75 lines
1.5 KiB
C
75 lines
1.5 KiB
C
#include <gint/display.h>
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#include <gint/defs/util.h>
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#include "../render/render.h"
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#ifdef FX9860G
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#include "../render-fx/render-fx.h"
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#endif
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/* dline(): Bresenham line drawing algorithm
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Remotely adapted from MonochromeLib code by Pierre "PerriotLL" Le Gall.
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Relies on platform-dependent dhline() and dvline() for optimized situations.
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@x1 @y1 @x2 @y2 Coordinates of endpoints of line (included)
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@color Any color accepted by dpixel() on the platform */
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void dline(int x1, int y1, int x2, int y2, int color)
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{
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if(color == C_NONE) return;
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/* Possible optimizations */
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if(y1 == y2)
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{
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#ifdef FX9860G
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DMODE_OVERRIDE(gint_dhline, x1, x2, y1, color);
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#endif
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gint_dhline(x1, x2, y1, color);
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return;
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}
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if(x1 == x2)
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{
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#ifdef FX9860G
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DMODE_OVERRIDE(gint_dvline, y1, y2, x1, color);
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#endif
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gint_dvline(y1, y2, x1, color);
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return;
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}
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/* Brensenham line drawing algorithm */
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int i, x = x1, y = y1, cumul;
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int dx = x2 - x1, dy = y2 - y1;
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int sx = sgn(dx), sy = sgn(dy);
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dx = (dx >= 0 ? dx : -dx), dy = (dy >= 0 ? dy : -dy);
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dpixel(x1, y1, color);
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if(dx >= dy)
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{
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/* Start with a non-zero cumul to even the overdue between the
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two ends of the line (for more regularity) */
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cumul = dx >> 1;
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for(i = 1; i < dx; i++)
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{
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x += sx;
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cumul += dy;
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if(cumul > dx) cumul -= dx, y += sy;
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dpixel(x, y, color);
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}
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}
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else
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{
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cumul = dy >> 1;
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for(i = 1; i < dy; i++)
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{
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y += sy;
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cumul += dx;
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if(cumul > dy) cumul -= dy, x += sx;
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dpixel(x, y, color);
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}
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}
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dpixel(x2, y2, color);
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}
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