cos2000v2/lib/2d.c

#include "types.h"
#include "vga.h"
#include "video.h"
#include "2d.h"
#include "math.h"

/******************************************************************************/

/* Affiche une ligne entre les points sp<73>cifi<66>s */

void linev(vertex2d *A, vertex2d *B, u8 color)
{
    line(A->x,A->y,B->x,B->y,color);
}

void line(u32 x1, u32 y1, u32 x2, u32 y2, u8 color)
{
	s32 dx, dy, sdx, sdy;
	u32 i, dxabs, dyabs, x, y, px, py;

	dx = x2 - x1;		/*  distance horizontale de la line */
	dy = y2 - y1;		/* distance verticale de la line * */
	dxabs = abs(dx);
	dyabs = abs(dy);
	sdx = sgn(dx);
	sdy = sgn(dy);
	x = dyabs >> 1;
	y = dxabs >> 1;
	px = x1;
	py = y1;

	writepxl(px, py, color);

	if (dxabs >= dyabs) {	/* la ligne est plus horizontale que verticale */
		for (i = 0; i < dxabs; i++) {
			y += dyabs;
			if (y >= dxabs) {
				y -= dxabs;
				py += sdy;
			}
			px += sdx;
			writepxl(px, py, color);
		}
	} else {		/* la ligne est plus verticale que horizontale */

		for (i = 0; i < dyabs; i++) {
			x += dxabs;
			if (x >= dyabs) {
				x -= dyabs;
				px += sdx;
			}
			py += sdy;
			writepxl(px, py, color);
		}
	}
}

/******************************************************************************/

/* Affiche une ligne horizontale entre les points sp<73>cifi<66>s */

void hline(u32 x1, u32 x2, u32 y, u8 color) {
    if (x2>x1)
        for(;x1<=x2;x1++)
            writepxl(x1, y, color);
    else
        for(;x2<=x1;x2++)
            writepxl(x2, y, color);
}

/******************************************************************************/

/* Affiche un triangle rempli entre les points sp<73>cifi<66>s */

void trianglefilled(vertex2d *AA, vertex2d *BB, vertex2d *CC, u8 color) {
    vertex2d *A,*B,*C;
 	u32 a, b, y, last;
    int dx1, dx2, dx3, dy1, dy2, dy3 , sa, sb;
    A=AA;
    B=BB;
    C=CC;
    if (AA->y > BB->y) {
        A=BB;
        B=AA;
    }
    if (BB->y > CC->y) {
        C=BB;
        B=CC;
    }
    if (AA->y > CC->y) {
        C=AA;
        A=CC;
    }
    if(A->y == C->y) { //meme ligne
    	a = b = A->x;
    	if(B->x < a)      a = B->x;
    	else if(B->x > b) b = B->x;
    	if(C->x < a)      a = C->x;
    	else if(C->x > b) b = C->x;
        hline(a, b, A->y, color);
        return;
    }
    dx1 = B->x - A->x;
    dy1 = B->y - A->y;
    dx2 = C->x - A->x;
    dy2 = C->y - A->y;
    dx3 = C->x - B->x;
    dy3 = C->y - B->y;
    sa = 0;
    sb = 0;

    if(B->y == C->y) 
        last = B->y;   
    else         
        last = B->y-1;

    for(y=A->y; y<=last; y++) {
        a   = A->x + sa / dy1;
        b   = A->x + sb / dy2;
        sa += dx1;
        sb += dx2;
        hline(a, b, y, color);
    }

    sa = dx3 * (y - B->y);
    sb = dx2 * (y - A->y);
    for(; y<=C->y; y++) {
        a   = B->x + sa / dy3;
        b   = A->x + sb / dy2;
        sa += dx3;
        sb += dx2;
        hline(a, b, y, color);
    }
}

/******************************************************************************/

/* Affiche un triangle  entre les points sp<73>cifi<66>s */

void triangle(vertex2d *AA, vertex2d *BB, vertex2d *CC, u8 color) {
    line(AA->x,AA->y,BB->x,BB->y,color);
    line(BB->x,BB->y,CC->x,CC->y,color);
    line(CC->x,CC->y,AA->x,AA->y,color);
}