drawmethods.h

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#ifndef _DRAWMETHODS_H
#define _DRAWMETHODS_H

#include "goomconfig.h"

#define DRAWMETHOD_NORMAL(adr,col) {*(adr) = (col);}

#ifdef MMX
#include "mmx.h"

#define DRAWMETHOD_PLUS(_out,_backbuf,_col) \
{\
movd_m2r (_backbuf, mm0); \
paddusb_m2r (_col, mm0); \
movd_r2m (mm0, _out); \
}

#else
#define DRAWMETHOD_PLUS(_out,_backbuf,_col) \
{\
      int tra=0,i=0;\
      unsigned char *bra = (unsigned char*)&(_backbuf);\
      unsigned char *dra = (unsigned char*)&(_out);\
      unsigned char *cra = (unsigned char*)&(_col);\
      for (;i<4;i++) {\
                                tra = *cra;\
                                tra += *bra;\
                                if (tra>255) tra=255;\
                                *dra = tra;\
                                ++dra;++cra;++bra;\
                        }\
}
#endif

#define DRAWMETHOD_OR(adr,col) {*(adr)|=(col);}

#ifdef MMX
#define DRAWMETHOD_DONE() {__asm__ __volatile__ ("emms");}
#else
#define DRAWMETHOD_DONE() {}
#endif

#ifndef DRAWMETHOD
#define DRAWMETHOD DRAWMETHOD_PLUS(*p,*p,col)

static void draw_line (int *data, int x1, int y1, int x2, int y2, int col, int screenx, int screeny) {
    int     x, y, dx, dy, yy, xx;       // am, tmp;
        int    *p;


        if ((y1 < 0) || (y2 < 0) || (x1 < 0) || (x2 < 0) || (y1 >= screeny) || (y2 >= screeny) || (x1 >= screenx) || (x2 >= screenx)) 
                        return;
        
        dx = x2 - x1;
        dy = y2 - y1;
        if (x1 > x2) {
                int     tmp;

                tmp = x1;
                x1 = x2;
                x2 = tmp;
                tmp = y1;
                y1 = y2;
                y2 = tmp;
                dx = x2 - x1;
                dy = y2 - y1;
        }

        /* vertical line */
        if (dx == 0) {
                if (y1 < y2) {
                        p = &(data[(screenx * y1) + x1]);
                        for (y = y1; y <= y2; y++) {
                                DRAWMETHOD;
                                p += screenx;
                        }
                }
                else {
                        p = &(data[(screenx * y2) + x1]);
                        for (y = y2; y <= y1; y++) {
                                DRAWMETHOD;
                                p += screenx;
                        }
                }
                return;
        }
        /* horizontal line */
        if (dy == 0) {
                if (x1 < x2) {
                        p = &(data[(screenx * y1) + x1]);
                        for (x = x1; x <= x2; x++) {
                                DRAWMETHOD;
                                p++;
                        }
                        return;
                }
                else {
                        p = &(data[(screenx * y1) + x2]);
                        for (x = x2; x <= x1; x++) {
                                DRAWMETHOD;
                                p++;
                        }
                        return;
                }
        }
        /* 1    */
        
        /* 2 */
        if (y2 > y1) {
                /* steep */
                if (dy > dx) {
                        dx = ((dx << 16) / dy);
                        x = x1 << 16;
                        for (y = y1; y <= y2; y++) {
                                xx = x >> 16;
                                p = &(data[(screenx * y) + xx]);
                                DRAWMETHOD;
                                if (xx < (screenx - 1)) {
                                        p++;
                                }
                                x += dx;
                        }
                        return;
                }
                /* shallow */
                else {
                        dy = ((dy << 16) / dx);
                        y = y1 << 16;
                        for (x = x1; x <= x2; x++) {
                                yy = y >> 16;
                                p = &(data[(screenx * yy) + x]);
                                DRAWMETHOD;
                                if (yy < (screeny - 1)) {
                                        p += screeny;
                                }
                                y += dy;
                        }
                }
        }
        /* 2 */
        
        /* 1    */
        else {
                /* steep */
                if (-dy > dx) {
                        dx = ((dx << 16) / -dy);
                        x = (x1 + 1) << 16;
                        for (y = y1; y >= y2; y--) {
                                xx = x >> 16;
                                p = &(data[(screenx * y) + xx]);
                                DRAWMETHOD;
                                if (xx < (screenx - 1)) {
                                        p--;
                                }
                                x += dx;
                        }
                        return;
                }
                /* shallow */
                else {
                        dy = ((dy << 16) / dx);
                        y = y1 << 16;
                        for (x = x1; x <= x2; x++) {
                                yy = y >> 16;
                                p = &(data[(screenx * yy) + x]);
                                DRAWMETHOD;
                                if (yy < (screeny - 1)) {
                                        p += screeny;
                                }
                                y += dy;
                        }
                        return;
                }
        }
}
#endif

#endif