SyphonServerRendererMetal.m

/*
 SyphonServerRendererMetal.m
 Syphon
 
 Copyright 2020-2023 Maxime Touroute & Philippe Chaurand (www.millumin.com),
 bangnoise (Tom Butterworth) & vade (Anton Marini). All rights reserved.
 
 Redistribution and use in source and binary forms, with or without
 modification, are permitted provided that the following conditions are met:
 
 * Redistributions of source code must retain the above copyright
 notice, this list of conditions and the following disclaimer.
 
 * Redistributions in binary form must reproduce the above copyright
 notice, this list of conditions and the following disclaimer in the
 documentation and/or other materials provided with the distribution.
 
 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY
 DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#import "SyphonServerRendererMetal.h"
#include <simd/simd.h>
#include "SyphonServerMetalTypes.h"

@implementation SyphonServerRendererMetal
{
    id<MTLRenderPipelineState> _pipelineState;
}

- (nonnull instancetype)initWithDevice:(id<MTLDevice>)device colorPixelFormat:(MTLPixelFormat)colorPixelFormat
{
    self = [super init];
    if( self )
    {
        NSError *error = NULL;
        NSBundle *bundle = [NSBundle bundleForClass:[self class]];
        id<MTLLibrary> defaultLibrary = [device newDefaultLibraryWithBundle:bundle error:&error];
        if(error)
        {
            SYPHONLOG(@"Metal library could not be loaded:%@", error);
        }
        
        // Load the vertex/shader function from the library
        id <MTLFunction> vertexFunction = [defaultLibrary newFunctionWithName:@"textureToScreenVertexShader"];
        id <MTLFunction> fragmentFunction = [defaultLibrary newFunctionWithName:@"textureToScreenSamplingShader"];
        
        
        // Set up a descriptor for creating a pipeline state object
        MTLRenderPipelineDescriptor *pipelineStateDescriptor = [MTLRenderPipelineDescriptor new];
        pipelineStateDescriptor.label = @"Syphon Pipeline";
        pipelineStateDescriptor.vertexFunction = vertexFunction;
        pipelineStateDescriptor.fragmentFunction = fragmentFunction;
        pipelineStateDescriptor.colorAttachments[0].pixelFormat = colorPixelFormat;
        
        _pipelineState = [device newRenderPipelineStateWithDescriptor:pipelineStateDescriptor error:&error];
        
        
        if( !_pipelineState )
        {
            SYPHONLOG(@"Failed to createe pipeline state, error %@", error);
            return nil;
        }
    }
    return self;
}


- (void)renderFromTexture:(id<MTLTexture>)offScreenTexture inTexture:(id<MTLTexture>)texture region:(NSRect)region onCommandBuffer:(id<MTLCommandBuffer>)commandBuffer flip:(BOOL)flip
{
    if( texture == nil )
    {
        return;
    }
    
    const MTLViewport viewport = (MTLViewport){region.origin.x, region.origin.y, region.size.width, region.size.height, -1.0, 1.0 };
    vector_uint2 viewportSize = simd_make_uint2(viewport.width, viewport.height);
    
    const float w = viewport.width/2;
    const float h = viewport.height/2;
    const float flipValue = flip ? 1 : -1;
    
    const SYPHONTextureVertex quadVertices[] =
    {
        // Pixel positions (NDC), Texture coordinates
        { {  w,   flipValue * h },  { 1.f, 1.f } },
        { { -w,   flipValue * h },  { 0.f, 1.f } },
        { { -w,  flipValue * -h },  { 0.f, 0.f } },
        
        { {  w,  flipValue * h },  { 1.f, 1.f } },
        { { -w,  flipValue * -h },  { 0.f, 0.f } },
        { {  w,  flipValue * -h },  { 1.f, 0.f } },
    };
    
    const NSUInteger numberOfVertices = sizeof(quadVertices) / sizeof(SYPHONTextureVertex);
    MTLRenderPassDescriptor *renderPassDescriptor = [MTLRenderPassDescriptor renderPassDescriptor];
    renderPassDescriptor.colorAttachments[0].loadAction = MTLLoadActionClear;
    renderPassDescriptor.colorAttachments[0].clearColor = MTLClearColorMake(0, 0, 0, 0);
    renderPassDescriptor.colorAttachments[0].texture = texture;
    renderPassDescriptor.colorAttachments[0].storeAction = MTLStoreActionStore;
    
    // Create a render command encoder so we can render into something
    id<MTLRenderCommandEncoder> renderEncoder = [commandBuffer renderCommandEncoderWithDescriptor:renderPassDescriptor];
    renderEncoder.label = @"Syphon Server Render Encoder";
    [renderEncoder setViewport:viewport];
    [renderEncoder setRenderPipelineState:_pipelineState];
    [renderEncoder setVertexBytes:quadVertices length:sizeof(quadVertices) atIndex:SYPHONVertexInputIndexVertices];
    [renderEncoder setVertexBytes:&viewportSize length:sizeof(viewportSize) atIndex:SYPHONVertexInputIndexViewportSize];
    [renderEncoder setFragmentTexture:offScreenTexture atIndex:SYPHONTextureIndexZero];
    [renderEncoder drawPrimitives:MTLPrimitiveTypeTriangle vertexStart:0 vertexCount:numberOfVertices];
    [renderEncoder endEncoding];
}

@end