diff --git a/src/main/java/net/coderbot/iris/Iris.java b/src/main/java/net/coderbot/iris/Iris.java
index 0900177688..277117b5a2 100644
--- a/src/main/java/net/coderbot/iris/Iris.java
+++ b/src/main/java/net/coderbot/iris/Iris.java
@@ -14,6 +14,7 @@
 import net.coderbot.iris.pipeline.WorldRenderingPipeline;
 import net.coderbot.iris.pipeline.newshader.NewWorldRenderingPipeline;
 import net.coderbot.iris.shaderpack.DimensionId;
+import net.coderbot.iris.shaderpack.IrisDefines;
 import net.coderbot.iris.shaderpack.OptionalBoolean;
 import net.coderbot.iris.shaderpack.ProgramSet;
 import net.coderbot.iris.shaderpack.ShaderPack;
diff --git a/src/main/java/net/coderbot/iris/gl/shader/StandardMacros.java b/src/main/java/net/coderbot/iris/gl/shader/StandardMacros.java
index b130660aed..515761e18c 100644
--- a/src/main/java/net/coderbot/iris/gl/shader/StandardMacros.java
+++ b/src/main/java/net/coderbot/iris/gl/shader/StandardMacros.java
@@ -38,7 +38,7 @@ private static void define(List<StringPair> defines, String key, String value) {
 		defines.add(new StringPair(key, value));
 	}
 
-	public static Iterable<StringPair> createStandardEnvironmentDefines() {
+	public static ImmutableList<StringPair> createStandardEnvironmentDefines() {
 		ArrayList<StringPair> standardDefines = new ArrayList<>();
 
 		define(standardDefines, "MC_VERSION", getMcVersion());
diff --git a/src/main/java/net/coderbot/iris/rendertarget/RenderTargets.java b/src/main/java/net/coderbot/iris/rendertarget/RenderTargets.java
index cc76d1bce3..d5559f80c0 100644
--- a/src/main/java/net/coderbot/iris/rendertarget/RenderTargets.java
+++ b/src/main/java/net/coderbot/iris/rendertarget/RenderTargets.java
@@ -372,4 +372,10 @@ public int getCurrentWidth() {
 	public int getCurrentHeight() {
 		return cachedHeight;
 	}
+
+	public void createIfUnsure(int index) {
+		if (targets[index] == null) {
+			create(index);
+		}
+	}
 }
diff --git a/src/main/java/net/coderbot/iris/samplers/IrisImages.java b/src/main/java/net/coderbot/iris/samplers/IrisImages.java
index 3cd91f0c22..d5a39e1d95 100644
--- a/src/main/java/net/coderbot/iris/samplers/IrisImages.java
+++ b/src/main/java/net/coderbot/iris/samplers/IrisImages.java
@@ -23,6 +23,8 @@ public static void addRenderTargetImages(ImageHolder images, Supplier<ImmutableS
 
 			if (!images.hasImage(name)) continue;
 
+			renderTargets.createIfUnsure(index);
+
 			// Note: image bindings *are* impacted by buffer flips.
 			IntSupplier textureID = () -> {
 				ImmutableSet<Integer> flippedBuffers = flipped.get();
diff --git a/src/main/java/net/coderbot/iris/samplers/IrisSamplers.java b/src/main/java/net/coderbot/iris/samplers/IrisSamplers.java
index 38bf55a8ad..f9f9aa55b5 100644
--- a/src/main/java/net/coderbot/iris/samplers/IrisSamplers.java
+++ b/src/main/java/net/coderbot/iris/samplers/IrisSamplers.java
@@ -78,6 +78,10 @@ public static void addRenderTargetSamplers(SamplerHolder samplers, Supplier<Immu
 			if (i < PackRenderTargetDirectives.LEGACY_RENDER_TARGETS.size()) {
 				String legacyName = PackRenderTargetDirectives.LEGACY_RENDER_TARGETS.get(i);
 
+				if (samplers.hasSampler(legacyName) || samplers.hasSampler(name)) {
+					renderTargets.createIfUnsure(index);
+				}
+
 				// colortex0 is the default sampler in fullscreen passes
 				if (i == 0 && isFullscreenPass) {
 					samplers.addDefaultSampler(TextureType.TEXTURE_2D, texture, null, null, name, legacyName);
@@ -85,6 +89,10 @@ public static void addRenderTargetSamplers(SamplerHolder samplers, Supplier<Immu
 					samplers.addDynamicSampler(TextureType.TEXTURE_2D, texture, null, name, legacyName);
 				}
 			} else {
+				if (samplers.hasSampler(name)) {
+					renderTargets.createIfUnsure(index);
+				}
+
 				samplers.addDynamicSampler(texture, name);
 			}
 		}
diff --git a/src/main/java/net/coderbot/iris/shaderpack/IrisDefines.java b/src/main/java/net/coderbot/iris/shaderpack/IrisDefines.java
new file mode 100644
index 0000000000..f6b9230587
--- /dev/null
+++ b/src/main/java/net/coderbot/iris/shaderpack/IrisDefines.java
@@ -0,0 +1,42 @@
+package net.coderbot.iris.shaderpack;
+
+import com.google.common.collect.ImmutableList;
+import net.coderbot.iris.Iris;
+import net.coderbot.iris.gl.shader.StandardMacros;
+import net.coderbot.iris.parsing.BiomeCategories;
+import net.coderbot.iris.uniforms.BiomeParameters;
+import net.minecraft.world.level.biome.Biome;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Locale;
+import java.util.regex.Pattern;
+
+public class IrisDefines {
+	private static final Pattern SEMVER_PATTERN = Pattern.compile("(?<major>\\d+)\\.(?<minor>\\d+)\\.*(?<bugfix>\\d*)(.*)");
+
+	private static void define(List<StringPair> defines, String key) {
+		defines.add(new StringPair(key, ""));
+	}
+
+	private static void define(List<StringPair> defines, String key, String value) {
+		defines.add(new StringPair(key, value));
+	}
+
+	public static ImmutableList<StringPair> createIrisReplacements() {
+		ArrayList<StringPair> s = new ArrayList<>(StandardMacros.createStandardEnvironmentDefines());
+		define(s, "PPT_NONE", "0");
+		define(s, "PPT_RAIN", "1");
+		define(s, "PPT_SNOW", "2");
+		define(s, "BIOME_SWAMP_HILLS", "-1");
+
+		BiomeParameters.getBiomeMap().forEach((biome, id) -> define(s, "BIOME_" + biome.location().getPath().toUpperCase(Locale.ROOT), String.valueOf(id)));
+
+		BiomeCategories[] categories = BiomeCategories.values();
+		for (int i = 0; i < categories.length; i++) {
+            define(s, "CAT_" + categories[i].name().toUpperCase(Locale.ROOT), String.valueOf(i));
+		}
+
+		return ImmutableList.copyOf(s);
+	}
+}
diff --git a/src/main/java/net/coderbot/iris/shaderpack/ShaderPack.java b/src/main/java/net/coderbot/iris/shaderpack/ShaderPack.java
index f9edbcd61f..6d733e3213 100644
--- a/src/main/java/net/coderbot/iris/shaderpack/ShaderPack.java
+++ b/src/main/java/net/coderbot/iris/shaderpack/ShaderPack.java
@@ -45,17 +45,7 @@
 import java.nio.file.Files;
 import java.nio.file.NoSuchFileException;
 import java.nio.file.Path;
-import java.util.ArrayList;
-import java.util.Collections;
-import java.util.EnumMap;
-import java.util.HashMap;
-import java.util.HashSet;
-import java.util.List;
-import java.util.Map;
-import java.util.Objects;
-import java.util.Optional;
-import java.util.Properties;
-import java.util.Set;
+import java.util.*;
 import java.util.function.Function;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
@@ -161,9 +151,10 @@ public ShaderPack(Path root, Map<String, String> changedConfigs, Iterable<String
 		this.shaderPackOptions = new ShaderPackOptions(graph, changedConfigs);
 		graph = this.shaderPackOptions.getIncludes();
 
+		Iterable<StringPair> replacements = IrisDefines.createIrisReplacements();
 		Iterable<StringPair> finalEnvironmentDefines = environmentDefines;
 		this.shaderProperties = loadProperties(root, "shaders.properties")
-				.map(source -> new ShaderProperties(source, shaderPackOptions, finalEnvironmentDefines))
+				.map(source -> new ShaderProperties(source, shaderPackOptions, finalEnvironmentDefines, replacements))
 				.orElseGet(ShaderProperties::empty);
 
 		activeFeatures = new HashSet<>();
@@ -248,7 +239,8 @@ public ShaderPack(Path root, Map<String, String> changedConfigs, Iterable<String
 		IncludeProcessor includeProcessor = new IncludeProcessor(graph);
 
 		// Set up our source provider for creating ProgramSets
-		Iterable<StringPair> finalEnvironmentDefines1 = environmentDefines;
+		ArrayList<StringPair> finalEnvironmentDefines1 = new ArrayList<>((Collection) finalEnvironmentDefines);
+		finalEnvironmentDefines1.addAll(IrisDefines.createIrisReplacements());
 		this.sourceProvider = (path) -> {
 			String pathString = path.getPathString();
 			// Removes the first "/" in the path if present, and the file
diff --git a/src/main/java/net/coderbot/iris/shaderpack/ShaderProperties.java b/src/main/java/net/coderbot/iris/shaderpack/ShaderProperties.java
index 31e12f2657..32bb6eddf8 100644
--- a/src/main/java/net/coderbot/iris/shaderpack/ShaderProperties.java
+++ b/src/main/java/net/coderbot/iris/shaderpack/ShaderProperties.java
@@ -111,7 +111,11 @@ private ShaderProperties() {
 	}
 
 	// TODO: Is there a better solution than having ShaderPack pass a root path to ShaderProperties to be able to read textures?
-	public ShaderProperties(String contents, ShaderPackOptions shaderPackOptions, Iterable<StringPair> environmentDefines) {
+	public ShaderProperties(String contents, ShaderPackOptions shaderPackOptions, Iterable<StringPair> environmentDefines, Iterable<StringPair> replacements) {
+		for (StringPair pair : replacements) {
+			contents = contents.replace(pair.getKey(), pair.getValue());
+		}
+
 		String preprocessedContents = PropertiesPreprocessor.preprocessSource(contents, shaderPackOptions, environmentDefines);
 
 		Properties preprocessed = new OrderBackedProperties();
diff --git a/src/main/java/net/coderbot/iris/uniforms/BiomeParameters.java b/src/main/java/net/coderbot/iris/uniforms/BiomeParameters.java
index 674715c1ca..4638325977 100644
--- a/src/main/java/net/coderbot/iris/uniforms/BiomeParameters.java
+++ b/src/main/java/net/coderbot/iris/uniforms/BiomeParameters.java
@@ -30,7 +30,6 @@ public static Object2IntMap<ResourceKey<Biome>> getBiomeMap() {
 	}
 
 	public static void addBiomeUniforms(UniformHolder uniforms) {
-
 		uniforms
 				.uniform1i(PER_TICK, "biome", playerI(player ->
 					biomeMap.getInt(player.level().getBiome(player.blockPosition()).unwrapKey().orElse(null))))
@@ -56,21 +55,7 @@ public static void addBiomeUniforms(UniformHolder uniforms) {
 				.uniform1f(PER_TICK, "rainfall", playerF(player ->
 					((ExtendedBiome) (Object) player.level().getBiome(player.blockPosition()).value()).getDownfall()))
 				.uniform1f(PER_TICK, "temperature", playerF(player ->
-						player.level().getBiome(player.blockPosition()).value().getBaseTemperature()))
-
-
-			.uniform1i(ONCE, "PPT_NONE", () -> 0)
-			.uniform1i(ONCE, "PPT_RAIN", () -> 1)
-			.uniform1i(ONCE, "PPT_SNOW", () -> 2)
-			// Temporary fix for Sildur's Vibrant
-			.uniform1i(ONCE, "BIOME_SWAMP_HILLS", () -> -1);
-
-
-
-
-		addBiomes(uniforms);
-		addCategories(uniforms);
-
+						player.level().getBiome(player.blockPosition()).value().getBaseTemperature()));
 	}
 
 	private static BiomeCategories getBiomeCategory(Holder<Biome> holder) {
@@ -114,18 +99,6 @@ private static BiomeCategories getBiomeCategory(Holder<Biome> holder) {
 		}
 	}
 
-	private static void addBiomes(UniformHolder uniforms) {
-		biomeMap.forEach((biome, id) -> uniforms.uniform1i(ONCE, "BIOME_" + biome.location().getPath().toUpperCase(Locale.ROOT), () -> id));
-	}
-
-	public static void addCategories(UniformHolder uniforms) {
-		BiomeCategories[] categories = BiomeCategories.values();
-		for (int i = 0; i < categories.length; i++) {
-			int finalI = i;
-			uniforms.uniform1i(ONCE, "CAT_" + categories[i].name().toUpperCase(Locale.ROOT), () -> finalI);
-		}
-	}
-
 	static IntSupplier playerI(ToIntFunction<LocalPlayer> function) {
 		return () -> {
 			LocalPlayer player = Minecraft.getInstance().player;