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//-----------------------------------------------------------------------------
// Name: heightmap.cpp
// Developer: Wolfire Games LLC
// Description:
// License: Read below
//-----------------------------------------------------------------------------
//
//
// Copyright 2022 Wolfire Games LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
//-----------------------------------------------------------------------------
#include "heightmap.h"
#include <Internal/checksum.h>
#include <Internal/common.h>
#include <Internal/error.h>
#include <Internal/datemodified.h>
#include <Internal/cachefile.h>
#include <Internal/filesystem.h>
#include <Compat/fileio.h>
#include <Images/stbimage_wrapper.h>
bool HeightmapImage::ReadCacheFile(const std::string& path, uint16_t checksum) {
FILE* file = my_fopen(path.c_str(), "rb");
if (!file) {
return false;
}
CacheFile::ScopedFileCloser file_closer(file);
unsigned char version;
fread(&version, sizeof(version), 1, file);
if (version != kHMCacheVersion) {
return false;
}
uint16_t file_checksum;
fread(&file_checksum, sizeof(file_checksum), 1, file);
if (checksum != 0 && checksum != file_checksum) {
return false;
}
checksum_ = file_checksum;
fread(&width_, sizeof(width_), 1, file);
fread(&depth_, sizeof(depth_), 1, file);
height_data_.resize(width_ * depth_);
fread(&height_data_[0], sizeof(height_data_[0]) * width_ * depth_, 1, file);
return true;
}
void HeightmapImage::WriteCacheFile(const std::string& path) {
FILE* file = my_fopen(path.c_str(), "wb");
CacheFile::ScopedFileCloser file_closer(file);
unsigned char version = kHMCacheVersion;
fwrite(&version, sizeof(version), 1, file);
fwrite(&checksum_, sizeof(checksum_), 1, file);
fwrite(&width_, sizeof(width_), 1, file);
fwrite(&depth_, sizeof(depth_), 1, file);
fwrite(&height_data_[0], sizeof(height_data_[0]), width_ * depth_, file);
}
bool HeightmapImage::LoadData(const std::string& rel_path, HMScale scaled) {
height_data_.clear();
rel_path_ = rel_path;
std::string cache_suffix = "_hmcache";
if (scaled == DOWNSAMPLED) {
cache_suffix += "_scaled";
}
std::string load_path;
ModID load_modsource;
if (CacheFile::CheckForCache(rel_path_, cache_suffix, &load_path, &load_modsource, &checksum_)) {
if (ReadCacheFile(load_path, checksum_)) {
modsource_ = load_modsource;
return true;
}
}
char abs_path[kPathSize];
ModID modsource;
FindFilePath(rel_path.c_str(), abs_path, kPathSize, kDataPaths | kModPaths, true, NULL, &modsource);
modsource_ = modsource;
// Tell stb_image that we want 4 components (RGBA)
int img_width = 0, img_height = 0, num_comp = 0;
float* data = stbi_loadf(abs_path, &img_width, &img_height, &num_comp, 0);
if (data == NULL) {
FatalError("Error", "Could not load heightmap: %s", rel_path.c_str());
} else {
if (scaled) {
width_ = kTerrainDimX;
depth_ = kTerrainDimY;
} else {
width_ = img_width;
depth_ = img_height;
}
int heightDataSize = width_ * depth_;
if (0 < heightDataSize) {
// ...allocate enough space for the height data...
height_data_.resize(heightDataSize, 0);
// m_flowData.resize(heightDataSize,vecf(2,0));
float scale_factor = kTerrainHeightScale;
float x_scale = img_width / (float)width_;
float z_scale = img_height / (float)depth_;
if (num_comp != 1) { // monochrome texture
for (int z = 0; z < depth_; z++) { // flipped
float* bits = &data[((int)(z * z_scale)) * img_height];
for (int x = 0; x < width_; x++) {
height_data_[x + (((depth_ - 1) - z) * width_)] = (bits[(int)(x * x_scale)] * 65535.0f) / scale_factor;
}
}
} else {
FatalError("Error", "Heightmaps must be 16-bit grayscale PNGs.");
}
stbi_image_free(data);
char path[kPathSize];
FormatString(path, kPathSize, "%s%s%s", GetWritePath(modsource).c_str(), rel_path.c_str(), cache_suffix.c_str());
WriteCacheFile(path);
return true;
}
}
return false;
}
float HeightmapImage::GetHeight(int x, int z) const {
if (!width_ || !depth_) {
return (0);
}
x = (x < 0) ? (0) : (x >= width_) ? (width_ - 1)
: (x);
z = (z < 0) ? (0) : (z >= depth_) ? (depth_ - 1)
: (z);
const int pos = x + (z * width_);
return float(height_data_[pos]);
}
float HeightmapImage::GetHeightXZ(float x, float z) const {
// ensure the heightmap is valid
if (!width_ || !depth_) {
return (0);
}
// clamp values to the resolution of the heightmap
x = (x < 0) ? (0) : (x >= width_) ? (width_ - 1)
: (x);
z = (z < 0) ? (0) : (z >= depth_) ? (depth_ - 1)
: (z);
const int ix = int(x);
const int iz = int(z);
float xoffset = x - ix;
float zoffset = z - iz;
xoffset = 1 - xoffset;
zoffset = 1 - zoffset;
float weightTL = xoffset * zoffset;
float weightTR = (1 - xoffset) * zoffset;
float weightBL = xoffset * (1 - zoffset);
float weightBR = (1 - xoffset) * (1 - zoffset);
float total = weightTL + weightTR + weightBL + weightBR;
weightTL /= total;
weightTR /= total;
weightBL /= total;
weightBR /= total;
return (
GetHeight(ix, iz) * weightTL +
GetHeight(ix + 1, iz) * weightTR +
GetHeight(ix, iz + 1) * weightBL +
GetHeight(ix + 1, iz + 1) * weightBR);
}
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