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/*
* 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 {
if (self = [super init]) {
_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_NOTREACHED() << "Virtual method not implemented in subclass.";
return nil;
}
- (void)uploadTexturesToRenderEncoder:(id<MTLRenderCommandEncoder>)renderEncoder {
RTC_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 RTCVideoFrame *)frame {
RTC_NOTREACHED() << "Virtual method not implemented in subclass.";
}
- (BOOL)setupTexturesForFrame:(nonnull RTCVideoFrame *)frame {
// Apply rotation override if set.
RTCVideoRotation rotation;
NSValue *rotationOverride = self.rotationOverride;
if (rotationOverride) {
#if defined(__IPHONE_11_0) && (__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 {
// 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: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:(RTCVideoFrame *)frame {
@autoreleasepool {
if ([self setupTexturesForFrame:frame]) {
[self render];
}
}
}
@end