Change behavior of tagged struct parsing in shaders

- Explicit call to Shader#parseStructs is required before they can be read.
 - Fixes a startup crash on some drivers (apparently nvidia is cool with #[...], but other drivers fail)

src/main/java/com/jozufozu/flywheel/backend/Backend.java

@@ -110,6 +110,9 @@ public class Backend {
 			throw new IllegalStateException("Material spec '" + name + "' already registered.");
 		}
 		materialRegistry.put(name, spec);
+
+		log.debug("registered material '" + name + "' with vertex size " + spec.getModelFormat().getStride() + " and instance size " + spec.getInstanceFormat().getStride());
+
 		return spec;
 	}
 

src/main/java/com/jozufozu/flywheel/backend/gl/shader/GlShader.java

@@ -28,6 +28,7 @@ public class GlShader extends GlObject {
 			Backend.log.error("Shader compilation log for " + shader.name + ": " + log);
 			Backend.log.error(shader.printSource());
 		}
+		Backend.log.debug(shader.printSource());
 
 		if (GL20.glGetShaderi(handle, GL20.GL_COMPILE_STATUS) != GL20.GL_TRUE) {
 			throw new RuntimeException("Could not compile " + shader.name + ". See log for details.");

src/main/java/com/jozufozu/flywheel/backend/loading/Shader.java

@@ -14,7 +14,6 @@ import java.util.regex.Pattern;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
-import com.jozufozu.flywheel.backend.Backend;
 import com.jozufozu.flywheel.backend.ShaderSources;
 import com.jozufozu.flywheel.backend.gl.shader.ShaderType;
 
@@ -53,19 +52,18 @@ public class Shader {
 	}
 
 	public TaggedStruct getTag(String tag) {
-		checkAndParse();
+		checkIfParsed();
 		return tag2Struct.get(tag);
 	}
 
 	public TaggedStruct getStruct(String name) {
-		checkAndParse();
+		checkIfParsed();
 		return name2Struct.get(name);
 	}
 
-	private void checkAndParse() {
+	private void checkIfParsed() {
 		if (!parsed) {
-			parsed = true;
-			parseStructs();
+			throw new IllegalStateException("tagged structs must be explicitly parsed before use");
 		}
 	}
 
@@ -94,7 +92,8 @@ public class Shader {
 
 			structs.add(struct);
 
-			structMatcher.appendReplacement(strippedSrc, decorator.matcher(struct.source).replaceFirst(""));
+			String replacement = decorator.matcher(struct.source).replaceFirst("");
+			structMatcher.appendReplacement(strippedSrc, replacement);
 
 			tag2Struct.put(struct.tag, struct);
 			name2Struct.put(struct.name, struct);
@@ -102,6 +101,7 @@ public class Shader {
 		structMatcher.appendTail(strippedSrc);
 
 		this.source = strippedSrc.toString();
+		parsed = true;
 	}
 
 	public void processIncludes() {

src/main/java/com/jozufozu/flywheel/backend/loading/ShaderTemplate.java

@@ -32,10 +32,9 @@ public class ShaderTemplate {
 	}
 
 	public String apply(Shader shader) {
+		shader.parseStructs();
 
-		return header +
-				shader.getSource() +
-				processBody(shader);
+		return header + shader.getSource() + processBody(shader);
 	}
 
 	public String processBody(Shader shader) {