FaderShader class and SplashScene logic

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/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;
@@ -58,6 +58,8 @@ 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 +1,45 @@
 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;
 
   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();
   }
 
   public void update() {
-    if (Objects.isNull(Window.get().getGlfwWindow())) {
-      return;
-    }
-
-    screenCover.draw();
-
-    fadeIn();
+    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,
+  private static final float[] screenCoverRectVertices = {
+    1.0f, -1.0f, 0.0f, /*           */ 0.0f, 0.0f, 0.0f, 1.0f,
+    -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,
     -1.0f, -1.0f, 0.0f, /*          */ 0.0f, 0.0f, 0.0f, 0.0f,
   };
+
+  private static final int[] screenCoverRectElements = {
+    2, 1, 0,
+    0, 1, 3
+  };
 }

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

@@ -74,7 +74,11 @@ public class Window {
     glfwShowWindow(glfwWindow);
 
     GL.createCapabilities();
-    glClearColor(0.0f, 0.0f, 2.0f, 0.0f);
+
+    glEnable(GL_BLEND);
+    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+
+    glClearColor(1.0f, 1.0f, 1.0f, 0.0f);
   }
 
   private void createShader() {
@@ -87,15 +91,14 @@ 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();
     }