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Files
OpenTTD/src/newgrf/newgrf_act6.cpp
2025-04-11 22:11:28 +02:00

120 lines
4.7 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 newgrf_act6.cpp NewGRF Action 0x06 handler. */
#include "../stdafx.h"
#include "../debug.h"
#include "newgrf_bytereader.h"
#include "newgrf_internal.h"
#include "../safeguards.h"
std::map<GRFLocation, std::pair<SpriteID, uint16_t>> _grm_sprites;
GRFLineToSpriteOverride _grf_line_to_action6_sprite_override;
/* Action 0x06 */
static void CfgApply(ByteReader &buf)
{
/* <06> <param-num> <param-size> <offset> ... <FF>
*
* B param-num Number of parameter to substitute (First = "zero")
* Ignored if that parameter was not specified in newgrf.cfg
* B param-size How many bytes to replace. If larger than 4, the
* bytes of the following parameter are used. In that
* case, nothing is applied unless *all* parameters
* were specified.
* B offset Offset into data from beginning of next sprite
* to place where parameter is to be stored. */
/* Preload the next sprite */
SpriteFile &file = *_cur_gps.file;
size_t pos = file.GetPos();
uint32_t num = file.GetContainerVersion() >= 2 ? file.ReadDword() : file.ReadWord();
uint8_t type = file.ReadByte();
/* Check if the sprite is a pseudo sprite. We can't operate on real sprites. */
if (type != 0xFF) {
GrfMsg(2, "CfgApply: Ignoring (next sprite is real, unsupported)");
/* Reset the file position to the start of the next sprite */
file.SeekTo(pos, SEEK_SET);
return;
}
/* Get (or create) the override for the next sprite. */
GRFLocation location(_cur_gps.grfconfig->ident.grfid, _cur_gps.nfo_line + 1);
std::vector<uint8_t> &preload_sprite = _grf_line_to_action6_sprite_override[location];
/* Load new sprite data if it hasn't already been loaded. */
if (preload_sprite.empty()) {
preload_sprite.resize(num);
file.ReadBlock(preload_sprite.data(), num);
}
/* Reset the file position to the start of the next sprite */
file.SeekTo(pos, SEEK_SET);
/* Now perform the Action 0x06 on our data. */
for (;;) {
uint i;
uint param_num;
uint param_size;
uint offset;
bool add_value;
/* Read the parameter to apply. 0xFF indicates no more data to change. */
param_num = buf.ReadByte();
if (param_num == 0xFF) break;
/* Get the size of the parameter to use. If the size covers multiple
* double words, sequential parameter values are used. */
param_size = buf.ReadByte();
/* Bit 7 of param_size indicates we should add to the original value
* instead of replacing it. */
add_value = HasBit(param_size, 7);
param_size = GB(param_size, 0, 7);
/* Where to apply the data to within the pseudo sprite data. */
offset = buf.ReadExtendedByte();
/* If the parameter is a GRF parameter (not an internal variable) check
* if it (and all further sequential parameters) has been defined. */
if (param_num < 0x80 && (param_num + (param_size - 1) / 4) >= std::size(_cur_gps.grffile->param)) {
GrfMsg(2, "CfgApply: Ignoring (param {} not set)", (param_num + (param_size - 1) / 4));
break;
}
GrfMsg(8, "CfgApply: Applying {} bytes from parameter 0x{:02X} at offset 0x{:04X}", param_size, param_num, offset);
bool carry = false;
for (i = 0; i < param_size && offset + i < num; i++) {
uint32_t value = GetParamVal(param_num + i / 4, nullptr);
/* Reset carry flag for each iteration of the variable (only really
* matters if param_size is greater than 4) */
if (i % 4 == 0) carry = false;
if (add_value) {
uint new_value = preload_sprite[offset + i] + GB(value, (i % 4) * 8, 8) + (carry ? 1 : 0);
preload_sprite[offset + i] = GB(new_value, 0, 8);
/* Check if the addition overflowed */
carry = new_value >= 256;
} else {
preload_sprite[offset + i] = GB(value, (i % 4) * 8, 8);
}
}
}
}
template <> void GrfActionHandler<0x06>::FileScan(ByteReader &) { }
template <> void GrfActionHandler<0x06>::SafetyScan(ByteReader &) { }
template <> void GrfActionHandler<0x06>::LabelScan(ByteReader &) { }
template <> void GrfActionHandler<0x06>::Init(ByteReader &buf) { CfgApply(buf); }
template <> void GrfActionHandler<0x06>::Reserve(ByteReader &buf) { CfgApply(buf); }
template <> void GrfActionHandler<0x06>::Activation(ByteReader &buf) { CfgApply(buf); }