VideoCapturerAndroid, handle cvo correctly

talk/app/webrtc/java/jni/native_handle_impl.cc

Index: talk/app/webrtc/java/jni/native_handle_impl.cc
diff --git a/talk/app/webrtc/java/jni/native_handle_impl.cc b/talk/app/webrtc/java/jni/native_handle_impl.cc
index 583a0380263659096660934cae8699babd5c7511..1a3a92fbe7ff2253036cb5f6b088a21eb04b4721 100644
--- a/talk/app/webrtc/java/jni/native_handle_impl.cc
+++ b/talk/app/webrtc/java/jni/native_handle_impl.cc
@@ -30,9 +30,47 @@
 #include "webrtc/base/checks.h"
 #include "webrtc/base/keep_ref_until_done.h"
 #include "webrtc/base/scoped_ref_ptr.h"
+#include "webrtc/base/logging.h"
 
 using webrtc::NativeHandleBuffer;
 
+namespace {
+
+void RotateMatrix(float a[16], webrtc::VideoRotation rotation) {
+  switch (rotation) {
+    case webrtc::kVideoRotation_0:
+      break;
+    case webrtc::kVideoRotation_90: {
+      const float ROTATE_90[16] =
+          { a[4], a[5], a[6], a[7],
+            -a[0], -a[1], -a[2], -a[3],
+            a[8], a[9], a[10], a[11],
+            a[0] + a[12], a[1] + a[13], a[2] + a[14], a[3] + a[15]};
+      memcpy(a, ROTATE_90, sizeof(ROTATE_90));
+    } break;
+    case webrtc::kVideoRotation_180: {
+      const float ROTATE_180[16] =
+          { -a[0], -a[1], -a[2], -a[3],
+            -a[4], -a[5], -a[6], -a[7],
+            a[8], a[9], a[10], a[11],
+            a[0] + a[4] + a[12], a[1] +a[5] + a[13], a[2] + a[6] + a[14],
+            a[3] + a[11]+ a[15]};
+        memcpy(a, ROTATE_180, sizeof(ROTATE_180));
+      }
+      break;
+    case webrtc::kVideoRotation_270: {
+      const float ROTATE_270[16] =
+          { -a[4], -a[5], -a[6], -a[7],

[nisse-chromium (ooo August 14), 2015/12/10 09:04:57]

I was surprised by the transformation of the last row, I had expected that
rotation only applies to the coefficients related to x and y. At least the
second to last row is unchanged.

Proposed comment:

/* Texture coordinates are in the range 0 to 1. The transformation of the last
row is needed for proper translation, e.g, to mirror x, we don't replace x by
-x, but by 1-x. */

If you want to, you could eliminate the memcpy and do a loop over the columns.
E.g, for the 180 case, something like

for (int i = 0; i < 4; i++)
{ float a0, a1, a3;
  a0   = a[i]; a1     = a[4+i]; a3      = a[12+i];
  a[i] = -a0;  a[4+1] = -a1;    a[12+i] = a0 + a1 + a3;
}

You judge whether or not that makes the code simpler. As far as I understand,
the function is not performance critical, so we don't need to eliminate the
memcpy as a micro optimization.

[perkj_chrome, 2015/12/10 13:22:07]

Acknowledged.

+            a[0], a[1], a[2], a[3],
+            a[8], a[9], a[10], a[11],
+            a[4] + a[12], a[5] + a[13], a[6] + a[14], a[7] + a[15]};
+        memcpy(a, ROTATE_270, sizeof(ROTATE_270));
+    } break;
+  }
+}
+
+}  // anonymouse namespace
+
 namespace webrtc_jni {
 
 NativeHandleImpl::NativeHandleImpl(JNIEnv* jni,
@@ -68,22 +106,26 @@ AndroidTextureBuffer::NativeToI420Buffer() {
   return nullptr;
 }
 
-rtc::scoped_refptr<AndroidTextureBuffer> AndroidTextureBuffer::CropAndScale(
-    int cropped_input_width,
-    int cropped_input_height,
-    int dst_widht,
-    int dst_height) {
-  // TODO(perkj) Implement cropping.
-  RTC_CHECK_EQ(cropped_input_width, width_);
-  RTC_CHECK_EQ(cropped_input_height, height_);
+rtc::scoped_refptr<AndroidTextureBuffer>
+AndroidTextureBuffer::ScaleAndRotate(int dst_widht,
+                                     int dst_height,
+                                     webrtc::VideoRotation rotation) {
+  if (width() == dst_widht && height() == dst_height &&
+      rotation == webrtc::kVideoRotation_0) {
+    return this;
+  }
+  int rotated_width = (rotation % 180 == 0) ? dst_widht : dst_height;
+  int rotated_height = (rotation % 180 == 0) ? dst_height : dst_widht;
 
   // Here we use Bind magic to add a reference count to |this| until the newly
-  // created AndroidTextureBuffer is destructed. ScaledFrameNotInUse will be
-  // called that happens and when it finishes, the reference count to |this|
-  // will be decreased by one.
-  return new rtc::RefCountedObject<AndroidTextureBuffer>(
-      dst_widht, dst_height, native_handle_,
-      rtc::KeepRefUntilDone(this));
+  // created AndroidTextureBuffer is destructed
+  rtc::scoped_refptr<AndroidTextureBuffer> buffer(
+      new rtc::RefCountedObject<AndroidTextureBuffer>(
+          rotated_width, rotated_height, native_handle_,
+          rtc::KeepRefUntilDone(this)));
+
+  RotateMatrix(buffer->native_handle_.sampling_matrix, rotation);
+  return buffer;
 }
 
 }  // namespace webrtc_jni