You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
90 lines
3.6 KiB
C++
90 lines
3.6 KiB
C++
/*
|
|
* This file is part of OpenTTD.
|
|
* OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
|
|
* OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
|
|
* See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
|
|
*/
|
|
|
|
/** @file landscape_ppz.cpp Functions related to landscape partial pixel z. */
|
|
|
|
#include "stdafx.h"
|
|
#include "slope_func.h"
|
|
|
|
#include "safeguards.h"
|
|
|
|
/**
|
|
* Determines height at given coordinate of a slope.
|
|
*
|
|
* At the northern corner (0, 0) the result is always a multiple of TILE_HEIGHT.
|
|
* When the height is a fractional Z, then the height is rounded down. For example,
|
|
* when at the height is 0 at x = 0 and the height is 8 at x = 16 (actually x = 0
|
|
* of the next tile), then height is 0 at x = 1, 1 at x = 2, and 7 at x = 15.
|
|
* @param x x coordinate (value from 0 to 15)
|
|
* @param y y coordinate (value from 0 to 15)
|
|
* @param corners slope to examine
|
|
* @return height of given point of given slope
|
|
*/
|
|
uint GetPartialPixelZ(int x, int y, Slope corners)
|
|
{
|
|
if (IsHalftileSlope(corners)) {
|
|
/* A foundation is placed on half the tile at a specific corner. This means that,
|
|
* depending on the corner, that one half of the tile is at the maximum height. */
|
|
switch (GetHalftileSlopeCorner(corners)) {
|
|
case CORNER_W:
|
|
if (x > y) return GetSlopeMaxPixelZ(corners);
|
|
break;
|
|
|
|
case CORNER_S:
|
|
if (x + y >= (int)TILE_SIZE) return GetSlopeMaxPixelZ(corners);
|
|
break;
|
|
|
|
case CORNER_E:
|
|
if (x <= y) return GetSlopeMaxPixelZ(corners);
|
|
break;
|
|
|
|
case CORNER_N:
|
|
if (x + y < (int)TILE_SIZE) return GetSlopeMaxPixelZ(corners);
|
|
break;
|
|
|
|
default: NOT_REACHED();
|
|
}
|
|
}
|
|
|
|
switch (RemoveHalftileSlope(corners)) {
|
|
case SLOPE_FLAT: return 0;
|
|
|
|
/* One corner is up.*/
|
|
case SLOPE_N: return x + y <= (int)TILE_SIZE ? (TILE_SIZE - x - y) >> 1 : 0;
|
|
case SLOPE_E: return y >= x ? (1 + y - x) >> 1 : 0;
|
|
case SLOPE_S: return x + y >= (int)TILE_SIZE ? (1 + x + y - TILE_SIZE) >> 1 : 0;
|
|
case SLOPE_W: return x >= y ? (x - y) >> 1 : 0;
|
|
|
|
/* Two corners next to eachother are up. */
|
|
case SLOPE_NE: return (TILE_SIZE - x) >> 1;
|
|
case SLOPE_SE: return (y + 1) >> 1;
|
|
case SLOPE_SW: return (x + 1) >> 1;
|
|
case SLOPE_NW: return (TILE_SIZE - y) >> 1;
|
|
|
|
/* Three corners are up on the same level. */
|
|
case SLOPE_ENW: return x + y >= (int)TILE_SIZE ? TILE_HEIGHT - ((1 + x + y - TILE_SIZE) >> 1) : TILE_HEIGHT;
|
|
case SLOPE_SEN: return y < x ? TILE_HEIGHT - ((x - y) >> 1) : TILE_HEIGHT;
|
|
case SLOPE_WSE: return x + y <= (int)TILE_SIZE ? TILE_HEIGHT - ((TILE_SIZE - x - y) >> 1) : TILE_HEIGHT;
|
|
case SLOPE_NWS: return x < y ? TILE_HEIGHT - ((1 + y - x) >> 1) : TILE_HEIGHT;
|
|
|
|
/* Two corners at opposite sides are up. */
|
|
case SLOPE_NS: return x + y < (int)TILE_SIZE ? (TILE_SIZE - x - y) >> 1 : (1 + x + y - TILE_SIZE) >> 1;
|
|
case SLOPE_EW: return x >= y ? (x - y) >> 1 : (1 + y - x) >> 1;
|
|
|
|
/* Very special cases. */
|
|
case SLOPE_ELEVATED: return TILE_HEIGHT;
|
|
|
|
/* Steep slopes. The top is at 2 * TILE_HEIGHT. */
|
|
case SLOPE_STEEP_N: return (TILE_SIZE - x + TILE_SIZE - y) >> 1;
|
|
case SLOPE_STEEP_E: return (TILE_SIZE + 1 + y - x) >> 1;
|
|
case SLOPE_STEEP_S: return (1 + x + y) >> 1;
|
|
case SLOPE_STEEP_W: return (TILE_SIZE + x - y) >> 1;
|
|
|
|
default: NOT_REACHED();
|
|
}
|
|
}
|