Implement Texture Units, bugfix guessChannelCountAndInternalFormat

assets/shaders/fader.frag.glsl

@@ -0,0 +1,10 @@
+#version 330 core
+
+in vec4 fColour;
+out vec4 colour;
+
+uniform float u_alpha;
+
+void main() {
+  colour = vec4(fColour.xyz, 1.0 - u_alpha);
+}

assets/shaders/texture.frag.glsl

@@ -0,0 +1,19 @@
+#version 330 core
+out vec4 FragColour;
+  
+in vec4 ourColour;
+in vec2 TexCoord;
+
+uniform sampler2D texture1;
+uniform sampler2D texture2;
+
+void main()
+{
+  vec4 tex1Color = texture(texture1, TexCoord);
+  vec4 tex2Color = texture(texture2, TexCoord);
+
+  if (tex2Color.a < 0.1)
+    tex2Color = tex1Color;
+
+  FragColour = mix(tex1Color, tex2Color, 0.4f);
+}

assets/shaders/texture.vert.glsl

@@ -0,0 +1,15 @@
+#version 330 core
+
+layout (location = 0) in vec3 aPos;
+layout (location = 1) in vec4 aColour;
+layout (location = 2) in vec2 aTexCoord;
+
+out vec4 ourColour;
+out vec2 TexCoord;
+
+void main()
+{
+  gl_Position = vec4(aPos, 1.0);
+  ourColour = aColour;
+  TexCoord = aTexCoord;
+}

pom.xml

@@ -10,7 +10,6 @@
 
   <name>game</name>
   <description>A simple game.</description>
-  <!-- FIXME change it to the project's website -->
   <url>http://www.hirw.org</url>
 
   <properties>

src/main/java/org/hirw/game/FaderShader.java

@@ -0,0 +1,58 @@
+package org.hirw.game;
+
+import static org.lwjgl.opengl.GL20.*;
+
+import lombok.Getter;
+import lombok.Setter;
+import org.hirw.game.util.Log;
+import org.hirw.game.util.Time;
+
+public class FaderShader extends Shader {
+  private static final String FADER_SHADER_FRAG_PATH = "assets/shaders/fader.frag.glsl";
+  private static final float DEFAULT_ALPHA_INCREASE_STEP = 1.0f / 3;
+  private final float INITIAL_ALPHA = 0.0f;
+
+  @Getter private final float alphaIncreaseStep;
+  @Getter @Setter private float alpha;
+  @Getter @Setter private int alphaUniformLocation;
+
+  public FaderShader(float alphaIncreaseStep) {
+    super(FADER_SHADER_FRAG_PATH, DEFAULT_VERT_PATH);
+    this.alpha = INITIAL_ALPHA;
+    this.alphaIncreaseStep = alphaIncreaseStep;
+  }
+
+  public FaderShader() {
+    this(DEFAULT_ALPHA_INCREASE_STEP);
+  }
+
+  public void init() {
+    super.init();
+    findAlphaUniformLocation();
+  }
+
+  public void update() {
+    super.update();
+    increaseAlpha();
+  }
+
+  private void findAlphaUniformLocation() {
+    int location = glGetUniformLocation(getShaderProgramID(), "u_alpha");
+    if (location == -1) {
+      Log.warning("FaderShader", "Failed to get 'u_alpha' uniform location, trying to continue...");
+    } else {
+      setAlphaUniformLocation(location);
+    }
+  }
+
+  private void increaseAlpha() {
+    if (getAlphaUniformLocation() == -1) return;
+    if (getAlpha() >= 1.0f) return;
+
+    setAlpha(getAlpha() + (getAlphaIncreaseStep() * Time.deltaTime()));
+
+    glUseProgram(getShaderProgramID());
+    glUniform1f(getAlphaUniformLocation(), getAlpha());
+    glUseProgram(0);
+  }
+}

src/main/java/org/hirw/game/Mesh.java

@@ -12,18 +12,22 @@ import org.lwjgl.BufferUtils;
 
 public class Mesh {
   @Getter @Setter private int vaoID, vboID, eboID;
-  @Getter private Shader shader;
+  @Getter protected Shader shader;
   @Getter float[] vertices;
   @Getter int[] elements;
 
-  private static final float[] defaultVertexArray = {
+  protected final int POSITION_SIZE = 3;
+  protected final int RGBA_SIZE = 4;
+  protected final int FLOAT_SIZE_IN_BYTES = Float.SIZE / Byte.SIZE;
+
+  protected static final float[] DEFAULT_VERTEX_ARRAY = {
     0.5f, -0.5f, 0.0f, /*           */ 1.0f, 0.0f, 0.0f, 1.0f,
     -0.5f, 0.5f, 0.0f, /*           */ 0.0f, 1.0f, 0.0f, 1.0f,
     0.5f, 0.5f, 0.0f, /*            */ 0.0f, 0.0f, 1.0f, 1.0f,
     -0.5f, -0.5f, 0.0f, /*          */ 1.0f, 1.0f, 0.0f, 1.0f,
   };
 
-  private static final int[] defaultElementArray = {
+  protected static final int[] DEFAULT_ELEMENT_ARRAY = {
     2, 1, 0,
     0, 1, 3
   };
@@ -38,7 +42,7 @@ public class Mesh {
   }
 
   public Mesh(Shader shader) {
-    this(shader, defaultVertexArray, defaultElementArray);
+    this(shader, DEFAULT_VERTEX_ARRAY, DEFAULT_ELEMENT_ARRAY);
   }
 
   public void init() {
@@ -61,7 +65,7 @@ public class Mesh {
         getEboID(), getVboID(), getEboID(), getShader().getShaderProgramID());
   }
 
-  private void glDraw() {
+  protected void glDraw() {
     glBindVertexArray(this.vaoID);
     glDrawElements(GL_TRIANGLES, getElements().length, GL_UNSIGNED_INT, 0);
     glBindVertexArray(0);
@@ -74,16 +78,24 @@ public class Mesh {
     initialiseVertexBufferObject();
     initialiseElementBufferObject();
 
-    int positionsSize = 3;
-    int colourSize = 4;
-    int floatSizeBytes = 4;
-    int vertexSizeBytes = (positionsSize + colourSize) * floatSizeBytes;
-    glVertexAttribPointer(0, positionsSize, GL_FLOAT, false, vertexSizeBytes, 0);
+    initialiseAttribPointers();
+  }
+
+  protected int initialiseAttribPointers() {
+    int vertexSizeInBytes = calculateVertexSizeInBytes();
+
+    glVertexAttribPointer(0, POSITION_SIZE, GL_FLOAT, false, vertexSizeInBytes, 0);
     glEnableVertexAttribArray(0);
 
     glVertexAttribPointer(
-        1, colourSize, GL_FLOAT, false, vertexSizeBytes, positionsSize * floatSizeBytes);
+        1, RGBA_SIZE, GL_FLOAT, false, vertexSizeInBytes, POSITION_SIZE * FLOAT_SIZE_IN_BYTES);
     glEnableVertexAttribArray(1);
+
+    return vertexSizeInBytes;
+  }
+
+  protected int calculateVertexSizeInBytes() {
+    return (POSITION_SIZE + RGBA_SIZE) * FLOAT_SIZE_IN_BYTES;
   }
 
   private void initialiseVertexBufferObject() {

src/main/java/org/hirw/game/Scene.java

@@ -1,15 +1,19 @@
 package org.hirw.game;
 
-public abstract class Scene {
-  public final SceneType SCENE_TYPE = SceneType.UNDEFINED;
+import lombok.Getter;
 
-  public Scene() {}
+public abstract class Scene {
+  @Getter private final SceneType sceneType;
+
+  public Scene(SceneType sceneType) {
+    this.sceneType = sceneType;
+  }
 
   public abstract void init();
 
   public abstract void update();
 
   public String toString() {
-    return SCENE_TYPE.toString();
+    return getSceneType().toString();
   }
 }

src/main/java/org/hirw/game/SceneManager.java

@@ -15,32 +15,42 @@ public final class SceneManager {
               SceneType.MENU, new SplashScene(),
               SceneType.GAME, new SplashScene()));
 
-  @Getter private static Scene scene = SCENES.get(DEFAULT_SCENE_TYPE);
+  @Getter private static Scene scene;
 
   public static void init() {
     setScene(DEFAULT_SCENE_TYPE);
   }
 
   public static void setScene(SceneType sceneType) {
-    scene = SCENES.get(sceneType);
+    Scene newScene = SCENES.get(sceneType);
+
+    if (scene == newScene) {
+      Log.warning("SceneManager", sameSceneWarningString());
+      return;
+    } else {
+      scene = newScene;
+    }
+
     scene.init();
     logSceneChange();
   }
 
   public static void update() {
-    if (scene.SCENE_TYPE == SceneType.UNDEFINED) return;
+    if (scene.getSceneType() == null) return;
 
     getScene().update();
   }
 
   private static void logSceneChange() {
-    SceneType newSceneType = getScene().SCENE_TYPE;
+    SceneType newSceneType = getScene().getSceneType();
     String loadedSceneMessage = String.format("Changed to scene '%s'", newSceneType.toString());
 
-    if (newSceneType == SceneType.UNDEFINED) {
-      Log.warning("SceneManager", loadedSceneMessage);
-    } else {
-      Log.success("SceneManager", loadedSceneMessage);
-    }
+    Log.success("SceneManager", loadedSceneMessage);
+  }
+
+  private static String sameSceneWarningString() {
+    return String.format(
+        "Tried to switch to scene '%s' but that scene is already loaded",
+        scene.getSceneType().toString());
   }
 }

src/main/java/org/hirw/game/SceneType.java

@@ -1,7 +1,6 @@
 package org.hirw.game;
 
 public enum SceneType {
-  UNDEFINED,
   SPLASH,
   MENU,
   GAME,

src/main/java/org/hirw/game/Shader.java

@@ -26,8 +26,8 @@ public class Shader {
               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";
+  protected static final String DEFAULT_FRAG_PATH = "assets/shaders/default.frag.glsl";
+  protected static final String DEFAULT_VERT_PATH = "assets/shaders/default.vert.glsl";
 
   @Getter private String vertexSource;
   @Getter private String fragmentSource;
@@ -40,6 +40,10 @@ public class Shader {
     this.vertexSource = readFromFile(vertPath);
   }
 
+  public Shader(String path) {
+    this(path + ".frag.glsl", path + ".vert.glsl");
+  }
+
   public Shader() {
     this(DEFAULT_FRAG_PATH, DEFAULT_VERT_PATH);
   }
@@ -58,6 +62,8 @@ public class Shader {
     glUseProgram(0);
   }
 
+  public void update() {}
+
   private void compileShader(ShaderType shaderType) {
     int shaderID = glCreateShader(SHADERS.get(shaderType));
 

src/main/java/org/hirw/game/SplashScene.java

@@ -1,53 +1,72 @@
 package org.hirw.game;
 
-import static org.lwjgl.opengl.GL11.*;
-
-import java.util.Objects;
 import lombok.Getter;
 import lombok.Setter;
-import org.hirw.game.util.Time;
 
 public class SplashScene extends Scene {
   @Getter public final SceneType SCENE_TYPE = SceneType.SPLASH;
-  private final float INITIAL_BRIGHTNESS = 0.0f;
-  private final float FADE_RATE = 0.5f;
-
-  private float brightness;
 
   @Getter @Setter private Mesh screenCover;
+  @Getter @Setter private FaderShader screenCoverFaderShader;
+  @Getter @Setter private Mesh logo;
 
   public SplashScene() {
-    this.brightness = INITIAL_BRIGHTNESS;
+    super(SceneType.SPLASH);
   }
 
   public void init() {
-    Shader faderShader = new Shader();
-    faderShader.init();
-    Mesh screenCover = new Mesh(faderShader);
-    screenCover.init();
-    setScreenCover(screenCover);
+    createScreenCover();
+    createLogo();
   }
 
   public void update() {
-    if (Objects.isNull(Window.get().getGlfwWindow())) {
-      return;
-    }
-
-    screenCover.draw();
-
-    fadeIn();
+    getLogo().draw();
+    getScreenCoverFaderShader().update();
+    getScreenCover().draw();
   }
 
-  private void fadeIn() {
-    glClearColor(this.brightness, this.brightness, this.brightness, 0.0f);
-    final float fadeAmount = FADE_RATE * Time.deltaTime();
-    this.brightness += fadeAmount;
+  private void createScreenCover() {
+    FaderShader faderShader = new FaderShader();
+    faderShader.init();
+    Mesh screenCover = new Mesh(faderShader, screenCoverRectVertices, screenCoverRectElements);
+    screenCover.init();
+    setScreenCoverFaderShader(faderShader);
+    setScreenCover(screenCover);
   }
 
-  private static final float[] screenCoverRect = {
-    1.0f, -0.0f, 0.0f, /*           */ 0.0f, 0.0f, 0.0f, 0.0f,
-    -0.0f, 1.0f, 0.0f, /*           */ 0.0f, 0.0f, 0.0f, 0.0f,
-    1.0f, 1.0f, 0.0f, /*            */ 0.0f, 0.0f, 0.0f, 0.0f,
-    -1.0f, -1.0f, 0.0f, /*          */ 0.0f, 0.0f, 0.0f, 0.0f,
+  private void createLogo() {
+    Shader texturedShader = new Shader("assets/shaders/texture");
+    texturedShader.init();
+    Texture logoTexture = new Texture(225, 225, "assets/textures/plink.png");
+    Texture flameTexture = new Texture(2500, 2500, "assets/textures/flames.png");
+    logoTexture.init();
+    flameTexture.init();
+    Mesh logoMesh =
+        new TexturedMesh(
+            texturedShader,
+            new Texture[] {logoTexture, flameTexture},
+            logoRectVertices,
+            screenCoverRectElements);
+    logoMesh.init();
+    setLogo(logoMesh);
+  }
+
+  private static final float[] screenCoverRectVertices = {
+    1.0f, 1.0f, 0.0f, /*            */ 0.0f, 0.0f, 0.0f, 0.0f, // 0 Top Right
+    1.0f, -1.0f, 0.0f, /*           */ 0.0f, 0.0f, 0.0f, 0.0f, // 1 Bottom Right
+    -1.0f, -1.0f, 0.0f, /*          */ 0.0f, 0.0f, 0.0f, 0.0f, // 2 Bottom Left
+    -1.0f, 1.0f, 0.0f, /*           */ 0.0f, 0.0f, 0.0f, 0.0f, // 3 Top Left
+  };
+
+  private static final int[] screenCoverRectElements = {
+    0, 1, 3,
+    1, 2, 3
+  };
+
+  private static final float[] logoRectVertices = {
+    0.1f, 0.1f, 0.0f, /*       */ 0.0f, 0.0f, 0.0f, 0.0f, /*    */ 1.0f, 1.0f, //   0 Top Right
+    0.1f, -0.1f, 0.0f, /*      */ 0.0f, 0.0f, 0.0f, 0.0f, /*    */ 1.0f, 0.0f, //  1 Bottom Right
+    -0.1f, -0.1f, 0.0f, /*     */ 0.0f, 0.0f, 0.0f, 0.0f, /*    */ 0.0f, 0.0f, // 2 Bottom Left
+    -0.1f, 0.1f, 0.0f, /*      */ 0.0f, 0.0f, 0.0f, 0.0f, /*    */ 0.0f, 1.0f, //  3 Top Left
   };
 }

src/main/java/org/hirw/game/Texture.java

@@ -0,0 +1,105 @@
+package org.hirw.game;
+
+import static org.lwjgl.opengl.GL11.*;
+import static org.lwjgl.opengl.GL12.*;
+import static org.lwjgl.stb.STBImage.stbi_image_free;
+import static org.lwjgl.stb.STBImage.stbi_load;
+import static org.lwjgl.stb.STBImage.stbi_set_flip_vertically_on_load;
+
+import java.nio.ByteBuffer;
+import lombok.Getter;
+import lombok.Setter;
+
+public class Texture {
+  @Getter private int width;
+  @Getter private int height;
+  @Getter private String texturePath;
+  @Getter @Setter private int textureID;
+  @Getter @Setter private int channelCount;
+  @Getter @Setter private int internalFormat;
+
+  public Texture(int width, int height, String texturePath) {
+    this.width = width;
+    this.height = height;
+    this.texturePath = texturePath;
+    guessChannelCountAndInternalFormat();
+  }
+
+  private void guessChannelCountAndInternalFormat() {
+    int fileExtensionIndex = getTexturePath().lastIndexOf(".");
+    if (fileExtensionIndex == -1) {
+      // No file extension, so just assume 4 channels (.png -> RGBA)
+      setChannelCount(4);
+      setInternalFormat(GL_RGBA);
+      return;
+    }
+
+    String fileExtension = getTexturePath().substring(fileExtensionIndex + 1);
+    switch (fileExtension) {
+      case "png":
+        setChannelCount(4);
+        setInternalFormat(GL_RGBA);
+        break;
+      case "jpg":
+        setChannelCount(3);
+        setInternalFormat(GL_RGB);
+        break;
+      default:
+        // just pray at this point
+        setChannelCount(3);
+        setInternalFormat(GL_RGB);
+    }
+  }
+
+  public void init() {
+    ByteBuffer imageBytes = loadImageBytes();
+    createTexture(imageBytes);
+    stbi_image_free(imageBytes);
+  }
+
+  private ByteBuffer loadImageBytes() {
+    stbi_set_flip_vertically_on_load(true);
+    return stbi_load(
+        getTexturePath(),
+        new int[getWidth()],
+        new int[getHeight()],
+        new int[getChannelCount()],
+        getChannelCount());
+  }
+
+  private void createTexture(ByteBuffer imageBytes) {
+    setTextureID(glGenTextures());
+    glBindTexture(GL_TEXTURE_2D, getTextureID());
+    glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
+
+    setupFilterParameters();
+    setupWrapParameters();
+
+    glTexImage2D(
+        GL_TEXTURE_2D,
+        0,
+        getInternalFormat(),
+        getWidth(),
+        getHeight(),
+        0,
+        getInternalFormat(),
+        GL_UNSIGNED_BYTE,
+        imageBytes);
+    // glGenerateMipmap(GL_TEXTURE_2D);
+  }
+
+  private void setupFilterParameters() {
+    // https://github.com/mattdesl/lwjgl-basics/wiki/textures#texture-parameters
+    // Set the minification and Magnifiation filters:
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+  }
+
+  private void setupWrapParameters() {
+    // https://github.com/mattdesl/lwjgl-basics/wiki/textures#texture-parameters
+    // Each Vertex has many attributes, including Position (x, y) and Texture Coordinates (s, t).
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+  }
+}

src/main/java/org/hirw/game/TexturedMesh.java

@@ -0,0 +1,47 @@
+package org.hirw.game;
+
+import static org.lwjgl.opengl.GL11.*;
+import static org.lwjgl.opengl.GL20.*;
+
+import lombok.Getter;
+
+public class TexturedMesh extends Mesh {
+  @Getter private Texture[] textures;
+
+  private final int TEXTURE_COORDS_SIZE = 2;
+
+  public TexturedMesh(Shader shader, Texture[] textures, float[] vertexArray, int[] elementArray) {
+    super(shader, vertexArray, elementArray);
+    this.textures = textures;
+  }
+
+  public TexturedMesh(Shader shader, Texture[] textures) {
+    this(shader, textures, DEFAULT_VERTEX_ARRAY, DEFAULT_ELEMENT_ARRAY);
+  }
+
+  protected int initialiseAttribPointers() {
+    int vertexSizeInBytes = super.initialiseAttribPointers();
+
+    int offset = (POSITION_SIZE + RGBA_SIZE) * FLOAT_SIZE_IN_BYTES;
+    glVertexAttribPointer(2, TEXTURE_COORDS_SIZE, GL_FLOAT, false, vertexSizeInBytes, offset);
+    glEnableVertexAttribArray(2);
+
+    return vertexSizeInBytes;
+  }
+
+  protected int calculateVertexSizeInBytes() {
+    return (POSITION_SIZE + RGBA_SIZE + TEXTURE_COORDS_SIZE) * FLOAT_SIZE_IN_BYTES;
+  }
+
+  protected void glDraw() {
+    for (int i = 0; i < textures.length; i++) {
+      int textureUnitIndexStart = GL_TEXTURE0;
+      int textureUnitIndex = textureUnitIndexStart + i;
+      glActiveTexture(textureUnitIndex);
+      glBindTexture(GL_TEXTURE_2D, getTextures()[i].getTextureID());
+      String uniformName = "texture" + Integer.toString(i + 1);
+      glUniform1i(glGetUniformLocation(getShader().getShaderProgramID(), uniformName), i);
+    }
+    super.glDraw();
+  }
+}

src/main/java/org/hirw/game/Window.java

@@ -14,7 +14,7 @@ import org.lwjgl.opengl.*;
 
 public class Window {
   private int width, height;
-  private final String title;
+  @Getter private String title;
   @Getter private long glfwWindow;
 
   private static Window window = null;
@@ -61,7 +61,7 @@ public class Window {
     glfwWindowHint(GLFW_VISIBLE, GLFW_FALSE);
     glfwWindowHint(GLFW_RESIZABLE, GLFW_TRUE);
 
-    glfwWindow = glfwCreateWindow(this.width, this.height, "Hello World!", NULL, NULL);
+    glfwWindow = glfwCreateWindow(this.width, this.height, getTitle(), NULL, NULL);
     if (glfwWindow == NULL) throw new RuntimeException("Failed to create the GLFW window");
 
     glfwSetCursorPosCallback(glfwWindow, Mouse::cursorPositionCallback);
@@ -74,7 +74,13 @@ public class Window {
     glfwShowWindow(glfwWindow);
 
     GL.createCapabilities();
-    glClearColor(0.0f, 0.0f, 2.0f, 0.0f);
+
+    glEnable(GL_BLEND);
+    glEnable(GL_TEXTURE_2D);
+
+    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+
+    glClearColor(1.0f, 1.0f, 1.0f, 0.0f);
   }
 
   private void createShader() {
@@ -87,15 +93,14 @@ public class Window {
     Mesh mesh = new Mesh(getShader());
     setMesh(mesh);
     mesh.init();
-    mesh.log();
   }
 
   private void loop() {
     while (!glfwWindowShouldClose(glfwWindow)) {
       Time.update();
-      SceneManager.update();
       glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
       getMesh().draw();
+      SceneManager.update();
       glfwSwapBuffers(glfwWindow);
       glfwPollEvents();
     }

src/main/java/org/hirw/game/util/Log.java

@@ -29,7 +29,8 @@ public final class Log {
           Map.of(
               LogType.SUCCESS, Colours.GREEN,
               LogType.ERROR, Colours.RED,
-              LogType.WARNING, Colours.PURPLE));
+              LogType.WARNING, Colours.PURPLE,
+              LogType.DEBUG, Colours.WHITE));
 
   public static void error(String errorStage, String errorDescription) {
     System.out.println(formatString(LogType.ERROR, errorStage, errorDescription));
@@ -43,6 +44,10 @@ public final class Log {
     System.out.println(formatString(LogType.WARNING, warningStage, warningDescription));
   }
 
+  public static void debug(String debugMessage) {
+    System.out.println(formatString(LogType.DEBUG, "DEBUG", debugMessage));
+  }
+
   private static String formatString(LogType logType, String stage, String description) {
     String formattedType = String.format("[%s]", colouriseString(logType, logType.toString()));
     String formattedStage = colouriseString(Colours.YELLOW, String.format("<%s>", stage));

src/main/java/org/hirw/game/util/LogType.java

@@ -4,4 +4,5 @@ public enum LogType {
   SUCCESS,
   WARNING,
   ERROR,
+  DEBUG,
 }