/* This file is part of the Spring engine (GPL v2 or later), see LICENSE.html */

#include "BasicMapDamage.h"

#include "ReadMap.h"

#include "MapInfo.h"

#include "Rendering/Env/GrassDrawer.h"

#include "Sim/Misc/GroundBlockingObjectMap.h"

#include "Sim/Misc/LosHandler.h"

#include "Sim/Misc/QuadField.h"

#include "Sim/Units/Unit.h"

#include "Sim/Units/UnitHandler.h"

#include "Sim/Path/IPathManager.h"

#include "Sim/Features/FeatureHandler.h"

#include "System/TimeProfiler.h"

CBasicMapDamage::CBasicMapDamage()

{

for (int a = 0; a <= CRATER_TABLE_SIZE; ++a) {

const float r = a / float(CRATER_TABLE_SIZE);

const float c1 = math::cos((r - 0.1f) * (PI + 0.3f));

const float c2 = math::cos(std::max(0.0f, r * 3.0f - 2.0f) * PI);

// faked Sombrero hat, cut in half

craterTable[a] = c1 * (1.0f - r) * (0.5f + 0.5f * c2);

}

for (int a = 0; a < CMapInfo::NUM_TERRAIN_TYPES; ++a) {

invHardness[a] = 1.0f / mapInfo->terrainTypes[a].hardness;

}

mapHardness = mapInfo->map.hardness;

disabled = false;

}

void CBasicMapDamage::Explosion(const float3& pos, float strength, float radius)

{

if (!pos.IsInMap())

return;

if (strength < 10.0f || radius < 8.0f)

return;

explosions.emplace_back();

Explo& e = explosions.back();

e.pos = pos;

e.strength = strength;

e.radius = radius;

e.ttl = EXPLOSION_LIFETIME;

e.x1 = Clamp<int>((pos.x - radius) / SQUARE_SIZE, 1, mapDims.mapxm1);

e.x2 = Clamp<int>((pos.x + radius) / SQUARE_SIZE, 1, mapDims.mapxm1);

e.y1 = Clamp<int>((pos.z - radius) / SQUARE_SIZE, 1, mapDims.mapym1);

e.y2 = Clamp<int>((pos.z + radius) / SQUARE_SIZE, 1, mapDims.mapym1);

e.squares.reserve((e.y2 - e.y1 + 1) * (e.x2 - e.x1 + 1));

const float* curHeightMap = readMap->GetCornerHeightMapSynced();

const float* orgHeightMap = readMap->GetOriginalHeightMapSynced();

const unsigned char* typeMap = readMap->GetTypeMapSynced();

const float baseStrength = -math::pow(strength, 0.6f) * 3 / mapHardness;

const float invRadius = 1.0f / radius;

// figure out how much height to add to each square

for (int y = e.y1; y <= e.y2; ++y) {

for (int x = e.x1; x <= e.x2; ++x) {

const CSolidObject* so = groundBlockingObjectMap->GroundBlockedUnsafe(y * mapDims.mapx + x);

// do not change squares with buildings on them here

if (so != nullptr && so->blockHeightChanges) {

e.squares.push_back(0.0f);

continue;

}

// calculate the distance and normalize it

const float expDist = pos.distance2D(float3(x * SQUARE_SIZE, 0, y * SQUARE_SIZE));

const float relDist = std::min(1.0f, expDist * invRadius);

const unsigned int tableIdx = relDist * CRATER_TABLE_SIZE;

const unsigned int ttypeIdx = typeMap[(y / 2) * mapDims.hmapx + x / 2];

float dif = baseStrength;

dif *= craterTable[tableIdx];

dif *= invHardness[ttypeIdx];

// FIXME: compensate for flattened ground under dead buildings

const float prevDif =

curHeightMap[y * mapDims.mapxp1 + x] -

orgHeightMap[y * mapDims.mapxp1 + x];

if ((prevDif * dif) > 0.0f)

dif /= ((math::fabs(prevDif) / EXPLOSION_LIFETIME) + 1);

if (dif < -0.3f && strength > 200.0f)

grassDrawer->RemoveGrass(float3(x * SQUARE_SIZE, 0.0f, y * SQUARE_SIZE));

e.squares.push_back(dif);

}

}

const std::vector<CUnit*>& units = quadField->GetUnitsExact(pos, radius);

// calculate how much to raise or lower buildings in the explosion radius

// (while still keeping the ground below them flat)

for (const CUnit* unit: units) {

if (!unit->blockHeightChanges)

continue;

if (!unit->IsBlocking())

continue;

float totalDif = 0.0f;

for (int z = unit->mapPos.y; z < unit->mapPos.y + unit->zsize; z++) {

for (int x = unit->mapPos.x; x < unit->mapPos.x + unit->xsize; x++) {

// calculate the distance and normalize it

const float expDist = pos.distance2D(float3(x * SQUARE_SIZE, 0.0f, z * SQUARE_SIZE));

const float relDist = std::min(1.0f, expDist * invRadius);

const unsigned int tableIdx = relDist * CRATER_TABLE_SIZE;

const unsigned int ttypeIdx = typeMap[(z / 2) * mapDims.hmapx + x / 2];

float dif = baseStrength;

dif *= craterTable[tableIdx];

dif *= invHardness[ttypeIdx];

const float prevDif =

curHeightMap[z * mapDims.mapxp1 + x] -

orgHeightMap[z * mapDims.mapxp1 + x];

if ((prevDif * dif) > 0.0f)

dif /= ((math::fabs(prevDif) / EXPLOSION_LIFETIME) + 1);

totalDif += dif;

}

}

totalDif /= (unit->xsize * unit->zsize);

if (totalDif != 0.0f) {

e.buildings.emplace_back();

ExploBuilding& eb = e.buildings.back();

eb.id = unit->id;

eb.dif = totalDif;

eb.tx1 = unit->mapPos.x;

eb.tx2 = unit->mapPos.x + unit->xsize;

eb.tz1 = unit->mapPos.y;

eb.tz2 = unit->mapPos.y + unit->zsize;

}

}

explosions.push_back(e);

}

void CBasicMapDamage::RecalcArea(int x1, int x2, int y1, int y2)

{

readMap->UpdateHeightMapSynced(SRectangle(x1, y1, x2, y2));

featureHandler->TerrainChanged(x1, y1, x2, y2);

losHandler->UpdateHeightMapSynced(SRectangle(x1, y1, x2, y2));

pathManager->TerrainChange(x1, y1, x2, y2, TERRAINCHANGE_DAMAGE_RECALCULATION);

}

void CBasicMapDamage::Update()

{

SCOPED_TIMER("BasicMapDamage::Update");

for (Explo& e: explosions) {

if (e.ttl <= 0)

continue;

--e.ttl;

auto si = e.squares.cbegin();

for (int y = e.y1; y <= e.y2; ++y) {

for (int x = e.x1; x <= e.x2; ++x) {

readMap->AddHeight(y * mapDims.mapxp1 + x, *(si++));

}

}

for (const ExploBuilding& b: e.buildings) {

CUnit* unit = unitHandler->GetUnit(b.id);

if (unit != nullptr) {

// only change ground level if building is still here

for (int z = b.tz1; z < b.tz2; z++) {

for (int x = b.tx1; x < b.tx2; x++) {

readMap->AddHeight(z * mapDims.mapxp1 + x, b.dif);

}

}

unit->Move(UpVector * b.dif, true);

}

}

if (e.ttl == 0) {

RecalcArea(e.x1 - 1, e.x2 + 1, e.y1 - 1, e.y2 + 1);

}

}

while (!explosions.empty()) {

const Explo& explosion = explosions.front();

if (explosion.ttl > 0)

break;

explosions.pop_front();

}

}