From c28ec45f8c21107324446373be0e1308dee1321c Mon Sep 17 00:00:00 2001
From: Ross W <rossw01@hotmail.com>
Date: Tue, 19 Aug 2025 19:56:37 +0100
Subject: [PATCH] Added Shader class, default shaders

---
 assets/shaders/default.frag.glsl        |   8 ++
 assets/shaders/default.vert.glsl        |  11 +++
 src/main/java/org/hirw/game/Shader.java | 115 ++++++++++++++++++++++++
 src/main/java/org/hirw/game/Window.java |   2 +
 4 files changed, 136 insertions(+)
 create mode 100644 assets/shaders/default.frag.glsl
 create mode 100644 assets/shaders/default.vert.glsl
 create mode 100644 src/main/java/org/hirw/game/Shader.java

diff --git a/assets/shaders/default.frag.glsl b/assets/shaders/default.frag.glsl
new file mode 100644
index 0000000..b69a2fb
--- /dev/null
+++ b/assets/shaders/default.frag.glsl
@@ -0,0 +1,8 @@
+#version 330 core
+
+in vec4 fColour;
+out vec4 colour;
+
+void main() {
+  colour = fColour;
+}
diff --git a/assets/shaders/default.vert.glsl b/assets/shaders/default.vert.glsl
new file mode 100644
index 0000000..a0b5cc4
--- /dev/null
+++ b/assets/shaders/default.vert.glsl
@@ -0,0 +1,11 @@
+#version 330 core
+
+layout (location = 0) in vec3 aPos;
+layout (location = 1) in vec4 aColour;
+
+out vec4 fColour;
+
+void main() {
+  fColour = aColour;
+  gl_Position = vec4(aPos, 1.0);
+}
diff --git a/src/main/java/org/hirw/game/Shader.java b/src/main/java/org/hirw/game/Shader.java
new file mode 100644
index 0000000..4229ccc
--- /dev/null
+++ b/src/main/java/org/hirw/game/Shader.java
@@ -0,0 +1,115 @@
+package org.hirw.game;
+
+import static org.lwjgl.opengl.GL20.*;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.InvalidPathException;
+import java.nio.file.NoSuchFileException;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.EnumMap;
+import java.util.Map;
+import lombok.Getter;
+import lombok.Setter;
+import org.hirw.game.util.Log;
+
+public class Shader {
+  private enum ShaderType {
+    FRAG,
+    VERT
+  }
+
+  private static final EnumMap<ShaderType, Integer> SHADERS =
+      new EnumMap<>(
+          Map.of(
+              ShaderType.FRAG, GL_FRAGMENT_SHADER,
+              ShaderType.VERT, GL_VERTEX_SHADER));
+
+  private static final String DEFAULT_FRAG_PATH = "assets/shaders/default.frag.glsl";
+  private static final String DEFAULT_VERT_PATH = "assets/shaders/default.vert.glsl";
+
+  @Getter private String vertexSource;
+  @Getter private String fragmentSource;
+  @Getter @Setter private int vertexID;
+  @Getter @Setter private int fragmentID;
+  @Getter @Setter private int shaderProgramID;
+
+  public Shader(String fragPath, String vertPath) {
+    this.fragmentSource = readFromFile(fragPath);
+    this.vertexSource = readFromFile(vertPath);
+  }
+
+  public Shader() {
+    this(DEFAULT_FRAG_PATH, DEFAULT_VERT_PATH);
+  }
+
+  public void init() {
+    compileShader(ShaderType.FRAG);
+    compileShader(ShaderType.VERT);
+    createProgram();
+  }
+
+  private void compileShader(ShaderType shaderType) {
+    int shaderID = glCreateShader(SHADERS.get(shaderType));
+
+    switch (shaderType) {
+      case ShaderType.FRAG -> {
+        setFragmentID(shaderID);
+        glShaderSource(shaderID, getFragmentSource());
+      }
+      case ShaderType.VERT -> {
+        setVertexID(shaderID);
+        glShaderSource(shaderID, getVertexSource());
+      }
+    }
+
+    glCompileShader(shaderID);
+
+    if (glGetShaderi(shaderID, GL_COMPILE_STATUS) == GL_FALSE) {
+      int len = glGetShaderi(shaderID, GL_INFO_LOG_LENGTH);
+      Log.error(
+          "Shader initialisation",
+          String.format(
+              "Failed to compile %s shader: %s",
+              shaderType.toString(), glGetShaderInfoLog(shaderID, len)));
+    }
+  }
+
+  private void createProgram() {
+    setShaderProgramID(glCreateProgram());
+    glAttachShader(shaderProgramID, getVertexID());
+    glAttachShader(shaderProgramID, getFragmentID());
+    glLinkProgram(shaderProgramID);
+
+    int success = glGetProgrami(getShaderProgramID(), GL_LINK_STATUS);
+    if (success == GL_FALSE) {
+      int len = glGetProgrami(getShaderProgramID(), GL_INFO_LOG_LENGTH);
+
+      Log.error(
+          "Shader initialisation",
+          String.format(
+              "Failed to create Shader Program: %s",
+              glGetShaderInfoLog(getShaderProgramID(), len)));
+    }
+  }
+
+  private String readFromFile(String stringFilePath) {
+    String source = "";
+
+    try {
+      Path filePath = Paths.get(stringFilePath);
+      source = Files.readString(filePath);
+
+    } catch (NoSuchFileException | InvalidPathException e) {
+      Log.error(
+          "Shader initialisation", "Couldn't open file (probably a bad path): " + stringFilePath);
+    } catch (IOException e) {
+      Log.error(
+          "Shader initialisation",
+          "An IO Exception occured while reading from file: " + stringFilePath);
+    }
+
+    return source;
+  }
+}
diff --git a/src/main/java/org/hirw/game/Window.java b/src/main/java/org/hirw/game/Window.java
index 4dd4068..3dd52ff 100644
--- a/src/main/java/org/hirw/game/Window.java
+++ b/src/main/java/org/hirw/game/Window.java
@@ -80,6 +80,8 @@ public class Window {
 
     GL.createCapabilities();
     glClearColor(0.0f, 0.0f, 2.0f, 0.0f);
+    Shader someShader = new Shader();
+    someShader.init();
   }
 
   private void loop() {