add webp support

src/image_loader_webp.cpp

@@ -0,0 +1,78 @@
+#include "./image_loader_webp.hpp"
+
+#include <webp/demux.h>
+#include <webp/mux.h>
+
+#include <cassert>
+
+ImageLoaderWebP::ImageInfo ImageLoaderWebP::loadInfoFromMemory(const uint8_t* data, uint64_t data_size) {
+	ImageInfo res;
+
+	WebPData webp_data;
+	WebPDataInit(&webp_data);
+	webp_data.bytes = data;
+	webp_data.size = data_size;
+
+	WebPAnimDecoderOptions dec_options;
+	WebPAnimDecoderOptionsInit(&dec_options);
+	// Tune 'dec_options' as needed.
+	dec_options.color_mode = MODE_RGBA;
+
+	WebPAnimDecoder* dec = WebPAnimDecoderNew(&webp_data, &dec_options);
+	if (dec == nullptr) {
+		return res;
+	}
+
+	WebPAnimInfo anim_info;
+	WebPAnimDecoderGetInfo(dec, &anim_info);
+	res.width = anim_info.canvas_width;
+	res.height = anim_info.canvas_height;
+
+	return res;
+}
+
+ImageLoaderWebP::ImageResult ImageLoaderWebP::loadFromMemoryRGBA(const uint8_t* data, uint64_t data_size) {
+	ImageResult res;
+
+	WebPData webp_data;
+	WebPDataInit(&webp_data);
+	webp_data.bytes = data;
+	webp_data.size = data_size;
+
+	WebPAnimDecoderOptions dec_options;
+	WebPAnimDecoderOptionsInit(&dec_options);
+	// Tune 'dec_options' as needed.
+	dec_options.color_mode = MODE_RGBA;
+
+	WebPAnimDecoder* dec = WebPAnimDecoderNew(&webp_data, &dec_options);
+	if (dec == nullptr) {
+		return res;
+	}
+
+	WebPAnimInfo anim_info;
+	WebPAnimDecoderGetInfo(dec, &anim_info);
+	res.width = anim_info.canvas_width;
+	res.height = anim_info.canvas_height;
+
+	int prev_timestamp = 0;
+	while (WebPAnimDecoderHasMoreFrames(dec)) {
+		uint8_t* buf;
+		int timestamp;
+		WebPAnimDecoderGetNext(dec, &buf, &timestamp);
+		// ... (Render 'buf' based on 'timestamp').
+		// ... (Do NOT free 'buf', as it is owned by 'dec').
+
+		// just be dumb and append
+		auto& new_frame = res.frames.emplace_back();
+		new_frame.ms = timestamp-prev_timestamp;
+		prev_timestamp = timestamp;
+		new_frame.data.insert(new_frame.data.end(), buf, buf+(res.width*res.height*4));
+	}
+
+	WebPAnimDecoderDelete(dec);
+
+	assert(anim_info.frame_count == res.frames.size());
+
+	return res;
+}
+