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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 "RTCMTLI420Renderer.h"
#import <Metal/Metal.h>
#import <MetalKit/MetalKit.h>
#import "base/RTCI420Buffer.h"
#import "base/RTCLogging.h"
#import "base/RTCVideoFrame.h"
#import "base/RTCVideoFrameBuffer.h"
#import "RTCMTLRenderer+Private.h"
static NSString *const shaderSource = MTL_STRINGIFY(
using namespace metal;
typedef struct {
packed_float2 position;
packed_float2 texcoord;
} Vertex;
typedef struct {
float4 position[[position]];
float2 texcoord;
} Varyings;
vertex Varyings vertexPassthrough(constant Vertex *verticies[[buffer(0)]],
unsigned int vid[[vertex_id]]) {
Varyings out;
constant Vertex &v = verticies[vid];
out.position = float4(float2(v.position), 0.0, 1.0);
out.texcoord = v.texcoord;
return out;
}
fragment half4 fragmentColorConversion(
Varyings in[[stage_in]],
texture2d<float, access::sample> textureY[[texture(0)]],
texture2d<float, access::sample> textureU[[texture(1)]],
texture2d<float, access::sample> textureV[[texture(2)]]) {
constexpr sampler s(address::clamp_to_edge, filter::linear);
float y;
float u;
float v;
float r;
float g;
float b;
y = textureY.sample(s, in.texcoord).r;
u = textureU.sample(s, in.texcoord).r;
v = textureV.sample(s, in.texcoord).r;
u = u - 0.5;
v = v - 0.5;
r = y + 1.403 * v;
g = y - 0.344 * u - 0.714 * v;
b = y + 1.770 * u;
float4 out = float4(r, g, b, 1.0);
return half4(out);
});
@implementation RTCMTLI420Renderer {
// Textures.
id<MTLTexture> _yTexture;
id<MTLTexture> _uTexture;
id<MTLTexture> _vTexture;
MTLTextureDescriptor *_descriptor;
MTLTextureDescriptor *_chromaDescriptor;
int _width;
int _height;
int _chromaWidth;
int _chromaHeight;
}
#pragma mark - Virtual
- (NSString *)shaderSource {
return shaderSource;
}
- (void)getWidth:(nonnull int *)width
height:(nonnull int *)height
cropWidth:(nonnull int *)cropWidth
cropHeight:(nonnull int *)cropHeight
cropX:(nonnull int *)cropX
cropY:(nonnull int *)cropY
ofFrame:(nonnull RTC_OBJC_TYPE(RTCVideoFrame) *)frame {
*width = frame.width;
*height = frame.height;
*cropWidth = frame.width;
*cropHeight = frame.height;
*cropX = 0;
*cropY = 0;
}
- (BOOL)setupTexturesForFrame:(nonnull RTC_OBJC_TYPE(RTCVideoFrame) *)frame {
if (![super setupTexturesForFrame:frame]) {
return NO;
}
id<MTLDevice> device = [self currentMetalDevice];
if (!device) {
return NO;
}
// Chroma size must be >= 1 as per the Apple documentation, so skip ?x1
// and 1x? frames.
if (frame.width < 2 || frame.height < 2) {
return NO;
}
id<RTC_OBJC_TYPE(RTCI420Buffer)> buffer = [frame.buffer toI420];
// Luma (y) texture.
if (!_descriptor || _width != frame.width || _height != frame.height) {
_width = frame.width;
_height = frame.height;
_descriptor = [MTLTextureDescriptor texture2DDescriptorWithPixelFormat:MTLPixelFormatR8Unorm
width:_width
height:_height
mipmapped:NO];
_descriptor.usage = MTLTextureUsageShaderRead;
_yTexture = [device newTextureWithDescriptor:_descriptor];
}
// Chroma (u,v) textures
[_yTexture replaceRegion:MTLRegionMake2D(0, 0, _width, _height)
mipmapLevel:0
withBytes:buffer.dataY
bytesPerRow:buffer.strideY];
if (!_chromaDescriptor || _chromaWidth != frame.width / 2 || _chromaHeight != frame.height / 2) {
_chromaWidth = frame.width / 2;
_chromaHeight = frame.height / 2;
_chromaDescriptor =
[MTLTextureDescriptor texture2DDescriptorWithPixelFormat:MTLPixelFormatR8Unorm
width:_chromaWidth
height:_chromaHeight
mipmapped:NO];
_chromaDescriptor.usage = MTLTextureUsageShaderRead;
_uTexture = [device newTextureWithDescriptor:_chromaDescriptor];
_vTexture = [device newTextureWithDescriptor:_chromaDescriptor];
}
[_uTexture replaceRegion:MTLRegionMake2D(0, 0, _chromaWidth, _chromaHeight)
mipmapLevel:0
withBytes:buffer.dataU
bytesPerRow:buffer.strideU];
[_vTexture replaceRegion:MTLRegionMake2D(0, 0, _chromaWidth, _chromaHeight)
mipmapLevel:0
withBytes:buffer.dataV
bytesPerRow:buffer.strideV];
return (_uTexture != nil) && (_yTexture != nil) && (_vTexture != nil);
}
- (void)uploadTexturesToRenderEncoder:(id<MTLRenderCommandEncoder>)renderEncoder {
[renderEncoder setFragmentTexture:_yTexture atIndex:0];
[renderEncoder setFragmentTexture:_uTexture atIndex:1];
[renderEncoder setFragmentTexture:_vTexture atIndex:2];
}
@end