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fix #5411
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rtri committed Dec 3, 2016
1 parent ae0ef2f commit e41d9be
Showing 1 changed file with 9 additions and 6 deletions.
15 changes: 9 additions & 6 deletions rts/Sim/Path/Default/PathFinderDef.cpp
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Expand Up @@ -31,13 +31,16 @@ bool CPathFinderDef::IsGoal(unsigned int xSquare, unsigned int zSquare) const {
// returns distance to goal center in heightmap-squares
float CPathFinderDef::Heuristic(unsigned int xSquare, unsigned int zSquare, unsigned int blockSize) const
{
const float s = 1.0f / blockSize;
const float dx = std::abs(int(xSquare) - int(goalSquareX)) * s;
const float dz = std::abs(int(zSquare) - int(goalSquareZ)) * s;
(void) blockSize;

// grid is 8-connected, so use octile distance (normalized by block-size)
constexpr const float C1 = 1.0f;
constexpr const float C2 = 1.4142f - (2.0f * C1);
const float dx = std::abs(int(xSquare) - int(goalSquareX));
const float dz = std::abs(int(zSquare) - int(goalSquareZ));

// grid is 8-connected, so use octile distance metric
// note that using C1=1 and C2=sqrt(2) will over-estimate
// on terrain with extreme speed modifiers, so scale both
constexpr const float C1 = 1.0f * 0.5f;
constexpr const float C2 = 1.4142f * 0.5f - (2.0f * C1);
return ((dx + dz) * C1 + std::min(dx, dz) * C2);
}

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9 comments on commit e41d9be

@ashdnazg
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maybe instead of scaling by an arbitrary number, scale by the highest known speed modifier?

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@rtri rtri commented on e41d9be Jan 19, 2017

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that's what I switched to a few commits after this one.

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great minds etc. :P

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@ashdnazg ashdnazg commented on e41d9be Jan 19, 2017 •
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although, wouldn't you want to add the multiplier here as well?

spring/rts/Sim/Path/Default/PathFinder.cpp

Line 262 in 4460dca

const float hCost = pfDef.Heuristic(square.x, square.y, BLOCK_SIZE); // h

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or here:

spring/rts/Sim/Path/Default/PathManager.cpp

Line 119 in 4460dca

const float heurGoalDist2D = pfDef->Heuristic(startPos.x / SQUARE_SIZE, startPos.z / SQUARE_SIZE, 1) + math::fabs(goalPos.y - startPos.y) / SQUARE_SIZE;

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@rtri rtri commented on e41d9be Jan 19, 2017

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first case: technically yes, but the PF is used over such short distances that suboptimal paths should not be a problem (famous last words).

making heurGoalDist2D smaller will engage the higher-res layers more often, could be risky.

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fair enough

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@ashdnazg ashdnazg commented on e41d9be Jan 19, 2017 •
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I'm daft, ignore

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@rtri rtri commented on e41d9be Jan 19, 2017 •
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it's an inverse scaling, the heuristic multiplier is 1 / max_speedmod

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