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Codechange: Add InverseRemapCoords2 function for remapping viewport coordinates to underlying tile coordinates (Patch by adf88, #6583)

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This commit is contained in:
Johannes E. Krause
2019-01-13 20:52:04 +01:00
committed by Niels Martin Hansen
parent 43852baace
commit f0290d5de7
4 changed files with 72 additions and 56 deletions
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51
src/landscape.cpp
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@@ -89,6 +89,57 @@ extern const byte _slope_to_sprite_offset[32] = {
*/
static SnowLine *_snow_line = NULL;
/**
* Map 2D viewport or smallmap coordinate to 3D world or tile coordinate.
* Function takes into account height of tiles and foundations.
*
* @param x X viewport 2D coordinate.
* @param y Y viewport 2D coordinate.
* @param clamp_to_map Clamp the coordinate outside of the map to the closest, non-void tile within the map.
* @return 3D world coordinate of point visible at the given screen coordinate (3D perspective).
*
* @note Inverse of #RemapCoords2 function. Smaller values may get rounded.
* @see InverseRemapCoords
*/
Point InverseRemapCoords2(int x, int y, bool clamp_to_map)
{
/* Initial x/y world coordinate is like if the landscape
* was completely flat on height 0. */
Point pt = InverseRemapCoords(x, y);
const uint min_coord = _settings_game.construction.freeform_edges ? TILE_SIZE : 0;
const uint max_x = MapMaxX() * TILE_SIZE - 1;
const uint max_y = MapMaxY() * TILE_SIZE - 1;
if (clamp_to_map) {
/* Bring the coordinates near to a valid range. At the top we allow a number
* of extra tiles. This is mostly due to the tiles on the north side of
* the map possibly being drawn higher due to the extra height levels. */
int extra_tiles = CeilDiv(_settings_game.construction.max_heightlevel * TILE_HEIGHT, TILE_PIXELS);
pt.x = Clamp(pt.x, -extra_tiles * TILE_SIZE, max_x);
pt.y = Clamp(pt.y, -extra_tiles * TILE_SIZE, max_y);
}
/* Now find the Z-world coordinate by fix point iteration.
* This is a bit tricky because the tile height is non-continuous at foundations.
* The clicked point should be approached from the back, otherwise there are regions that are not clickable.
* (FOUNDATION_HALFTILE_LOWER on SLOPE_STEEP_S hides north halftile completely)
* So give it a z-malus of 4 in the first iterations. */
int z = 0;
for (int i = 0; i < 5; i++) z = GetSlopePixelZ(Clamp(pt.x + max(z, 4) - 4, min_coord, max_x), Clamp(pt.y + max(z, 4) - 4, min_coord, max_y)) / 2;
for (int m = 3; m > 0; m--) z = GetSlopePixelZ(Clamp(pt.x + max(z, m) - m, min_coord, max_x), Clamp(pt.y + max(z, m) - m, min_coord, max_y)) / 2;
for (int i = 0; i < 5; i++) z = GetSlopePixelZ(Clamp(pt.x + z, min_coord, max_x), Clamp(pt.y + z, min_coord, max_y)) / 2;
pt.x += z;
pt.y += z;
if (clamp_to_map) {
pt.x = Clamp(pt.x, min_coord, max_x);
pt.y = Clamp(pt.y, min_coord, max_y);
}
return pt;
}
/**
* Applies a foundation to a slope.
*