Target and optimize GPU binaries with Metal 3

4:47 - Using a JSON editor: render pipeline descriptor

// An existing Obj-C render pipeline descriptor
NSError *error = nil;
id<MTLDevice> device = MTLCreateSystemDefaultDevice();

id<MTLLibrary> library = [device newLibraryWithFile:@"default.metallib" error:&error];

MTLRenderPipelineDescriptor *desc = [MTLRenderPipelineDescriptor new];
desc.vertexFunction = [library newFunctionWithName:@"vert_main"];
desc.fragmentFunction = [library newFunctionWithName:@"frag_main"];
desc.rasterSampleCount = 2;
desc.colorAttachments[0].pixelFormat = MTLPixelFormatBGRA8Unorm;
desc.depthAttachmentPixelFormat = MTLPixelFormatDepth32Float;

4:47 - Using a JSON editor: pipelines script

{
  "//comment": "Its equivalent new JSON script",
  "libraries": {
    "paths": [
      {
        "path": "default.metallib"
      }
    ]
  },
  "pipelines": {
    "render_pipelines": [
      {
        "vertex_function": "vert_main",
        "fragment_function": "frag_main",
        "raster_sample_count": 2,
        "color_attachments": [
          {
            "pixel_format": "BGRA8Unorm"
          },
        ],
        "depth_attachment_pixel_format": "Depth32Float"
      }
    ]
  }
}

5:33 - Harvesting sample

// Create pipeline descriptor
MTLRenderPipelineDescriptor *pipeline_desc = [MTLRenderPipelineDescriptor new];
pipeline_desc.vertexFunction = [library newFunctionWithName:@"vert_main"];
pipeline_desc.fragmentFunction = [library newFunctionWithName:@"frag_main"];
pipeline_desc.rasterSampleCount = 2;
pipeline_desc.colorAttachments[0].pixelFormat = MTLPixelFormatBGRA8Unorm;
pipeline_desc.depthAttachmentPixelFormat = MTLPixelFormatDepth32Float;

// Add pipeline descriptor to new archive
MTLBinaryArchiveDescriptor* archive_desc = [MTLBinaryArchiveDescriptor new];
id<MTLBinaryArchive> archive = [device newBinaryArchiveWithDescriptor:archive_desc error:&error];
bool success = [archive addRenderPipelineFunctionsWithDescriptor:pipeline_desc error:&error];

// Serialize archive to file system
NSURL *url = [NSURL fileURLWithPath:@"harvested-binaryArchive.metallib"];
success = [archive serializeToURL:url error:&error];

6:01 - Extracting a JSON script

metal-source -flatbuffers=json harvested-binaryArchive.metallib -o /tmp/descriptors.mtlp-json

6:24 - Generate a GPU binary from source

metal shaders.metal -N descriptors.mtlp-json -o archive.metallib

6:48 - Generate a GPU binary from Metal library

metal-tt shaders.metallib descriptors.mtlp-json -o archive.metallib

7:07 - Load GPU binaries via the runtime API

MTLBinaryArchiveDescriptor *desc = [MTLBinaryArchiveDescriptor new];
desc.url = [NSURL fileURLWithPath:@"archive.metallib"];
NSError *error = nil;
id<MTLDevice> device = MTLCreateSystemDefaultDevice();
id<MTLBinaryArchive> binaryArchive = [device newBinaryArchiveWithDescriptor:desc error:&error];

12:11 - Enable optimize for size in command lines

xcrun metal -Os large_shader.metal

# or

xcrun metal -c -Os large_shader.metal
xcrun metal -c     more_shaders.metal
xcrun metal large_shader.air more_shaders.air

12:44 - Enable optimize for size with Metal framework

MTLCompileOptions* options = [MTLCompileOptions new];
options.optimizationLevel = MTLLibraryOptimizationLevelSize;

NSString* source = @"...";
NSError* error = nil;
id<MTLLibrary> lib = [device newLibraryWithSource:source
                                          options:options
                                            error:&error];