What happened?
Since Minecraft 1.21.5, there has been a significant performance degradation when using Iris. After investigation, I've traced the root cause to an inefficient rendering mode in HorizonRenderer.java.
The issue stems from a mismatch between the generated vertex primitive type (QUADS) and the format expected by Minecraft's new RenderPass system for the sky pipeline (RenderPipelines.SKY), which is TRIANGLE_FAN.
It effectively tripling the number of primitives to be rendered. On my hardware, this single draw call takes up to 9ms, reducing my framerate to around 30 FPS.
Screenshots
1.21.4:
1.21.5:
Log output
No response
Minecraft Version
≥Minecraft 1.21.5
Iris Version
≥1.8.8
Operating System
Windows 11
What is your GPU?
Nvidia GeForce GTX 1060 3GB
Additional context
No response
What happened?
Since Minecraft 1.21.5, there has been a significant performance degradation when using Iris. After investigation, I've traced the root cause to an inefficient rendering mode in HorizonRenderer.java.
The issue stems from a mismatch between the generated vertex primitive type (QUADS) and the format expected by Minecraft's new RenderPass system for the sky pipeline (RenderPipelines.SKY), which is TRIANGLE_FAN.
It effectively tripling the number of primitives to be rendered. On my hardware, this single draw call takes up to 9ms, reducing my framerate to around 30 FPS.
Screenshots
1.21.4:
1.21.5:
Log output
No response
Minecraft Version
≥Minecraft 1.21.5
Iris Version
≥1.8.8
Operating System
Windows 11
What is your GPU?
Nvidia GeForce GTX 1060 3GB
Additional context
No response