From d195789abdf88ccc56780797be4db06793f92c2b Mon Sep 17 00:00:00 2001
From: "Reed A. Cartwright" <cartwright@asu.edu>
Date: Sun, 11 Apr 2021 22:05:48 -0700
Subject: [PATCH] Implement MainActivity::getImageData (merged from
 feature-jnivm branch)

---
 src/jni/jni_descriptors.cpp |  1 +
 src/jni/jni_support.cpp     |  6 +++++-
 src/jni/jni_support.h       |  3 ++-
 src/jni/main_activity.cpp   | 23 +++++++++++++++++++++++
 src/jni/main_activity.h     |  7 ++++++-
 src/main.cpp                |  4 +++-
 6 files changed, 40 insertions(+), 4 deletions(-)

diff --git a/src/jni/jni_descriptors.cpp b/src/jni/jni_descriptors.cpp
index 83a57f2b..31c15b90 100644
--- a/src/jni/jni_descriptors.cpp
+++ b/src/jni/jni_descriptors.cpp
@@ -106,6 +106,7 @@ BEGIN_NATIVE_DESCRIPTOR(MainActivity)
 // {Function<&MainActivity::getSecureStorageKey> {}, "getSecureStorageKey"},
 {Function<&MainActivity::lockCursor> {}, "lockCursor"},
 {Function<&MainActivity::unlockCursor> {}, "unlockCursor"},
+{Function<&MainActivity::getImageData> {}, "getImageData"},
 END_NATIVE_DESCRIPTOR
 
 BEGIN_NATIVE_DESCRIPTOR(AccountManager)
diff --git a/src/jni/jni_support.cpp b/src/jni/jni_support.cpp
index 820df4a7..e90766aa 100644
--- a/src/jni/jni_support.cpp
+++ b/src/jni/jni_support.cpp
@@ -148,7 +148,8 @@ void JniSupport::registerNatives(std::shared_ptr<FakeJni::JClass const> clazz,
         throw std::runtime_error("RegisterNatives failed");
 }
 
-void JniSupport::startGame(ANativeActivity_createFunc *activityOnCreate) {
+void JniSupport::startGame(ANativeActivity_createFunc *activityOnCreate,
+        void *stbiLoadFromMemory, void *stbiImageFree) {
     FakeJni::LocalFrame frame (vm);
 
     vm.attachLibrary("libfmod.so", "", {linker::dlopen, linker::dlsym, linker::dlclose_unlocked});
@@ -167,6 +168,9 @@ void JniSupport::startGame(ANativeActivity_createFunc *activityOnCreate) {
     activity->textInput = &textInput;
     activity->quitCallback = [this]() { requestExitGame(); };
     activity->storageDirectory = PathHelper::getPrimaryDataDirectory();
+    activity->stbi_load_from_memory = (decltype(activity->stbi_load_from_memory)) stbiLoadFromMemory;
+    activity->stbi_image_free = (decltype(activity->stbi_image_free)) stbiImageFree;
+
     assetManager = std::make_unique<FakeAssetManager>(PathHelper::getGameDir() + "/assets");
 
     XboxLiveHelper::getInstance().setJvm(&vm);
diff --git a/src/jni/jni_support.h b/src/jni/jni_support.h
index 2a12b840..d61d4b34 100644
--- a/src/jni/jni_support.h
+++ b/src/jni/jni_support.h
@@ -41,7 +41,8 @@ struct JniSupport {
 
     void registerMinecraftNatives(void *(*symResolver)(const char *));
 
-    void startGame(ANativeActivity_createFunc *activityOnCreate);
+    void startGame(ANativeActivity_createFunc *activityOnCreate,
+        void *stbiLoadFromMemory, void *stbiImageFree);
 
     void stopGame();
 
diff --git a/src/jni/main_activity.cpp b/src/jni/main_activity.cpp
index 74466613..640e3f97 100644
--- a/src/jni/main_activity.cpp
+++ b/src/jni/main_activity.cpp
@@ -10,6 +10,8 @@
 #include <file_picker_factory.h>
 #include <game_window_manager.h>
 #include "uuid.h"
+#include <climits>
+#include <sstream>
 
 FakeJni::JInt BuildVersion::SDK_INT = 27;
 std::shared_ptr<FakeJni::JString> BuildVersion::RELEASE = std::make_shared<FakeJni::JString>("AndroidX");
@@ -113,3 +115,24 @@ void MainActivity::initializeXboxLive(FakeJni::JLong xalinit, FakeJni::JLong xbl
     FakeJni::LocalFrame frame;
     method->invoke(frame.getJniEnv(), this, xalinit, xblinit);
 }
+
+std::shared_ptr<FakeJni::JIntArray> MainActivity::getImageData(std::shared_ptr<FakeJni::JString> filename) {
+    if(!stbi_load_from_memory || !stbi_image_free) return 0;
+    int width, height, channels;
+    std::ifstream f(filename->asStdString().data());
+    if(!f.is_open()) return 0;
+    std::stringstream s;
+    s << f.rdbuf();
+    auto buf = s.str();
+    auto image = stbi_load_from_memory((unsigned char*)buf.data(), buf.length(), &width, &height, &channels, 4);
+    if(!image) return 0;
+    auto ret = std::make_shared<FakeJni::JIntArray>(2 + width * height);
+    (*ret)[0] = width;
+    (*ret)[1] = height;
+
+    for(int x = 0; x < width * height; x++) {
+        (*ret)[2 + x] = (image[x * 4 + 2]) | (image[x * 4 + 1] << 8) | (image[x * 4 + 0] << 16) | (image[x * 4 + 3] << 24);
+    }
+    stbi_image_free(image);
+    return ret;
+} 
\ No newline at end of file
diff --git a/src/jni/main_activity.h b/src/jni/main_activity.h
index 65f53eaf..858fefa6 100644
--- a/src/jni/main_activity.h
+++ b/src/jni/main_activity.h
@@ -99,13 +99,16 @@ class HardwareInfo : public FakeJni::JObject {
     }
 
 };
-
+#include <fstream>
 class MainActivity : public NativeActivity {
 
 private:
     bool ignoreNextHideKeyboard = false;
 
 public:
+    unsigned char* (*stbi_load_from_memory)(unsigned char const *buffer, int len, int *x, int *y, int *channels_in_file, int desired_channels);
+    void (*stbi_image_free)(void *retval_from_stbi_load);
+
     DEFINE_CLASS_NAME("com/mojang/minecraftpe/MainActivity", NativeActivity)
 
     std::string storageDirectory;
@@ -213,6 +216,8 @@ class MainActivity : public NativeActivity {
     void pickImage(FakeJni::JLong callback);
 
     void initializeXboxLive(FakeJni::JLong xalinit, FakeJni::JLong xblinit);
+
+    std::shared_ptr<FakeJni::JIntArray> getImageData(std::shared_ptr<FakeJni::JString> filename);
 };
 
 class JellyBeanDeviceManager : public FakeJni::JObject {
diff --git a/src/main.cpp b/src/main.cpp
index bd129d91..93856973 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -171,7 +171,9 @@ int main(int argc, char *argv[]) {
         return linker::dlsym(handle, sym);
     });
     std::thread startThread([&support]() {
-        support.startGame((ANativeActivity_createFunc *) linker::dlsym(handle, "ANativeActivity_onCreate"));
+        support.startGame((ANativeActivity_createFunc *) linker::dlsym(handle, "ANativeActivity_onCreate"),
+            linker::dlsym(handle, "stbi_load_from_memory"),
+            linker::dlsym(handle, "stbi_image_free"));
         linker::dlclose(handle);
     });
     startThread.detach();