separated main and lib

.gitignore

@@ -1 +1,2 @@
 fb_dash
+*.o

Makefile

@@ -1,7 +1,10 @@
 CFLAGS = -g -Wall
 
-fb_dash: fb_dash.c
-	gcc -o $@ $(CFLAGS) $<
+fbdash: fbdash.c fblib
+	gcc fblib.o -o $@ $(CFLAGS) $<
+
+fblib: fblib.o
+	gcc -c fblib.c
 
 clean:
-	rm fb_dash
+	rm fbdash fblib.o

fbdash.c

@@ -0,0 +1,113 @@
+/*
+ * fbdash.c
+ *
+ * Adapted by Florian Klemenz for use in the fb_dash project
+ *
+ * Source and all credit goes to 
+ * http://raspberrycompote.blogspot.ie/2014/03/low-level-graphics-on-raspberry-pi-part_14.html
+ *
+ * Original work by J-P Rosti (a.k.a -rst- and 'Raspberry Compote')
+ *
+ * Licensed under the Creative Commons Attribution 3.0 Unported License
+ * (http://creativecommons.org/licenses/by/3.0/deed.en_US)
+ *
+ * Distributed in the hope that this will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ */
+
+#include "fblib.h"
+
+// 'global' variables to store screen info
+char *fbp = 0;
+struct fb_var_screeninfo vinfo;
+struct fb_fix_screeninfo finfo;
+
+
+// helper function for drawing - no more need to go mess with
+// the main function when just want to change what to draw...
+void draw() {
+   
+    clear_screen(fbp);
+
+    // horizontal spacersint x_space = 10;
+    int y_step_width = vinfo.yres / 4;
+    for (int i = 1; i < 4; i++) {
+        int x0 = 15;
+        int x1 = vinfo.xres - x0;
+        int y = y_step_width * i;
+
+        int r = 200;
+        int g = 32;
+        int b = 32;
+        
+        draw_line(fbp, x0, y-1, x1, y-1, r, g, b);
+        draw_line(fbp, x0, y  , x1, y  , r, g, b);
+        draw_line(fbp, x0, y+1, x1, y+1, r, g, b);
+    }
+
+
+
+
+
+
+}
+
+// application entry point
+int main(int argc, char* argv[])
+{
+
+    int fbfd = 0;
+    //struct fb_var_screeninfo orig_vinfo;
+    long int screensize = 0;
+
+    // Open the framebuffer file for reading and writing
+    fbfd = open("/dev/fb1", O_RDWR);
+    if (fbfd == -1) {
+        printf("Error: cannot open framebuffer device.\n");
+        return(1);
+    }
+    printf("The framebuffer device was opened successfully.\n");
+
+    // Get variable screen information
+    if (ioctl(fbfd, FBIOGET_VSCREENINFO, &vinfo)) {
+        printf("Error reading variable information.\n");
+    }
+    printf("Variable info: %dx%d, %dbpp\n", 
+            vinfo.xres, vinfo.yres, 
+            vinfo.bits_per_pixel );
+
+    // Get fixed screen information
+    if (ioctl(fbfd, FBIOGET_FSCREENINFO, &finfo)) {
+        printf("Error reading fixed information.\n");
+    }
+    printf("Fixed info: smem_len %d, line_length %d\n", finfo.smem_len, finfo.line_length);
+
+    // map fb to user mem 
+    screensize = finfo.smem_len;
+    fbp = (char*)mmap(0, 
+              screensize, 
+              PROT_READ | PROT_WRITE, 
+              MAP_SHARED, 
+              fbfd, 
+              0);
+
+    if ((int)fbp == -1) {
+        printf("Failed to mmap.\n");
+    }
+    else {
+        // draw...
+        draw();
+    }
+
+    // cleanup
+    //clear_screen(fbp);
+    // unmap fb file from memory
+    munmap(fbp, screensize);
+    // close fb file    
+    close(fbfd);
+
+    return 0;
+  
+}

fblib.c

@@ -0,0 +1,168 @@
+/*
+ * fblib.c
+ *
+ * Adapted by Florian Klemenz for use in the fb_dash project
+ *
+ * Source and all credit goes to 
+ * http://raspberrycompote.blogspot.ie/2014/03/low-level-graphics-on-raspberry-pi-part_14.html
+ *
+ * Original work by J-P Rosti (a.k.a -rst- and 'Raspberry Compote')
+ *
+ * Licensed under the Creative Commons Attribution 3.0 Unported License
+ * (http://creativecommons.org/licenses/by/3.0/deed.en_US)
+ *
+ * Distributed in the hope that this will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ */
+
+#include "fblib.h"
+
+
+// helper function to 'plot' a pixel in given color
+void put_pixel(char *fbp, int x, int y, int r, int g, int b)
+{
+    // calculate the pixel's byte offset inside the buffer
+    // note: x * 2 as every pixel is 2 consecutive bytes
+    //unsigned int pix_offset = x * 2 + y * finfo.line_length;
+    unsigned int pix_offset = x * 2 + y * (WIDTH * 2);
+
+    // now this is about the same as 'fbp[pix_offset] = value'
+    // but a bit more complicated for RGB565
+    //unsigned short c = ((r / 8) << 11) + ((g / 4) << 5) + (b / 8);
+    unsigned short c = ((r / 8) * 2048) + ((g / 4) * 32) + (b / 8);
+    // write 'two bytes at once'
+    *((unsigned short*)(fbp + pix_offset)) = c;
+
+}
+
+// helper function to draw a rectangle in given color
+void fill_rect(char *fbp, int x, int y, int w, int h, int r, int g, int b) {
+    int cx, cy;
+    for (cy = 0; cy < h; cy++) {
+        for (cx = 0; cx < w; cx++) {
+           put_pixel(fbp, x + cx, y + cy, r, g, b);
+        }
+    }
+}
+
+// helper function to draw a rectangle outline in given color
+void draw_rect(char *fbp, int x0, int y0, int w, int h, int r, int g, int b) {
+    draw_line(fbp, x0, y0, x0 + w, y0, r, g, b); // top
+    draw_line(fbp, x0, y0, x0, y0 + h, r, g, b); // left
+    draw_line(fbp, x0, y0 + h, x0 + w, y0 + h, r, g, b); // bottom
+    draw_line(fbp, x0 + w, y0, x0 + w, y0 + h, r, g, b); // right
+}
+
+// helper function to draw a circle outline in given color
+// (uses Bresenham's circle algorithm)
+void draw_circle(char *fbp, int x0, int y0, int radius, int r, int g, int b)
+{
+    int x = radius;
+    int y = 0;
+    int radiusError = 1 - x;
+
+    while(x >= y)
+    {
+        // top left
+        put_pixel(fbp, -y + x0, -x + y0, r, g, b);
+        // top right
+        put_pixel(fbp, y + x0, -x + y0, r, g, b);
+        // upper middle left
+        put_pixel(fbp, -x + x0, -y + y0, r, g, b);
+        // upper middle right
+        put_pixel(fbp, x + x0, -y + y0, r, g, b);
+        // lower middle left
+        put_pixel(fbp, -x + x0, y + y0, r, g, b);
+        // lower middle right
+        put_pixel(fbp, x + x0, y + y0, r, g, b);
+        // bottom left
+        put_pixel(fbp, -y + x0, x + y0, r, g, b);
+        // bottom right
+        put_pixel(fbp, y + x0, x + y0, r, g, b);
+
+        y++;
+        if (radiusError < 0)
+        {
+            radiusError += 2 * y + 1;
+        } else {
+            x--;
+            radiusError+= 2 * (y - x + 1);
+        }
+    }
+}
+
+// helper function to draw a filled circle in given color
+// (uses Bresenham's circle algorithm)
+void fill_circle(char *fbp, int x0, int y0, int radius, int r, int g, int b) {
+    int x = radius;
+    int y = 0;
+    int radiusError = 1 - x;
+
+    while(x >= y)
+    {
+        // top
+        draw_line(fbp, -y + x0, -x + y0, y + x0, -x + y0, r, g, b);
+        // upper middle
+        draw_line(fbp, -x + x0, -y + y0, x + x0, -y + y0, r, g, b);
+        // lower middle
+        draw_line(fbp, -x + x0, y + y0, x + x0, y + y0, r, g, b);
+        // bottom 
+        draw_line(fbp, -y + x0, x + y0, y + x0, x + y0, r, g, b);
+
+        y++;
+        if (radiusError < 0)
+        {
+            radiusError += 2 * y + 1;
+        } else {
+            x--;
+            radiusError+= 2 * (y - x + 1);
+        }
+    }
+}
+
+// helper function to clear the screen - fill whole 
+// screen with given color
+void clear_screen(char *fbp) {
+   //memset(fbp, 0, vinfo.xres * vinfo.yres * 2); // 16Bit = 8Bit * 2
+   memset(fbp, 0, WIDTH * HEIGHT * 2); // 16Bit = 8Bit * 2
+}
+
+// helper function to draw a line in given color
+// (uses Bresenham's line algorithm)
+void draw_line(char *fbp, int x0, int y0, int x1, int y1, int r, int g, int b) {
+    int dx = x1 - x0;
+    dx = (dx >= 0) ? dx : -dx; // abs()
+    int dy = y1 - y0;
+    dy = (dy >= 0) ? dy : -dy; // abs()
+    int sx;
+    int sy;
+    if (x0 < x1)
+        sx = 1;
+    else
+        sx = -1;
+    if (y0 < y1)
+        sy = 1;
+    else
+        sy = -1;
+    int err = dx - dy;
+    int e2;
+    int done = 0;
+    while (!done) {
+        put_pixel(fbp, x0, y0, r, g, b);
+        if ((x0 == x1) && (y0 == y1))
+            done = 1;
+        else {
+            e2 = 2 * err;
+            if (e2 > -dy) {
+                err = err - dy;
+                x0 = x0 + sx;
+            }
+            if (e2 < dx) {
+                err = err + dx;
+                y0 = y0 + sy;
+            }
+        }
+    }
+}

fblib.h

@@ -0,0 +1,48 @@
+/*
+ * fblib.h
+ *
+ * Adapted by Florian Klemenz for use in the fb_dash project
+ *
+ * Source and all credit goes to 
+ * http://raspberrycompote.blogspot.ie/2014/03/low-level-graphics-on-raspberry-pi-part_14.html
+ *
+ * Original work by J-P Rosti (a.k.a -rst- and 'Raspberry Compote')
+ *
+ * Licensed under the Creative Commons Attribution 3.0 Unported License
+ * (http://creativecommons.org/licenses/by/3.0/deed.en_US)
+ *
+ * Distributed in the hope that this will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ */
+
+
+#ifndef FBLIB_H
+#define FBLIB_H
+
+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <fcntl.h>
+#include <linux/fb.h>
+#include <sys/mman.h>
+#include <linux/kd.h>
+
+
+#define WIDTH 240
+#define HEIGHT 320
+
+void put_pixel(char *fbp, int x, int y, int r, int g, int b);
+void clear_screen(char *fbp);
+
+void draw_line(char *fbp, int x0, int y0, int x1, int y1, int r, int g, int b);
+
+void draw_rect(char *fbp, int x0, int y0, int w, int h, int r, int g, int b);
+void fill_rect(char *fbp, int x, int y, int w, int h, int r, int g, int b);
+
+void draw_circle(char *fbp, int x0, int y0, int radius, int r, int g, int b);
+void fill_circle(char *fbp, int x0, int y0, int radius, int r, int g, int b);
+
+#endif