recipes · recipe ·
Example · Paint an image with compute
Map a one-dimensional buffer index to a two-dimensional pixel.
An image is a grid, but a buffer is a sequence. We can store rows one after another. For a width of 32, index / 32 gives the row. Subtract row * 32 from index to find the column. This kernel fills a 32 by 32 grayscale image. The pixel value combines horizontal and vertical ramps, producing a diagonal gradient. The host prints the integer pixels; the displayed image was saved from the actual Metal output.
start.yh · compute exampleStatus: complete-program
Example · Paint an image with compute
Map a one-dimensional buffer index to a two-dimensional pixel.
gpu · cpu · type checked
[auto]
compute Paint(buffer of int pixels)
{
int index = compute.index
if index >= pixels.count { return }
int y = index / 32
int x = index - y * 32
float red = Math.IntToFloat(x) / 31.0
float green = Math.IntToFloat(y) / 31.0
pixels[index] = Math.RoundToInt((red + green) * 0.5 * 255.0)
}
buffer of int pixels
pixels.Resize(1024)
computeTask job = dispatch Paint(pixels)
wait job
if job.failed { Console.Error(job.error.message) Process.Exit(1) }
for index from 0 < pixels.count { Console.Log(Text.From(pixels[index])) }project.mech
manifestVersion = "2"
package = "api.example.recipe__compute_image"
version = "0.1.0"
languageEdition = "yeho-core-2026.1"
[app]
kind = "headless"
Notes and source
Use red alone for the output, then green alone. Compare horizontal, vertical, and combined gradients.
demonhunterlabs/app/lib/yeho-walkthrough.ts