Texture: allow png/jpg to be used interchangeably

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

@@ -37,7 +37,7 @@ public class SplashScene extends Scene {
   private void createLogo() {
     Shader texturedShader = new Shader("assets/shaders/texture");
     texturedShader.init();
-    Texture logoTexture = new Texture(225, 225, "assets/textures/plink.jpg", 3);
+    Texture logoTexture = new Texture(225, 225, "assets/textures/plink.png");
     logoTexture.init();
     Mesh logoMesh =
         new TexturedMesh(texturedShader, logoTexture, logoRectVertices, screenCoverRectElements);

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

@@ -13,15 +13,40 @@ import lombok.Setter;
 public class Texture {
   @Getter private int width;
   @Getter private int height;
-  @Getter private int channelCount;
   @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, int channelCount) {
+  public Texture(int width, int height, String texturePath) {
     this.width = width;
     this.height = height;
     this.texturePath = texturePath;
-    this.channelCount = channelCount;
+    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);
+      case "jpg":
+        setChannelCount(3);
+        setInternalFormat(GL_RGB);
+      default:
+        // just pray at this point
+        setChannelCount(3);
+        setInternalFormat(GL_RGB);
+    }
   }
 
   public void init() {
@@ -33,7 +58,11 @@ public class Texture {
   private ByteBuffer loadImageBytes() {
     stbi_set_flip_vertically_on_load(true);
     return stbi_load(
-        getTexturePath(), new int[getWidth()], new int[getHeight()], new int[getChannelCount()], 0);
+        getTexturePath(),
+        new int[getWidth()],
+        new int[getHeight()],
+        new int[getChannelCount()],
+        getChannelCount());
   }
 
   private void createTexture(ByteBuffer imageBytes) {
@@ -46,7 +75,15 @@ public class Texture {
     setupWrapParameters();
 
     glTexImage2D(
-        GL_TEXTURE_2D, 0, GL_RGB, getWidth(), getHeight(), 0, GL_RGB, GL_UNSIGNED_BYTE, imageBytes);
+        GL_TEXTURE_2D,
+        0,
+        getInternalFormat(),
+        getWidth(),
+        getHeight(),
+        0,
+        getInternalFormat(),
+        GL_UNSIGNED_BYTE,
+        imageBytes);
     // glGenerateMipmap(GL_TEXTURE_2D);
   }