forked from KolibriOS/kolibrios
122 lines
2.6 KiB
C
122 lines
2.6 KiB
C
{
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int n, dx, dy, sx, pp_inc_1, pp_inc_2;
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register int a;
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register PIXEL *pp;
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#if defined(INTERP_RGB) || TGL_FEATURE_RENDER_BITS == 24
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register unsigned int r, g, b;
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#endif
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#ifdef INTERP_RGB
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register unsigned int rinc, ginc, binc;
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#endif
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#ifdef INTERP_Z
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register unsigned short *pz;
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int zinc;
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register int z, zz;
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#endif
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if (p1->y > p2->y || (p1->y == p2->y && p1->x > p2->x)) {
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ZBufferPoint *tmp;
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tmp = p1;
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p1 = p2;
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p2 = tmp;
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}
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sx = zb->xsize;
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pp = (PIXEL *) ((char *) zb->pbuf + zb->linesize * p1->y + p1->x * PSZB);
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#ifdef INTERP_Z
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pz = zb->zbuf + (p1->y * sx + p1->x);
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z = p1->z;
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#endif
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dx = p2->x - p1->x;
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dy = p2->y - p1->y;
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#ifdef INTERP_RGB
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r = p1->r << 8;
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g = p1->g << 8;
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b = p1->b << 8;
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#elif TGL_FEATURE_RENDER_BITS == 24
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/* for 24 bits, we store the colors in different variables */
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r = p2->r >> 8;
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g = p2->g >> 8;
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b = p2->b >> 8;
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#endif
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#ifdef INTERP_RGB
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#define RGB(x) x
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#if TGL_FEATURE_RENDER_BITS == 24
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#define RGBPIXEL pp[0] = r >> 16, pp[1] = g >> 16, pp[2] = b >> 16
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#else
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#define RGBPIXEL *pp = RGB_TO_PIXEL(r >> 8,g >> 8,b >> 8)
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#endif
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#else /* INTERP_RGB */
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#define RGB(x)
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#if TGL_FEATURE_RENDER_BITS == 24
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#define RGBPIXEL pp[0] = r, pp[1] = g, pp[2] = b
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#else
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#define RGBPIXEL *pp = color
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#endif
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#endif /* INTERP_RGB */
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#ifdef INTERP_Z
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#define ZZ(x) x
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#define PUTPIXEL() \
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{ \
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zz=z >> ZB_POINT_Z_FRAC_BITS; \
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if (ZCMP(zz,*pz)) { \
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RGBPIXEL; \
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*pz=zz; \
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} \
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}
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#else /* INTERP_Z */
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#define ZZ(x)
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#define PUTPIXEL() RGBPIXEL
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#endif /* INTERP_Z */
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#define DRAWLINE(dx,dy,inc_1,inc_2) \
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n=dx;\
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ZZ(zinc=(p2->z-p1->z)/n);\
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RGB(rinc=((p2->r-p1->r) << 8)/n;\
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ginc=((p2->g-p1->g) << 8)/n;\
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binc=((p2->b-p1->b) << 8)/n);\
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a=2*dy-dx;\
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dy=2*dy;\
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dx=2*dx-dy;\
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pp_inc_1 = (inc_1) * PSZB;\
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pp_inc_2 = (inc_2) * PSZB;\
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do {\
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PUTPIXEL();\
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ZZ(z+=zinc);\
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RGB(r+=rinc;g+=ginc;b+=binc);\
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if (a>0) { pp=(PIXEL *)((char *)pp + pp_inc_1); ZZ(pz+=(inc_1)); a-=dx; }\
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else { pp=(PIXEL *)((char *)pp + pp_inc_2); ZZ(pz+=(inc_2)); a+=dy; }\
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} while (--n >= 0);
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/* fin macro */
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if (dx == 0 && dy == 0) {
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PUTPIXEL();
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} else if (dx > 0) {
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if (dx >= dy) {
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DRAWLINE(dx, dy, sx + 1, 1);
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} else {
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DRAWLINE(dy, dx, sx + 1, sx);
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}
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} else {
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dx = -dx;
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if (dx >= dy) {
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DRAWLINE(dx, dy, sx - 1, -1);
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} else {
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DRAWLINE(dy, dx, sx - 1, sx);
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}
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}
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}
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#undef INTERP_Z
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#undef INTERP_RGB
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/* internal defines */
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#undef DRAWLINE
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#undef PUTPIXEL
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#undef ZZ
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#undef RGB
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#undef RGBPIXEL
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