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- did some tests with the inside function and decided to only retain the 'old' one.

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The one from EDuke32 is ambiguous - it considers any point on a wall to be part of both sectors touching that wall. This wasn't used anyway with the current engine compatibility settings.
I was not able to get different values out of the 'ps' version - this seems to only be important for demo playback concerns, for regular playback the differences appear to be totally irrelevant.

Ultimately this should be replaced anyway with a license-unencumbered variant of the same basic common algorithm.
This commit is contained in:
Christoph Oelckers 2021-11-08 19:46:22 +01:00
parent eeaa7f98f0
commit 5cfc418c5f
1 changed files with 1 additions and 91 deletions
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92
source/build/src/engine.cpp
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@ -702,33 +702,8 @@ void initspritelists(void)
//
// See http://fabiensanglard.net/duke3d/build_engine_internals.php,
// "Inside details" for the idea behind the algorithm.
int32_t inside_ps(int32_t x, int32_t y, int16_t sectnum)
{
if (validSectorIndex(sectnum))
{
int32_t cnt = 0;
auto wal = (uwallptr_t)&wall[sector[sectnum].wallptr];
int wallsleft = sector[sectnum].wallnum;
do
{
vec2_t v1 = { wal->x - x, wal->y - y };
auto const &wal2 = *(uwallptr_t)&wall[wal->point2];
vec2_t v2 = { wal2.x - x, wal2.y - y };
if ((v1.y^v2.y) < 0)
cnt ^= (((v1.x^v2.x) < 0) ? (v1.x*v2.y<v2.x*v1.y)^(v1.y<v2.y) : (v1.x >= 0));
wal++;
}
while (--wallsleft);
return cnt;
}
return -1;
}
int32_t inside_old(int32_t x, int32_t y, int16_t sectnum)
int32_t inside(int32_t x, int32_t y, int16_t sectnum)
{
if (validSectorIndex(sectnum))
{
@ -763,71 +738,6 @@ int32_t inside_old(int32_t x, int32_t y, int16_t sectnum)
return -1;
}
int32_t inside(int32_t x, int32_t y, int sectnum)
{
switch (enginecompatibility_mode)
{
case ENGINECOMPATIBILITY_NONE:
break;
case ENGINECOMPATIBILITY_19950829:
return inside_ps(x, y, sectnum);
default:
return inside_old(x, y, sectnum);
}
if (validSectorIndex(sectnum))
{
uint32_t cnt1 = 0, cnt2 = 0;
auto wal = (uwallptr_t)&wall[sector[sectnum].wallptr];
int wallsleft = sector[sectnum].wallnum;
do
{
// Get the x and y components of the [tested point]-->[wall
// point{1,2}] vectors.
vec2_t v1 = { wal->x - x, wal->y - y };
auto const &wal2 = *(uwallptr_t)&wall[wal->point2];
vec2_t v2 = { wal2.x - x, wal2.y - y };
// First, test if the point is EXACTLY_ON_WALL_POINT.
if ((v1.x|v1.y) == 0 || (v2.x|v2.y)==0)
return 1;
// If their signs differ[*], ...
//
// [*] where '-' corresponds to <0 and '+' corresponds to >=0.
// Equivalently, the branch is taken iff
// y1 != y2 AND y_m <= y < y_M,
// where y_m := min(y1, y2) and y_M := max(y1, y2).
if ((v1.y^v2.y) < 0)
cnt1 ^= (((v1.x^v2.x) >= 0) ? v1.x : (v1.x*v2.y-v2.x*v1.y)^v2.y);
v1.y--;
v2.y--;
// Now, do the same comparisons, but with the interval half-open on
// the other side! That is, take the branch iff
// y1 != y2 AND y_m < y <= y_M,
// For a rectangular sector, without EXACTLY_ON_WALL_POINT, this
// would still leave the lower left and upper right points
// "outside" the sector.
if ((v1.y^v2.y) < 0)
{
v1.x--;
v2.x--;
cnt2 ^= (((v1.x^v2.x) >= 0) ? v1.x : (v1.x*v2.y-v2.x*v1.y)^v2.y);
}
wal++;
}
while (--wallsleft);
return (cnt1|cnt2)>>31;
}
return -1;
}
int32_t getangle(int32_t xvect, int32_t yvect)
{