From 2694138060829260aec88e94655f1063b8b525f6 Mon Sep 17 00:00:00 2001 From: Hugo Locurcio Date: Wed, 16 Feb 2022 01:43:44 +0100 Subject: Add an option to clamp HDR exposure to reduce environment fireflies HDRI panoramas designed for realistic lighting can have extremely bright suns, causing fireflies to appear in the environment reflection (in addition to making environment lighting too bright when a DirectionalLight3D is used). This uses the Filament tonemapping formula. --- editor/import/resource_importer_texture.cpp | 30 +++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) (limited to 'editor') diff --git a/editor/import/resource_importer_texture.cpp b/editor/import/resource_importer_texture.cpp index 1dec4b00bb..769ce43616 100644 --- a/editor/import/resource_importer_texture.cpp +++ b/editor/import/resource_importer_texture.cpp @@ -217,6 +217,7 @@ void ResourceImporterTexture::get_import_options(const String &p_path, Listpush_back(ImportOption(PropertyInfo(Variant::BOOL, "process/premult_alpha"), false)); r_options->push_back(ImportOption(PropertyInfo(Variant::BOOL, "process/normal_map_invert_y"), false)); r_options->push_back(ImportOption(PropertyInfo(Variant::BOOL, "process/hdr_as_srgb"), false)); + r_options->push_back(ImportOption(PropertyInfo(Variant::BOOL, "process/hdr_clamp_exposure"), false)); r_options->push_back(ImportOption(PropertyInfo(Variant::INT, "process/size_limit", PROPERTY_HINT_RANGE, "0,4096,1"), 0)); r_options->push_back(ImportOption(PropertyInfo(Variant::INT, "detect_3d/compress_to", PROPERTY_HINT_ENUM, "Disabled,VRAM Compressed,Basis Universal"), (p_preset == PRESET_DETECT) ? 1 : 0)); @@ -411,6 +412,7 @@ Error ResourceImporterTexture::import(const String &p_source_file, const String const bool stream = p_options["compress/streamed"]; const int size_limit = p_options["process/size_limit"]; const bool hdr_as_srgb = p_options["process/hdr_as_srgb"]; + const bool hdr_clamp_exposure = p_options["process/hdr_clamp_exposure"]; const int normal = p_options["compress/normal_map"]; const int hdr_compression = p_options["compress/hdr_compression"]; const int bptc_ldr = p_options["compress/bptc_ldr"]; @@ -482,6 +484,34 @@ Error ResourceImporterTexture::import(const String &p_source_file, const String } } + if (hdr_clamp_exposure) { + // Clamp HDR exposure following Filament's tonemapping formula. + // This can be used to reduce fireflies in environment maps or reduce the influence + // of the sun from an HDRI panorama on environment lighting (when a DirectionalLight3D is used instead). + const int height = image->get_height(); + const int width = image->get_width(); + + // These values are chosen arbitrarily and seem to produce good results with 4,096 samples. + const float linear = 4096.0; + const float compressed = 16384.0; + + for (int i = 0; i < width; i++) { + for (int j = 0; j < height; j++) { + const Color color = image->get_pixel(i, j); + const float luma = color.get_luminance(); + + Color clamped_color; + if (luma <= linear) { + clamped_color = color; + } else { + clamped_color = (color / luma) * ((linear * linear - compressed * luma) / (2 * linear - compressed - luma)); + } + + image->set_pixel(i, j, clamped_color); + } + } + } + if (compress_mode == COMPRESS_BASIS_UNIVERSAL && image->get_format() >= Image::FORMAT_RF) { //basis universal does not support float formats, fall back compress_mode = COMPRESS_VRAM_COMPRESSED; -- cgit v1.2.3