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0ad/source/graphics/Terrain.cpp

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/* Copyright (C) 2011 Wildfire Games.
* This file is part of 0 A.D.
*
* 0 A.D. 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, either version 2 of the License, or
* (at your option) any later version.
*
* 0 A.D. 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 0 A.D. If not, see <http://www.gnu.org/licenses/>.
*/
/*
* Describes ground via heightmap and array of CPatch.
*/
#include "precompiled.h"
#include "lib/res/graphics/ogl_tex.h"
#include "lib/sysdep/cpu.h"
#include "renderer/Renderer.h"
#include "TerrainProperties.h"
#include "TerrainTextureEntry.h"
#include "TerrainTextureManager.h"
#include <string.h>
#include "Terrain.h"
#include "Patch.h"
#include "maths/FixedVector3D.h"
#include "maths/MathUtil.h"
#include "ps/CLogger.h"
///////////////////////////////////////////////////////////////////////////////
// CTerrain constructor
CTerrain::CTerrain()
: m_Heightmap(0), m_Patches(0), m_MapSize(0), m_MapSizePatches(0),
m_BaseColour(255, 255, 255, 255)
{
}
///////////////////////////////////////////////////////////////////////////////
// CTerrain constructor
CTerrain::~CTerrain()
{
ReleaseData();
}
///////////////////////////////////////////////////////////////////////////////
// ReleaseData: delete any data allocated by this terrain
void CTerrain::ReleaseData()
{
delete[] m_Heightmap;
delete[] m_Patches;
}
///////////////////////////////////////////////////////////////////////////////
// Initialise: initialise this terrain to the given size
// using given heightmap to setup elevation data
bool CTerrain::Initialize(ssize_t patchesPerSide,const u16* data)
{
// clean up any previous terrain
ReleaseData();
// store terrain size
m_MapSize=patchesPerSide*PATCH_SIZE+1;
m_MapSizePatches=patchesPerSide;
// allocate data for new terrain
m_Heightmap=new u16[m_MapSize*m_MapSize];
m_Patches=new CPatch[m_MapSizePatches*m_MapSizePatches];
// given a heightmap?
if (data) {
// yes; keep a copy of it
memcpy(m_Heightmap,data,m_MapSize*m_MapSize*sizeof(u16));
} else {
// build a flat terrain
memset(m_Heightmap,0,m_MapSize*m_MapSize*sizeof(u16));
}
// setup patch parents, indices etc
InitialisePatches();
return true;
}
///////////////////////////////////////////////////////////////////////////////
CStr8 CTerrain::GetMovementClass(ssize_t i, ssize_t j) const
{
CMiniPatch* tile = GetTile(i, j);
if (tile && tile->GetTextureEntry())
return tile->GetTextureEntry()->GetProperties().GetMovementClass();
return "default";
}
///////////////////////////////////////////////////////////////////////////////
// CalcPosition: calculate the world space position of the vertex at (i,j)
// If i,j is off the map, it acts as if the edges of the terrain are extended
// outwards to infinity
void CTerrain::CalcPosition(ssize_t i, ssize_t j, CVector3D& pos) const
{
ssize_t hi = clamp(i, (ssize_t)0, m_MapSize-1);
ssize_t hj = clamp(j, (ssize_t)0, m_MapSize-1);
u16 height = m_Heightmap[hj*m_MapSize + hi];
pos.X = float(i*CELL_SIZE);
pos.Y = float(height*HEIGHT_SCALE);
pos.Z = float(j*CELL_SIZE);
}
///////////////////////////////////////////////////////////////////////////////
// CalcPositionFixed: calculate the world space position of the vertex at (i,j)
void CTerrain::CalcPositionFixed(ssize_t i, ssize_t j, CFixedVector3D& pos) const
{
ssize_t hi = clamp(i, (ssize_t)0, m_MapSize-1);
ssize_t hj = clamp(j, (ssize_t)0, m_MapSize-1);
u16 height = m_Heightmap[hj*m_MapSize + hi];
pos.X = fixed::FromInt(i) * (int)CELL_SIZE;
pos.Y = fixed::FromInt(height) / (int)HEIGHT_UNITS_PER_METRE;
pos.Z = fixed::FromInt(j) * (int)CELL_SIZE;
}
///////////////////////////////////////////////////////////////////////////////
// CalcNormal: calculate the world space normal of the vertex at (i,j)
void CTerrain::CalcNormal(ssize_t i, ssize_t j, CVector3D& normal) const
{
CVector3D left, right, up, down;
// Calculate normals of the four half-tile triangles surrounding this vertex:
// get position of vertex where normal is being evaluated
CVector3D basepos;
CalcPosition(i, j, basepos);
if (i > 0) {
CalcPosition(i-1, j, left);
left -= basepos;
left.Normalize();
}
if (i < m_MapSize-1) {
CalcPosition(i+1, j, right);
right -= basepos;
right.Normalize();
}
if (j > 0) {
CalcPosition(i, j-1, up);
up -= basepos;
up.Normalize();
}
if (j < m_MapSize-1) {
CalcPosition(i, j+1, down);
down -= basepos;
down.Normalize();
}
CVector3D n0 = up.Cross(left);
CVector3D n1 = left.Cross(down);
CVector3D n2 = down.Cross(right);
CVector3D n3 = right.Cross(up);
// Compute the mean of the normals
normal = n0 + n1 + n2 + n3;
float nlen=normal.Length();
if (nlen>0.00001f) normal*=1.0f/nlen;
}
///////////////////////////////////////////////////////////////////////////////
// CalcNormalFixed: calculate the world space normal of the vertex at (i,j)
void CTerrain::CalcNormalFixed(ssize_t i, ssize_t j, CFixedVector3D& normal) const
{
CFixedVector3D left, right, up, down;
// Calculate normals of the four half-tile triangles surrounding this vertex:
// get position of vertex where normal is being evaluated
CFixedVector3D basepos;
CalcPositionFixed(i, j, basepos);
if (i > 0) {
CalcPositionFixed(i-1, j, left);
left -= basepos;
left.Normalize();
}
if (i < m_MapSize-1) {
CalcPositionFixed(i+1, j, right);
right -= basepos;
right.Normalize();
}
if (j > 0) {
CalcPositionFixed(i, j-1, up);
up -= basepos;
up.Normalize();
}
if (j < m_MapSize-1) {
CalcPositionFixed(i, j+1, down);
down -= basepos;
down.Normalize();
}
CFixedVector3D n0 = up.Cross(left);
CFixedVector3D n1 = left.Cross(down);
CFixedVector3D n2 = down.Cross(right);
CFixedVector3D n3 = right.Cross(up);
// Compute the mean of the normals
normal = n0 + n1 + n2 + n3;
normal.Normalize();
}
///////////////////////////////////////////////////////////////////////////////
// GetPatch: return the patch at (i,j) in patch space, or null if the patch is
// out of bounds
CPatch* CTerrain::GetPatch(ssize_t i, ssize_t j) const
{
// range check (invalid indices are passed in by the culling and
// patch blend code because they iterate from 0..#patches and examine
// neighbors without checking if they're already on the edge)
if( (size_t)i >= (size_t)m_MapSizePatches || (size_t)j >= (size_t)m_MapSizePatches )
return 0;
return &m_Patches[(j*m_MapSizePatches)+i];
}
///////////////////////////////////////////////////////////////////////////////
// GetTile: return the tile at (i,j) in tile space, or null if the tile is out
// of bounds
CMiniPatch* CTerrain::GetTile(ssize_t i, ssize_t j) const
{
// see comment above
if( (size_t)i >= (size_t)(m_MapSize-1) || (size_t)j >= (size_t)(m_MapSize-1) )
return 0;
CPatch* patch=GetPatch(i/PATCH_SIZE, j/PATCH_SIZE); // can't fail (due to above check)
return &patch->m_MiniPatches[j%PATCH_SIZE][i%PATCH_SIZE];
}
float CTerrain::GetVertexGroundLevel(ssize_t i, ssize_t j) const
{
i = clamp(i, (ssize_t)0, m_MapSize-1);
j = clamp(j, (ssize_t)0, m_MapSize-1);
return HEIGHT_SCALE * m_Heightmap[j*m_MapSize + i];
}
fixed CTerrain::GetVertexGroundLevelFixed(ssize_t i, ssize_t j) const
{
i = clamp(i, (ssize_t)0, m_MapSize-1);
j = clamp(j, (ssize_t)0, m_MapSize-1);
// Convert to fixed metres (being careful to avoid intermediate overflows)
return fixed::FromInt(m_Heightmap[j*m_MapSize + i] / 2) / (int)(HEIGHT_UNITS_PER_METRE / 2);
}
fixed CTerrain::GetSlopeFixed(ssize_t i, ssize_t j) const
{
// Clamp to size-2 so we can use the tiles (i,j)-(i+1,j+1)
i = clamp(i, (ssize_t)0, m_MapSize-2);
j = clamp(j, (ssize_t)0, m_MapSize-2);
u16 h00 = m_Heightmap[j*m_MapSize + i];
u16 h01 = m_Heightmap[(j+1)*m_MapSize + i];
u16 h10 = m_Heightmap[j*m_MapSize + (i+1)];
u16 h11 = m_Heightmap[(j+1)*m_MapSize + (i+1)];
// Difference of highest point from lowest point
u16 delta = std::max(std::max(h00, h01), std::max(h10, h11)) -
std::min(std::min(h00, h01), std::min(h10, h11));
// Compute fractional slope (being careful to avoid intermediate overflows)
return fixed::FromInt(delta / CELL_SIZE) / (int)HEIGHT_UNITS_PER_METRE;
}
float CTerrain::GetExactGroundLevel(float x, float z) const
{
// Clamp to size-2 so we can use the tiles (xi,zi)-(xi+1,zi+1)
const ssize_t xi = clamp((ssize_t)floor(x/CELL_SIZE), (ssize_t)0, m_MapSize-2);
const ssize_t zi = clamp((ssize_t)floor(z/CELL_SIZE), (ssize_t)0, m_MapSize-2);
const float xf = clamp(x/CELL_SIZE-xi, 0.0f, 1.0f);
const float zf = clamp(z/CELL_SIZE-zi, 0.0f, 1.0f);
float h00 = m_Heightmap[zi*m_MapSize + xi];
float h01 = m_Heightmap[(zi+1)*m_MapSize + xi];
float h10 = m_Heightmap[zi*m_MapSize + (xi+1)];
float h11 = m_Heightmap[(zi+1)*m_MapSize + (xi+1)];
// Linearly interpolate
return (HEIGHT_SCALE * (
(1 - zf) * ((1 - xf) * h00 + xf * h10)
+ zf * ((1 - xf) * h01 + xf * h11)));
}
fixed CTerrain::GetExactGroundLevelFixed(fixed x, fixed z) const
{
// Clamp to size-2 so we can use the tiles (xi,zi)-(xi+1,zi+1)
const ssize_t xi = clamp((ssize_t)(x / (int)CELL_SIZE).ToInt_RoundToZero(), (ssize_t)0, m_MapSize-2);
const ssize_t zi = clamp((ssize_t)(z / (int)CELL_SIZE).ToInt_RoundToZero(), (ssize_t)0, m_MapSize-2);
const fixed one = fixed::FromInt(1);
const fixed xf = clamp((x / (int)CELL_SIZE) - fixed::FromInt(xi), fixed::Zero(), one);
const fixed zf = clamp((z / (int)CELL_SIZE) - fixed::FromInt(zi), fixed::Zero(), one);
u16 h00 = m_Heightmap[zi*m_MapSize + xi];
u16 h01 = m_Heightmap[(zi+1)*m_MapSize + xi];
u16 h10 = m_Heightmap[zi*m_MapSize + (xi+1)];
u16 h11 = m_Heightmap[(zi+1)*m_MapSize + (xi+1)];
// Intermediate scaling of xf, so we don't overflow in the multiplications below
// (h00 <= 65535, xf <= 1, max fixed is < 32768; divide by 2 here so xf1*h00 <= 32767.5)
const fixed xf0 = xf / 2;
const fixed xf1 = (one - xf) / 2;
// Linearly interpolate
return ((one - zf).Multiply(xf1 * h00 + xf0 * h10)
+ zf.Multiply(xf1 * h01 + xf0 * h11)) / (int)(HEIGHT_UNITS_PER_METRE / 2);
}
///////////////////////////////////////////////////////////////////////////////
// Resize: resize this terrain to the given size (in patches per side)
void CTerrain::Resize(ssize_t size)
{
if (size==m_MapSizePatches) {
// inexplicable request to resize terrain to the same size .. ignore it
return;
}
if (!m_Heightmap) {
// not yet created a terrain; build a default terrain of the given size now
Initialize(size,0);
return;
}
// allocate data for new terrain
ssize_t newMapSize=size*PATCH_SIZE+1;
u16* newHeightmap=new u16[newMapSize*newMapSize];
CPatch* newPatches=new CPatch[size*size];
if (size>m_MapSizePatches) {
// new map is bigger than old one - zero the heightmap so we don't get uninitialised
// height data along the expanded edges
memset(newHeightmap,0,newMapSize*newMapSize*sizeof(u16));
}
// now copy over rows of data
u16* src=m_Heightmap;
u16* dst=newHeightmap;
ssize_t copysize=std::min(newMapSize, m_MapSize);
for (ssize_t j=0;j<copysize;j++) {
memcpy(dst,src,copysize*sizeof(u16));
dst+=copysize;
src+=m_MapSize;
if (newMapSize>m_MapSize) {
// extend the last height to the end of the row
for (size_t i=0;i<newMapSize-(size_t)m_MapSize;i++) {
*dst++=*(src-1);
}
}
}
if (newMapSize>m_MapSize) {
// copy over heights of the last row to any remaining rows
src=newHeightmap+((m_MapSize-1)*newMapSize);
dst=src+newMapSize;
for (ssize_t i=0;i<newMapSize-m_MapSize;i++) {
memcpy(dst,src,newMapSize*sizeof(u16));
dst+=newMapSize;
}
}
// now build new patches
for (ssize_t j=0;j<size;j++) {
for (ssize_t i=0;i<size;i++) {
// copy over texture data from existing tiles, if possible
if (i<m_MapSizePatches && j<m_MapSizePatches) {
memcpy(newPatches[j*size+i].m_MiniPatches,m_Patches[j*m_MapSizePatches+i].m_MiniPatches,sizeof(CMiniPatch)*PATCH_SIZE*PATCH_SIZE);
}
}
if (j<m_MapSizePatches && size>m_MapSizePatches) {
// copy over the last tile from each column
for (ssize_t n=0;n<size-m_MapSizePatches;n++) {
for (ssize_t m=0;m<PATCH_SIZE;m++) {
CMiniPatch& src=m_Patches[j*m_MapSizePatches+m_MapSizePatches-1].m_MiniPatches[m][15];
for (ssize_t k=0;k<PATCH_SIZE;k++) {
CMiniPatch& dst=newPatches[j*size+m_MapSizePatches+n].m_MiniPatches[m][k];
dst = src;
}
}
}
}
}
if (size>m_MapSizePatches) {
// copy over the last tile from each column
CPatch* srcpatch=&newPatches[(m_MapSizePatches-1)*size];
CPatch* dstpatch=srcpatch+size;
for (ssize_t p=0;p<(ssize_t)size-m_MapSizePatches;p++) {
for (ssize_t n=0;n<(ssize_t)size;n++) {
for (ssize_t m=0;m<PATCH_SIZE;m++) {
for (ssize_t k=0;k<PATCH_SIZE;k++) {
CMiniPatch& src=srcpatch->m_MiniPatches[15][k];
CMiniPatch& dst=dstpatch->m_MiniPatches[m][k];
dst = src;
}
}
srcpatch++;
dstpatch++;
}
}
}
// release all the original data
ReleaseData();
// store new data
m_Heightmap=newHeightmap;
m_Patches=newPatches;
m_MapSize=(ssize_t)newMapSize;
m_MapSizePatches=(ssize_t)size;
// initialise all the new patches
InitialisePatches();
}
///////////////////////////////////////////////////////////////////////////////
// InitialisePatches: initialise patch data
void CTerrain::InitialisePatches()
{
for (ssize_t j=0;j<m_MapSizePatches;j++) {
for (ssize_t i=0;i<m_MapSizePatches;i++) {
CPatch* patch=GetPatch(i,j); // can't fail
patch->Initialize(this,i,j);
}
}
}
///////////////////////////////////////////////////////////////////////////////
// SetHeightMap: set up a new heightmap from 16-bit source data;
// assumes heightmap matches current terrain size
void CTerrain::SetHeightMap(u16* heightmap)
{
// keep a copy of the given heightmap
memcpy(m_Heightmap,heightmap,m_MapSize*m_MapSize*sizeof(u16));
// recalculate patch bounds, invalidate vertices
for (ssize_t j=0;j<m_MapSizePatches;j++) {
for (ssize_t i=0;i<m_MapSizePatches;i++) {
CPatch* patch=GetPatch(i,j); // can't fail
patch->InvalidateBounds();
patch->SetDirty(RENDERDATA_UPDATE_VERTICES);
}
}
}
///////////////////////////////////////////////////////////////////////////////
// FlattenArea: flatten out an area of terrain (specified in world space
// coords); return the average height of the flattened area
float CTerrain::FlattenArea(float x0, float x1, float z0, float z1)
{
const ssize_t tx0 = clamp(ssize_t(x0/CELL_SIZE), (ssize_t)0, m_MapSize-1);
const ssize_t tx1 = clamp(ssize_t(x1/CELL_SIZE)+1, (ssize_t)0, m_MapSize-1);
const ssize_t tz0 = clamp(ssize_t(z0/CELL_SIZE), (ssize_t)0, m_MapSize-1);
const ssize_t tz1 = clamp(ssize_t(z1/CELL_SIZE)+1, (ssize_t)0, m_MapSize-1);
size_t count=0;
double sum=0.0f;
for (ssize_t z=tz0;z<=tz1;z++) {
for (ssize_t x=tx0;x<=tx1;x++) {
sum+=m_Heightmap[z*m_MapSize + x];
count++;
}
}
const u16 avgY = u16(sum/count);
for (ssize_t z=tz0;z<=tz1;z++) {
for (ssize_t x=tx0;x<=tx1;x++) {
m_Heightmap[z*m_MapSize + x]=avgY;
}
}
MakeDirty(tx0, tz0, tx1, tz1, RENDERDATA_UPDATE_VERTICES);
return avgY*HEIGHT_SCALE;
}
///////////////////////////////////////////////////////////////////////////////
void CTerrain::MakeDirty(ssize_t i0, ssize_t j0, ssize_t i1, ssize_t j1, int dirtyFlags)
{
// flag vertex data as dirty for affected patches, and rebuild bounds of these patches
ssize_t pi0 = clamp((i0/PATCH_SIZE)-1, (ssize_t)0, m_MapSizePatches);
ssize_t pi1 = clamp((i1/PATCH_SIZE)+1, (ssize_t)0, m_MapSizePatches);
ssize_t pj0 = clamp((j0/PATCH_SIZE)-1, (ssize_t)0, m_MapSizePatches);
ssize_t pj1 = clamp((j1/PATCH_SIZE)+1, (ssize_t)0, m_MapSizePatches);
for (ssize_t j = pj0; j < pj1; j++) {
for (ssize_t i = pi0; i < pi1; i++) {
CPatch* patch = GetPatch(i,j); // can't fail (i,j were clamped)
if (dirtyFlags & RENDERDATA_UPDATE_VERTICES)
patch->CalcBounds();
patch->SetDirty(dirtyFlags);
}
}
}
void CTerrain::MakeDirty(int dirtyFlags)
{
for (ssize_t j = 0; j < m_MapSizePatches; j++) {
for (ssize_t i = 0; i < m_MapSizePatches; i++) {
CPatch* patch = GetPatch(i,j); // can't fail
if (dirtyFlags & RENDERDATA_UPDATE_VERTICES)
patch->CalcBounds();
patch->SetDirty(dirtyFlags);
}
}
}
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