diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
new file mode 100644
index 0000000..5d67bd8
--- /dev/null
+++ b/.github/workflows/ci.yml
@@ -0,0 +1,228 @@
+name: CI
+
+on:
+  push:
+  pull_request:
+
+jobs:
+  build-on-ubuntu1804:
+    runs-on: ubuntu-18.04
+    env:
+      RUNS_ON: ubuntu1804
+      GH_WORKSPACE: /home/runner/work/SolTrace/SolTrace #= $GITHUB_WORKSPACE
+    steps:
+    - name: Install OS dependencies
+      run: |
+        sudo apt-get update
+        sudo apt-get install -y \
+          build-essential \
+          cmake \
+          freeglut3-dev \
+          g++ \
+          libcurl4-openssl-dev \
+          libfontconfig-dev \
+          libgl1-mesa-dev \
+          libgtk2.0-dev \
+          mesa-common-dev \
+          unzip
+    - name: Get GCC version
+      run: gcc --version
+    - name: Get libc version
+      run: ldd --version
+
+    - name: Install wxWidgets
+      run: |
+        sudo apt-get install -y libwxgtk*-dev
+        sudo ln -s $(which wx-config) /usr/local/bin/wx-config-3
+        wx-config-3 --cflags | grep I
+
+    - name: Get git ref of sibling dependency LK
+      run: |
+        ref=$(git ls-remote --exit-code git://github.com/NREL/lk.git refs/heads/develop | awk '{print $1}')
+        echo "ref_of_lk=$ref" | tee --append $GITHUB_ENV
+    - name: Get cached build data of sibling dependency LK
+      uses: actions/cache@v2
+      id: cachedlk
+      with:
+        path: ${{ env.GH_WORKSPACE }}/lk
+        key: ${{ env.RUNS_ON }}-${{ env.ref_of_lk }}-LK
+    - name: Clone sibling dependency LK
+      if: steps.cachedlk.outputs.cache-hit != 'true'
+      uses: actions/checkout@v2
+      with:
+        ref: ${{ env.ref_of_lk }}
+        path: lk
+        repository: NREL/lk
+    - name: Build LK
+      if: steps.cachedlk.outputs.cache-hit != 'true'
+      run: |
+        cd $GITHUB_WORKSPACE/lk
+        cmake -Bbuild_linux -DCMAKE_BUILD_TYPE=Debug
+        cmake --build build_linux -- -j
+    - name: Set LKDIR and LKD_LIB envs
+      run: |
+        echo "LKDIR=$GITHUB_WORKSPACE/lk" >>$GITHUB_ENV
+        echo "LKD_LIB=$GITHUB_WORKSPACE/lk/build_linux" >>$GITHUB_ENV # iff CMAKE_BUILD_TYPE=Debug
+
+    - name: Get git ref of sibling dependency WEX
+      run: |
+        ref=$(git ls-remote --exit-code git://github.com/NREL/wex.git refs/heads/develop | awk '{print $1}')
+        echo "ref_of_wex=$ref" | tee --append $GITHUB_ENV
+    - name: Get cached build data of sibling dependency WEX
+      uses: actions/cache@v2
+      id: cachedwex
+      with:
+        path: ${{ env.GH_WORKSPACE }}/wex
+        key: ${{ env.RUNS_ON }}-${{ env.ref_of_wex }}-WEX
+    - name: Clone sibling dependency WEX
+      if: steps.cachedwex.outputs.cache-hit != 'true'
+      uses: actions/checkout@v2
+      with:
+        ref: ${{ env.ref_of_wex }}
+        path: wex
+        repository: NREL/wex
+    - name: Build WEX
+      if: steps.cachedwex.outputs.cache-hit != 'true'
+      run: |
+        cd $GITHUB_WORKSPACE/wex
+        cmake -Bbuild_linux -DCMAKE_BUILD_TYPE=Debug
+        cmake --build build_linux
+    - name: Set WEXDIR env
+      run: echo "WEXDIR=$GITHUB_WORKSPACE/wex/build_linux" >>$GITHUB_ENV
+
+    - name: Checkout
+      uses: actions/checkout@v2
+      with:
+        path: SolTrace
+
+    - name: Build coretrace
+      run: |
+        cd $GITHUB_WORKSPACE/SolTrace/coretrace/build_linux
+        make -j
+
+    - name: Set app-specific envs
+      run: |
+        echo "WEXDIR=$GITHUB_WORKSPACE/wex" >>$GITHUB_ENV
+        echo "WEXLIB=$GITHUB_WORKSPACE/wex/build_linux/wexd.a" >>$GITHUB_ENV # iff CMAKE_BUILD_TYPE=Debug
+        echo "LKLIB=$GITHUB_WORKSPACE/lk/build_linux/lkd.a"    >>$GITHUB_ENV # iff CMAKE_BUILD_TYPE=Debug
+    - name: Build desktop app
+      run: |
+        cd $GITHUB_WORKSPACE/SolTrace/app/build_linux
+        make -j
+
+    - name: Save soltrace
+      uses: actions/upload-artifact@v2
+      with:
+        name: soltrace-${{ env.RUNS_ON }}-x86_64
+        path: ${{ env.GH_WORKSPACE }}/SolTrace/app/deploy/linux_64/soltrace
+
+  build-on-ubuntu2004:
+    runs-on: ubuntu-20.04
+    env:
+      RUNS_ON: ubuntu2004
+      GH_WORKSPACE: /home/runner/work/SolTrace/SolTrace #= $GITHUB_WORKSPACE
+    steps:
+    - name: Install OS dependencies
+      run: |
+        sudo apt-get update
+        sudo apt-get install -y \
+          build-essential \
+          cmake \
+          freeglut3-dev \
+          g++ \
+          libcurl4-openssl-dev \
+          libfontconfig-dev \
+          libgl1-mesa-dev \
+          libgtk2.0-dev \
+          mesa-common-dev \
+          unzip
+    - name: Get GCC version
+      run: gcc --version
+    - name: Get libc version
+      run: ldd --version
+
+    - name: Install wxWidgets
+      run: |
+        sudo apt-get install -y libwxgtk*-dev
+        sudo ln -s $(which wx-config) /usr/local/bin/wx-config-3
+        wx-config-3 --cflags | grep I
+
+    - name: Get git ref of sibling dependency LK
+      run: |
+        ref=$(git ls-remote --exit-code git://github.com/NREL/lk.git refs/heads/develop | awk '{print $1}')
+        echo "ref_of_lk=$ref" | tee --append $GITHUB_ENV
+    - name: Get cached build data of sibling dependency LK
+      uses: actions/cache@v2
+      id: cachedlk
+      with:
+        path: ${{ env.GH_WORKSPACE }}/lk
+        key: ${{ env.RUNS_ON }}-${{ env.ref_of_lk }}-LK
+    - name: Clone sibling dependency LK
+      if: steps.cachedlk.outputs.cache-hit != 'true'
+      uses: actions/checkout@v2
+      with:
+        ref: ${{ env.ref_of_lk }}
+        path: lk
+        repository: NREL/lk
+    - name: Build LK
+      if: steps.cachedlk.outputs.cache-hit != 'true'
+      run: |
+        cd $GITHUB_WORKSPACE/lk
+        cmake -Bbuild_linux -DCMAKE_BUILD_TYPE=Debug
+        cmake --build build_linux -- -j
+    - name: Set LKDIR and LKD_LIB envs
+      run: |
+        echo "LKDIR=$GITHUB_WORKSPACE/lk" >>$GITHUB_ENV
+        echo "LKD_LIB=$GITHUB_WORKSPACE/lk/build_linux" >>$GITHUB_ENV # iff CMAKE_BUILD_TYPE=Debug
+
+    - name: Get git ref of sibling dependency WEX
+      run: |
+        ref=$(git ls-remote --exit-code git://github.com/NREL/wex.git refs/heads/develop | awk '{print $1}')
+        echo "ref_of_wex=$ref" | tee --append $GITHUB_ENV
+    - name: Get cached build data of sibling dependency WEX
+      uses: actions/cache@v2
+      id: cachedwex
+      with:
+        path: ${{ env.GH_WORKSPACE }}/wex
+        key: ${{ env.RUNS_ON }}-${{ env.ref_of_wex }}-WEX
+    - name: Clone sibling dependency WEX
+      if: steps.cachedwex.outputs.cache-hit != 'true'
+      uses: actions/checkout@v2
+      with:
+        ref: ${{ env.ref_of_wex }}
+        path: wex
+        repository: NREL/wex
+    - name: Build WEX
+      if: steps.cachedwex.outputs.cache-hit != 'true'
+      run: |
+        cd $GITHUB_WORKSPACE/wex
+        cmake -Bbuild_linux -DCMAKE_BUILD_TYPE=Debug
+        cmake --build build_linux
+    - name: Set WEXDIR env
+      run: echo "WEXDIR=$GITHUB_WORKSPACE/wex/build_linux" >>$GITHUB_ENV
+
+    - name: Checkout
+      uses: actions/checkout@v2
+      with:
+        path: SolTrace
+
+    - name: Build coretrace
+      run: |
+        cd $GITHUB_WORKSPACE/SolTrace/coretrace/build_linux
+        make -j
+
+    - name: Set app-specific envs
+      run: |
+        echo "WEXDIR=$GITHUB_WORKSPACE/wex" >>$GITHUB_ENV
+        echo "WEXLIB=$GITHUB_WORKSPACE/wex/build_linux/wexd.a" >>$GITHUB_ENV # iff CMAKE_BUILD_TYPE=Debug
+        echo "LKLIB=$GITHUB_WORKSPACE/lk/build_linux/lkd.a"    >>$GITHUB_ENV # iff CMAKE_BUILD_TYPE=Debug
+    - name: Build desktop app
+      run: |
+        cd $GITHUB_WORKSPACE/SolTrace/app/build_linux
+        make -j
+
+    - name: Save soltrace
+      uses: actions/upload-artifact@v2
+      with:
+        name: soltrace-${{ env.RUNS_ON }}-x86_64
+        path: ${{ env.GH_WORKSPACE }}/SolTrace/app/deploy/linux_64/soltrace
diff --git a/app/build_linux/Makefile-ui b/app/build_linux/Makefile-ui
index eafc28c..beac1a4 100644
--- a/app/build_linux/Makefile-ui
+++ b/app/build_linux/Makefile-ui
@@ -1,10 +1,10 @@
 VPATH = ../src/
 
 
-WEXDIR = ../../../wex
-WEXLIB = $(WEXDIR)/build/wex.a
-LKDIR = ../../../lk
-LKLIB = $(LKDIR)/build/lk.a
+WEXDIR ?= ../../../wex
+WEXLIB ?= $(WEXDIR)/build/wex.a
+LKDIR ?= ../../../lk
+LKLIB ?= $(LKDIR)/build/lk.a
 CORETRACEDIR = ../../coretrace
 CORETRACELIB = $(CORETRACEDIR)/build_linux/coretrace.a
 
@@ -14,7 +14,7 @@ CXX = g++
 CFLAGS = -g -O2 -std=c++11 -I. -I$(LKDIR)/include -I$(WEXDIR)/include -I$(CORETRACEDIR) -DLK_USE_WXWIDGETS `wx-config-3 --cflags`
 
 CXXFLAGS = $(CFLAGS)
-LDFLAGS =  $(WEXLIB) $(LKLIB) $(CORETRACELIB) `wx-config-3 --libs stc` `wx-config-3 --libs aui` `wx-config-3 --libs gl` `wx-config-3 --libs` -lm -lcurl  -lfontconfig -ldl 
+LDFLAGS =  $(WEXLIB) $(LKLIB) $(CORETRACELIB) `wx-config-3 --libs stc` `wx-config-3 --libs aui` `wx-config-3 --libs gl` -lGL `wx-config-3 --libs` -lm -lcurl  -lfontconfig -ldl 
 
 
 OBJECTS = \