Extremely fancy shader templating

- Nothing is properly hooked up yet.
 - A single shader file will be able to be compiled with different opengl targets.
 - I plan on using this to implement meshlet rendering as an alternate backend-backend that will be used when available.
 - It could also be used to enable compatibility with opengl 3.0 or potentially even 2.0.

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

@@ -58,6 +58,16 @@ public class ShaderLoader {
 				shaderSource.clear();
 				loadShaderSources(manager);
 
+//				ResourceLocation test = new ResourceLocation("create", "model_new.vert");
+//				ResourceLocation vert = new ResourceLocation("create", "skeleton/instanced/instanced.vert");
+//
+//				InstancedArraysShaderTemplate template = new InstancedArraysShaderTemplate(getShaderSource(vert));
+//				ParsedShader parsedShader = new ParsedShader(getShaderSource(test));
+//
+//				String apply = template.apply(parsedShader);
+//
+//				printSource(test, apply);
+
 				for (ShaderContext<?> context : Backend.contexts.values()) {
 					context.load(this);
 				}
@@ -134,6 +144,13 @@ public class ShaderLoader {
 			source = defines.process(source);
 
 		if (debugDumpFile) {
+			printSource(name, source);
+		}
+
+		return new GlShader(type, name, source);
+	}
+
+	private void printSource(ResourceLocation name, String source) {
 		Backend.log.debug("Finished processing '" + name + "':");
 		int i = 1;
 		for (String s : source.split("\n")) {
@@ -141,9 +158,6 @@ public class ShaderLoader {
 		}
 	}
 
-		return new GlShader(type, name, source);
-	}
-
 	private String processIncludes(String source, ResourceLocation baseName) {
 		HashSet<ResourceLocation> seen = new HashSet<>();
 		seen.add(baseName);

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

@@ -0,0 +1,102 @@
+package com.jozufozu.flywheel.backend.loading;
+
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+public class InstancedArraysShaderTemplate {
+
+	private static final String delimiter = "#flwbeginbody";
+	private static final Pattern headerFinder = Pattern.compile(delimiter);
+
+	private static final Pattern prefixer = Pattern.compile("#FLWPrefixFields\\((\\S+),\\s*([^\\n]+)\\)");
+	private static final Pattern assigner = Pattern.compile("#FLWAssignFields\\(([\\w\\d_]+),\\s*([\\w\\d_.]+),\\s*([\\w\\d_.]+)\\)");
+
+	public static final String[] required = {"FLWInstanceData", "FLWVertexData", "FLWFragment"};
+
+	final String header;
+	final String body;
+
+	public InstancedArraysShaderTemplate(String templateSrc) {
+		Matcher matcher = headerFinder.matcher(templateSrc);
+
+		if (!matcher.find()) {
+			throw new RuntimeException("Shader template must have a header and footer delimited by '" + delimiter + "'");
+		}
+
+		this.header = templateSrc.substring(0, matcher.start());
+		this.body = templateSrc.substring(matcher.end());
+
+	}
+
+	public String apply(ParsedShader shader) {
+
+		return header +
+				shader.src +
+				processBody(shader);
+	}
+
+	public String processBody(ParsedShader shader) {
+		String s = body;
+
+		for (String name : required) {
+			TaggedStruct struct = shader.getTag(name);
+
+			s = s.replace(name, struct.name);
+		}
+
+		s = fillPrefixes(shader, s);
+		s = fillAssigns(shader, s);
+
+		return s;
+	}
+
+	private String fillPrefixes(ParsedShader shader, String s) {
+		Matcher prefixMatches = prefixer.matcher(s);
+
+		StringBuffer out = new StringBuffer();
+		while (prefixMatches.find()) {
+			String structName = prefixMatches.group(1);
+			String prefix = prefixMatches.group(2);
+
+			TaggedStruct struct = shader.getStruct(structName);
+
+			StringBuilder builder = new StringBuilder();
+			for (String field : struct.fields.keySet()) {
+				builder.append(prefix);
+				builder.append(field);
+				builder.append(";\n");
+			}
+
+			prefixMatches.appendReplacement(out, builder.toString());
+		}
+		prefixMatches.appendTail(out);
+		return out.toString();
+	}
+
+	private String fillAssigns(ParsedShader shader, String s) {
+		Matcher assignMatches = assigner.matcher(s);
+
+		StringBuffer out = new StringBuffer();
+		while (assignMatches.find()) {
+			String structName = assignMatches.group(1);
+			String lhs = assignMatches.group(2);
+			String rhs = assignMatches.group(3);
+
+			TaggedStruct struct = shader.getStruct(structName);
+
+			StringBuilder builder = new StringBuilder();
+			for (String field : struct.fields.keySet()) {
+				builder.append(lhs);
+				builder.append(field);
+				builder.append(" = ");
+				builder.append(rhs);
+				builder.append(field);
+				builder.append(";\n");
+			}
+
+			assignMatches.appendReplacement(out, builder.toString());
+		}
+		assignMatches.appendTail(out);
+		return out.toString();
+	}
+}

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

@@ -0,0 +1,42 @@
+package com.jozufozu.flywheel.backend.loading;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+public class ParsedShader {
+	private static final Pattern decorator = Pattern.compile("#\\[([\\w_]*)]");
+	private static final Pattern taggedStruct = Pattern.compile("#\\[([\\w_]*)]\\s*struct\\s+([\\w\\d_]*)\\s*\\{(\\s*(?:.*;\\s*\\n)+\\s*)}\\s*;");
+
+	final String src;
+
+	final Map<String, TaggedStruct> tag2Struct = new HashMap<>();
+	final Map<String, TaggedStruct> name2Struct = new HashMap<>();
+
+	public ParsedShader(String src) {
+
+		Matcher structs = taggedStruct.matcher(src);
+
+		StringBuffer strippedSrc = new StringBuffer();
+		while (structs.find()) {
+			TaggedStruct struct = new TaggedStruct(structs);
+
+			structs.appendReplacement(strippedSrc, decorator.matcher(struct.source).replaceFirst(""));
+
+			tag2Struct.put(struct.tag, struct);
+			name2Struct.put(struct.name, struct);
+		}
+		structs.appendTail(strippedSrc);
+
+		this.src = strippedSrc.toString();
+	}
+
+	public TaggedStruct getTag(String tag) {
+		return tag2Struct.get(tag);
+	}
+
+	public TaggedStruct getStruct(String name) {
+		return name2Struct.get(name);
+	}
+}

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

@@ -0,0 +1,36 @@
+package com.jozufozu.flywheel.backend.loading;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+public class TaggedStruct {
+
+	public static final Pattern fieldPattern = Pattern.compile("(\\S+)\\s*(\\S+);");
+
+	int srcStart, srcEnd;
+	String source;
+	String tag;
+	String name;
+	String body;
+
+	Map<String, String> fields = new HashMap<>();
+
+	public TaggedStruct(Matcher foundMatcher) {
+		this.source = foundMatcher.group();
+
+		srcStart = foundMatcher.start();
+		srcEnd = foundMatcher.end();
+
+		tag = foundMatcher.group(1);
+		name = foundMatcher.group(2);
+		body = foundMatcher.group(3);
+
+		Matcher fielder = fieldPattern.matcher(body);
+
+		while (fielder.find()) {
+			fields.put(fielder.group(2), fielder.group(1));
+		}
+	}
+}

src/main/resources/assets/create/flywheel/shaders/block_new.frag

@@ -0,0 +1,19 @@
+#version 110
+
+#flwbuiltins
+
+#[FLWFragment]
+struct Raster {
+    vec2 texCoords;
+    vec4 color;
+    float diffuse;
+    vec2 light;
+};
+
+void FLWMain(Raster r) {
+    vec4 tex = FLWBlockTexture(r.texCoords);
+
+    vec4 color = vec4(tex.rgb * FLWLight(r.light).rgb * r.diffuse, tex.a) * r.color;
+
+    FLWFinalizeColor(color);
+}

src/main/resources/assets/create/flywheel/shaders/model_new.vert

@@ -0,0 +1,45 @@
+#flwbuiltins
+#flwinclude <"create:core/matutils.glsl">
+#flwinclude <"create:core/diffuse.glsl">
+
+#[FLWVertexData]
+struct Vertex {
+    vec3 pos;
+    vec3 normal;
+    vec2 texCoords;
+};
+
+#[FLWInstanceData]
+struct Instance {
+    vec2 light;
+    vec4 color;
+    mat4 transform;
+    mat3 normalMat;
+};
+
+#[FLWFragment]
+struct Raster {
+    vec2 texCoords;
+    vec4 color;
+    float diffuse;
+    vec2 light;
+};
+
+Raster FLWMain(Vertex v, Instance i) {
+    vec4 worldPos = i.transform * vec4(v.pos, 1.);
+
+    vec3 norm = i.normalMat * v.normal;
+
+    FLWFinalizeWorldPos(worldPos);
+    FLWFinalizeNormal(norm);
+
+    norm = normalize(norm);
+
+    Raster r;
+    r.diffuse = diffuse(norm);
+    r.texCoords = v.texCoords;
+    r.light = i.light;
+    r.color = i.color;
+
+    return r;
+}

src/main/resources/assets/create/flywheel/shaders/skeleton/instanced/instanced.frag

@@ -0,0 +1,12 @@
+#version 110
+
+#flwbeginbody
+
+#FLWPrefixFields(FLWFragment, varying __v2f_)
+
+void main() {
+    FLWFragment f;
+    #FLWAssignFields(FLWFragment, f., __v2f_)
+
+    FLWMain(f);
+}

src/main/resources/assets/create/flywheel/shaders/skeleton/instanced/instanced.vert

@@ -1,17 +1,19 @@
 #version 110
+
+#flwbeginbody
 #FLWPrefixFields(FLWVertexData, attribute __a_)
 #FLWPrefixFields(FLWInstanceData, attribute __a_)
 
-#FLWPrefixFields(FLWOut, varying __v2f_)
+#FLWPrefixFields(FLWFragment, varying __v2f_)
 
 void main() {
     FLWVertexData v;
-    #FLWAssignToFields(FLWVertexData, v, a_)
+    #FLWAssignFields(FLWVertexData, v., __a_)
 
     FLWInstanceData i;
-    #FLWAssignToFields(FLWInstanceData, i, a_)
+    #FLWAssignFields(FLWInstanceData, i., __a_)
 
-    FLWOut o = FLWMain(v, i);
+    FLWFragment o = FLWMain(v, i);
 
-    #FLWAssignFromFields(FLWOut, o, v2f_)
+    #FLWAssignFields(FLWFragment, __v2f_, o.)
 }