Camera and Camera2 preview is rendered via OpenGL textures and can be modified on CPU via C++ code. No OpenCL yet.

samples/android/tutorial-4-opencl/jni/common.hpp

@@ -0,0 +1,19 @@
+#include <android/log.h>
+#define LOG_TAG "JNIRenderer"
+//#define LOGD(...)
+#define LOGD(...) ((void)__android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, __VA_ARGS__))
+#define LOGE(...) ((void)__android_log_print(ANDROID_LOG_ERROR, LOG_TAG, __VA_ARGS__))
+
+#include <time.h> // clock_gettime
+
+static inline int64_t getTimeMs()
+{
+    struct timespec now;
+    clock_gettime(CLOCK_MONOTONIC, &now);
+    return (int64_t) now.tv_sec*1000 + now.tv_nsec/1000000;
+}
+
+static inline int getTimeInterval(int64_t startTime)
+{
+    return int(getTimeMs() - startTime);
+}