Moving src/webrtc into src/.

In order to eliminate the WebRTC Subtree mirror in Chromium, 
WebRTC is moving the content of the src/webrtc directory up
to the src/ directory.

NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
TBR=tommi@webrtc.org

Bug: chromium:611808
Change-Id: Iac59c5b51b950f174119565bac87955a7994bc38
Reviewed-on: https://webrtc-review.googlesource.com/1560
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Reviewed-by: Henrik Kjellander <kjellander@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#19845}

sdk/objc/Framework/Classes/Metal/RTCMTLRenderer.mm

@@ -0,0 +1,244 @@
+/*
+ *  Copyright 2017 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#import "RTCMTLRenderer+Private.h"
+
+#import <Metal/Metal.h>
+#import <MetalKit/MetalKit.h>
+
+#import "WebRTC/RTCLogging.h"
+#import "WebRTC/RTCVideoFrame.h"
+
+#include "webrtc/api/video/video_rotation.h"
+#include "webrtc/rtc_base/checks.h"
+
+// As defined in shaderSource.
+static NSString *const vertexFunctionName = @"vertexPassthrough";
+static NSString *const fragmentFunctionName = @"fragmentColorConversion";
+
+static NSString *const pipelineDescriptorLabel = @"RTCPipeline";
+static NSString *const commandBufferLabel = @"RTCCommandBuffer";
+static NSString *const renderEncoderLabel = @"RTCEncoder";
+static NSString *const renderEncoderDebugGroup = @"RTCDrawFrame";
+
+static const float cubeVertexData[64] = {
+    -1.0, -1.0, 0.0, 1.0, 1.0, -1.0, 1.0, 1.0, -1.0, 1.0, 0.0, 0.0, 1.0, 1.0, 1.0, 0.0,
+
+    // rotation = 90, offset = 16.
+    -1.0, -1.0, 1.0, 1.0, 1.0, -1.0, 1.0, 0.0, -1.0, 1.0, 0.0, 1.0, 1.0, 1.0, 0.0, 0.0,
+
+    // rotation = 180, offset = 32.
+    -1.0, -1.0, 1.0, 0.0, 1.0, -1.0, 0.0, 0.0, -1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 0.0, 1.0,
+
+    // rotation = 270, offset = 48.
+    -1.0, -1.0, 0.0, 0.0, 1.0, -1.0, 0.0, 1.0, -1.0, 1.0, 1.0, 0.0, 1.0, 1.0, 1.0, 1.0,
+};
+
+static inline int offsetForRotation(RTCVideoRotation rotation) {
+  switch (rotation) {
+    case RTCVideoRotation_0:
+      return 0;
+    case RTCVideoRotation_90:
+      return 16;
+    case RTCVideoRotation_180:
+      return 32;
+    case RTCVideoRotation_270:
+      return 48;
+  }
+  return 0;
+}
+
+// The max number of command buffers in flight (submitted to GPU).
+// For now setting it up to 1.
+// In future we might use triple buffering method if it improves performance.
+static const NSInteger kMaxInflightBuffers = 1;
+
+@implementation RTCMTLRenderer {
+  __kindof MTKView *_view;
+
+  // Controller.
+  dispatch_semaphore_t _inflight_semaphore;
+
+  // Renderer.
+  id<MTLDevice> _device;
+  id<MTLCommandQueue> _commandQueue;
+  id<MTLLibrary> _defaultLibrary;
+  id<MTLRenderPipelineState> _pipelineState;
+
+  // Buffers.
+  id<MTLBuffer> _vertexBuffer;
+
+  // RTC Frame parameters.
+  int _offset;
+}
+
+- (instancetype)init {
+  if (self = [super init]) {
+    // _offset of 0 is equal to rotation of 0.
+    _offset = 0;
+    _inflight_semaphore = dispatch_semaphore_create(kMaxInflightBuffers);
+  }
+
+  return self;
+}
+
+- (BOOL)addRenderingDestination:(__kindof MTKView *)view {
+  return [self setupWithView:view];
+}
+
+#pragma mark - Private
+
+- (BOOL)setupWithView:(__kindof MTKView *)view {
+  BOOL success = NO;
+  if ([self setupMetal]) {
+    [self setupView:view];
+    [self loadAssets];
+    [self setupBuffers];
+    success = YES;
+  }
+  return success;
+}
+#pragma mark - Inheritance
+
+- (id<MTLDevice>)currentMetalDevice {
+  return _device;
+}
+
+- (NSString *)shaderSource {
+  RTC_NOTREACHED() << "Virtual method not implemented in subclass.";
+  return nil;
+}
+
+- (void)uploadTexturesToRenderEncoder:(id<MTLRenderCommandEncoder>)renderEncoder {
+  RTC_NOTREACHED() << "Virtual method not implemented in subclass.";
+}
+
+- (BOOL)setupTexturesForFrame:(nonnull RTCVideoFrame *)frame {
+  _offset = offsetForRotation(frame.rotation);
+  return YES;
+}
+
+#pragma mark - GPU methods
+
+- (BOOL)setupMetal {
+  // Set the view to use the default device.
+  _device = MTLCreateSystemDefaultDevice();
+  if (!_device) {
+    return NO;
+  }
+
+  // Create a new command queue.
+  _commandQueue = [_device newCommandQueue];
+
+  // Load metal library from source.
+  NSError *libraryError = nil;
+
+  id<MTLLibrary> sourceLibrary =
+      [_device newLibraryWithSource:[self shaderSource] options:NULL error:&libraryError];
+
+  if (libraryError) {
+    RTCLogError(@"Metal: Library with source failed\n%@", libraryError);
+    return NO;
+  }
+
+  if (!sourceLibrary) {
+    RTCLogError(@"Metal: Failed to load library. %@", libraryError);
+    return NO;
+  }
+  _defaultLibrary = sourceLibrary;
+
+  return YES;
+}
+
+- (void)setupView:(__kindof MTKView *)view {
+  view.device = _device;
+
+  view.preferredFramesPerSecond = 30;
+  view.autoResizeDrawable = NO;
+
+  // We need to keep reference to the view as it's needed down the rendering pipeline.
+  _view = view;
+}
+
+- (void)loadAssets {
+  id<MTLFunction> vertexFunction = [_defaultLibrary newFunctionWithName:vertexFunctionName];
+  id<MTLFunction> fragmentFunction = [_defaultLibrary newFunctionWithName:fragmentFunctionName];
+
+  MTLRenderPipelineDescriptor *pipelineDescriptor = [[MTLRenderPipelineDescriptor alloc] init];
+  pipelineDescriptor.label = pipelineDescriptorLabel;
+  pipelineDescriptor.vertexFunction = vertexFunction;
+  pipelineDescriptor.fragmentFunction = fragmentFunction;
+  pipelineDescriptor.colorAttachments[0].pixelFormat = _view.colorPixelFormat;
+  pipelineDescriptor.depthAttachmentPixelFormat = MTLPixelFormatInvalid;
+  NSError *error = nil;
+  _pipelineState = [_device newRenderPipelineStateWithDescriptor:pipelineDescriptor error:&error];
+
+  if (!_pipelineState) {
+    RTCLogError(@"Metal: Failed to create pipeline state. %@", error);
+  }
+}
+
+- (void)setupBuffers {
+  _vertexBuffer = [_device newBufferWithBytes:cubeVertexData
+                                       length:sizeof(cubeVertexData)
+                                      options:MTLResourceOptionCPUCacheModeDefault];
+}
+
+- (void)render {
+  // Wait until the inflight (curently sent to GPU) command buffer
+  // has completed the GPU work.
+  dispatch_semaphore_wait(_inflight_semaphore, DISPATCH_TIME_FOREVER);
+
+  id<MTLCommandBuffer> commandBuffer = [_commandQueue commandBuffer];
+  commandBuffer.label = commandBufferLabel;
+
+  __block dispatch_semaphore_t block_semaphore = _inflight_semaphore;
+  [commandBuffer addCompletedHandler:^(id<MTLCommandBuffer> _Nonnull) {
+    // GPU work completed.
+    dispatch_semaphore_signal(block_semaphore);
+  }];
+
+  MTLRenderPassDescriptor *renderPassDescriptor = _view.currentRenderPassDescriptor;
+  if (renderPassDescriptor) {  // Valid drawable.
+    id<MTLRenderCommandEncoder> renderEncoder =
+        [commandBuffer renderCommandEncoderWithDescriptor:renderPassDescriptor];
+    renderEncoder.label = renderEncoderLabel;
+
+    // Set context state.
+    [renderEncoder pushDebugGroup:renderEncoderDebugGroup];
+    [renderEncoder setRenderPipelineState:_pipelineState];
+    [renderEncoder setVertexBuffer:_vertexBuffer offset:_offset * sizeof(float) atIndex:0];
+    [self uploadTexturesToRenderEncoder:renderEncoder];
+
+    [renderEncoder drawPrimitives:MTLPrimitiveTypeTriangleStrip
+                      vertexStart:0
+                      vertexCount:4
+                    instanceCount:1];
+    [renderEncoder popDebugGroup];
+    [renderEncoder endEncoding];
+
+    [commandBuffer presentDrawable:_view.currentDrawable];
+  }
+
+  // CPU work is completed, GPU work can be started.
+  [commandBuffer commit];
+}
+
+#pragma mark - RTCMTLRenderer
+
+- (void)drawFrame:(RTCVideoFrame *)frame {
+  @autoreleasepool {
+    if ([self setupTexturesForFrame:frame]) {
+      [self render];
+    }
+  }
+}
+
+@end