ref: 711de5682e829770a1f2f68d863929d3cd5ca837
dir: /src/zline.h/
{ GLint n, dx, dy, sx, pp_inc_1, pp_inc_2; register GLint a; register PIXEL* pp; #if defined(INTERP_RGB) register GLuint r, g, b; #endif #ifdef INTERP_RGB register GLuint rinc, ginc, binc; #endif #ifdef INTERP_Z register GLushort* pz; GLint zinc; register GLint z, zz; #endif if (p1->y > p2->y || (p1->y == p2->y && p1->x > p2->x)) { ZBufferPoint* tmp; tmp = p1; p1 = p2; p2 = tmp; } sx = zb->xsize; pp = (PIXEL*)((GLbyte*)zb->pbuf + zb->linesize * p1->y + p1->x * PSZB); #ifdef INTERP_Z pz = zb->zbuf + (p1->y * sx + p1->x); z = p1->z; #endif dx = p2->x - p1->x; dy = p2->y - p1->y; #ifdef INTERP_RGB r = p2->r << 8; g = p2->g << 8; b = p2->b << 8; #endif #ifdef INTERP_RGB #define RGB(x) x #define RGBPIXEL *pp = RGB_TO_PIXEL(r >> 8, g >> 8, b >> 8) //#define RGBPIXEL TGL_BLEND_FUNC_RGB(r>>8, g>>8, b>>8, (*pp)) #else /* INTERP_RGB */ #define RGB(x) #if TGL_FEATURE_RENDER_BITS == 24 #define RGBPIXEL pp[0] = r, pp[1] = g, pp[2] = b #else #define RGBPIXEL *pp = color //#define RGBPIXEL *pp = color #endif #endif /* INTERP_RGB */ #ifdef INTERP_Z #define ZZ(x) x #define PUTPIXEL() \ { \ zz = z >> ZB_POINT_Z_FRAC_BITS; \ if (ZCMP(zz, *pz)) { \ RGBPIXEL; \ if(zbdw) {*pz = zz;} \ } \ } #else /* INTERP_Z */ #define ZZ(x) #define PUTPIXEL() RGBPIXEL #endif /* INTERP_Z */ #define DRAWLINE(dx, dy, inc_1, inc_2) \ n = dx; \ ZZ(zinc = (p2->z - p1->z) / n); \ RGB(rinc = ((p2->r - p1->r) << 8) / n; ginc = ((p2->g - p1->g) << 8) / n; binc = ((p2->b - p1->b) << 8) / n); \ a = 2 * dy - dx; \ dy = 2 * dy; \ dx = 2 * dx - dy; \ pp_inc_1 = (inc_1)*PSZB; \ pp_inc_2 = (inc_2)*PSZB; \ do { \ PUTPIXEL(); \ ZZ(z += zinc); \ RGB(r += rinc; g += ginc; b += binc); \ if (a > 0) { \ pp = (PIXEL*)((GLbyte*)pp + pp_inc_1); \ ZZ(pz += (inc_1)); \ a -= dx; \ } else { \ pp = (PIXEL*)((GLbyte*)pp + pp_inc_2); \ ZZ(pz += (inc_2)); \ a += dy; \ } \ } while (--n >= 0); /* fin macro */ if (dx == 0 && dy == 0) { PUTPIXEL(); } else if (dx > 0) { if (dx >= dy) { DRAWLINE(dx, dy, sx + 1, 1); } else { DRAWLINE(dy, dx, sx + 1, sx); } } else { dx = -dx; if (dx >= dy) { DRAWLINE(dx, dy, sx - 1, -1); } else { DRAWLINE(dy, dx, sx - 1, sx); } } } #undef INTERP_Z #undef INTERP_RGB /* GLinternal defines */ #undef DRAWLINE #undef PUTPIXEL #undef ZZ #undef RGB #undef RGBPIXEL