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

remove unnecessary conversion

src/core/CMakeLists.txt

@@ -102,6 +102,7 @@ add_library(core STATIC
     frontend/emu_window.h
     frontend/framebuffer_layout.cpp
     frontend/framebuffer_layout.h
+    frontend/image_interface.h
     frontend/input.h
     frontend/mic.h
     frontend/mic.cpp
@@ -460,7 +461,7 @@ endif()
 create_target_directory_groups(core)
 
 target_link_libraries(core PUBLIC common PRIVATE audio_core network video_core)
-target_link_libraries(core PUBLIC Boost::boost PRIVATE cryptopp fmt open_source_archives lodepng)
+target_link_libraries(core PUBLIC Boost::boost PRIVATE cryptopp fmt open_source_archives)
 if (ENABLE_WEB_SERVICE)
     target_compile_definitions(core PRIVATE -DENABLE_WEB_SERVICE)
     target_link_libraries(core PRIVATE web_service)

src/core/core.cpp

@@ -4,7 +4,6 @@
 
 #include <memory>
 #include <utility>
-#include <lodepng.h>
 #include "audio_core/dsp_interface.h"
 #include "audio_core/hle/hle.h"
 #include "audio_core/lle/lle.h"
@@ -126,15 +125,14 @@ void System::PreloadCustomTextures() {
                 u32 png_height;
                 std::vector<u8> decoded_png;
 
-                u32 lodepng_ret =
-                    lodepng::decode(decoded_png, png_width, png_height, file.physicalName);
-                if (lodepng_ret) {
-                    LOG_CRITICAL(Render_OpenGL, "Failed to preload custom texture: {}",
-                                 lodepng_error_text(lodepng_ret));
-                } else {
+                if (registered_image_interface->DecodePNG(decoded_png, png_width, png_height,
+                                                          file.physicalName)) {
                     LOG_INFO(Render_OpenGL, "Preloaded custom texture from {}", file.physicalName);
                     Common::FlipRGBA8Texture(decoded_png, png_width, png_height);
                     custom_tex_cache->CacheTexture(hash, decoded_png, png_width, png_height);
+                } else {
+                    // Error should be reported by frontend
+                    LOG_CRITICAL(Render_OpenGL, "Failed to preload custom texture");
                 }
             }
         }
@@ -404,6 +402,10 @@ void System::RegisterSoftwareKeyboard(std::shared_ptr<Frontend::SoftwareKeyboard
     registered_swkbd = std::move(swkbd);
 }
 
+void System::RegisterImageInterface(std::shared_ptr<Frontend::ImageInterface> image_interface) {
+    registered_image_interface = std::move(image_interface);
+}
+
 void System::Shutdown() {
     // Log last frame performance stats
     const auto perf_results = GetAndResetPerfStats();

src/core/core.h

@@ -10,6 +10,7 @@
 #include "core/custom_tex_cache.h"
 #include "core/frontend/applets/mii_selector.h"
 #include "core/frontend/applets/swkbd.h"
+#include "core/frontend/image_interface.h"
 #include "core/loader/loader.h"
 #include "core/memory.h"
 #include "core/perf_stats.h"
@@ -256,6 +257,14 @@ public:
         return registered_swkbd;
     }
 
+    /// Image interface
+
+    void RegisterImageInterface(std::shared_ptr<Frontend::ImageInterface> image_interface);
+
+    std::shared_ptr<Frontend::ImageInterface> GetImageInterface() const {
+        return registered_image_interface;
+    }
+
 private:
     /**
      * Initialize the emulated system.
@@ -300,6 +309,9 @@ private:
     /// Custom texture cache system
     std::unique_ptr<Core::CustomTexCache> custom_tex_cache;
 
+    /// Image interface
+    std::shared_ptr<Frontend::ImageInterface> registered_image_interface;
+
     /// RPC Server for scripting support
     std::unique_ptr<RPC::RPCServer> rpc_server;
 

src/core/custom_tex_cache.cpp

@@ -8,9 +8,9 @@
 #include "custom_tex_cache.h"
 
 namespace Core {
-CustomTexCache::CustomTexCache() {}
+CustomTexCache::CustomTexCache() = default;
 
-CustomTexCache::~CustomTexCache() {}
+CustomTexCache::~CustomTexCache() = default;
 
 bool CustomTexCache::IsTextureDumped(u64 hash) const {
     return dumped_textures.find(hash) != dumped_textures.end();

src/core/frontend/image_interface.h

@@ -0,0 +1,28 @@
+// Copyright 2019 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <string>
+#include <vector>
+#include "common/common_types.h"
+#include "common/logging/log.h"
+
+namespace Frontend {
+
+class ImageInterface {
+public:
+    // Error logging should be handled by the frontend
+    virtual bool DecodePNG(std::vector<u8>& dst, u32& width, u32& height, const std::string& path) {
+        LOG_CRITICAL(Frontend, "Attempted to decode PNG without an image interface!");
+        return false;
+    };
+    virtual bool EncodePNG(const std::string& path, const std::vector<u8>& src, u32 width,
+                           u32 height) {
+        LOG_CRITICAL(Frontend, "Attempted to encode PNG without an image interface!");
+        return false;
+    };
+};
+
+} // namespace Frontend