SkArCamera* files

Bug: skia:
Change-Id: I711143c53bf66ebc8130b2401738da3cde644fbe
Reviewed-on: https://skia-review.googlesource.com/140560
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>

platform_tools/android/apps/arcore/CMakeLists.txt

@@ -33,7 +33,9 @@ add_library(hello_ar_native SHARED
            "src/main/cpp/point_cloud_renderer.cc"
            "src/main/cpp/util.cc"
            "src/main/cpp/pending_anchor.cc"
-           "src/main/cpp/anchor_wrapper.cc")
+           "src/main/cpp/anchor_wrapper.cc"
+
+           "src/main/cpp/SkArCamera.cpp")
 
 target_include_directories(hello_ar_native PRIVATE
             #BASIC AR NATIVE CODE

platform_tools/android/apps/arcore/src/main/cpp/SkArCamera.cpp

@@ -0,0 +1,38 @@
+/*
+ * Copyright 2018 Google LLC
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include <arcore_c_api.h>
+#include "SkArCamera.h"
+#include "SkArUtil.h"
+
+std::unique_ptr<SkArCamera> SkArCamera::Make(SkArSession* session, SkArFrame* frame) {
+    return std::unique_ptr<SkArCamera>(new SkArCamera(session, frame));
+}
+
+SkArCamera::~SkArCamera() {
+    ArCamera_release(fArCamera);
+}
+
+SkArCamera::SkArCamera(SkArSession* session, SkArFrame* frame) : fArCamera(nullptr) {
+    ArFrame_acquireCamera(session->getArSession(), frame->getArFrame(), &fArCamera);
+}
+
+void SkArCamera::getViewMatrix(const SkArSession* session, float outColMajor[16]) {
+    ArCamera_getViewMatrix(session->getArSession(), fArCamera, outColMajor);
+}
+
+void SkArCamera::getProjectionMatrix(const SkArSession* session, float nearClip,
+                                     float farClip, float outColMajor[16]) {
+    ArCamera_getProjectionMatrix(session->getArSession(), fArCamera, nearClip, farClip,
+                                 outColMajor);
+}
+
+SkArTrackingState SkArCamera::getTrackingState(const SkArSession* session) {
+    ArTrackingState arTrackingState;
+    ArCamera_getTrackingState(session->getArSession(), fArCamera, &arTrackingState);
+    return SkArUtil::MakeSkArTrackingState(arTrackingState);
+}

platform_tools/android/apps/arcore/src/main/cpp/SkArCamera.h

@@ -0,0 +1,68 @@
+/*
+ * Copyright 2018 Google LLC
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkArCamera_DEFINED
+#define SkArCamera_DEFINED
+
+#include <memory>
+#include "SkArTrackingState.h"
+
+class ArCamera;
+class SkArFrame;
+class SkArSession;
+
+/**
+ * Provides information about the camera that is used to capture images. Such information
+ * includes projection matrices, pose of camera...
+ */
+
+class SkArCamera {
+
+public:
+    /**
+     * Factory method used to construct an SkArCamera from the current frame, using the current
+     * session
+     * @param session   raw pointer to the current SkArSession
+     * @param frame     raw pointer to the current SkArFrame
+     * @return          unique pointer to an SkArCamera. Never nullptr
+     */
+    static std::unique_ptr<SkArCamera> Make(SkArSession* session, SkArFrame* frame);
+
+    ~SkArCamera();
+
+    /**
+     * Fills outColMajor with the values of the camera's current View matrix in column-major order
+     * @param session       current SkArSession
+     * @param outColMajor   16-float array that will contain the View matrix content
+     */
+    void getViewMatrix(const SkArSession* session, float outColMajor[16]);
+
+    /**
+     * Fills outColMajor with the values of the camera's current Projection matrix in
+     * column-major order
+     * @param session       current SkArSession
+     * @param nearClip      wanted near clip value for the camera
+     * @param farClip       wanted far clip value for the camera
+     * @param outColMajor   16-float array that will contain the Projection matrix content
+     */
+    void getProjectionMatrix(const SkArSession* session, float nearClip, float farClip,
+                             float outColMajor[16]);
+
+    /**
+     * Used to check the current SkArTrackingState of the camera
+     * @param session   current SkArSession
+     * @return          tracking state of the SkArCamera described by the SkArTrackingState enum
+     */
+    SkArTrackingState getTrackingState(const SkArSession* session);
+
+private:
+    SkArCamera(SkArSession* session, SkArFrame* frame);
+
+    // This is a raw pointer. Its lifetime matches that of this class (SkArCamera)
+    ArCamera* fArCamera;
+};
+#endif  // SkArCamera_DEFINED