AppImage: Add script for generating AppImages with desktop integration

appimage/duckstation-qt.desktop

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+[Desktop Entry]
+Type=Application
+Name=DuckStation Qt
+GenericName=PlayStation 1 Emulator
+Comment=Fast-ish PlayStation 1 emulator
+Icon=duckstation-qt
+TryExec=duckstation-qt
+Exec=duckstation-qt %f
+Terminal=true
+Categories=Game;Emulator;Qt;

appimage/duckstation-sdl.desktop

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+[Desktop Entry]
+Type=Application
+Name=DuckStation SDL
+GenericName=PlayStation 1 Emulator
+Comment=Fast-ish PlayStation 1 emulator
+Icon=duckstation-sdl
+TryExec=duckstation-sdl
+Exec=duckstation-sdl %f
+Terminal=true
+Categories=Game;Emulator;

appimage/generate-appimages.sh

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+#!/bin/bash
+
+function get_tools_and_plugins() {
+  wget https://github.com/linuxdeploy/linuxdeploy/releases/download/continuous/linuxdeploy-x86_64.AppImage
+  chmod a+x linuxdeploy-x86_64.AppImage
+  wget https://github.com/linuxdeploy/linuxdeploy-plugin-qt/releases/download/continuous/linuxdeploy-plugin-qt-x86_64.AppImage
+  chmod a+x linuxdeploy-plugin-qt-x86_64.AppImage
+}
+
+# NOTE: Keep this script in the same directory as resources for AppImage creation
+APPIMAGE_RESOURCES_DIR=$(dirname $(readlink -f $0))
+echo "APPIMAGE_RESOURCES_DIR set to ${APPIMAGE_RESOURCES_DIR}"
+
+if [[ "$#" -ne 1 ]]; then
+  echo "Wrong number of arguments (\$# = $# args) provided."
+  echo "Usage: create-appimage.sh <build_directory_path>"
+  exit 1
+else
+  BUILD_DIR=$1
+  echo "BUILD_DIR set to ${BUILD_DIR}"
+fi
+
+# Acquire linuxdeploy and linuxdeploy-plugin-qt
+get_tools_and_plugins
+
+# Copy icons into the <resolution>/<app_name>.<ext> directory structure that linuxdeploy nominally expects,
+# e.g. 16x16/duckstation-qt.png, 32x32/duckstation-qt.png, etc.
+FRONTENDS=("qt" "sdl")
+ICONS_QT=()
+ICONS_SDL=()
+
+ICON_PNG_RESOLUTIONS=($(seq 16 16 64)) # 16, 32, 48, 64
+for res in ${ICON_PNG_RESOLUTIONS[@]}; do
+  mkdir -p ${BUILD_DIR}/AppImage-icons/${res}x${res}
+  for frontend in ${FRONTENDS[@]}; do
+    # Copy icon to proper directory
+    cp ${APPIMAGE_RESOURCES_DIR}/icon-${res}px.png ${BUILD_DIR}/AppImage-icons/${res}x${res}/duckstation-${frontend}.png
+    # Append icon filepath to array that will later be passed to linuxdeploy
+    eval "ICONS_${frontend^^}+=(${BUILD_DIR}/AppImage-icons/${res}x${res}/duckstation-${frontend}.png)"
+  done
+done
+
+# Outputted file from linuxdeploy is named based on the .desktop file Name key;
+# We rename it to something generic that buildbot or CI scripts can modify
+# as they wish outside of this script, e.g. to distinguish between Release or
+# Debug builds, since we don't have awareness of that inside this script
+
+./linuxdeploy-x86_64.AppImage --appdir=./AppDir-duckstation-qt \
+  --executable=${BUILD_DIR}/src/duckstation-qt/duckstation-qt \
+  --desktop-file=${APPIMAGE_RESOURCES_DIR}/duckstation-qt.desktop \
+  ${ICONS_QT[@]/#/--icon-file=} \
+  --plugin=qt \
+  --output=appimage \
+  && mv DuckStation_Qt*.AppImage duckstation-qt-x64.AppImage
+
+./linuxdeploy-x86_64.AppImage --appdir=./AppDir-duckstation-sdl \
+  --executable=${BUILD_DIR}/src/duckstation-sdl/duckstation-sdl \
+  --desktop-file=${APPIMAGE_RESOURCES_DIR}/duckstation-sdl.desktop \
+  ${ICONS_SDL[@]/#/--icon-file=} \
+  --output=appimage \
+  && mv DuckStation_SDL*.AppImage duckstation-sdl-x64.AppImage
+
+# Resulting AppImage files will be located in the directory this script is called from