{"id":126102,"date":"2022-06-08T14:05:16","date_gmt":"2022-06-08T14:05:16","guid":{"rendered":"https:\/\/developer.apple.com\/news\/?id=yrb1yuf3"},"modified":"2022-06-08T14:05:16","modified_gmt":"2022-06-08T14:05:16","slug":"challenge-draw-with-metal-cpp","status":"publish","type":"post","link":"https:\/\/sickgaming.net\/blog\/2022\/06\/08\/challenge-draw-with-metal-cpp\/","title":{"rendered":"Challenge: Draw with metal-cpp"},"content":{"rendered":"
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Metal is the foundation for accelerated graphics and compute power on Apple platforms \u2014 and if you\u2019re familiar with C++, now\u2019s the perfect time to explore its incredible power. For this challenge, we’re inviting you to try out metal-cpp and render your own triangle, sphere, or even a mesh in Xcode.<\/p>\n

We also welcome you to visit the Graphics & Games Study Hall during the day to collaborate on this challenge! Ask questions, connect with other developers, and share your creations.<\/p>\n

Begin the challenge<\/h3>\n

Before you begin, you\u2019ll want to watch \u201cProgram Metal in C++ with metal-cpp\u201d and download the LearnMetalCPP project, which contains a series of C++ samples.<\/p>\n

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Program Metal in C++ with metal-cpp<\/h4>\n

Your C++ games and apps can now tap into the power of Metal. We’ll show you how metal-cpp helps you bridge your C++ code to Metal, explore how each manages object lifecycles, and demonstrate utilities that can help these language cooperate in your app. We’ll also share best practices for designing…<\/p>\n

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Download the LearnMetalCPP project<\/a><\/p>\n

Open the project in Xcode, and choose 00-window.cpp as your base code. To render your image, you\u2019ll need to set up a few things within your project.<\/p>\n

First, create a MTL::RenderPipelineState<\/code> object with a MTL::RenderPipelineDescriptor<\/code>. To do this, you\u2019ll need to create a function, like buildShaders()<\/code>. In the code snippet below, we\u2019ve provided the shader code needed to render a single triangle. <\/p>\n

void Renderer::buildShaders()\n{ using NS::StringEncoding::UTF8StringEncoding; const char* shaderSrc = R\"( #include  using namespace metal; struct AAPLVertex { float3 position; half3 color; }; \/\/ Welcome to modify the mesh as you want constant AAPLVertex triangles[] = { { float3{ -0.8f, 0.8f, 0.0f }, half3{ 1.0, 0.3f, 0.2f } }, { float3{ 0.0f, -0.8f, 0.0f }, half3{ 0.8f, 1.0, 0.0f } }, { float3{ +0.8f, 0.8f, 0.0f }, half3{ 0.8f, 0.0f, 1.0 } } }; struct v2f { float4 position [[position]]; half3 color; }; v2f vertex vertexMain( uint vertexId [[vertex_id]]) { v2f o; o.position = float4( triangles[ vertexId ].position, 1.0 ); o.color = half3 ( triangles[ vertexId ].color ); return o; } half4 fragment fragmentMain( v2f in [[stage_in]] ) { return half4( in.color, 1.0 ); } )\"; \/\/ TODO: Create a MTL::RenderPipelineDescriptor \/\/ TODO: Allocate a MTL::RenderPipelineState object\n}<\/code><\/pre>\n
Then, extend the Renderer::draw( MTK::View* pView)<\/code> function by setting a MTL::RenderPipelineState<\/code> and inserting draw calls. <\/p>\n
void<\/span> Renderer::draw<\/span>( MTK::View* pView )<\/span>\n<\/span>{\n... ...\n}<\/code><\/pre>\n
After that:<\/p>\n