Fix Iris matrices when rendering sublevels

buildSrc/src/main/groovy/multiloader-common.gradle

@@ -93,6 +93,7 @@ repositories {
 dependencies {
     compileOnly "maven.modrinth:lithium:mc1.21.1-0.15.3-neoforge"
     compileOnly "maven.modrinth:sodium:$sodium_version"
+    compileOnly "maven.modrinth:iris:$iris_version"
     compileOnly "maven.modrinth:distanthorizons:$distant_horizons_version"
     compileOnly("cc.tweaked:cc-tweaked-$minecraft_version-forge:$cc_tweaked_version")
     compileOnly("io.github.mortuusars.exposure:exposure-${minecraft_version}-neoforge:${exposure_version}") { transitive = false }

common/src/main/java/dev/ryanhcode/sable/mixin/compatibility/iris/ExtendedShaderMixin.java

@@ -0,0 +1,58 @@
+package dev.ryanhcode.sable.mixin.compatibility.iris;
+
+import com.mojang.blaze3d.shaders.Uniform;
+import dev.ryanhcode.sable.mixinterface.compatibility.iris.ExtendedShaderExtension;
+import net.irisshaders.iris.pipeline.programs.ExtendedShader;
+import net.minecraft.client.renderer.ShaderInstance;
+import org.joml.Matrix3f;
+import org.joml.Matrix4f;
+import org.spongepowered.asm.mixin.Final;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Shadow;
+import org.spongepowered.asm.mixin.Unique;
+
+@Mixin(ExtendedShader.class)
+public class ExtendedShaderMixin implements ExtendedShaderExtension {
+
+    @Shadow
+    @Final
+    private Uniform modelViewInverse;
+
+    @Shadow
+    @Final
+    private Uniform normalMatrix;
+
+    @Shadow
+    @Final
+    private Matrix4f tempMatrix4f;
+
+    @Shadow
+    @Final
+    private Matrix3f tempMatrix3f;
+
+    @Shadow
+    @Final
+    private float[] tempFloats;
+
+    @Shadow
+    @Final
+    private float[] tempFloats2;
+
+    @Override
+    @Unique
+    public void sable$refreshModelViewDerivedMatrices() {
+        final var modelView = ((ShaderInstance) (Object) this).MODEL_VIEW_MATRIX;
+
+        if (modelView != null) {
+            if (this.modelViewInverse != null) {
+                this.modelViewInverse.set(this.tempMatrix4f.set(modelView.getFloatBuffer()).invert().get(this.tempFloats));
+                this.modelViewInverse.upload();
+            }
+
+            if (this.normalMatrix != null) {
+                this.normalMatrix.set(this.tempMatrix3f.set(this.tempMatrix4f.set(modelView.getFloatBuffer())).invert().transpose().get(this.tempFloats2));
+                this.normalMatrix.upload();
+            }
+        }
+    }
+}

common/src/main/java/dev/ryanhcode/sable/mixinterface/compatibility/iris/ExtendedShaderExtension.java

@@ -0,0 +1,5 @@
+package dev.ryanhcode.sable.mixinterface.compatibility.iris;
+
+public interface ExtendedShaderExtension {
+    void sable$refreshModelViewDerivedMatrices();
+}

common/src/main/java/dev/ryanhcode/sable/sublevel/render/vanilla/VanillaChunkedSubLevelRenderData.java

@@ -9,6 +9,7 @@
 import dev.ryanhcode.sable.companion.math.JOMLConversion;
 import dev.ryanhcode.sable.companion.math.Pose3dc;
 import dev.ryanhcode.sable.mixin.sublevel_render.RenderSectionAccessor;
+import dev.ryanhcode.sable.mixinterface.compatibility.iris.ExtendedShaderExtension;
 import dev.ryanhcode.sable.mixinterface.sublevel_render.vanilla.RenderSectionExtension;
 import dev.ryanhcode.sable.sublevel.ClientSubLevel;
 import dev.ryanhcode.sable.sublevel.render.SubLevelRenderData;
@@ -319,6 +320,10 @@ public void renderChunkedSubLevel(final RenderType layer, final ShaderInstance s
         if (shader.MODEL_VIEW_MATRIX != null) {
             shader.MODEL_VIEW_MATRIX.set(modelView.mul(transform, MODEL_MATRIX));
             shader.MODEL_VIEW_MATRIX.upload();
+
+            if (shader instanceof final ExtendedShaderExtension ext) {
+                ext.sable$refreshModelViewDerivedMatrices();
+            }
         }
 
         // TODO: sorting

common/src/main/resources/sable.mixins.json

@@ -16,6 +16,7 @@
     "camera.new_camera_types.MinecraftMixin",
     "clip_overwrite.ClientLevelMixin",
     "clip_overwrite.GameRendererMixin",
+    "compatibility.iris.ExtendedShaderMixin",
     "config.GameRendererAccessor",
     "debug_render.DebugRendererMixin",
     "debug_render.DebugScreenOverlayMixin",