diff --git a/services/camera/virtualcamera/Android.bp b/services/camera/virtualcamera/Android.bp
index 90530f6..fc186fb 100644
--- a/services/camera/virtualcamera/Android.bp
+++ b/services/camera/virtualcamera/Android.bp
@@ -50,7 +50,6 @@
         "util/JpegUtil.cc",
         "util/MetadataUtil.cc",
         "util/Util.cc",
-        "util/TestPatternHelper.cc",
         "util/EglDisplayContext.cc",
         "util/EglFramebuffer.cc",
         "util/EglProgram.cc",
@@ -72,6 +71,7 @@
         "VirtualCameraStream.cc",
         "VirtualCameraService.cc",
         "VirtualCameraSessionContext.cc",
+        "VirtualCameraTestInstance.cc",
         "VirtualCameraRenderThread.cc",
     ],
     defaults: [
diff --git a/services/camera/virtualcamera/VirtualCameraRenderThread.cc b/services/camera/virtualcamera/VirtualCameraRenderThread.cc
index f5cf092..a5ee922 100644
--- a/services/camera/virtualcamera/VirtualCameraRenderThread.cc
+++ b/services/camera/virtualcamera/VirtualCameraRenderThread.cc
@@ -51,7 +51,6 @@
 #include "util/EglFramebuffer.h"
 #include "util/JpegUtil.h"
 #include "util/MetadataUtil.h"
-#include "util/TestPatternHelper.h"
 #include "util/Util.h"
 #include "utils/Errors.h"
 
@@ -300,11 +299,10 @@
 VirtualCameraRenderThread::VirtualCameraRenderThread(
     VirtualCameraSessionContext& sessionContext,
     const Resolution inputSurfaceSize, const Resolution reportedSensorSize,
-    std::shared_ptr<ICameraDeviceCallback> cameraDeviceCallback, bool testMode)
+    std::shared_ptr<ICameraDeviceCallback> cameraDeviceCallback)
     : mCameraDeviceCallback(cameraDeviceCallback),
       mInputSurfaceSize(inputSurfaceSize),
       mReportedSensorSize(reportedSensorSize),
-      mTestMode(testMode),
       mSessionContext(sessionContext) {
 }
 
@@ -401,10 +399,6 @@
   mEglSurfaceTexture = std::make_unique<EglSurfaceTexture>(
       mInputSurfaceSize.width, mInputSurfaceSize.height);
 
-  sp<Surface> inputSurface = mEglSurfaceTexture->getSurface();
-  if (mTestMode) {
-    inputSurface->connect(NATIVE_WINDOW_API_CPU, false, nullptr);
-  }
   mInputSurfacePromise.set_value(mEglSurfaceTexture->getSurface());
 
   while (std::unique_ptr<ProcessCaptureRequestTask> task = dequeueTask()) {
@@ -422,12 +416,6 @@
 
 void VirtualCameraRenderThread::processCaptureRequest(
     const ProcessCaptureRequestTask& request) {
-  if (mTestMode) {
-    // In test mode let's just render something to the Surface ourselves.
-    renderTestPatternYCbCr420(mEglSurfaceTexture->getSurface(),
-                              request.getFrameNumber());
-  }
-
   std::chrono::nanoseconds timestamp =
       std::chrono::duration_cast<std::chrono::nanoseconds>(
           std::chrono::steady_clock::now().time_since_epoch());
diff --git a/services/camera/virtualcamera/VirtualCameraRenderThread.h b/services/camera/virtualcamera/VirtualCameraRenderThread.h
index dfb6f7b..ce8965f 100644
--- a/services/camera/virtualcamera/VirtualCameraRenderThread.h
+++ b/services/camera/virtualcamera/VirtualCameraRenderThread.h
@@ -111,8 +111,7 @@
       Resolution reportedSensorSize,
       std::shared_ptr<
           ::aidl::android::hardware::camera::device::ICameraDeviceCallback>
-          cameraDeviceCallback,
-      bool testMode = false);
+          cameraDeviceCallback);
 
   ~VirtualCameraRenderThread();
 
@@ -184,7 +183,6 @@
 
   const Resolution mInputSurfaceSize;
   const Resolution mReportedSensorSize;
-  const int mTestMode;
 
   VirtualCameraSessionContext& mSessionContext;
 
diff --git a/services/camera/virtualcamera/VirtualCameraService.cc b/services/camera/virtualcamera/VirtualCameraService.cc
index b5b07f0..b78f120 100644
--- a/services/camera/virtualcamera/VirtualCameraService.cc
+++ b/services/camera/virtualcamera/VirtualCameraService.cc
@@ -30,10 +30,12 @@
 
 #include "VirtualCameraDevice.h"
 #include "VirtualCameraProvider.h"
+#include "VirtualCameraTestInstance.h"
 #include "aidl/android/companion/virtualcamera/Format.h"
 #include "aidl/android/companion/virtualcamera/LensFacing.h"
 #include "aidl/android/companion/virtualcamera/VirtualCameraConfiguration.h"
 #include "android/binder_auto_utils.h"
+#include "android/binder_interface_utils.h"
 #include "android/binder_libbinder.h"
 #include "android/binder_status.h"
 #include "binder/Status.h"
@@ -64,6 +66,7 @@
 constexpr int kVgaWidth = 640;
 constexpr int kVgaHeight = 480;
 constexpr int kMaxFps = 60;
+constexpr int kTestCameraInputFps = 30;
 constexpr char kEnableTestCameraCmd[] = "enable_test_camera";
 constexpr char kDisableTestCameraCmd[] = "disable_test_camera";
 constexpr char kHelp[] = "help";
@@ -94,6 +97,13 @@
         Status::EX_ILLEGAL_ARGUMENT);
   }
 
+  if (configuration.virtualCameraCallback == nullptr) {
+    ALOGE("%s: Input configuration is missing virtual camera callback",
+          __func__);
+    return ndk::ScopedAStatus::fromServiceSpecificError(
+        Status::EX_ILLEGAL_ARGUMENT);
+  }
+
   for (const SupportedStreamConfiguration& config :
        configuration.supportedStreamConfigs) {
     if (!isFormatSupportedForInput(config.width, config.height,
@@ -418,9 +428,11 @@
   VirtualCameraConfiguration configuration;
   configuration.supportedStreamConfigs.push_back({.width = kVgaWidth,
                                                   .height = kVgaHeight,
-                                                  Format::YUV_420_888,
+                                                  Format::RGBA_8888,
                                                   .maxFps = kMaxFps});
   configuration.lensFacing = lensFacing.value_or(LensFacing::EXTERNAL);
+  configuration.virtualCameraCallback =
+      ndk::SharedRefBase::make<VirtualCameraTestInstance>(kTestCameraInputFps);
   registerCamera(mTestCameraToken, configuration, cameraId.value_or(sNextId++),
                  kDefaultDeviceId, &ret);
   if (ret) {
diff --git a/services/camera/virtualcamera/VirtualCameraSession.cc b/services/camera/virtualcamera/VirtualCameraSession.cc
index 28fa495..7f0adc3 100644
--- a/services/camera/virtualcamera/VirtualCameraSession.cc
+++ b/services/camera/virtualcamera/VirtualCameraSession.cc
@@ -66,7 +66,6 @@
 #include "util/EglProgram.h"
 #include "util/JpegUtil.h"
 #include "util/MetadataUtil.h"
-#include "util/TestPatternHelper.h"
 #include "util/Util.h"
 
 namespace android {
@@ -360,12 +359,9 @@
       return cameraStatus(Status::ILLEGAL_ARGUMENT);
     }
     if (mRenderThread == nullptr) {
-      // If there's no client callback, start camera in test mode.
-      const bool testMode = mVirtualCameraClientCallback == nullptr;
       mRenderThread = std::make_unique<VirtualCameraRenderThread>(
           mSessionContext, resolutionFromInputConfig(*inputConfig),
-          virtualCamera->getMaxInputResolution(), mCameraDeviceCallback,
-          testMode);
+          virtualCamera->getMaxInputResolution(), mCameraDeviceCallback);
       mRenderThread->start();
       inputSurface = mRenderThread->getInputSurface();
     }
diff --git a/services/camera/virtualcamera/VirtualCameraTestInstance.cc b/services/camera/virtualcamera/VirtualCameraTestInstance.cc
new file mode 100644
index 0000000..5e1d450
--- /dev/null
+++ b/services/camera/virtualcamera/VirtualCameraTestInstance.cc
@@ -0,0 +1,154 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// #define LOG_NDEBUG 0
+#define LOG_TAG "VirtualCameraTestInstance"
+
+#include "VirtualCameraTestInstance.h"
+
+#include <atomic>
+#include <chrono>
+#include <memory>
+#include <mutex>
+#include <ratio>
+#include <thread>
+
+#include "GLES/gl.h"
+#include "android/binder_auto_utils.h"
+#include "android/native_window.h"
+#include "log/log.h"
+#include "util/EglDisplayContext.h"
+#include "util/EglProgram.h"
+
+namespace android {
+namespace companion {
+namespace virtualcamera {
+
+using ::aidl::android::companion::virtualcamera::Format;
+using ::aidl::android::view::Surface;
+using ::ndk::ScopedAStatus;
+
+namespace {
+
+std::shared_ptr<ANativeWindow> nativeWindowFromSurface(const Surface& surface) {
+  ANativeWindow* nativeWindow = surface.get();
+  if (nativeWindow != nullptr) {
+    ANativeWindow_acquire(nativeWindow);
+  }
+  return std::shared_ptr<ANativeWindow>(nativeWindow, ANativeWindow_release);
+}
+
+std::chrono::nanoseconds getCurrentTimestamp() {
+  return std::chrono::duration_cast<std::chrono::nanoseconds>(
+      std::chrono::steady_clock::now().time_since_epoch());
+}
+
+}  // namespace
+
+TestPatternRenderer::TestPatternRenderer(
+    std::shared_ptr<ANativeWindow> nativeWindow, int fps)
+    : mFps(fps), mNativeWindow(nativeWindow) {
+}
+
+void TestPatternRenderer::start() {
+  std::lock_guard<std::mutex> lock(mLock);
+  if (mRunning.exchange(true, std::memory_order_relaxed)) {
+    ALOGW("Render thread already started.");
+    return;
+  }
+  mThread =
+      std::thread(&TestPatternRenderer::renderThreadLoop, this, mNativeWindow);
+}
+
+void TestPatternRenderer::stop() {
+  std::lock_guard<std::mutex> lock(mLock);
+  if (!mRunning.exchange(false, std::memory_order_relaxed)) {
+    ALOGW("Render thread already stopped.");
+    return;
+  }
+  mThread.detach();
+  mRunning = false;
+}
+
+void TestPatternRenderer::renderThreadLoop(
+    std::shared_ptr<ANativeWindow> nativeWindow) {
+  // Prevent destruction of this instance until the thread terminates.
+  std::shared_ptr<TestPatternRenderer> thiz = shared_from_this();
+
+  ALOGV("Starting test client render loop");
+
+  EglDisplayContext eglDisplayContext(nativeWindow);
+  EglTestPatternProgram testPatternProgram;
+
+  const std::chrono::nanoseconds frameDuration(
+      static_cast<uint64_t>(1e9 / mFps));
+
+  std::chrono::nanoseconds lastFrameTs(0);
+  int frameNumber = 0;
+  while (mRunning) {
+    // Wait for appropriate amount of time to meet configured FPS.
+    std::chrono::nanoseconds ts = getCurrentTimestamp();
+    std::chrono::nanoseconds currentDuration = ts - lastFrameTs;
+    if (currentDuration < frameDuration) {
+      std::this_thread::sleep_for(frameDuration - currentDuration);
+    }
+
+    // Render the test pattern and update timestamp.
+    testPatternProgram.draw(frameNumber++);
+    eglDisplayContext.swapBuffers();
+    lastFrameTs = getCurrentTimestamp();
+  }
+
+  ALOGV("Terminating test client render loop");
+}
+
+VirtualCameraTestInstance::VirtualCameraTestInstance(const int fps)
+    : mFps(fps) {
+}
+
+ScopedAStatus VirtualCameraTestInstance::onStreamConfigured(
+    const int32_t streamId, const Surface& surface, const int32_t width,
+    const int32_t height, const Format pixelFormat) {
+  ALOGV("%s: streamId %d, %dx%d pixFmt=%d", __func__, streamId, width, height,
+        pixelFormat);
+
+  std::lock_guard<std::mutex> lock(mLock);
+  mRenderer = std::make_shared<TestPatternRenderer>(
+      nativeWindowFromSurface(surface), mFps);
+  mRenderer->start();
+
+  return ScopedAStatus::ok();
+}
+
+ScopedAStatus VirtualCameraTestInstance::onProcessCaptureRequest(
+    const int32_t /*in_streamId*/, const int32_t /*in_frameId*/) {
+  return ScopedAStatus::ok();
+}
+
+ScopedAStatus VirtualCameraTestInstance::onStreamClosed(const int32_t streamId) {
+  ALOGV("%s: streamId %d", __func__, streamId);
+
+  std::lock_guard<std::mutex> lock(mLock);
+  if (mRenderer != nullptr) {
+    mRenderer->stop();
+    mRenderer.reset();
+  }
+  return ScopedAStatus::ok();
+}
+
+}  // namespace virtualcamera
+}  // namespace companion
+}  // namespace android
diff --git a/services/camera/virtualcamera/VirtualCameraTestInstance.h b/services/camera/virtualcamera/VirtualCameraTestInstance.h
new file mode 100644
index 0000000..43e33d5
--- /dev/null
+++ b/services/camera/virtualcamera/VirtualCameraTestInstance.h
@@ -0,0 +1,90 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#ifndef ANDROID_COMPANION_VIRTUALCAMERA_VIRTUALCAMERATESTINSTANCE_H
+#define ANDROID_COMPANION_VIRTUALCAMERA_VIRTUALCAMERATESTINSTANCE_H
+
+#include <atomic>
+#include <condition_variable>
+#include <memory>
+#include <thread>
+
+#include "aidl/android/companion/virtualcamera/BnVirtualCameraCallback.h"
+#include "android/native_window.h"
+#include "utils/Mutex.h"
+
+namespace android {
+namespace companion {
+namespace virtualcamera {
+
+// Wraps render loop run in a dedicated thread, rendering test pattern to
+// provided Surface (a.k.a. native window) at configured FPS.
+class TestPatternRenderer
+    : public std::enable_shared_from_this<TestPatternRenderer> {
+ public:
+  TestPatternRenderer(std::shared_ptr<ANativeWindow> nativeWindow, int fps);
+
+  // Start rendering.
+  void start() EXCLUDES(mLock);
+
+  // Stop rendering.
+  // Call returns immediatelly, render thread might take some time (1 frame)
+  // to finish rendering and terminate the thread.
+  void stop() EXCLUDES(mLock);
+
+ private:
+  // Render thread entry point.
+  void renderThreadLoop(std::shared_ptr<ANativeWindow> nativeWindow);
+
+  const int mFps;
+
+  std::shared_ptr<ANativeWindow> mNativeWindow;
+
+  std::mutex mLock;
+  std::atomic_bool mRunning;
+  std::thread mThread GUARDED_BY(mLock);
+};
+
+// VirtualCamera callback implementation for test camera.
+//
+// For every configure call, starts rendering of test pattern on provided surface.
+class VirtualCameraTestInstance
+    : public aidl::android::companion::virtualcamera::BnVirtualCameraCallback {
+ public:
+  explicit VirtualCameraTestInstance(int fps = 30);
+
+  ::ndk::ScopedAStatus onStreamConfigured(
+      int32_t streamId, const ::aidl::android::view::Surface& surface,
+      int32_t width, int32_t height,
+      ::aidl::android::companion::virtualcamera::Format pixelFormat) override
+      EXCLUDES(mLock);
+
+  ::ndk::ScopedAStatus onProcessCaptureRequest(int32_t in_streamId,
+                                               int32_t in_frameId) override;
+
+  ::ndk::ScopedAStatus onStreamClosed(int32_t streamId) override EXCLUDES(mLock);
+
+ private:
+  const int mFps;
+
+  std::mutex mLock;
+  std::shared_ptr<TestPatternRenderer> mRenderer GUARDED_BY(mLock);
+};
+
+}  // namespace virtualcamera
+}  // namespace companion
+}  // namespace android
+
+#endif  // ANDROID_COMPANION_VIRTUALCAMERA_VIRTUALCAMERATESTINSTANCE_H
diff --git a/services/camera/virtualcamera/tests/EglUtilTest.cc b/services/camera/virtualcamera/tests/EglUtilTest.cc
index 589e312..813be75 100644
--- a/services/camera/virtualcamera/tests/EglUtilTest.cc
+++ b/services/camera/virtualcamera/tests/EglUtilTest.cc
@@ -55,6 +55,11 @@
 };
 
 TEST_F(EglTest, EglTestPatternProgramSuccessfulInit) {
+  if (!isGlExtensionSupported(kGlExtYuvTarget)) {
+    GTEST_SKIP() << "Skipping test because of missing required GL extension "
+                 << kGlExtYuvTarget;
+  }
+
   EglTestPatternProgram eglTestPatternProgram;
 
   // Verify the shaders compiled and linked successfully.
diff --git a/services/camera/virtualcamera/tests/VirtualCameraServiceTest.cc b/services/camera/virtualcamera/tests/VirtualCameraServiceTest.cc
index 5927b05..550227e 100644
--- a/services/camera/virtualcamera/tests/VirtualCameraServiceTest.cc
+++ b/services/camera/virtualcamera/tests/VirtualCameraServiceTest.cc
@@ -15,6 +15,7 @@
  */
 
 #include <algorithm>
+#include <cstdint>
 #include <cstdio>
 #include <iterator>
 #include <memory>
@@ -75,6 +76,17 @@
 
 const VirtualCameraConfiguration kEmptyVirtualCameraConfiguration;
 
+class MockVirtualCameraCallback : public BnVirtualCameraCallback {
+ public:
+  MOCK_METHOD(ndk::ScopedAStatus, onStreamConfigured,
+              (int32_t, const ::aidl::android::view::Surface&, int, int,
+               ::aidl::android::companion::virtualcamera::Format pixelFormat),
+              (override));
+  MOCK_METHOD(ndk::ScopedAStatus, onProcessCaptureRequest, (int32_t, int32_t),
+              (override));
+  MOCK_METHOD(ndk::ScopedAStatus, onStreamClosed, (int32_t), (override));
+};
+
 VirtualCameraConfiguration createConfiguration(const int width, const int height,
                                                const Format format,
                                                const int maxFps) {
@@ -85,6 +97,8 @@
                                                   .maxFps = maxFps});
   configuration.sensorOrientation = kSensorOrientation;
   configuration.lensFacing = kLensFacing;
+  configuration.virtualCameraCallback =
+      ndk::SharedRefBase::make<MockVirtualCameraCallback>();
   return configuration;
 }
 
@@ -247,6 +261,24 @@
   EXPECT_THAT(getCameraIds(), IsEmpty());
 }
 
+TEST_F(VirtualCameraServiceTest,
+       ConfigurationWithoutVirtualCameraCallbackFails) {
+  sp<BBinder> token = sp<BBinder>::make();
+  ndk::SpAIBinder ndkToken(AIBinder_fromPlatformBinder(token));
+  bool aidlRet;
+
+  VirtualCameraConfiguration config =
+      createConfiguration(kVgaWidth, kVgaHeight, Format::RGBA_8888, kMaxFps);
+  config.virtualCameraCallback = nullptr;
+
+  ASSERT_FALSE(mCameraService
+                   ->registerCamera(ndkToken, config, kDefaultDeviceId, &aidlRet)
+                   .isOk());
+
+  EXPECT_FALSE(aidlRet);
+  EXPECT_THAT(getCameraIds(), IsEmpty());
+}
+
 TEST_F(VirtualCameraServiceTest, ConfigurationWithUnsupportedPixelFormatFails) {
   bool aidlRet;
 
diff --git a/services/camera/virtualcamera/util/EglDisplayContext.cc b/services/camera/virtualcamera/util/EglDisplayContext.cc
index 6d343a2..166ac75 100644
--- a/services/camera/virtualcamera/util/EglDisplayContext.cc
+++ b/services/camera/virtualcamera/util/EglDisplayContext.cc
@@ -30,8 +30,9 @@
 namespace companion {
 namespace virtualcamera {
 
-EglDisplayContext::EglDisplayContext()
+EglDisplayContext::EglDisplayContext(std::shared_ptr<ANativeWindow> nativeWindow)
     : mEglDisplay(EGL_NO_DISPLAY),
+      mEglSurface(EGL_NO_SURFACE),
       mEglContext(EGL_NO_CONTEXT),
       mEglConfig(nullptr) {
   EGLBoolean result;
@@ -52,8 +53,10 @@
 
   EGLint numConfigs = 0;
   EGLint configAttribs[] = {
-      EGL_SURFACE_TYPE, EGL_PBUFFER_BIT, EGL_RENDERABLE_TYPE,
-      EGL_OPENGL_ES2_BIT, EGL_RED_SIZE, 8, EGL_GREEN_SIZE, 8, EGL_BLUE_SIZE, 8,
+      EGL_SURFACE_TYPE,
+      nativeWindow == nullptr ? EGL_PBUFFER_BIT : EGL_WINDOW_BIT,
+      EGL_RENDERABLE_TYPE, EGL_OPENGL_ES2_BIT, EGL_RED_SIZE, 8, EGL_GREEN_SIZE,
+      8, EGL_BLUE_SIZE, 8,
       // no alpha
       EGL_NONE};
 
@@ -72,6 +75,14 @@
     return;
   }
 
+  if (nativeWindow != nullptr) {
+    mEglSurface = eglCreateWindowSurface(mEglDisplay, mEglConfig,
+                                         nativeWindow.get(), NULL);
+    if (mEglSurface == EGL_NO_SURFACE) {
+      ALOGE("eglCreateWindowSurface error: %#x", eglGetError());
+    }
+  }
+
   if (!makeCurrent()) {
     ALOGE(
         "Failed to set newly initialized EGLContext and EGLDisplay connection "
@@ -82,6 +93,9 @@
 }
 
 EglDisplayContext::~EglDisplayContext() {
+  if (mEglSurface != EGL_NO_SURFACE) {
+    eglDestroySurface(mEglDisplay, mEglSurface);
+  }
   if (mEglDisplay != EGL_NO_DISPLAY) {
     eglTerminate(mEglDisplay);
   }
@@ -99,8 +113,14 @@
   return mEglContext != EGL_NO_CONTEXT && mEglDisplay != EGL_NO_DISPLAY;
 }
 
+void EglDisplayContext::swapBuffers() const {
+  if (mEglSurface != EGL_NO_SURFACE) {
+    eglSwapBuffers(mEglDisplay, mEglSurface);
+  }
+}
+
 bool EglDisplayContext::makeCurrent() {
-  if (!eglMakeCurrent(mEglDisplay, EGL_NO_SURFACE, EGL_NO_SURFACE, mEglContext)) {
+  if (!eglMakeCurrent(mEglDisplay, mEglSurface, mEglSurface, mEglContext)) {
     ALOGE("eglMakeCurrent failed: %#x", eglGetError());
     return false;
   }
diff --git a/services/camera/virtualcamera/util/EglDisplayContext.h b/services/camera/virtualcamera/util/EglDisplayContext.h
index 402ca3c..6dc3080 100644
--- a/services/camera/virtualcamera/util/EglDisplayContext.h
+++ b/services/camera/virtualcamera/util/EglDisplayContext.h
@@ -17,7 +17,10 @@
 #ifndef ANDROID_COMPANION_VIRTUALCAMERA_EGLDISPLAYCONTEXT_H
 #define ANDROID_COMPANION_VIRTUALCAMERA_EGLDISPLAYCONTEXT_H
 
+#include <memory>
+
 #include "EGL/egl.h"
+#include "system/window.h"
 
 namespace android {
 namespace companion {
@@ -30,7 +33,7 @@
 // out of scope.
 class EglDisplayContext {
  public:
-  EglDisplayContext();
+  EglDisplayContext(std::shared_ptr<ANativeWindow> nativeWindow = nullptr);
   ~EglDisplayContext();
 
   // Sets EGLDisplay & EGLContext for current thread.
@@ -44,8 +47,13 @@
   // EGLDisplay & EGLContext.
   bool isInitialized() const;
 
+  void swapBuffers() const;
+
  private:
+  std::shared_ptr<ANativeWindow> mNativeWindow;
+
   EGLDisplay mEglDisplay;
+  EGLSurface mEglSurface;
   EGLContext mEglContext;
   EGLConfig mEglConfig;
 };
diff --git a/services/camera/virtualcamera/util/EglProgram.cc b/services/camera/virtualcamera/util/EglProgram.cc
index 7554a67..61f5005 100644
--- a/services/camera/virtualcamera/util/EglProgram.cc
+++ b/services/camera/virtualcamera/util/EglProgram.cc
@@ -35,19 +35,28 @@
 
 constexpr char kGlExtYuvTarget[] = "GL_EXT_YUV_target";
 
-constexpr char kIdentityVertexShader[] = R"(
-    attribute vec4 vPosition;
+constexpr char kJuliaFractalVertexShader[] = R"(#version 300 es
+    in vec4 aPosition;
+    in vec2 aTextureCoord;
+    out vec2 vFractalCoord;
+    out vec2 vUVCoord;
     void main() {
-      gl_Position = vPosition;
+      gl_Position = aPosition;
+      vUVCoord = aTextureCoord;
+      vFractalCoord = vec2(aTextureCoord.x - 0.5, aTextureCoord.y - 0.5) * 4.0;
     })";
 
-constexpr char kJuliaFractalFragmentShader[] = R"(
+constexpr char kJuliaFractalFragmentShader[] = R"(#version 300 es
+    #extension GL_EXT_YUV_target : require
     precision mediump float;
-    uniform vec2 uResolution;
-    uniform vec2 uC;
-    uniform vec2 uUV;
+
     const float kIter = 64.0;
 
+    in vec2 vFractalCoord;
+    in vec2 vUVCoord;
+    out vec4 fragColor;
+    uniform vec2 uC;
+
     vec2 imSq(vec2 n){
       return vec2(pow(n.x,2.0)-pow(n.y,2.0), 2.0*n.x*n.y);
     }
@@ -62,9 +71,8 @@
     }
 
     void main() {
-      vec2 uv = vec2(gl_FragCoord.x / uResolution.x - 0.5, gl_FragCoord.y / uResolution.y - 0.5);
-      float juliaVal = julia(uv * 4.0, uC);
-      gl_FragColor = vec4( juliaVal,uUV.x,uUV.y,0.0);
+      float juliaVal = julia(vFractalCoord, uC);
+      fragColor = vec4(yuv_2_rgb(vec3(juliaVal, vUVCoord.x, vUVCoord.y), itu_601_full_range), 0.0);
     })";
 
 constexpr char kExternalTextureVertexShader[] = R"(#version 300 es
@@ -200,17 +208,28 @@
 }
 
 EglTestPatternProgram::EglTestPatternProgram() {
-  if (initialize(kIdentityVertexShader, kJuliaFractalFragmentShader)) {
+  if (initialize(kJuliaFractalVertexShader, kJuliaFractalFragmentShader)) {
     ALOGV("Successfully initialized EGL shaders for test pattern program.");
   } else {
     ALOGE("Test pattern EGL shader program initialization failed.");
   }
+
+  mCHandle = glGetUniformLocation(mProgram, "uC");
+  mPositionHandle = glGetAttribLocation(mProgram, "aPosition");
+  mTextureCoordHandle = glGetAttribLocation(mProgram, "aTextureCoord");
+
+  // Pass vertex array to draw.
+  glEnableVertexAttribArray(mPositionHandle);
+  // Prepare the triangle coordinate data.
+  glVertexAttribPointer(mPositionHandle, kCoordsPerVertex, GL_FLOAT, false,
+                        kSquareCoords.size(), kSquareCoords.data());
+
+  glEnableVertexAttribArray(mTextureCoordHandle);
+  glVertexAttribPointer(mTextureCoordHandle, 2, GL_FLOAT, false,
+                        kTextureCoords.size(), kTextureCoords.data());
 }
 
-bool EglTestPatternProgram::draw(int width, int height, int frameNumber) {
-  glViewport(0, 0, static_cast<GLsizei>(width), static_cast<GLsizei>(height));
-  checkEglError("glViewport");
-
+bool EglTestPatternProgram::draw(int frameNumber) {
   // Load compiled shader.
   glUseProgram(mProgram);
   checkEglError("glUseProgram");
@@ -219,28 +238,8 @@
   float time = float(frameNumber) / 120.0f;
   const std::complex<float> c(std::sin(time) * 0.78f, std::cos(time) * 0.78f);
 
-  // Pass uniform values to the shader.
-  int resolutionHandle = glGetUniformLocation(mProgram, "uResolution");
-  checkEglError("glGetUniformLocation -> uResolution");
-  glUniform2f(resolutionHandle, static_cast<float>(width),
-              static_cast<float>(height));
-  checkEglError("glUniform2f -> uResolution");
-
   // Pass "C" constant value determining the Julia set to the shader.
-  int cHandle = glGetUniformLocation(mProgram, "uC");
-  glUniform2f(cHandle, c.imag(), c.real());
-
-  // Pass chroma value to the shader.
-  int uvHandle = glGetUniformLocation(mProgram, "uUV");
-  glUniform2f(uvHandle, (c.imag() + 1.f) / 2.f, (c.real() + 1.f) / 2.f);
-
-  // Pass vertex array to draw.
-  int positionHandle = glGetAttribLocation(mProgram, "vPosition");
-  glEnableVertexAttribArray(positionHandle);
-
-  // Prepare the triangle coordinate data.
-  glVertexAttribPointer(positionHandle, kCoordsPerVertex, GL_FLOAT, false,
-                        kSquareCoords.size(), kSquareCoords.data());
+  glUniform2f(mCHandle, c.imag(), c.real());
 
   // Draw triangle strip forming a square filling the viewport.
   glDrawElements(GL_TRIANGLES, kDrawOrder.size(), GL_UNSIGNED_BYTE,
diff --git a/services/camera/virtualcamera/util/EglProgram.h b/services/camera/virtualcamera/util/EglProgram.h
index c695cbb..d09f11e 100644
--- a/services/camera/virtualcamera/util/EglProgram.h
+++ b/services/camera/virtualcamera/util/EglProgram.h
@@ -46,7 +46,12 @@
  public:
   EglTestPatternProgram();
 
-  bool draw(int width, int height, int frameNumber);
+  bool draw(int frameNumber);
+
+ private:
+  int mPositionHandle = -1;
+  int mTextureCoordHandle = -1;
+  int mCHandle = -1;
 };
 
 // Shader program to  draw texture.
diff --git a/services/camera/virtualcamera/util/TestPatternHelper.cc b/services/camera/virtualcamera/util/TestPatternHelper.cc
deleted file mode 100644
index 274996a..0000000
--- a/services/camera/virtualcamera/util/TestPatternHelper.cc
+++ /dev/null
@@ -1,152 +0,0 @@
-/*
- * Copyright (C) 2023 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-// #define LOG_NDEBUG 0
-
-#define LOG_TAG "TestPatternHelper"
-
-#include "TestPatternHelper.h"
-
-#include <complex>
-#include <cstdint>
-
-#include "log/log.h"
-#include "nativebase/nativebase.h"
-#include "system/graphics.h"
-#include "ui/GraphicBuffer.h"
-#include "utils/Errors.h"
-
-namespace android {
-namespace companion {
-namespace virtualcamera {
-
-namespace {
-
-using namespace std::chrono_literals;
-
-static constexpr std::chrono::milliseconds kAcquireFenceTimeout = 500ms;
-
-uint8_t julia(const std::complex<float> n, const std::complex<float> c) {
-  std::complex<float> z = n;
-  for (int i = 0; i < 64; i++) {
-    z = z * z + c;
-    if (std::abs(z) > 2.0) return i * 4;
-  }
-  return 0xff;
-}
-
-uint8_t pixelToFractal(const int x, const int y, const int width,
-                       const int height, const std::complex<float> c) {
-  std::complex<float> n(float(x) / float(width) - 0.5,
-                        float(y) / float(height) - 0.5);
-  return julia(n * 5.f, c);
-}
-
-void renderTestPatternYcbCr420(const android_ycbcr& ycbr, const int width,
-                               const int height, const int frameNumber) {
-  float time = float(frameNumber) / 120.0f;
-  const std::complex<float> c(std::sin(time), std::cos(time));
-
-  uint8_t* y = reinterpret_cast<uint8_t*>(ycbr.y);
-  uint8_t* cb = reinterpret_cast<uint8_t*>(ycbr.cb);
-  uint8_t* cr = reinterpret_cast<uint8_t*>(ycbr.cr);
-
-  for (int row = 0; row < height; row++) {
-    for (int col = 0; col < width; col++) {
-      y[row * ycbr.ystride + col] =
-          pixelToFractal(col, row, width, height, c * 0.78f);
-    }
-  }
-
-  int cWidth = width / 2;
-  int cHeight = height / 2;
-  for (int row = 0; row < cHeight; row++) {
-    for (int col = 0; col < cWidth; col++) {
-      cb[row * ycbr.cstride + col * ycbr.chroma_step] =
-          static_cast<uint8_t>((float(col) / float(cWidth)) * 255.f);
-      cr[row * ycbr.cstride + col * ycbr.chroma_step] =
-          static_cast<uint8_t>((float(row) / float(cHeight)) * 255.f);
-    }
-  }
-}
-
-}  // namespace
-
-void renderTestPatternYCbCr420(sp<Surface> surface, int frameNumber) {
-  if (surface == nullptr) {
-    ALOGE("%s: null surface, skipping render", __func__);
-    return;
-  }
-
-  ANativeWindowBuffer* buffer;
-  int fenceFd;
-  int ret = ANativeWindow_dequeueBuffer(surface.get(), &buffer, &fenceFd);
-  if (ret != NO_ERROR) {
-    ALOGE(
-        "%s: Error while deuqueing buffer from surface, "
-        "ANativeWindow_dequeueBuffer returned %d",
-        __func__, ret);
-    return;
-  }
-
-  if (buffer == nullptr) {
-    ALOGE("%s: ANativeWindowBuffer is null after dequeing", __func__);
-    return;
-  }
-
-  sp<Fence> fence = sp<Fence>::make(fenceFd);
-  if (fence->isValid()) {
-    ret = fence->wait(kAcquireFenceTimeout.count());
-    if (ret != NO_ERROR) {
-      ALOGE("%s: Timeout while waiting for the fence to clear", __func__);
-      ANativeWindow_queueBuffer(surface.get(), buffer, fence->dup());
-      return;
-    }
-  }
-
-  sp<GraphicBuffer> gBuffer = GraphicBuffer::from(buffer);
-  android_ycbcr ycbr;
-
-  ret = gBuffer->lockAsyncYCbCr(GraphicBuffer::USAGE_SW_WRITE_OFTEN, &ycbr,
-                                fence->dup());
-  if (ret != NO_ERROR) {
-    ALOGE("%s: Failed to lock buffer retrieved from surface, ret %d", __func__,
-          ret);
-    return;
-  }
-
-  renderTestPatternYcbCr420(ycbr, gBuffer->getWidth(), gBuffer->getHeight(),
-                            frameNumber);
-
-  ret = gBuffer->unlock();
-  if (ret != NO_ERROR) {
-    ALOGE("%s: Failed to unlock buffer, ret %d", __func__, ret);
-    return;
-  }
-
-  ret = ANativeWindow_queueBuffer(surface.get(), buffer, /*fenceFd=*/-1);
-  if (ret != NO_ERROR) {
-    ALOGE(
-        "%s: Error while queing buffer to surface, ANativeWindow_queueBuffer "
-        "returned %d",
-        __func__, ret);
-    return;
-  }
-}
-
-}  // namespace virtualcamera
-}  // namespace companion
-}  // namespace android
diff --git a/services/camera/virtualcamera/util/TestPatternHelper.h b/services/camera/virtualcamera/util/TestPatternHelper.h
deleted file mode 100644
index f842b29..0000000
--- a/services/camera/virtualcamera/util/TestPatternHelper.h
+++ /dev/null
@@ -1,33 +0,0 @@
-/*
- * Copyright (C) 2023 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#ifndef ANDROID_COMPANION_VIRTUALCAMERA_TESTPATTERNHELPER_H
-#define ANDROID_COMPANION_VIRTUALCAMERA_TESTPATTERNHELPER_H
-
-#include "gui/Surface.h"
-
-namespace android {
-namespace companion {
-namespace virtualcamera {
-
-// Helper function for rendering test pattern into Surface.
-void renderTestPatternYCbCr420(sp<Surface> surface, int frameNumber);
-
-}  // namespace virtualcamera
-}  // namespace companion
-}  // namespace android
-
-#endif  // ANDROID_COMPANION_VIRTUALCAMERA_TESTPATTERNHELPER_H