Program Metal in C++ with metal-cpp

3:10 - Draw a single triangle in C++

MTL::CommandBuffer* pCmd = _pCommandQueue->commandBuffer();
MTL::RenderCommandEncoder* pEnc = pCmd->renderCommandEncoder( pRpd );
pEnc->setRenderPipelineState( _pPSO );
pEnc->drawPrimitives( MTL::PrimitiveTypeTriangle, 
                      NS::UInteger(0), 
                      NS::UInteger(3));
pEnc->endEncoding();
pCmd->presentDrawable( pView->currentDrawable() );
pCmd->commit();

3:27 - Draw a single triangle in Objective-C

id<MTLCommandBuffer> cmd = [_commandQueue commandBuffer];
id<MTLRenderCommandEncoder> enc = [cmd renderCommandEncoderWithDescriptor:pRpd];
[enc setRenderPipelineState:_pPSO];
[enc drawPrimitives:MTLPrimitiveTypeTriangle 
        vertexStart:0 
        vertexCount:3];
[enc endEncoding];
[cmd presentDrawable:view.currentDrawable];
[cmd commit];

6:10 - Generate the implementation

#define NS_PRIVATE_IMPLEMENTATION
#define CA_PRIVATE_IMPLEMENTATION
#define MTL_PRIVATE_IMPLEMENTATION

#include <Foundation/Foundation.hpp>
#include <Metal/Metal.hpp>
#include <QuartzCore/QuartzCore.hpp>

11:46 - How to use autoreleased objects and AutoreleasePool

NS::AutoreleasePool* pPool = NS::AutoreleasePool::alloc()->init();
MTL::CommandBuffer* pCmd = _pCommandQueue->commandBuffer();
MTL::RenderPassDescriptor* pRpd = pView->currentRenderPassDescriptor();
MTL::RenderCommandEncoder* pEnc = pCmd->renderCommandEncoder( pRpd );
pEnc->endEncoding();
pCmd->presentDrawable( pView->currentDrawable() );
pCmd->commit();
pPool->release();

11:47 - How NS::TransferPtr works

{
   auto ptr = NS::TransferPtr( pMRR );
   // Do something with ptr 
   . . . 
}

17:19 - How NS::RetainPtr works

{
   auto ptr = NS::RetainPtr( pMRR );
   // Do something with ptr 
   . . . 
}

20:43 - Create an adapter class calling C++ from Objective-C files

@interface AAPLRendererAdapter () 
{
    AAPLRenderer* _pRenderer;
}
@end

@implementation AAPLRendererAdapter
- (void)drawInMTKView:(MTKView *)pMtkView
{
    _pRenderer->draw((__bridge MTK::View*)pMtkView);
}

@end

21:49 - Create an adapter class calling Objective-C from C++ files

CA::MetalDrawable* AAPLViewAdapter::currentDrawable() const
{
    return (__bridge CA::MetalDrawable*)[(__bridge MTKView *)m_pMTKView currentDrawable];
}

MTL::Texture* AAPLViewAdapter::depthStencilTexture() const
{
    return (__bridge MTL::Texture*)[(__bridge MTKView *)m_pMTKView depthStencilTexture];
}

24:59 - Cast between Objective-C and C++ objects and transfer ownership

MTL::Texture* newTextureFromCatalog( MTL::Device* pDevice, const char* name,   
                                     MTL::StorageMode storageMode, MTL::TextureUsage usage )
{
    NSDictionary<MTKTextureLoaderOption, id>* options = @{
            MTKTextureLoaderOptionTextureStorageMode : @( (MTLStorageMode)storageMode ),
            MTKTextureLoaderOptionTextureUsage : @( (MTLTextureUsage)usage )
    };

    MTKTextureLoader* textureLoader = [[MTKTextureLoader alloc] 
                                        initWithDevice:(__bridge id<MTLDevice>)pDevice];
    
    NSError* __autoreleasing err = nil;
    id< MTLTexture > texture = [textureLoader 
                        newTextureWithName:[NSString stringWithUTF8String:name] 
                               scaleFactor:1 
                                            bundle:nil 
                                           options:options 
                                             error:&err];

    return (__bridge_retained MTL::Texture*)texture;
}