Implement lossless WebP encoding

9 files changed, 114 insertions, 37 deletions

diff --git a/core/io/image.cpp b/core/io/image.cpp
index c36fa6e45f..96f7db4882 100644
--- a/core/io/image.cpp
+++ b/core/io/image.cpp
@@ -2718,10 +2718,11 @@ void (*Image::_image_decompress_bptc)(Image *) = nullptr;
 void (*Image::_image_decompress_etc1)(Image *) = nullptr;
 void (*Image::_image_decompress_etc2)(Image *) = nullptr;
 
-Vector<uint8_t> (*Image::lossy_packer)(const Ref<Image> &, float) = nullptr;
-Ref<Image> (*Image::lossy_unpacker)(const Vector<uint8_t> &) = nullptr;
-Vector<uint8_t> (*Image::lossless_packer)(const Ref<Image> &) = nullptr;
-Ref<Image> (*Image::lossless_unpacker)(const Vector<uint8_t> &) = nullptr;
+Vector<uint8_t> (*Image::webp_lossy_packer)(const Ref<Image> &, float) = nullptr;
+Vector<uint8_t> (*Image::webp_lossless_packer)(const Ref<Image> &) = nullptr;
+Ref<Image> (*Image::webp_unpacker)(const Vector<uint8_t> &) = nullptr;
+Vector<uint8_t> (*Image::png_packer)(const Ref<Image> &) = nullptr;
+Ref<Image> (*Image::png_unpacker)(const Vector<uint8_t> &) = nullptr;
 Vector<uint8_t> (*Image::basis_universal_packer)(const Ref<Image> &, Image::UsedChannels) = nullptr;
 Ref<Image> (*Image::basis_universal_unpacker)(const Vector<uint8_t> &) = nullptr;
 
diff --git a/core/io/image.h b/core/io/image.h
index df8f9b35a1..060e54a308 100644
--- a/core/io/image.h
+++ b/core/io/image.h
@@ -148,10 +148,11 @@ public:
 	static void (*_image_decompress_etc1)(Image *);
 	static void (*_image_decompress_etc2)(Image *);
 
-	static Vector<uint8_t> (*lossy_packer)(const Ref<Image> &p_image, float p_quality);
-	static Ref<Image> (*lossy_unpacker)(const Vector<uint8_t> &p_buffer);
-	static Vector<uint8_t> (*lossless_packer)(const Ref<Image> &p_image);
-	static Ref<Image> (*lossless_unpacker)(const Vector<uint8_t> &p_buffer);
+	static Vector<uint8_t> (*webp_lossy_packer)(const Ref<Image> &p_image, float p_quality);
+	static Vector<uint8_t> (*webp_lossless_packer)(const Ref<Image> &p_image);
+	static Ref<Image> (*webp_unpacker)(const Vector<uint8_t> &p_buffer);
+	static Vector<uint8_t> (*png_packer)(const Ref<Image> &p_image);
+	static Ref<Image> (*png_unpacker)(const Vector<uint8_t> &p_buffer);
 	static Vector<uint8_t> (*basis_universal_packer)(const Ref<Image> &p_image, UsedChannels p_channels);
 	static Ref<Image> (*basis_universal_unpacker)(const Vector<uint8_t> &p_buffer);
 
diff --git a/doc/classes/ProjectSettings.xml b/doc/classes/ProjectSettings.xml
index a200858a3c..8a7a94332b 100644
--- a/doc/classes/ProjectSettings.xml
+++ b/doc/classes/ProjectSettings.xml
@@ -1578,6 +1578,12 @@
 		<member name="rendering/textures/default_filters/use_nearest_mipmap_filter" type="bool" setter="" getter="" default="false">
 			If [code]true[/code], uses nearest-neighbor mipmap filtering when using mipmaps (also called "bilinear filtering"), which will result in visible seams appearing between mipmap stages. This may increase performance in mobile as less memory bandwidth is used. If [code]false[/code], linear mipmap filtering (also called "trilinear filtering") is used.
 		</member>
+		<member name="rendering/textures/lossless_compression/force_png" type="bool" setter="" getter="" default="false">
+			If [code]true[/code], the texture importer will import lossless textures using the PNG format. Otherwise, it will default to using WebP.
+		</member>
+		<member name="rendering/textures/lossless_compression/webp_compression_level" type="int" setter="" getter="" default="2">
+			The default compression level for lossless WebP. Higher levels result in smaller files at the cost of compression speed. Decompression speed is mostly unaffected by the compression level. Supported values are 0 to 9. Note that compression levels above 6 are very slow and offer very little savings.
+		</member>
 		<member name="rendering/textures/vram_compression/import_bptc" type="bool" setter="" getter="" default="false">
 			If [code]true[/code], the texture importer will import VRAM-compressed textures using the BPTC algorithm. This texture compression algorithm is only supported on desktop platforms, and only when using the Vulkan renderer.
 		</member>
diff --git a/drivers/png/image_loader_png.cpp b/drivers/png/image_loader_png.cpp
index 8b2e786146..8cc76b01e1 100644
--- a/drivers/png/image_loader_png.cpp
+++ b/drivers/png/image_loader_png.cpp
@@ -101,6 +101,6 @@ Vector<uint8_t> ImageLoaderPNG::lossless_pack_png(const Ref<Image> &p_image) {
 
 ImageLoaderPNG::ImageLoaderPNG() {
 	Image::_png_mem_loader_func = load_mem_png;
-	Image::lossless_unpacker = lossless_unpack_png;
-	Image::lossless_packer = lossless_pack_png;
+	Image::png_unpacker = lossless_unpack_png;
+	Image::png_packer = lossless_pack_png;
 }
diff --git a/editor/import/resource_importer_texture.cpp b/editor/import/resource_importer_texture.cpp
index de8031af35..0f2c919820 100644
--- a/editor/import/resource_importer_texture.cpp
+++ b/editor/import/resource_importer_texture.cpp
@@ -218,14 +218,21 @@ void ResourceImporterTexture::get_import_options(List<ImportOption> *r_options,
 void ResourceImporterTexture::save_to_stex_format(FileAccess *f, const Ref<Image> &p_image, CompressMode p_compress_mode, Image::UsedChannels p_channels, Image::CompressMode p_compress_format, float p_lossy_quality) {
 	switch (p_compress_mode) {
 		case COMPRESS_LOSSLESS: {
-			f->store_32(StreamTexture2D::DATA_FORMAT_LOSSLESS);
+			bool lossless_force_png = ProjectSettings::get_singleton()->get("rendering/textures/lossless_compression/force_png");
+			bool use_webp = !lossless_force_png && p_image->get_width() <= 16383 && p_image->get_height() <= 16383; // WebP has a size limit
+			f->store_32(use_webp ? StreamTexture2D::DATA_FORMAT_WEBP : StreamTexture2D::DATA_FORMAT_PNG);
 			f->store_16(p_image->get_width());
 			f->store_16(p_image->get_height());
 			f->store_32(p_image->get_mipmap_count());
 			f->store_32(p_image->get_format());
 
 			for (int i = 0; i < p_image->get_mipmap_count() + 1; i++) {
-				Vector<uint8_t> data = Image::lossless_packer(p_image->get_image_from_mipmap(i));
+				Vector<uint8_t> data;
+				if (use_webp) {
+					data = Image::webp_lossless_packer(p_image->get_image_from_mipmap(i));
+				} else {
+					data = Image::png_packer(p_image->get_image_from_mipmap(i));
+				}
 				int data_len = data.size();
 				f->store_32(data_len);
 
@@ -235,14 +242,14 @@ void ResourceImporterTexture::save_to_stex_format(FileAccess *f, const Ref<Image
 
 		} break;
 		case COMPRESS_LOSSY: {
-			f->store_32(StreamTexture2D::DATA_FORMAT_LOSSY);
+			f->store_32(StreamTexture2D::DATA_FORMAT_WEBP);
 			f->store_16(p_image->get_width());
 			f->store_16(p_image->get_height());
 			f->store_32(p_image->get_mipmap_count());
 			f->store_32(p_image->get_format());
 
 			for (int i = 0; i < p_image->get_mipmap_count() + 1; i++) {
-				Vector<uint8_t> data = Image::lossy_packer(p_image->get_image_from_mipmap(i), p_lossy_quality);
+				Vector<uint8_t> data = Image::webp_lossy_packer(p_image->get_image_from_mipmap(i), p_lossy_quality);
 				int data_len = data.size();
 				f->store_32(data_len);
 
diff --git a/modules/webp/image_loader_webp.cpp b/modules/webp/image_loader_webp.cpp
index 1f2a456619..772445190c 100644
--- a/modules/webp/image_loader_webp.cpp
+++ b/modules/webp/image_loader_webp.cpp
@@ -30,6 +30,7 @@
 
 #include "image_loader_webp.h"
 
+#include "core/config/project_settings.h"
 #include "core/io/marshalls.h"
 #include "core/os/os.h"
 #include "core/string/print_string.h"
@@ -69,12 +70,77 @@ static Vector<uint8_t> _webp_lossy_pack(const Ref<Image> &p_image, float p_quali
 	w[2] = 'B';
 	w[3] = 'P';
 	memcpy(&w[4], dst_buff, dst_size);
-	free(dst_buff);
+	WebPFree(dst_buff);
 
 	return dst;
 }
 
-static Ref<Image> _webp_lossy_unpack(const Vector<uint8_t> &p_buffer) {
+static Vector<uint8_t> _webp_lossless_pack(const Ref<Image> &p_image) {
+	ERR_FAIL_COND_V(p_image.is_null() || p_image->is_empty(), Vector<uint8_t>());
+
+	int compression_level = ProjectSettings::get_singleton()->get("rendering/textures/lossless_compression/webp_compression_level");
+	compression_level = CLAMP(compression_level, 0, 9);
+
+	Ref<Image> img = p_image->duplicate();
+	if (img->detect_alpha()) {
+		img->convert(Image::FORMAT_RGBA8);
+	} else {
+		img->convert(Image::FORMAT_RGB8);
+	}
+
+	Size2 s(img->get_width(), img->get_height());
+	Vector<uint8_t> data = img->get_data();
+	const uint8_t *r = data.ptr();
+
+	// we need to use the more complex API in order to access the 'exact' flag...
+
+	WebPConfig config;
+	WebPPicture pic;
+	if (!WebPConfigInit(&config) || !WebPConfigLosslessPreset(&config, compression_level) || !WebPPictureInit(&pic)) {
+		ERR_FAIL_V(Vector<uint8_t>());
+	}
+
+	WebPMemoryWriter wrt;
+	config.exact = 1;
+	pic.use_argb = 1;
+	pic.width = s.width;
+	pic.height = s.height;
+	pic.writer = WebPMemoryWrite;
+	pic.custom_ptr = &wrt;
+	WebPMemoryWriterInit(&wrt);
+
+	bool success_import = false;
+	if (img->get_format() == Image::FORMAT_RGB8) {
+		success_import = WebPPictureImportRGB(&pic, r, 3 * s.width);
+	} else {
+		success_import = WebPPictureImportRGBA(&pic, r, 4 * s.width);
+	}
+	bool success_encode = false;
+	if (success_import) {
+		success_encode = WebPEncode(&config, &pic);
+	}
+	WebPPictureFree(&pic);
+
+	if (!success_encode) {
+		WebPMemoryWriterClear(&wrt);
+		ERR_FAIL_V_MSG(Vector<uint8_t>(), "WebP packing failed.");
+	}
+
+	// copy from wrt
+	Vector<uint8_t> dst;
+	dst.resize(4 + wrt.size);
+	uint8_t *w = dst.ptrw();
+	w[0] = 'W';
+	w[1] = 'E';
+	w[2] = 'B';
+	w[3] = 'P';
+	memcpy(&w[4], wrt.mem, wrt.size);
+	WebPMemoryWriterClear(&wrt);
+
+	return dst;
+}
+
+static Ref<Image> _webp_unpack(const Vector<uint8_t> &p_buffer) {
 	int size = p_buffer.size() - 4;
 	ERR_FAIL_COND_V(size <= 0, Ref<Image>());
 	const uint8_t *r = p_buffer.ptr();
@@ -168,6 +234,7 @@ void ImageLoaderWEBP::get_recognized_extensions(List<String> *p_extensions) cons
 
 ImageLoaderWEBP::ImageLoaderWEBP() {
 	Image::_webp_mem_loader_func = _webp_mem_loader_func;
-	Image::lossy_packer = _webp_lossy_pack;
-	Image::lossy_unpacker = _webp_lossy_unpack;
+	Image::webp_lossy_packer = _webp_lossy_pack;
+	Image::webp_lossless_packer = _webp_lossless_pack;
+	Image::webp_unpacker = _webp_unpack;
 }
diff --git a/scene/resources/texture.cpp b/scene/resources/texture.cpp
index 4475179431..064563d4b5 100644
--- a/scene/resources/texture.cpp
+++ b/scene/resources/texture.cpp
@@ -327,7 +327,7 @@ Ref<Image> StreamTexture2D::load_image_from_file(FileAccess *f, int p_size_limit
 	uint32_t mipmaps = f->get_32();
 	Image::Format format = Image::Format(f->get_32());
 
-	if (data_format == DATA_FORMAT_LOSSLESS || data_format == DATA_FORMAT_LOSSY || data_format == DATA_FORMAT_BASIS_UNIVERSAL) {
+	if (data_format == DATA_FORMAT_PNG || data_format == DATA_FORMAT_WEBP || data_format == DATA_FORMAT_BASIS_UNIVERSAL) {
 		//look for a PNG or WEBP file inside
 
 		int sw = w;
@@ -360,10 +360,10 @@ Ref<Image> StreamTexture2D::load_image_from_file(FileAccess *f, int p_size_limit
 			Ref<Image> img;
 			if (data_format == DATA_FORMAT_BASIS_UNIVERSAL) {
 				img = Image::basis_universal_unpacker(pv);
-			} else if (data_format == DATA_FORMAT_LOSSLESS) {
-				img = Image::lossless_unpacker(pv);
+			} else if (data_format == DATA_FORMAT_PNG) {
+				img = Image::png_unpacker(pv);
 			} else {
-				img = Image::lossy_unpacker(pv);
+				img = Image::webp_unpacker(pv);
 			}
 
 			if (img.is_null() || img->is_empty()) {
diff --git a/scene/resources/texture.h b/scene/resources/texture.h
index df8c00f8ff..95e960b5a5 100644
--- a/scene/resources/texture.h
+++ b/scene/resources/texture.h
@@ -136,8 +136,8 @@ class StreamTexture2D : public Texture2D {
 public:
 	enum DataFormat {
 		DATA_FORMAT_IMAGE,
-		DATA_FORMAT_LOSSLESS,
-		DATA_FORMAT_LOSSY,
+		DATA_FORMAT_PNG,
+		DATA_FORMAT_WEBP,
 		DATA_FORMAT_BASIS_UNIVERSAL,
 	};
 
@@ -146,9 +146,6 @@ public:
 	};
 
 	enum FormatBits {
-		FORMAT_MASK_IMAGE_FORMAT = (1 << 20) - 1,
-		FORMAT_BIT_LOSSLESS = 1 << 20,
-		FORMAT_BIT_LOSSY = 1 << 21,
 		FORMAT_BIT_STREAM = 1 << 22,
 		FORMAT_BIT_HAS_MIPMAPS = 1 << 23,
 		FORMAT_BIT_DETECT_3D = 1 << 24,
@@ -389,8 +386,8 @@ class StreamTextureLayered : public TextureLayered {
 public:
 	enum DataFormat {
 		DATA_FORMAT_IMAGE,
-		DATA_FORMAT_LOSSLESS,
-		DATA_FORMAT_LOSSY,
+		DATA_FORMAT_PNG,
+		DATA_FORMAT_WEBP,
 		DATA_FORMAT_BASIS_UNIVERSAL,
 	};
 
@@ -399,9 +396,6 @@ public:
 	};
 
 	enum FormatBits {
-		FORMAT_MASK_IMAGE_FORMAT = (1 << 20) - 1,
-		FORMAT_BIT_LOSSLESS = 1 << 20,
-		FORMAT_BIT_LOSSY = 1 << 21,
 		FORMAT_BIT_STREAM = 1 << 22,
 		FORMAT_BIT_HAS_MIPMAPS = 1 << 23,
 	};
@@ -532,8 +526,8 @@ class StreamTexture3D : public Texture3D {
 public:
 	enum DataFormat {
 		DATA_FORMAT_IMAGE,
-		DATA_FORMAT_LOSSLESS,
-		DATA_FORMAT_LOSSY,
+		DATA_FORMAT_PNG,
+		DATA_FORMAT_WEBP,
 		DATA_FORMAT_BASIS_UNIVERSAL,
 	};
 
@@ -542,9 +536,6 @@ public:
 	};
 
 	enum FormatBits {
-		FORMAT_MASK_IMAGE_FORMAT = (1 << 20) - 1,
-		FORMAT_BIT_LOSSLESS = 1 << 20,
-		FORMAT_BIT_LOSSY = 1 << 21,
 		FORMAT_BIT_STREAM = 1 << 22,
 		FORMAT_BIT_HAS_MIPMAPS = 1 << 23,
 	};
diff --git a/servers/rendering_server.cpp b/servers/rendering_server.cpp
index 4741e90a81..349330afd1 100644
--- a/servers/rendering_server.cpp
+++ b/servers/rendering_server.cpp
@@ -2282,6 +2282,10 @@ RenderingServer::RenderingServer() {
 	GLOBAL_DEF_RST("rendering/textures/vram_compression/import_etc2", true);
 	GLOBAL_DEF_RST("rendering/textures/vram_compression/import_pvrtc", false);
 
+	GLOBAL_DEF("rendering/textures/lossless_compression/force_png", false);
+	GLOBAL_DEF("rendering/textures/lossless_compression/webp_compression_level", 2);
+	ProjectSettings::get_singleton()->set_custom_property_info("rendering/textures/lossless_compression/webp_compression_level", PropertyInfo(Variant::INT, "rendering/textures/lossless_compression/webp_compression_level", PROPERTY_HINT_RANGE, "0,9,1"));
+
 	GLOBAL_DEF("rendering/limits/time/time_rollover_secs", 3600);
 	ProjectSettings::get_singleton()->set_custom_property_info("rendering/limits/time/time_rollover_secs", PropertyInfo(Variant::FLOAT, "rendering/limits/time/time_rollover_secs", PROPERTY_HINT_RANGE, "0,10000,1,or_greater"));