add image interface, remove lodepng from video_core/core, address more comments, fix comments

remove unnecessary conversion

src/citra/CMakeLists.txt

@@ -8,13 +8,15 @@ add_executable(citra
     default_ini.h
     emu_window/emu_window_sdl2.cpp
     emu_window/emu_window_sdl2.h
+    generic_image_interface.cpp
+    generic_image_interface.h
     resource.h
 )
 
 create_target_directory_groups(citra)
 
 target_link_libraries(citra PRIVATE common core input_common network)
-target_link_libraries(citra PRIVATE inih glad)
+target_link_libraries(citra PRIVATE inih glad lodepng)
 if (MSVC)
     target_link_libraries(citra PRIVATE getopt)
 endif()

src/citra/citra.cpp

@@ -40,6 +40,7 @@
 #include "core/loader/loader.h"
 #include "core/movie.h"
 #include "core/settings.h"
+#include "generic_image_interface.h"
 #include "network/network.h"
 #include "video_core/video_core.h"
 
@@ -342,6 +343,9 @@ int main(int argc, char** argv) {
     // Register frontend applets
     Frontend::RegisterDefaultApplets();
 
+    // Register generic image interface
+    Core::System::GetInstance().RegisterImageInterface(std::make_shared<GenericImageInterface>());
+
     std::unique_ptr<EmuWindow_SDL2> emu_window{std::make_unique<EmuWindow_SDL2>(fullscreen)};
 
     Core::System& system{Core::System::GetInstance()};

src/citra/generic_image_interface.cpp

@@ -0,0 +1,29 @@
+// Copyright 2019 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include <lodepng.h>
+#include "common/logging/log.h"
+#include "generic_image_interface.h"
+
+bool GenericImageInterface::DecodePNG(std::vector<u8>& dst, u32& width, u32& height,
+                                      const std::string& path) {
+    u32 lodepng_ret = lodepng::decode(dst, width, height, path);
+    if (lodepng_ret) {
+        LOG_CRITICAL(Frontend, "Failed to decode {} because {}", path,
+                     lodepng_error_text(lodepng_ret));
+        return false;
+    }
+    return true;
+}
+
+bool GenericImageInterface::EncodePNG(const std::string& path, const std::vector<u8>& src,
+                                      u32 width, u32 height) {
+    u32 lodepng_ret = lodepng::encode(path, src, width, height);
+    if (lodepng_ret) {
+        LOG_CRITICAL(Frontend, "Failed to encode {} because {}", path,
+                     lodepng_error_text(lodepng_ret));
+        return false;
+    }
+    return true;
+}

src/citra/generic_image_interface.h

@@ -0,0 +1,14 @@
+// Copyright 2019 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include "core/frontend/image_interface.h"
+
+class GenericImageInterface final : public Frontend::ImageInterface {
+public:
+    bool DecodePNG(std::vector<u8>& dst, u32& width, u32& height, const std::string& path) override;
+    bool EncodePNG(const std::string& path, const std::vector<u8>& src, u32 width,
+                   u32 height) override;
+};