How to use color interpolation in a Metal shader

We recommend that you clone our Open Source Swift Starter Project, checking out the main branch and carrying out the steps below. The changes can be found on the tutorial/metal/interpolation branch.

The tutorial outlined below supplies a position and color for each vertex, and the render pipeline uses that data to render the triangle, interpolating color values between the colors specified for the triangle’s vertices.

This behavior is considered out-of-the-box and automatic. To learn more consult the guide below.

Follow the tutorial below to setup a MTKView within a UIView that shows a polygon.

Update the metal shader to the code found below.

This metal shader:

• Determine the color based on the angular position of the vertex to create a color wheel.
• Passes data from the swift file to the metal shader using a methodology explained in a link below.
• Passes data from the vertex function to the fragment function using a methodology explained in a link below.
  

Please note that we renamed the Metal shader to ColorWheelPolygonMetalShader.metal.

Run the code on a device and confirm that the shader works as expected.

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