Using Basis Universal Texture Compression with Metal

In this short article, we’ll take a look at a relatively new compressed texture format called Basis. Basis is developed by Binomial, LLC, a company founded by Rich Geldreich (of crunch fame) and Stephanie Hurlburt. Basis is unique among compression formats in that it emphasizes efficient transcoding between compressed formats. This means that a single …

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What’s New in Metal (2019)

With WWDC 2019 over, it’s a good time to reflect on everything that was announced and start seeing how we can put it into practice. The purpose of this article is to round up the changes to the Metal framework and tools and provide pointers to where you can learn more. This was a banner …

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Rendering Physically-Based ModelIO Materials

In this article, we’ll take a look at a portion of the ModelIO framework we haven’t used so far: materials. In previous articles, we’ve used ModelIO to do the heavy lifting of loading 3D geometry, but have loaded and applied textures manually. This ad hoc approach works when we only have a base color map, …

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Translucency and Transparency in Metal

Introduction One of the topics we’ve handily avoided so far in our exploration of Metal is rendering of materials that are not opaque. In this post, we’ll explore a couple of related techniques for achieving transparency and translucency: alpha testing and alpha blending. The sample scene for this post is a desert containing many palm …

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Instanced Rendering in Metal

In this article, we will discuss an important technique for efficiently drawing many objects with a single draw call: instanced rendering. This technique helps you get the most out of the GPU while keeping memory and CPU usage to a minimum. The sample app for this post renders several dozen animated cows moving on top …

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Cubic Environment Mapping in Metal: Reflection and Refraction

In this post, we’ll talk about some of the more advanced features of texturing in Metal. We’ll apply a cube map to a skybox to simulate a detailed environment surrounding the scene. We’ll also introduce a technique called cubic environment mapping to simulate reflection and refraction, to further enhance the realism of our virtual world.

Fundamentals of Image Processing in Metal

In this post, we will start exploring the world of image processing with the Metal shading language. We will create a framework capable of representing chains of image filters, then write a pair of image filters that will allow us to adjust the saturation and blur of an image. The end result will be an …

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Introduction to Compute Programming in Metal

This post is an introduction to topics in compute (or data-parallel) programming. It is designed to be read before its companion article, Fundamentals of Image Processing. In this article, we will cover the basics of setting up the compute pipeline and executing kernel functions on large sets of data in parallel. The companion article covers …

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Feature Sets and Capabilities

One of the changes made to the Metal API in the iOS 8 GM was the addition of the supportsFeatureSet: method to the MTLDevice protocol. The purpose of this method is to differentiate between devices powered by the A7 and A8 processor, because these chips offer different capabilities to Metal.