sdk/objc/components/renderer/metal/RTCMTLRenderer.mm - src - Git at Google

 /*
  *  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 "base/RTCLogging.h"
 #import "base/RTCVideoFrame.h"
 #import "base/RTCVideoFrameBuffer.h"

 #include "api/video/video_rotation.h"
 #include "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";

 // Computes the texture coordinates given rotation and cropping.
 static inline void getCubeVertexData(int cropX,
                                      int cropY,
                                      int cropWidth,
                                      int cropHeight,
                                      size_t frameWidth,
                                      size_t frameHeight,
                                      RTCVideoRotation rotation,
                                      float *buffer) {
   // The computed values are the adjusted texture coordinates, in [0..1].
   // For the left and top, 0.0 means no cropping and e.g. 0.2 means we're skipping 20% of the
   // left/top edge.
   // For the right and bottom, 1.0 means no cropping and e.g. 0.8 means we're skipping 20% of the
   // right/bottom edge (i.e. render up to 80% of the width/height).
   float cropLeft = cropX / (float)frameWidth;
   float cropRight = (cropX + cropWidth) / (float)frameWidth;
   float cropTop = cropY / (float)frameHeight;
   float cropBottom = (cropY + cropHeight) / (float)frameHeight;

   // These arrays map the view coordinates to texture coordinates, taking cropping and rotation
   // into account. The first two columns are view coordinates, the last two are texture coordinates.
   switch (rotation) {
     case RTCVideoRotation_0: {
       float values[16] = {-1.0, -1.0, cropLeft, cropBottom,
                            1.0, -1.0, cropRight, cropBottom,
                           -1.0,  1.0, cropLeft, cropTop,
                            1.0,  1.0, cropRight, cropTop};
       memcpy(buffer, &values, sizeof(values));
     } break;
     case RTCVideoRotation_90: {
       float values[16] = {-1.0, -1.0, cropRight, cropBottom,
                            1.0, -1.0, cropRight, cropTop,
                           -1.0,  1.0, cropLeft, cropBottom,
                            1.0,  1.0, cropLeft, cropTop};
       memcpy(buffer, &values, sizeof(values));
     } break;
     case RTCVideoRotation_180: {
       float values[16] = {-1.0, -1.0, cropRight, cropTop,
                            1.0, -1.0, cropLeft, cropTop,
                           -1.0,  1.0, cropRight, cropBottom,
                            1.0,  1.0, cropLeft, cropBottom};
       memcpy(buffer, &values, sizeof(values));
     } break;
     case RTCVideoRotation_270: {
       float values[16] = {-1.0, -1.0, cropLeft, cropTop,
                            1.0, -1.0, cropLeft, cropBottom,
                           -1.0, 1.0, cropRight, cropTop,
                            1.0, 1.0, cropRight, cropBottom};
       memcpy(buffer, &values, sizeof(values));
     } break;
   }
 }

 // 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;

   // Values affecting the vertex buffer. Stored for comparison to avoid unnecessary recreation.
   int _oldFrameWidth;
   int _oldFrameHeight;
   int _oldCropWidth;
   int _oldCropHeight;
   int _oldCropX;
   int _oldCropY;
   RTCVideoRotation _oldRotation;
 }

 @synthesize rotationOverride = _rotationOverride;

 - (instancetype)init {
   self = [super init];
   if (self) {
     _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]) {
     _view = view;
     view.device = _device;
     view.preferredFramesPerSecond = 30;
     view.autoResizeDrawable = NO;

     [self loadAssets];

     float vertexBufferArray[16] = {0};
     _vertexBuffer = [_device newBufferWithBytes:vertexBufferArray
                                          length:sizeof(vertexBufferArray)
                                         options:MTLResourceCPUCacheModeWriteCombined];
     success = YES;
   }
   return success;
 }
 #pragma mark - Inheritance

 - (id<MTLDevice>)currentMetalDevice {
   return _device;
 }

 - (NSString *)shaderSource {
   RTC_DCHECK_NOTREACHED() << "Virtual method not implemented in subclass.";
   return nil;
 }

 - (void)uploadTexturesToRenderEncoder:(id<MTLRenderCommandEncoder>)renderEncoder {
   RTC_DCHECK_NOTREACHED() << "Virtual method not implemented in subclass.";
 }

 - (void)getWidth:(int *)width
           height:(int *)height
        cropWidth:(int *)cropWidth
       cropHeight:(int *)cropHeight
            cropX:(int *)cropX
            cropY:(int *)cropY
          ofFrame:(nonnull RTC_OBJC_TYPE(RTCVideoFrame) *)frame {
   RTC_DCHECK_NOTREACHED() << "Virtual method not implemented in subclass.";
 }

 - (BOOL)setupTexturesForFrame:(nonnull RTC_OBJC_TYPE(RTCVideoFrame) *)frame {
   // Apply rotation override if set.
   RTCVideoRotation rotation;
   NSValue *rotationOverride = self.rotationOverride;
   if (rotationOverride) {
 #if defined(__IPHONE_11_0) && defined(__IPHONE_OS_VERSION_MAX_ALLOWED) && \
     (__IPHONE_OS_VERSION_MAX_ALLOWED >= __IPHONE_11_0)
     if (@available(iOS 11, *)) {
       [rotationOverride getValue:&rotation size:sizeof(rotation)];
     } else
 #endif
     {
       [rotationOverride getValue:&rotation];
     }
   } else {
     rotation = frame.rotation;
   }

   int frameWidth, frameHeight, cropWidth, cropHeight, cropX, cropY;
   [self getWidth:&frameWidth
           height:&frameHeight
        cropWidth:&cropWidth
       cropHeight:&cropHeight
            cropX:&cropX
            cropY:&cropY
          ofFrame:frame];

   // Recompute the texture cropping and recreate vertexBuffer if necessary.
   if (cropX != _oldCropX || cropY != _oldCropY || cropWidth != _oldCropWidth ||
       cropHeight != _oldCropHeight || rotation != _oldRotation || frameWidth != _oldFrameWidth ||
       frameHeight != _oldFrameHeight) {
     getCubeVertexData(cropX,
                       cropY,
                       cropWidth,
                       cropHeight,
                       frameWidth,
                       frameHeight,
                       rotation,
                       (float *)_vertexBuffer.contents);
     _oldCropX = cropX;
     _oldCropY = cropY;
     _oldCropWidth = cropWidth;
     _oldCropHeight = cropHeight;
     _oldRotation = rotation;
     _oldFrameWidth = frameWidth;
     _oldFrameHeight = frameHeight;
   }

   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;
   NSString *shaderSource = [self shaderSource];

   id<MTLLibrary> sourceLibrary =
       [_device newLibraryWithSource: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)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)render {
   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:0 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:(RTC_OBJC_TYPE(RTCVideoFrame) *)frame {
   @autoreleasepool {
     // Wait until the inflight (curently sent to GPU) command buffer
     // has completed the GPU work.
     dispatch_semaphore_wait(_inflight_semaphore, DISPATCH_TIME_FOREVER);

     if ([self setupTexturesForFrame:frame]) {
       [self render];
     } else {
       dispatch_semaphore_signal(_inflight_semaphore);
     }
   }
 }

 @end
	/*
	* 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 "base/RTCLogging.h"
	#import "base/RTCVideoFrame.h"
	#import "base/RTCVideoFrameBuffer.h"

	#include "api/video/video_rotation.h"
	#include "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";

	// Computes the texture coordinates given rotation and cropping.
	static inline void getCubeVertexData(int cropX,
	int cropY,
	int cropWidth,
	int cropHeight,
	size_t frameWidth,
	size_t frameHeight,
	RTCVideoRotation rotation,
	float *buffer) {
	// The computed values are the adjusted texture coordinates, in [0..1].
	// For the left and top, 0.0 means no cropping and e.g. 0.2 means we're skipping 20% of the
	// left/top edge.
	// For the right and bottom, 1.0 means no cropping and e.g. 0.8 means we're skipping 20% of the
	// right/bottom edge (i.e. render up to 80% of the width/height).
	float cropLeft = cropX / (float)frameWidth;
	float cropRight = (cropX + cropWidth) / (float)frameWidth;
	float cropTop = cropY / (float)frameHeight;
	float cropBottom = (cropY + cropHeight) / (float)frameHeight;

	// These arrays map the view coordinates to texture coordinates, taking cropping and rotation
	// into account. The first two columns are view coordinates, the last two are texture coordinates.
	switch (rotation) {
	case RTCVideoRotation_0: {
	float values[16] = {-1.0, -1.0, cropLeft, cropBottom,
	1.0, -1.0, cropRight, cropBottom,
	-1.0, 1.0, cropLeft, cropTop,
	1.0, 1.0, cropRight, cropTop};
	memcpy(buffer, &values, sizeof(values));
	} break;
	case RTCVideoRotation_90: {
	float values[16] = {-1.0, -1.0, cropRight, cropBottom,
	1.0, -1.0, cropRight, cropTop,
	-1.0, 1.0, cropLeft, cropBottom,
	1.0, 1.0, cropLeft, cropTop};
	memcpy(buffer, &values, sizeof(values));
	} break;
	case RTCVideoRotation_180: {
	float values[16] = {-1.0, -1.0, cropRight, cropTop,
	1.0, -1.0, cropLeft, cropTop,
	-1.0, 1.0, cropRight, cropBottom,
	1.0, 1.0, cropLeft, cropBottom};
	memcpy(buffer, &values, sizeof(values));
	} break;
	case RTCVideoRotation_270: {
	float values[16] = {-1.0, -1.0, cropLeft, cropTop,
	1.0, -1.0, cropLeft, cropBottom,
	-1.0, 1.0, cropRight, cropTop,
	1.0, 1.0, cropRight, cropBottom};
	memcpy(buffer, &values, sizeof(values));
	} break;
	}
	}

	// 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;

	// Values affecting the vertex buffer. Stored for comparison to avoid unnecessary recreation.
	int _oldFrameWidth;
	int _oldFrameHeight;
	int _oldCropWidth;
	int _oldCropHeight;
	int _oldCropX;
	int _oldCropY;
	RTCVideoRotation _oldRotation;
	}

	@synthesize rotationOverride = _rotationOverride;

	- (instancetype)init {
	self = [super init];
	if (self) {
	_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]) {
	_view = view;
	view.device = _device;
	view.preferredFramesPerSecond = 30;
	view.autoResizeDrawable = NO;

	[self loadAssets];

	float vertexBufferArray[16] = {0};
	_vertexBuffer = [_device newBufferWithBytes:vertexBufferArray
	length:sizeof(vertexBufferArray)
	options:MTLResourceCPUCacheModeWriteCombined];
	success = YES;
	}
	return success;
	}
	#pragma mark - Inheritance

	- (id<MTLDevice>)currentMetalDevice {
	return _device;
	}

	- (NSString *)shaderSource {
	RTC_DCHECK_NOTREACHED() << "Virtual method not implemented in subclass.";
	return nil;
	}

	- (void)uploadTexturesToRenderEncoder:(id<MTLRenderCommandEncoder>)renderEncoder {
	RTC_DCHECK_NOTREACHED() << "Virtual method not implemented in subclass.";
	}

	- (void)getWidth:(int *)width
	height:(int *)height
	cropWidth:(int *)cropWidth
	cropHeight:(int *)cropHeight
	cropX:(int *)cropX
	cropY:(int *)cropY
	ofFrame:(nonnull RTC_OBJC_TYPE(RTCVideoFrame) *)frame {
	RTC_DCHECK_NOTREACHED() << "Virtual method not implemented in subclass.";
	}

	- (BOOL)setupTexturesForFrame:(nonnull RTC_OBJC_TYPE(RTCVideoFrame) *)frame {
	// Apply rotation override if set.
	RTCVideoRotation rotation;
	NSValue *rotationOverride = self.rotationOverride;
	if (rotationOverride) {
	#if defined(__IPHONE_11_0) && defined(__IPHONE_OS_VERSION_MAX_ALLOWED) && \
	(__IPHONE_OS_VERSION_MAX_ALLOWED >= __IPHONE_11_0)
	if (@available(iOS 11, *)) {
	[rotationOverride getValue:&rotation size:sizeof(rotation)];
	} else
	#endif
	{
	[rotationOverride getValue:&rotation];
	}
	} else {
	rotation = frame.rotation;
	}

	int frameWidth, frameHeight, cropWidth, cropHeight, cropX, cropY;
	[self getWidth:&frameWidth
	height:&frameHeight
	cropWidth:&cropWidth
	cropHeight:&cropHeight
	cropX:&cropX
	cropY:&cropY
	ofFrame:frame];

	// Recompute the texture cropping and recreate vertexBuffer if necessary.
	if (cropX != _oldCropX \|\| cropY != _oldCropY \|\| cropWidth != _oldCropWidth \|\|
	cropHeight != _oldCropHeight \|\| rotation != _oldRotation \|\| frameWidth != _oldFrameWidth \|\|
	frameHeight != _oldFrameHeight) {
	getCubeVertexData(cropX,
	cropY,
	cropWidth,
	cropHeight,
	frameWidth,
	frameHeight,
	rotation,
	(float *)_vertexBuffer.contents);
	_oldCropX = cropX;
	_oldCropY = cropY;
	_oldCropWidth = cropWidth;
	_oldCropHeight = cropHeight;
	_oldRotation = rotation;
	_oldFrameWidth = frameWidth;
	_oldFrameHeight = frameHeight;
	}

	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;
	NSString *shaderSource = [self shaderSource];

	id<MTLLibrary> sourceLibrary =
	[_device newLibraryWithSource: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)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)render {
	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:0 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:(RTC_OBJC_TYPE(RTCVideoFrame) *)frame {
	@autoreleasepool {
	// Wait until the inflight (curently sent to GPU) command buffer
	// has completed the GPU work.
	dispatch_semaphore_wait(_inflight_semaphore, DISPATCH_TIME_FOREVER);

	if ([self setupTexturesForFrame:frame]) {
	[self render];
	} else {
	dispatch_semaphore_signal(_inflight_semaphore);
	}
	}
	}

	@end