/**
* Reads the heightmap and/or size of the heightmap from a PNG file.
* If map == NULL only the size of the PNG is read, otherwise a map
* with grayscale pixels is allocated and assigned to *map.
*/
static bool ReadHeightmapPNG(char *filename, uint *x, uint *y, byte **map)
{
FILE *fp;
png_structp png_ptr = NULL;
png_infop info_ptr = NULL;
fp = FioFOpenFile(filename, "rb");
if (fp == NULL) {
ShowErrorMessage(STR_ERROR_PNGMAP, STR_ERROR_PNGMAP_FILE_NOT_FOUND, WL_ERROR);
return false;
}
png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
if (png_ptr == NULL) {
ShowErrorMessage(STR_ERROR_PNGMAP, STR_ERROR_PNGMAP_MISC, WL_ERROR);
fclose(fp);
return false;
}
info_ptr = png_create_info_struct(png_ptr);
if (info_ptr == NULL || setjmp(png_jmpbuf(png_ptr))) {
ShowErrorMessage(STR_ERROR_PNGMAP, STR_ERROR_PNGMAP_MISC, WL_ERROR);
fclose(fp);
png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
return false;
}
png_init_io(png_ptr, fp);
/* Allocate memory and read image, without alpha or 16-bit samples
* (result is either 8-bit indexed/grayscale or 24-bit RGB) */
png_set_packing(png_ptr);
png_read_png(png_ptr, info_ptr, PNG_TRANSFORM_PACKING | PNG_TRANSFORM_STRIP_ALPHA | PNG_TRANSFORM_STRIP_16, NULL);
/* Maps of wrong colour-depth are not used.
* (this should have been taken care of by stripping alpha and 16-bit samples on load) */
if ((png_get_channels(png_ptr, info_ptr) != 1) && (png_get_channels(png_ptr, info_ptr) != 3) && (png_get_bit_depth(png_ptr, info_ptr) != 8)) {
ShowErrorMessage(STR_ERROR_PNGMAP, STR_ERROR_PNGMAP_IMAGE_TYPE, WL_ERROR);
fclose(fp);
png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
return false;
}
if (map != NULL) {
*map = MallocT<byte>(png_get_image_width(png_ptr, info_ptr) * png_get_image_height(png_ptr, info_ptr));
ReadHeightmapPNGImageData(*map, png_ptr, info_ptr);
}
*x = png_get_image_width(png_ptr, info_ptr);
*y = png_get_image_height(png_ptr, info_ptr);
fclose(fp);
png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
return true;
}
/**
* Reads the heightmap and/or size of the heightmap from a PNG file.
* If map == nullptr only the size of the PNG is read, otherwise a map
* with grayscale pixels is allocated and assigned to *map.
*/
static bool ReadHeightmapPNG(const char *filename, uint *x, uint *y, byte **map)
{
FILE *fp;
png_structp png_ptr = nullptr;
png_infop info_ptr = nullptr;
fp = FioFOpenFile(filename, "rb", HEIGHTMAP_DIR);
if (fp == nullptr) {
ShowErrorMessage(STR_ERROR_PNGMAP, STR_ERROR_PNGMAP_FILE_NOT_FOUND, WL_ERROR);
return false;
}
png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, nullptr, nullptr, nullptr);
if (png_ptr == nullptr) {
ShowErrorMessage(STR_ERROR_PNGMAP, STR_ERROR_PNGMAP_MISC, WL_ERROR);
fclose(fp);
return false;
}
info_ptr = png_create_info_struct(png_ptr);
if (info_ptr == nullptr || setjmp(png_jmpbuf(png_ptr))) {
ShowErrorMessage(STR_ERROR_PNGMAP, STR_ERROR_PNGMAP_MISC, WL_ERROR);
fclose(fp);
png_destroy_read_struct(&png_ptr, &info_ptr, nullptr);
return false;
}
png_init_io(png_ptr, fp);
/* Allocate memory and read image, without alpha or 16-bit samples
* (result is either 8-bit indexed/grayscale or 24-bit RGB) */
png_set_packing(png_ptr);
png_read_png(png_ptr, info_ptr, PNG_TRANSFORM_PACKING | PNG_TRANSFORM_STRIP_ALPHA | PNG_TRANSFORM_STRIP_16, nullptr);
/* Maps of wrong colour-depth are not used.
* (this should have been taken care of by stripping alpha and 16-bit samples on load) */
if ((png_get_channels(png_ptr, info_ptr) != 1) && (png_get_channels(png_ptr, info_ptr) != 3) && (png_get_bit_depth(png_ptr, info_ptr) != 8)) {
ShowErrorMessage(STR_ERROR_PNGMAP, STR_ERROR_PNGMAP_IMAGE_TYPE, WL_ERROR);
fclose(fp);
png_destroy_read_struct(&png_ptr, &info_ptr, nullptr);
return false;
}
uint width = png_get_image_width(png_ptr, info_ptr);
uint height = png_get_image_height(png_ptr, info_ptr);
/* Check if image dimensions don't overflow a size_t to avoid memory corruption. */
if ((uint64)width * height >= (size_t)-1) {
ShowErrorMessage(STR_ERROR_PNGMAP, STR_ERROR_HEIGHTMAP_TOO_LARGE, WL_ERROR);
fclose(fp);
png_destroy_read_struct(&png_ptr, &info_ptr, nullptr);
return false;
}
if (map != nullptr) {
*map = MallocT<byte>(width * height);
ReadHeightmapPNGImageData(*map, png_ptr, info_ptr);
}
*x = width;
*y = height;
fclose(fp);
png_destroy_read_struct(&png_ptr, &info_ptr, nullptr);
return true;
}
