CSM Shaders (1.20.4, 1.19.4) – Cascaded Shadow Mapping for Minecraft

CSM Shaders is a proof-of-concept shader that demonstrates cascaded shadow mapping in Minecraft. It’s a learning resource and template for other shader creators, not a finished product.

Features

What’s Included

• Dynamic shadows
• Colored shadows from translucent blocks like stained glass
• Shadow bias to prevent shadow acne
• Shadow distortion for better detail near the player
• Examples of excluding certain blocks from shadows

What’s Not Included

• PCSS
• Volumetric light
• Custom light colors (uses vanilla lightmap)
• Block shading

Shadow Modes

None – No shadows at all. Use this for performance testing.

Basic – Standard Optifine shadow mapping without improvements. Looks rough, but shows the baseline.

Distorted – Adds distortion to improve nearby shadow detail. Much better quality, but long shadows will appear warped.

Cascading – Splits shadows into 4 cascades with varying detail. Great quality without distortion, though transitions between cascades may be visible.

Filter Types

None – Binary shadows with no filtering.

PCF – Percent-closer filtering softens shadow edges. Fixed softening, but can create artifacts at different light angles.

PCF + PCSS – Extends PCF with percent-closer soft shadows. Uses a pre-blocker check to adjust filter radius, eliminating PCF artifacts.

Requirements

You need Optifine. Iris Shaders Mod is optional.

How to Install

See our guide on how to download and install shaders with Optifine for detailed steps.

Compatible Versions

Minecraft 1.20.4 and 1.19.4.

Download