Handmade Hero » Forums » Code » Day 50: Minkowski-based collision detection bug?
martincohen
Martin Cohen
38 posts / 1 project

Code, art and music artisan.

#2827 Day 50: Minkowski-based collision detection bug?
3 years, 9 months ago

Hello guys,

I'm trying to validate my article on collision detection by implementing all of the example code. I found something I'm pretty sure is a bug. Althogh not serious (especially for HH's case), I'd like to have my example code in the article correct and just want to confirm (in case I'm not missing something).

To be concrete, I'm taking about Day 50, handmade.cpp, method MovePlayer, excerpt starting at line 416:

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uint32 MinTileX = Minimum(OldPlayerP.AbsTileX, NewPlayerP.AbsTileX);
uint32 MinTileY = Minimum(OldPlayerP.AbsTileY, NewPlayerP.AbsTileY);
uint32 MaxTileX = Maximum(OldPlayerP.AbsTileX, NewPlayerP.AbsTileX);
uint32 MaxTileY = Maximum(OldPlayerP.AbsTileY, NewPlayerP.AbsTileY);

uint32 EntityTileWidth = CeilReal32ToInt32(Entity.High->Width / TileMap->TileSideInMeters);
uint32 EntityTileHeight = CeilReal32ToInt32(Entity.High->Height / TileMap->TileSideInMeters);

MinTileX -= EntityTileWidth;
MinTileY -= EntityTileHeight;
MaxTileX += EntityTileWidth;
MaxTileY += EntityTileHeight;


On the last 4 lines, we should be adding (ceiled) half of EntityTileWidth/EntityTileHeight to the MinTileX/MinTileY/MaxTileX/MaxTileY. Is that correct?

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