vga640x480g_functions.h

00001 #include "vga_font.h"
00002 #define FRAMEBUFFERMAX 32000
00003 #define EXTENSIONMAX 6400
00004 #define VGA_HEIGHT 400
00005 #define VGA_WIDTH 640
00006 #include "mbed.h"
00007 
00008 extern unsigned char *framebuffer;
00009 extern unsigned char *framebuffer2;
00010 
00011 static const unsigned char rmask[]={0x7f,0xbf,0xdf,0xef,0xf7,0xfb,0xfd,0xfe};
00012 static const unsigned char smask[]={0x80,0x40,0x20,0x10,0x08,0x04,0x02,0x01};
00013 
00014 // clear the screen
00015 void vga_cls() {
00016     memset(framebuffer,0,FRAMEBUFFERMAX);
00017     memset(framebuffer2,0,EXTENSIONMAX);
00018 }
00019 
00020 // scroll the screen one text line up
00021 void vga_scroll() {
00022     // move first part up
00023     memcpy(framebuffer,framebuffer+(FONTHEIGHT*80),FRAMEBUFFERMAX-80*(FONTHEIGHT));
00024     // copy top line of second part into bottom of first part
00025     memcpy(framebuffer+FRAMEBUFFERMAX-80*(FONTHEIGHT),framebuffer2,FONTHEIGHT*80);
00026     // move bottom part up
00027     memcpy(framebuffer2,framebuffer2+(FONTHEIGHT*80),EXTENSIONMAX-80*(FONTHEIGHT));
00028     // clear bottom row of second part
00029     memset(framebuffer2+EXTENSIONMAX-80*(FONTHEIGHT),0,FONTHEIGHT*80);
00030 }
00031 
00032 // set or reset a single pixel on screen
00033 void vga_plot(int x,int y,char color) {
00034     unsigned char *ad;
00035 
00036     ad=framebuffer+80*y+((x/8)^1);                      // calculate offset
00037     if (ad>=framebuffer+FRAMEBUFFERMAX) {               // first test for end of framebuffer
00038         ad=framebuffer2+80*(y-400)+((x/8)^1);                // calculate offset in framebuffer2
00039         if (ad>framebuffer2+EXTENSIONMAX) return;            // clip if exceeded
00040     }
00041     *ad &= rmask[x%8];             // clear the bit
00042     if (color) *ad |= smask[x%8]; // if color != 0 set the bit
00043 
00044 }
00045 
00046 // put a character from the vga font on screen
00047 void vga_putchar(int x,int y,int ch, char color) {
00048     int n,m;
00049     for (n=0; n<FONTHEIGHT; n++) {
00050         for (m=0; m<FONTWIDTH; m++) {
00051             if (vga_font8x16[ch*FONTHEIGHT+n] & (1<<(7-m))) vga_plot(x+m,y+n, color);
00052             else vga_plot(x+m,y+n,0);
00053         }
00054     }
00055 }
00056 
00057 // put a string on screen
00058 void vga_putstring(int x,int y, char *s, char color) {
00059     while (*s) {
00060         vga_putchar(x,y,*(s++),color);
00061         x+=FONTWIDTH;
00062     }
00063 }
00064 
00065 // Bresenham line routine
00066 void vga_line(int x0, int y0, int x1, int y1,char color) {
00067 
00068     char steep=1;
00069     int li,dx,dy,le;
00070     int sx,sy;
00071 
00072     // if same coordinates
00073     if (x0==x1 && y0==y1) {
00074         vga_plot(x0,y0,color);
00075         return;
00076     }
00077 
00078     dx = abs(x1-x0);
00079     sx = ((x1 - x0) >0) ? 1 : -1;
00080     dy=abs(y1-y0);
00081     sy = ((y1 - y0) >0) ? 1 : -1;
00082 
00083     if (dy > dx) {
00084         steep=0;
00085         // swap X0 and Y0
00086         x0=x0 ^ y0;
00087         y0=x0 ^ y0;
00088         x0=x0 ^ y0;
00089 
00090         // swap DX and DY
00091         dx=dx ^ dy;
00092         dy=dx ^ dy;
00093         dx=dx ^ dy;
00094 
00095         // swap SX and SY
00096         sx=sx ^ sy;
00097         sy=sx ^ sy;
00098         sx=sx ^ sy;
00099     }
00100 
00101     le = (dy << 1) - dx;
00102 
00103     for (li=0; li<=dx; li++) {
00104         if (steep) {
00105             vga_plot(x0,y0,color);
00106         } else {
00107             vga_plot(y0,x0,color);
00108         }
00109         while (le >= 0) {
00110             y0 += sy;
00111             le -= (dx << 1);
00112         }
00113         x0 += sx;
00114         le += (dy << 1);
00115     }
00116 }
00117 
00118 // draw an outline box
00119 void vga_box(int x0, int y0, int x1, int y1,char color) {
00120     vga_line(x0,y0,x1,y0,color);
00121     vga_line(x1,y0,x1,y1,color);
00122     vga_line(x1,y1,x0,y1,color);
00123     vga_line(x0,y1,x0,y0,color);
00124 }
00125 
00126 // draw a filled box
00127 void vga_filledbox(int x0, int y0, int x1, int y1,char color) {
00128     int n,dn;
00129 
00130     if (y1>y0) dn=1;
00131     else dn=-1;
00132 
00133     for (n=abs(y1-y0); n>=0; n--) {
00134         vga_line(x0,y0,x1,y0,color);
00135         y0+=dn;
00136     }
00137 }
00138 
00139 // Bresenham circle routine
00140 void vga_circle(int x0,int y0, int radius, char color) {
00141 
00142     int cf = 1 - radius;
00143     int dx = 1;
00144     int dy = -2 * radius;
00145     int cx = 0;
00146     int py = radius;
00147 
00148     vga_plot(x0, y0 + radius,color);
00149     vga_plot(x0, y0 - radius,color);
00150     vga_plot(x0 + radius, y0,color);
00151     vga_plot(x0 - radius, y0,color);
00152 
00153     while (cx < py) {
00154         if (cf >= 0) {
00155             py--;
00156             dy += 2;
00157             cf += dy;
00158         }
00159         cx++;
00160         dx += 2;
00161         cf += dx;
00162         vga_plot(x0 + cx, y0 + py,color);
00163         vga_plot(x0 - cx, y0 + py,color);
00164         vga_plot(x0 + cx, y0 - py,color);
00165         vga_plot(x0 - cx, y0 - py,color);
00166         vga_plot(x0 + py, y0 + cx,color);
00167         vga_plot(x0 - py, y0 + cx,color);
00168         vga_plot(x0 + py, y0 - cx,color);
00169         vga_plot(x0 - py, y0 - cx,color);
00170     }
00171 }