Replaces fullscreen quad with a viewport covering triangle

jme3-core/src/main/java/com/jme3/post/FilterPostProcessor.java

@@ -46,6 +46,8 @@
 import com.jme3.renderer.Renderer;
 import com.jme3.renderer.ViewPort;
 import com.jme3.renderer.queue.RenderQueue;
+import com.jme3.scene.Geometry;
+import com.jme3.scene.shape.FullscreenTriangle;
 import com.jme3.texture.FrameBuffer;
 import com.jme3.texture.FrameBuffer.FrameBufferTarget;
 import com.jme3.texture.Image.Format;
@@ -88,7 +90,8 @@ public class FilterPostProcessor implements SceneProcessor, Savable {
     private Texture2D depthTexture;
     private SafeArrayList<Filter> filters = new SafeArrayList<>(Filter.class);
     private AssetManager assetManager;
-    private Picture fsQuad;
+    private boolean useFullscreenTriangle = false;
+    private Geometry fsQuad;
     private boolean computeDepth = false;
     private FrameBuffer outputBuffer;
     private int width;
@@ -116,6 +119,18 @@ public FilterPostProcessor(AssetManager assetManager) {
         this.assetManager = assetManager;
     }
 
+    /**
+     * Constructs a new instance of FilterPostProcessor.
+     *
+     * @param assetManager The asset manager used to load resources needed by the processor.
+     * @param useFullscreenTriangle If true, a fullscreen triangle will be used for rendering;
+     *                              otherwise, a quad will be used.
+     */
+    public FilterPostProcessor(AssetManager assetManager, boolean useFullscreenTriangle) {
+        this(assetManager);
+        this.useFullscreenTriangle = useFullscreenTriangle;
+    }
+
     /**
      * Serialization-only constructor. Do not use this constructor directly;
      * use {@link #FilterPostProcessor(AssetManager)}.
@@ -181,9 +196,14 @@ public void initialize(RenderManager rm, ViewPort vp) {
         renderManager = rm;
         renderer = rm.getRenderer();
         viewPort = vp;
-        fsQuad = new Picture("filter full screen quad");
-        fsQuad.setWidth(1);
-        fsQuad.setHeight(1);
+        if(useFullscreenTriangle) {
+            fsQuad = new Geometry("FsQuad", new FullscreenTriangle());
+        }else{
+            Picture fullscreenQuad = new Picture("filter full screen quad");
+            fullscreenQuad.setWidth(1);
+            fullscreenQuad.setHeight(1);
+            fsQuad = fullscreenQuad;
+        }
 
         // Determine optimal framebuffer format based on renderer capabilities
         if (!renderer.getCaps().contains(Caps.PackedFloatTexture)) {
@@ -715,6 +735,7 @@ public Format getFrameBufferDepthFormat() {
     public void write(JmeExporter ex) throws IOException {
         OutputCapsule oc = ex.getCapsule(this);
         oc.write(numSamples, "numSamples", 0);
+        oc.write(useFullscreenTriangle, "useFullscreenTriangle", false);
         oc.writeSavableArrayList(new ArrayList(filters), "filters", null);
     }
 
@@ -723,6 +744,7 @@ public void write(JmeExporter ex) throws IOException {
     public void read(JmeImporter im) throws IOException {
         InputCapsule ic = im.getCapsule(this);
         numSamples = ic.readInt("numSamples", 0);
+        useFullscreenTriangle = ic.readBoolean("useFullscreenTriangle", false);
         filters = new SafeArrayList<>(Filter.class, ic.readSavableArrayList("filters", null));
         for (Filter filter : filters.getArray()) {
             filter.setProcessor(this);

jme3-core/src/main/java/com/jme3/scene/shape/FullscreenTriangle.java

@@ -0,0 +1,39 @@
+package com.jme3.scene.shape;
+
+import com.jme3.scene.Mesh;
+import com.jme3.scene.VertexBuffer;
+
+
+/**
+ * The FullscreenTriangle class defines a mesh representing a single
+ * triangle that spans the entire screen. It is typically used in rendering
+ * techniques where a fullscreen quad or triangle is needed, such as in
+ * post-processing effects or screen-space operations.
+ */
+public class FullscreenTriangle extends Mesh {
+
+    /**
+     * Encapsulates the vertex positions for a fullscreen triangle.
+     * The positions are transformed by the vertex shader to cover the entire screen.
+     */
+    private static final float[] POSITIONS = {
+        0, 0, 0,  // -1 -1 0  after vertex shader transform
+        2, 0, 0,  //  3 -1 0  after vertex shader transform
+        0, 2, 0   // -1  3 0  after vertex shader transform
+    };
+
+    private static final float[] TEXCOORDS = {
+            0,0,
+            2,0,
+            0,2
+    };
+
+
+    public FullscreenTriangle() {
+        super();
+        setBuffer(VertexBuffer.Type.Position, 3, POSITIONS);
+        setBuffer(VertexBuffer.Type.TexCoord, 2, TEXCOORDS);
+        setBuffer(VertexBuffer.Type.Index, 3, new short[]{0, 1, 2});
+        updateBound();
+    }
+}

jme3-effects/src/main/resources/Common/MatDefs/Post/Post.vert

@@ -4,8 +4,8 @@ attribute vec2 inTexCoord;
 
 varying vec2 texCoord;
 
-void main() {     
+void main() {
     vec2 pos = inPosition.xy * 2.0 - 1.0;
-    gl_Position = vec4(pos, 0.0, 1.0);    
+    gl_Position = vec4(pos, 0.0, 1.0);
     texCoord = inTexCoord;
 }

jme3-effects/src/main/resources/Common/MatDefs/Post/Post15.vert

@@ -6,7 +6,7 @@ in vec2 inTexCoord;
 out vec2 texCoord;
 
 void main() {
-    vec2 pos = inPosition.xy * 2.0 - 1.0;      
+    vec2 pos = inPosition.xy * 2.0 - 1.0;
     gl_Position = vec4(pos, 0.0, 1.0);
     texCoord = inTexCoord;
 }