VGA图形控制器编程实例

VGA图形控制器编程实例

VGA图形控制器编程实例

#include "graphics.h"
#include "dos.h"
#include "stdio.h"
#define ENABLE 0x0F
#define INDEXREG 0x3CE
/*定义索引寄存器端口地址*/
#define VALREG 0x3CF
/*定义数据寄存器端口地址*/
#define VGABASE 0xA0000000L
#define WIDTH 80L
#define XMAX 639
#define YMAX 479
#define XMIX 0
#define YMIN 0
#define OUTINDEX(index,val) outport(INDEXREG,index);outport(VALREG,val);
char far *vgabase;
void putpoint(int x,int y,int color,int how);
main()
{
int gmode=VGAHI,gdriver=VGA;
int color=1,x,y;
initgraph(&gdriver,&gmode,"");
/*绘制各种颜色的直线段*/
for(y=1;y<=479;++y){
for(x=1;x<=639;++x)
putpoint(x,y,color,0);
color++;}
getch();
/*用异或方式擦除各条直线*/
color=1;
for(y=1;y<=479;++y){
for(x=1;x<=639;++x)
putpoint(x,y,color,0x18);
color++;}
getch();
closegraph();
}

/*利用图形控制寄存器功能写像素函数*/
void putpoint(int x,int y,int color,int how)
{
register unsigned char mask=0x80;
register char far *base;
unsigned dummy;
vgabase=(char far *)MK_FP(0xA000,0);
base=(char far *)(vgabase+((long)y*
WIDTH+(long)x/8L));
mask>>=x%8;
dummy=*base;
OUTINDEX(0,color);/*设定额色*/
OUTINDEX(1,ENABLE);/*启动位平面*/
OUTINDEX(3,how); /*确定逻辑操作方式*/
OUTINDEX(8,mask);/*设置屏蔽位*/
*base=1;
OUTINDEX(0,0);/*寄存器复位*/
OUTINDEX(1,0);
OUTINDEX(3,0);
OUTINDEX(8,0xff);
}