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- Restore the original Doom algorithm for calculating xtoviewangle[] for the inner 90 degrees

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of the field of vision, since it reduces the chances of duplicate sky columns output next to
  each other compared to a straight tangent-to-angle calculation.

SVN r3189 (trunk)
This commit is contained in:
Randy Heit 2011-04-24 17:05:50 +00:00
parent fd225e168c
commit 65977c2d0c
1 changed files with 48 additions and 11 deletions
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59
src/r_main.cpp
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@ -425,6 +425,31 @@ void R_InitTables (void)
memcpy (&finesine[FINEANGLES], &finesine[0], sizeof(angle_t)*FINEANGLES/4);
}
//==========================================================================
//
// viewangletox
//
// Used solely for construction the xtoviewangle table.
//
//==========================================================================
static inline int viewangletox(int i)
{
if (finetangent[i] > FRACUNIT*2)
{
return -1;
}
else if (finetangent[i] < -FRACUNIT*2)
{
return viewwidth+1;
}
else
{
int t = FixedMul(finetangent[i], FocalLengthX);
t = (centerxfrac - t + FRACUNIT-1) >> FRACBITS;
return clamp(t, -1, viewwidth+1);
}
}
//==========================================================================
//
@ -434,8 +459,7 @@ void R_InitTables (void)
void R_InitTextureMapping ()
{
int i;
fixed_t slope;
int i, x;
int fov = FieldOfView;
// For widescreen displays, increase the FOV so that the middle part of the
@ -464,24 +488,37 @@ void R_InitTextureMapping ()
// This is 1/FocalTangent before the widescreen extension of FOV.
viewingrangerecip = DivScale32(1, finetangent[FINEANGLES/4+(FieldOfView/2)]);
// Now generate xtoviewangle for sky texture mapping.
// [RH] Do not generate viewangletox, because texture mapping is no
// longer done with trig, so it's not needed.
const int t = MIN<int> ((FocalLengthX >> FRACBITS) + centerx, viewwidth);
const fixed_t slopestep = hitan / centerx;
// Now generate xtoviewangle for sky texture mapping.
// We do this with a hybrid approach: The center 90 degree span is
// constructed as per the original code:
// Scan xtoviewangle to find the smallest view angle that maps to x.
// (viewangletox is sorted in non-increasing order.)
// This reduces the chances of "doubling-up" of texture columns in
// the drawn sky texture.
// The remaining arcs are done with tantoangle instead.
const int t1 = MAX<int>(centerx - (FocalLengthX >> FRACBITS), 0);
const int t2 = MIN<int>(centerx + (FocalLengthX >> FRACBITS), viewwidth);
const fixed_t dfocus = FocalLengthX >> DBITS;
for (i = centerx, slope = 0; i <= t; i++, slope += slopestep)
for (i = 0, x = t2; x >= t1; --x)
{
xtoviewangle[i] = (angle_t)-(signed)tantoangle[slope >> DBITS];
while(viewangletox(i) > x)
{
++i;
}
xtoviewangle[x] = (i << ANGLETOFINESHIFT) - ANGLE_90;
}
for (; i <= viewwidth; i++)
for (x = t2 + 1; x <= viewwidth; ++x)
{
xtoviewangle[i] = ANG270+tantoangle[dfocus / (i - centerx)];
xtoviewangle[x] = ANGLE_270 + tantoangle[dfocus / (x - centerx)];
}
for (i = 0; i < centerx; i++)
for (x = 0; x < t1; ++x)
{
xtoviewangle[i] = (angle_t)(-(signed)xtoviewangle[viewwidth-i]);
xtoviewangle[x] = (angle_t)(-(signed)xtoviewangle[viewwidth - x]);
}
}