filled_rectangle(INT32 x1, INT32 y1, INT32 x2, INT32 y2, UINT16 color, BOOL xor);
+
+#endif /* __FBPRIMITIVE_H_INCLUDED */
diff --git a/src/main.c b/src/main.c
index 8716e56..bd939e9 100644
--- a/src/main.c
+++ b/src/main.c
@@ -6,23 +6,18 @@
 #include "gpio.h"
 #include "log.h"
 #include "fbinit.h"
+#include "fbprimitive.h"
 #include "time_func.h"
 #include "sysinput.h"
 
 static void do_draw(void)
 {
-  /*
-  tmp = (char *)Fb_Ptr;
-  memset(tmp, 0xFF, Fb_Info->screenbytes / 2);
-  memset(tmp + (Fb_Info->screenbytes / 2), 0x1B, Fb_Info->screenbytes / 2);
-  */
-  UINT16 pixel = Fb_Info->green_mask;
-  unsigned npix = Fb_Info->screenbytes / sizeof(UINT16);
-  UINT16 *p = Fb_Ptr;
-  unsigned i;
-
-  for (i=0; i<npix; i++)
-    *p++ = pixel;
+  Fb_filled_rectangle(10, 10, 50, 50, FBPRIMCLR_RED, FALSE);
+  Fb_filled_rectangle(60, 10, 100, 50, FBPRIMCLR_GREEN, FALSE);
+  Fb_filled_rectangle(110, 10, 160, 50, FBPRIMCLR_BLUE, FALSE);
+  Fb_filled_rectangle(10, 60, 50, 100, FBPRIMCLR_CYAN, FALSE);
+  Fb_filled_rectangle(60, 60, 100, 100, FBPRIMCLR_MAGENTA, FALSE);
+  Fb_filled_rectangle(110, 60, 160, 100, FBPRIMCLR_YELLOW, FALSE);
 }
 
 int main(int argc, char *argv[])
diff --git a/src/wintype.h b/src/wintype.h
index 01a2401..96c3645 100644
--- a/src/wintype.h
+++ b/src/wintype.h
@@ -139,6 +139,7 @@ typedef UINT64 TIMESTAMP;
 #ifndef MAX
 #define MAX(x, y)         (((x) > (y)) ? (x) : (y))
 #endif
+#define ABS(v)            ((v) < 0 ? -(v) : (v))
 
 #define MAKEWORD(a, b)    ((WORD)((((UINT_PTR)(a)) & 0xFF) | ((((UINT_PTR)(b)) & 0xFF) << 8)))
 #define MAKELONG(a, b)    ((LONG)((((UINT_PTR)(a)) & 0xFFFF) | ((((UINT_PTR)(b)) & 0xFFFF) << 16)))