feat: Use ShaderCompatibilityHelper for macOS OpenGL 3+ support.

This was accidentally removed in #26.

src/main/java/de/eskalon/commons/screen/transition/impl/GLTransitionsShaderTransition.java

@@ -20,6 +20,8 @@
 import com.badlogic.gdx.graphics.glutils.ShaderProgram;
 import com.badlogic.gdx.math.Interpolation;
 
+import de.damios.guacamole.gdx.graphics.ShaderCompatibilityHelper;
+
 /**
  * A transition that is using shader code conforming to the <i>GL Transition
  * Specification v1</i>. This allows using the shaders provided at
@@ -101,8 +103,11 @@ public class GLTransitionsShaderTransition extends ShaderTransition {
 	 * "https://github.com/crykn/libgdx-screenmanager/wiki/How-to-use-GL-Transitions#some-example-code">wiki</a>
 	 * for an in-depth explanation and example.
 	 * <p>
-	 * Ignores code in {@link ShaderProgram#prependFragmentCode} and
-	 * {@link ShaderProgram#prependVertexCode}.
+	 * Code in {@link ShaderProgram#prependFragmentCode} and
+	 * {@link ShaderProgram#prependVertexCode} is ignored. The provided shader
+	 * is {@linkplain ShaderCompatibilityHelper#fromString(String, String)
+	 * automatically ported} from from version 120 (~ OpenGL 2.1) to version 150
+	 * (~ OpenGL 3.2) if needed.
 	 * 
 	 * @param glTransitionsCode
 	 *            the GL Transitions shader code
@@ -127,8 +132,11 @@ public GLTransitionsShaderTransition(String glTransitionsCode,
 	 * "https://github.com/crykn/libgdx-screenmanager/wiki/How-to-use-GL-Transitions#some-example-code">wiki</a>
 	 * for an in-depth explanation and example.
 	 * <p>
-	 * Ignores code in {@link ShaderProgram#prependFragmentCode} and
-	 * {@link ShaderProgram#prependVertexCode}.
+	 * Code in {@link ShaderProgram#prependFragmentCode} and
+	 * {@link ShaderProgram#prependVertexCode} is ignored. The provided shader
+	 * is {@linkplain ShaderCompatibilityHelper#fromString(String, String)
+	 * automatically ported} from from version 120 (~ OpenGL 2.1) to version 150
+	 * (~ OpenGL 3.2) if needed.
 	 * 
 	 * @param glTransitionsCode
 	 *            the GL Transitions shader code
@@ -141,7 +149,7 @@ public GLTransitionsShaderTransition(String glTransitionsCode,
 			float duration, @Nullable Interpolation interpolation) {
 		super(VERT_SHADER,
 				FRAG_SHADER_PREPEND + glTransitionsCode + FRAG_SHADER_POSTPEND,
-				true, duration, interpolation);
+				true, duration, interpolation, true);
 	}
 
 }

src/main/java/de/eskalon/commons/screen/transition/impl/ShaderTransition.java

@@ -29,7 +29,9 @@
 import com.badlogic.gdx.utils.viewport.Viewport;
 
 import de.damios.guacamole.Preconditions;
+import de.damios.guacamole.annotations.Beta;
 import de.damios.guacamole.gdx.graphics.QuadMeshGenerator;
+import de.damios.guacamole.gdx.graphics.ShaderCompatibilityHelper;
 import de.damios.guacamole.gdx.graphics.ShaderProgramFactory;
 import de.eskalon.commons.screen.transition.TimedTransition;
 
@@ -97,13 +99,28 @@ public ShaderTransition(String vert, String frag, boolean ignorePrepend,
 	 * Creates a shader transition. Please note that this entails the shader
 	 * being compiled which needs to happen on the rendering thread!
 	 * 
+	 * @param vert
+	 *            the vertex shader code
+	 * @param frag
+	 *            the fragment shader code
+	 * @param ignorePrepend
+	 *            whether to ignore the code in
+	 *            {@link ShaderProgram#prependFragmentCode} and
+	 *            {@link ShaderProgram#prependVertexCode}
 	 * @param duration
 	 *            the transition's duration in seconds
 	 * @param interpolation
 	 *            the interpolation to use
 	 */
 	public ShaderTransition(String vert, String frag, boolean ignorePrepend,
 			float duration, @Nullable Interpolation interpolation) {
+		this(vert, frag, ignorePrepend, duration, interpolation, false);
+	}
+
+	@Beta
+	public ShaderTransition(String vert, String frag, boolean ignorePrepend,
+			float duration, @Nullable Interpolation interpolation,
+			boolean useCompatibilityHandler) {
 		super(duration, interpolation);
 
 		Preconditions.checkNotNull(vert, "The vertex shader cannot be null.");
@@ -114,8 +131,13 @@ public ShaderTransition(String vert, String frag, boolean ignorePrepend,
 												// screen
 
 		// Compile the shader; this needs to happen on the rendering thread!
-		this.program = ShaderProgramFactory.fromString(vert, frag, true,
-				ignorePrepend);
+		if (useCompatibilityHandler)
+			this.program = ShaderCompatibilityHelper.fromString(vert, frag); // ignorePrepend
+																				// is
+																				// ignored
+		else
+			this.program = ShaderProgramFactory.fromString(vert, frag, true,
+					ignorePrepend);
 
 		this.projTransLoc = this.program.getUniformLocation("u_projTrans");
 		this.lastScreenLoc = this.program.getUniformLocation("lastScreen");