139 lines
4.5 KiB
HTML
139 lines
4.5 KiB
HTML
<!DOCTYPE html>
|
|
|
|
<html xmlns="http://www.w3.org/1999/xhtml">
|
|
<head>
|
|
<meta name="vsisbn" content="1576101746" />
|
|
<meta name="vstitle" content="Michael Abrash's Graphics Programming Black Book, Special Edition" />
|
|
<meta name="vsauthor" content="Michael Abrash" />
|
|
<meta name="vspublisher" content="The Coriolis Group" />
|
|
<meta name="vspubdate" content="07/01/97" />
|
|
<meta name="vscategory" content="Web and Software Development: Game Development,Web and Software Development: Graphics and Multimedia Development" />
|
|
|
|
<title>Michael Abrash's Graphics Programming Black Book Special Edition: The Good, the Bad, and the Run-Sliced</title>
|
|
<meta name="chapter" content="36" />
|
|
<meta name="pages" content="692-693" />
|
|
</head>
|
|
|
|
<body>
|
|
<center>
|
|
<table border="1">
|
|
<tr>
|
|
<td>
|
|
<a href="36-03.html">Previous</a>
|
|
</td>
|
|
|
|
<td>
|
|
<a href="index.html">Table of Contents</a>
|
|
</td>
|
|
|
|
<td>
|
|
<a href="37-01.html">Next</a>
|
|
</td>
|
|
</tr>
|
|
</table>
|
|
</center>
|
|
|
|
<p>Notwithstanding that it’s not optimized, Listing 36.1 is reasonably fast. If you run Listing 36.2 (a sample line-drawing program that you can use to test-drive Listing 36.1), you may be as surprised as I was at how quickly the screen fills with vectors, considering that Listing 36.1 is entirely in C and has some redundant divides. Or perhaps you won’t be surprised—in which case I suggest you <i>not</i> miss the next chapter.</p>
|
|
|
|
<p><b>LISTING 36.2 L36-2.C</b></p>
|
|
<pre>
|
|
/* Sample line-drawing program. Uses the optimized
|
|
line-drawing functions coded in LListing L36.1.C.
|
|
Tested with Borland C++ in the small model. */
|
|
|
|
#include <dos.h>
|
|
|
|
#define GRAPHICS_MODE 0x13
|
|
#define TEXT_MODE 0x03
|
|
#define BIOS_VIDEO_INT 0x10
|
|
#define X_MAX 320 /* working screen width */
|
|
#define Y_MAX 200 /* working screen height */
|
|
|
|
extern void LineDraw(int XStart, int YStart, int XEnd, int YEnd, int Color);
|
|
|
|
/* Subroutine to draw a rectangle full of vectors, of the specified
|
|
* length and color, around the specified rectangle center. */
|
|
void VectorsUp(XCenter, YCenter, XLength, YLength, Color)
|
|
int XCenter, YCenter; /* center of rectangle to fill */
|
|
int XLength, YLength; /* distance from center to edge of rectangle */
|
|
int Color; /* color to draw lines in */
|
|
{
|
|
int WorkingX, WorkingY;
|
|
|
|
/* lines from center to top of rectangle */
|
|
WorkingX = XCenter - XLength;
|
|
WorkingY = YCenter - YLength;
|
|
for ( ; WorkingX < ( XCenter + XLength ); WorkingX++ )
|
|
{
|
|
LineDraw(XCenter, YCenter, WorkingX, WorkingY, Color);
|
|
}
|
|
/* lines from center to right of rectangle */
|
|
WorkingX = XCenter + XLength - 1;
|
|
WorkingY = YCenter - YLength;
|
|
for ( ; WorkingY < ( YCenter + YLength ); WorkingY++ )
|
|
{
|
|
LineDraw(XCenter, YCenter, WorkingX, WorkingY, Color);
|
|
}
|
|
/* lines from center to bottom of rectangle */
|
|
WorkingX = XCenter + XLength - 1;
|
|
WorkingY = YCenter + YLength - 1;
|
|
for ( ; WorkingX >= ( XCenter - XLength ); WorkingX-- )
|
|
{
|
|
LineDraw(XCenter, YCenter, WorkingX, WorkingY, Color);
|
|
}
|
|
/* lines from center to left of rectangle */
|
|
WorkingX = XCenter - XLength;
|
|
WorkingY = YCenter + YLength - 1;
|
|
for ( ; WorkingY >= ( YCenter - YLength ); WorkingY-- )
|
|
{
|
|
LineDraw(XCenter, YCenter, WorkingX, WorkingY, Color);
|
|
}
|
|
}
|
|
/* Sample program to draw four rectangles full of lines. */
|
|
int main()
|
|
{
|
|
union REGS regs;
|
|
|
|
/* Set graphics mode */
|
|
regs.x.ax = GRAPHICS_MODE;
|
|
int86(BIOS_VIDEO_INT, &regs, &regs);
|
|
|
|
/* Draw each of four rectangles full of vectors */
|
|
VectorsUp(X_MAX / 4, Y_MAX / 4, X_MAX / 4, Y_MAX / 4, 1);
|
|
VectorsUp(X_MAX * 3 / 4, Y_MAX / 4, X_MAX / 4, Y_MAX / 4, 2);
|
|
VectorsUp(X_MAX / 4, Y_MAX * 3 / 4, X_MAX / 4, Y_MAX / 4, 3);
|
|
VectorsUp(X_MAX * 3 / 4, Y_MAX * 3 / 4, X_MAX / 4, Y_MAX / 4, 4);
|
|
|
|
/* Wait for a key to be pressed */
|
|
getch();
|
|
|
|
/* Return back to text mode */
|
|
regs.x.ax = TEXT_MODE;
|
|
int86(BIOS_VIDEO_INT, &regs, &regs);
|
|
}
|
|
</pre>
|
|
|
|
<center>
|
|
<table border="1">
|
|
<tr>
|
|
<td>
|
|
<a href="36-03.html">Previous</a>
|
|
</td>
|
|
|
|
<td>
|
|
<a href="index.html">Table of Contents</a>
|
|
</td>
|
|
|
|
<td>
|
|
<a href="37-01.html">Next</a>
|
|
</td>
|
|
</tr>
|
|
</table>
|
|
</center>
|
|
<hr width="90%" size="1" noshade="noshade" />
|
|
|
|
<div align="center">
|
|
Graphics Programming Black Book © 2001 Michael Abrash
|
|
</div>
|
|
</body>
|
|
</html>
|