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/*
* file: tritemp.h
* auth: Peter McDermott
* desc: template for triangle functions
*
* This is by far the most complicated algorithm I've ever had to create
* and implement. I'm graduating in 2 weeks and am now convinced that I
* should have taken Numerical Analysis and Algorithms instead of Chinese,
* and Networks.
*
* As it stands now, this function _STILL_ doesn't draw triangles correctly.
* In fact, most of the time it's off by a pixel at at least one of the
* end points. It will hopefully be fixed shortly.
*
* #define's:
* OPCODE actual opcode the 5470 is sent (in color-indexed mode)
* OPCODE1 opcode sent to 5470 for red & green banks in rgba mode
* OPCODE2 opcode sent to 5470 for blue bank in rgba mode
* FLAT_INDEX flat shaded, 8bpp
* INTERP_INDEX gouraud shaded, 8pp
* FLAT_COLOR flat shaded, 24 bpp
* INTERP_COLOR gouraud shaded 24bpp
* NOVB function passes args as x1, y1, etc instead of three
* vertices v1, v2, v3
*
* The six trianges:
*
* left to right rendering:
*
* \ /\
* |\ \ \ /..\
* | \ \..\ /....\
* | \ \...\ /......\
* | \ \...| /........\
* | / \..| /......../
* | / \..| /...../
* |/ \.| /../
* \| /.
*
*
* right to left rendering:
*
*/
/* #define DEBUG_TRITEMP_H */
{
uint min, mid, max;
int dy_main, dx_main;
int count1, span1, rung1, count2, span2, rung2, px, width, t1, t2;
int rungmain,dxm,wbp,dw,wopp,dwopp,xbp;
int tf; int i;
#ifdef INTERP_COLOR
int rmin,gmin,bmin, rmid,gmid,bmid, rmax,gmax,bmax;
#endif
#ifdef NOVB
/* the following code is used for the 'user-friendly' polygonalization
* routines. It's not actually compiled in the routines called by Mesa.
* Mesa passes 3 (or 4) vertices, whereas the 'user-friendly' routines pass
* all of the parameters as parameters and not vertices. This setup code
* fakes the Mesa interface.
*/
uint v0=0; /* fake the four vertices passed to the routine */
uint v1=1;
uint v2=2;
uint pv=0; /* used to selecting color in flat-shaded tris */
struct vertex_buff { /* create the vertex_buff struct */
float Win[3][3];
int Win2[3][3];
uint Color[3][4];
uint Index[3];
};
struct vertex_buff VB; /* fake the vertex buffer */
/* fill in the 3 vertices in the faked vertex buffer */
VB.Win2[0][0]=x1<<12;
VB.Win2[0][1]=y1<<12;
VB.Win2[0][2]=((-z2 & 0x7fff) >> 1)<<12;
VB.Win2[1][0]=x2<<12;
VB.Win2[1][1]=y2<<12;
VB.Win2[1][2]=((-z2 & 0x7fff) >> 1)<<12;
VB.Win2[2][0]=x3<<12;
VB.Win2[2][1]=y3<<12;
VB.Win2[2][2]=((-z3 & 0x7fff) >> 1)<<12;
VB.Color[0][0]=VB.Color[1][0]=VB.Color[2][0]=0xff; /* color=red */
VB.Color[0][1]=VB.Color[0][2]=VB.Color[0][3]=VB.Color[1][1]=VB.Color[1][2]=
VB.Color[1][3]=
VB.Color[2][1]=VB.Color[2][2]=VB.Color[2][3]=0;
VB.Index[0]=VB.Index[1]=VB.Index[2]=2<<12; /* color index=2 */
#else
/*
* Mesa uses floating point math! (and it's still fast?!) Convert floats
* to fixed point numbers and fixup the z-coords since, the Mondello's
* z-buffer is a little broken.
*/
/* unrolling ensues */
/* note: fix Mesa to do this for us. As it is, many vertices are
converted from floats to fixed more than once wasting cycles!
*/
VB.Win2[v0][0]=(uint)VB.Win[v0][0] << 12;
VB.Win2[v0][1]=(uint)FLIP(VB.Win[v0][1]) << 12;
VB.Win2[v0][2]=(uint)VB.Win[v0][2] << 12;
i=(uint)(VB.Win[v0][2]*DEPTH_SCALE);
VB.Win2[v0][2]=((-i & 0x7fff) >> 1) << 12;
VB.Win2[v1][0]=(uint)VB.Win[v1][0] << 12;
VB.Win2[v1][1]=(uint)FLIP(VB.Win[v1][1]) << 12;
VB.Win2[v1][2]=(uint)VB.Win[v1][2] << 12;
i=(uint)(VB.Win[v1][2]*DEPTH_SCALE);
VB.Win2[v1][2]=((-i & 0x7fff) >> 1) << 12;
VB.Win2[v2][0]=(uint)VB.Win[v2][0] << 12;
VB.Win2[v2][1]=(uint)FLIP(VB.Win[v2][1]) << 12;
VB.Win2[v2][2]=(uint)VB.Win[v2][2] << 12;
i=(uint)(VB.Win[v2][2]*DEPTH_SCALE);
VB.Win2[v2][2]=((-i & 0x7fff) >> 1) << 12;
#endif
#ifdef SETUP_CODE
SETUP_CODE
#endif
#ifndef DEBUG_TRITEMP_H
VB.Win2[v0][1]+=yoffs << 12;
VB.Win2[v1][1]+=yoffs << 12;
VB.Win2[v2][1]+=yoffs << 12;
#endif
#ifdef DEBUG_TRITEMP_H
clear24(0,0,0);
line24_2fc(VB.Win2[v0][0]>>12,0,VB.Win2[v0][0]>>12,400,0xa5,0xa5,0xa5,0);
line24_2fc(VB.Win2[v1][0]>>12,0,VB.Win2[v1][0]>>12,400,0xa5,0xa5,0xa5,0);
line24_2fc(VB.Win2[v2][0]>>12,0,VB.Win2[v2][0]>>12,400,0xa5,0xa5,0xa5,0);
/* line24_2fc(0,VB.Win2[v0][1]>>12,640,VB.Win2[v0][1]>>12,0xa5,0xa5,0xa5,0);
line24_2fc(0,VB.Win2[v1][1]>>12,640,VB.Win2[v1][1]>>12,0xa5,0xa5,0xa5,0);
line24_2fc(0,VB.Win2[v2][1]>>12,640,VB.Win2[v2][1]>>12,0xa5,0xa5,0xa5,0);
*/
#endif
if( VB.Win2[v0][1] <= VB.Win2[v1][1] ) {
if( VB.Win2[v0][1] < VB.Win2[v2][1] ) {
if ( VB.Win2[v1][1] < VB.Win2[v2][1] ) { /* 0,1,2 */
min=v0; mid=v1; max=v2;
}
else { /* 0,2,1 */
min=v0; mid=v2; max=v1;
}
}
else if( VB.Win2[v0][1] == VB.Win2[v2][1] &&
VB.Win2[v0][1] == VB.Win2[v1][1]) { /* flat line */
return;
}
else { /* 2,0,1 */
min=v2; mid=v0; max=v1;
}
}
else {
if( VB.Win2[v1][1] < VB.Win2[v2][1] ) {
if ( VB.Win2[v0][1] < VB.Win2[v2][1]) { /* 1,0,2 */
min=v1; mid=v0; max=v2;
}
else { /* 1,2,0 */
min=v1; mid=v2; max=v0;
}
}
else { /* 2,1,0 */
min=v2; mid=v1; max=v0;
}
}
#ifdef DEBUG_TRITEMP_H
printf("# (%d,%d) (%d,%d) (%d,%d)\n",
VB.Win2[min][0]>>12,VB.Win2[min][1]>>12,
VB.Win2[mid][0]>>12,VB.Win2[mid][1]>>12,
VB.Win2[max][0]>>12,VB.Win2[max][1]>>12);
#endif
#ifdef INTERP_COLOR
rmin=VB.Color[min][0] >> 3;
gmin=VB.Color[min][1] >> 3;
bmin=VB.Color[min][2] >> 3;
rmid=VB.Color[mid][0] >> 3;
gmid=VB.Color[mid][1] >> 3;
bmid=VB.Color[mid][2] >> 3;
rmax=VB.Color[max][0] >> 3;
gmax=VB.Color[max][1] >> 3;
bmax=VB.Color[max][2] >> 3;
#endif
/* note: Win2[min][0] <= Win2[mid][0] <= Win2[max][0] */
count1=VB.Win2[mid][1]-VB.Win2[min][1]; /* distance btw min and mid */
count2=VB.Win2[max][1]-VB.Win2[mid][1]; /* distance btw max and mid */
dy_main=VB.Win2[max][1]-VB.Win2[min][1]; /* distance btw max and min */
dx_main=VB.Win2[max][0]-VB.Win2[min][0];
tf=dx_main/(dy_main>>12); /* dx/dy */
px=VB.Win2[min][0]+(count1>>6)*(tf>>6); /* x-intercept on main @ mid */
width=VB.Win2[mid][0]-px; /* may be neg */
/* note: (count1 >= 0) && (count2 >= 0) && (dy_main >= 0) */
if (dx_main) {
if (dx_main >= 0)
rungmain=(dx_main+0x1000)/((dy_main>>12)+1);
else
rungmain=(dx_main-0x1000)/((dy_main>>12)+1);
}
else
rungmain=0;
/* width is always const or increasing from starting point */
t1=VB.Win2[mid][0] - VB.Win2[min][0];
if (t1 <0) t1=-t1; /* t1 = abs(t1) */
rung1=(t1+0x1000)/((count1>>12)+1); /* rung1 is pos */
/* width may be increasing or decreasing after mid point */
t1=VB.Win2[max][0] - VB.Win2[mid][0];
if (t1 >=0 ) { /* maxx >= midx */
rung2=(t1+0x1000)/((count2>>12)+1);
}
else { /* maxx < midx */
rung2=(t1-0x1000)/((count2>>12)+1);
}
/* note: (rung1 >= 0) && (rung2 may be neg) */
/* fixup the width for a _very_ thin ( < 1 pixel ) line */
t1 = (width<0) ? -width : width; /* t1 = abs(width) */
t2 = (rungmain<0) ? -rungmain : rungmain; /* t2 = abs(rungmain) */
if (t1<t2)
width=rungmain;
if (width>0) {
wopp=width+rung2-rungmain+0x1000; /* width count+1 scan line */
if (wopp<t2)
wopp=t2;
if (rungmain < 0) {
wbp=rung1-rungmain; /* width 1st scan line */
xbp=VB.Win2[min][0]+rungmain; /* subtract a little */
span2=wopp+rung2;
}
else {
wbp=rung1; /* width 1st scan line */
xbp=VB.Win2[min][0];
if ( rung2 > 0 )
span2=wopp-rungmain;
else
span2=wopp+rung2-rungmain;
}
/* if (wbp<0x1000) {
wbp+=0x1000;
} */
span1=width+0x1800-wbp;
}
else { /* width < 0 */
wopp=-width-rung2+rungmain+0x1000; /* width of count+1 line */
if (wopp<t2)
wopp=t2;
if (rungmain > 0) {
wbp=rung1+rungmain; /* width 1st scan line */
xbp=VB.Win2[min][0]+rungmain|0x80000000;/* subtract a little */
span2=wopp-rung2;
}
else {
wbp=rung1; /* width 1st scan line */
xbp=VB.Win2[min][0] | 0x80000000;
if (rung2 < 0)
span2=wopp+rungmain;
else
span2=wopp-rung2+rungmain;
}
width=-width;
/* if (wbp<0x1000)
wbp+=0x1000; */
span1=width+0x1000-wbp;
}
if (dy_main) { /* dy_main has no fractional part */
if (rungmain > 0)
dxm=(VB.Win2[max][0]-(xbp & 0x7fffffff))/((dy_main>>12)+1);
else
dxm=(VB.Win2[max][0]-(xbp & 0x7fffffff))/((dy_main>>12)+1);
}
else
dxm=0;
if (count1>>12) {
dw=span1/(count1>>12);
}
else
dw=0;
if (count2>>12) {
dwopp=span2/-(count2>>12);
}
else
dwopp=0;
#ifdef FLAT_INDEX
*listPtr++ = load_short_ro(BANK_MASK_REG, BLUE_BANK);
#endif
#ifdef INTERP_INDEX
*listPtr++ = load_short_ro(BANK_MASK_REG, BLUE_BANK);
#endif
#ifdef FLAT_COLOR
*listPtr++ = load_short_ro(BANK_MASK_REG, RED_BANK);
#endif
#ifdef INTERP_COLOR
*listPtr++ = load_short_ro(BANK_MASK_REG, RED_BANK);
#endif
*listPtr++ = OPCODE;
count1 &= 0x00ffff00;
dy_main=(dy_main>>12)+1;
count2 &= 0x00ffff00;
width=(width>>12)+1;
*listPtr++ = ((count1 << 4) & 0xff000000) | VB.Win2[min][1]; /* r1 */
*listPtr++ = (count1 << 12) | 0x00001000; /* r2 */
*listPtr++ = xbp; /* r3 */
*listPtr++ = dxm; /* r4 */
*listPtr++ = VB.Win2[min][2]; /* r5 */
*listPtr++ = (VB.Win2[max][2]-VB.Win2[min][2])/dy_main; /* r6 */
#ifdef FLAT_INDEX
*listPtr++ = VB.Index[pv]; /* r7 */
*listPtr++ = 0; /* r8 */
#endif
#ifdef INTERP_INDEX
*listPtr++ = VB.Index[mid]; /* r7 */
*listPtr++ = (VB.Index[max]-VB.Index[min])/dy_main; /* r8 */
#endif
#ifdef FLAT_COLOR
*listPtr++ = VB.Color[pv][0]<<12; /* r7 */
*listPtr++ = 0; /* r8 */
#endif
#ifdef INTERP_COLOR
*listPtr++ = rmin; /* r7 */
*listPtr++ = (rmax-rmin)/dy_main; /* r8 */
#endif
*listPtr++ = wbp; /* r9 */
*listPtr++ = dw; /* r10 */
*listPtr++ = (count2<<4) & 0xff000000 | wopp & 0x00ffffff; /* r11 */
*listPtr++ = (count2<<12) | (dwopp & 0x00ffffff); /* r12 */
*listPtr++ = 0; /* r13 */
*listPtr++ = (VB.Win2[mid][2]-VB.Win2[min][2])/width; /* r14 */
*listPtr++ = 0; /* r15 */
#ifdef FLAT_INDEX
*listPtr++ = 0; /* r16 */
#endif
#ifdef INTERP_INDEX
*listPtr++ = 0; /* r16 */
#endif
#ifdef FLAT_COLOR
*listPtr++ = 0; /* r16 */
/* redraw triangle in green plane */
*listPtr++ = load_short_ro(BANK_MASK_REG,GREEN_BANK);/* set bank = green */
*listPtr++ = load_long_ro(IMAIN_REG,1); /* load imain */
*listPtr++ = VB.Color[pv][1]<<12; /* load green */
*listPtr++ = OPCODE & ~0x3f; /* exec, no loads */
/* redraw triangle in blue plane */
*listPtr++ = load_short_ro(BANK_MASK_REG,BLUE_BANK); /* set bank = blue */
*listPtr++ = load_long_ro(IMAIN_REG,1); /* load imain */
*listPtr++ = VB.Color[pv][2]<<12; /* load blue */
*listPtr++ = OPCODE2 & ~0x3f; /* exec, no loads */
#endif
#ifdef INTERP_COLOR
*listPtr++ = 0; /* r16 */
/* redraw triangle in green plane */
*listPtr++ = load_short_ro(BANK_MASK_REG,GREEN_BANK);/* set bank = green */
*listPtr++ = load_long_ro(IMAIN_REG,2); /* load imain, di */
*listPtr++ = gmin; /* load green */
*listPtr++ = (gmax-gmin)/dy_main; /* load del green */
*listPtr++ = load_long_ro(IORTHO_REG,1); /* load iortho */
*listPtr++ = (gmid-gmin)/width; /* load ortho green */
*listPtr++ = OPCODE & ~0x3f; /* exec, no loads */
/* redraw triangle in blue plane */
*listPtr++ = load_short_ro(BANK_MASK_REG,BLUE_BANK); /* set bank = blue */
*listPtr++ = load_long_ro(IMAIN_REG,2); /* load imain, di */
*listPtr++ = bmin; /* load blue */
*listPtr++ = (bmax-bmin)/dy_main; /* load del blue */
*listPtr++ = load_long_ro(IORTHO_REG,1); /* load iortho */
*listPtr++ = (bmid-bmin)/width; /* load ortho blue */
*listPtr++ = OPCODE2 & ~0x3f; /* exec, no loads */
#endif
if ((wopp + dwopp*(count2>>12))<0) {
printf("** UNDERFLOW **\n");
exit(-1);
}
CHKEXECPOLY;
/*
* check if dpy list full, if is start exec and switch to dpy list 2,
* else continue
*/
/* CHKEXEC; */
}
#undef OPCODE
#undef FLAT_INDEX
#undef INTERP_INDEX
#undef FLAT_COLOR
#undef INTERP_COLOR
#undef NOVB
These are the contents of the former NiCE NeXT User Group NeXTSTEP/OpenStep software archive, currently hosted by Netfuture.ch.