A target that did not resize, and what targets cost
Sizes are printed in real pixels. The last two lines are plain arithmetic: width × height × bytes per pixel.
A render target is a picture the GPU draws into instead of the screen. It becomes a texture you can show on a mirror, a screen inside the scene, or feed to an effect. It costs memory, and it does not resize by itself.
Change the code and press Run (Ctrl+Enter). Predict what will happen first, then break it on purpose and read what changes. Your edits are saved and match the lesson page.
Ready for more? This phase has 4 hands-on exercises with automatic checks.
Practice questions
Write the code in the editor, run it, then open the model answer to compare.
Compute the memory of a half-float target for a 1366 × 768 screen at ratio 1, and of a chain holding two.
Write the lines that draw photoScene into target and then world to the canvas, restoring whatever target was active before.
Explain it without notes
What is a render target, and when would a showroom need one?
Why does a render target not resize with the canvas, and how do you keep them in step on a phone with pixel ratio 3?
Console
Nothing logged yet.Expected console output
start: canvas 300 x 150 | target 300 x 150
resized: canvas 600 x 300 | target 300 x 150 <- the target did not follow
fixed: canvas 1200 x 600 | target 1200 x 600
1920 x 1080, ratio 1 | 8-bit RGBA 7.9 MB | half-float RGBA 15.8 MB | a composer holds two of the half-float ones: 31.6 MB
390 x 844, ratio 3 | 8-bit RGBA 11.3 MB | half-float RGBA 22.6 MB | a composer holds two of the half-float ones: 45.2 MB