Restore texture and framebuffer bindings after invalidation

jme3-core/src/main/java/com/jme3/renderer/RenderContext.java

@@ -207,14 +207,20 @@ private static <T> WeakReference<T>[] newWeakReferenceArray(int size) {
     public Shader boundShader;
 
     /**
-     * ID of the bound FrameBuffer.
+     * ID of the bound FrameBuffer. This value is untrusted while
+     * {@link #isFrameBufferBindingValid()} is false.
      *
      * @see Renderer#setFrameBuffer(com.jme3.texture.FrameBuffer)
      */
     public int boundFBO;
 
+    private boolean frameBufferBindingValid = true;
+
     /**
-     * Currently bound FrameBuffer.
+     * Java object associated with the known framebuffer binding, or null when
+     * there is no associated object or the binding is unknown. A null value
+     * does not imply a native framebuffer name of zero; presentation and
+     * externally managed framebuffers can have nonzero names.
      *
      * @see Renderer#setFrameBuffer(com.jme3.texture.FrameBuffer)
      */
@@ -289,7 +295,7 @@ private static <T> WeakReference<T>[] newWeakReferenceArray(int size) {
     public final IDList textureIndexList = new IDList();
 
     /**
-     * Currently bound texture unit.
+     * Currently bound texture unit, or -1 when the active unit is unknown.
      *
      * @see Renderer#setTexture(int, com.jme3.texture.Texture)
      */
@@ -374,6 +380,52 @@ public RenderContext() {
         init();
     }
 
+    /**
+     * Tests whether the cached framebuffer binding can suppress a GL bind.
+     *
+     * @return true if the binding is known
+     */
+    public boolean isFrameBufferBindingValid() {
+        return frameBufferBindingValid;
+    }
+
+    /**
+     * Records the object and native name of a known framebuffer binding.
+     * Call after establishing native state or restoring a known binding.
+     *
+     * @param fb the associated Java framebuffer, or null if there is none
+     * @param fbo the known native framebuffer name
+     */
+    public void setFrameBufferBinding(FrameBuffer fb, int fbo) {
+        boundFB = fb;
+        boundFBO = fbo;
+        frameBufferBindingValid = true;
+    }
+
+    /**
+     * Invalidates only the framebuffer binding, leaving texture bindings alone.
+     * The numeric name is retained as an untrusted value, and the associated
+     * Java object is cleared. This does not modify native state.
+     */
+    public void invalidateFrameBufferBinding() {
+        frameBufferBindingValid = false;
+        boundFB = null;
+    }
+
+    /**
+     * Invalidates texture and framebuffer bindings after external GL changes.
+     * This does not modify native state. Unlike reset(), it does not assume
+     * that texture unit zero or the default framebuffer is bound.
+     */
+    public void invalidateBindings() {
+        boundTextureUnit = -1;
+        invalidateFrameBufferBinding();
+        for (int i = 0; i < boundTextures.length; i++) {
+            boundTextures[i] = null;
+        }
+        textureIndexList.reset();
+    }
+
 
     private void init() {
         cullMode = RenderState.FaceCullMode.Off;
@@ -399,6 +451,7 @@ private void init() {
         boundShader = null;
         boundFBO = 0;
         boundFB = null;
+        frameBufferBindingValid = true;
         boundRB = 0;
 
         boundElementArrayVBO = 0;

jme3-core/src/main/java/com/jme3/renderer/opengl/GLRenderer.java

@@ -903,6 +903,7 @@ public void initialize() {
     @Override
     public void invalidateState() {
         context.reset();
+        context.invalidateBindings();
         if (gl2 != null) {
             context.initialDrawBuf = getInteger(GL2.GL_DRAW_BUFFER);
             context.initialReadBuf = getInteger(GL2.GL_READ_BUFFER);
@@ -2004,6 +2005,13 @@ public void copyFrameBuffer(FrameBuffer src, FrameBuffer dst, boolean copyColor,
 
             int prevFBO = context.boundFBO;
             FrameBuffer prevFB = context.boundFB;
+            boolean prevBindingValid = context.isFrameBufferBindingValid();
+            // Attachment updates below can bind another framebuffer. An unknown
+            // binding may also have different native read and draw targets.
+            final int prevReadFramebuffer = prevBindingValid ? prevFBO
+                    : getInteger(GLFbo.GL_READ_FRAMEBUFFER_BINDING_EXT);
+            final int prevDrawFramebuffer = prevBindingValid ? prevFBO
+                    : getInteger(GLFbo.GL_DRAW_FRAMEBUFFER_BINDING_EXT);
 
             if (mainFbOverride != null) {
                 if (src == null) {
@@ -2062,10 +2070,18 @@ public void copyFrameBuffer(FrameBuffer src, FrameBuffer dst, boolean copyColor,
                     GL.GL_NEAREST);
 
 
-            glfbo.glBindFramebufferEXT(GLFbo.GL_FRAMEBUFFER_EXT, prevFBO);
-            context.boundFBO = prevFBO;
-            context.boundFB = prevFB;
-            toggleFramebufferSrgb(prevFB);
+            if (prevBindingValid) {
+                glfbo.glBindFramebufferEXT(GLFbo.GL_FRAMEBUFFER_EXT, prevFBO);
+                context.setFrameBufferBinding(prevFB, prevFBO);
+                if (prevFB != null || prevFBO == defaultFBO) {
+                    toggleFramebufferSrgb(prevFB);
+                }
+            } else {
+                glfbo.glBindFramebufferEXT(GLFbo.GL_READ_FRAMEBUFFER_EXT, prevReadFramebuffer);
+                glfbo.glBindFramebufferEXT(GLFbo.GL_DRAW_FRAMEBUFFER_EXT, prevDrawFramebuffer);
+                context.invalidateFrameBufferBinding();
+                context.boundFBO = prevFBO;
+            }
         } else {
             throw new RendererException("Framebuffer blitting not supported by the video hardware");
         }
@@ -2220,18 +2236,16 @@ public void updateFrameBufferAttachment(FrameBuffer fb, RenderBuffer rb) {
 
     private void bindFrameBuffer(FrameBuffer fb) {
         if (fb == null) {
-            if (context.boundFBO != defaultFBO) {
+            if (!context.isFrameBufferBindingValid() || context.boundFBO != defaultFBO) {
                 glfbo.glBindFramebufferEXT(GLFbo.GL_FRAMEBUFFER_EXT, defaultFBO);
                 statistics.onFrameBufferUse(null, true);
-                context.boundFBO = defaultFBO;
-                context.boundFB = null;
+                context.setFrameBufferBinding(null, defaultFBO);
             }
         } else {
             assert fb.getId() != -1 && fb.getId() != 0;
-            if (context.boundFBO != fb.getId()) {
+            if (!context.isFrameBufferBindingValid() || context.boundFBO != fb.getId()) {
                 glfbo.glBindFramebufferEXT(GLFbo.GL_FRAMEBUFFER_EXT, fb.getId());
-                context.boundFBO = fb.getId();
-                context.boundFB = fb;
+                context.setFrameBufferBinding(fb, fb.getId());
                 statistics.onFrameBufferUse(fb, true);
             } else {
                 statistics.onFrameBufferUse(fb, false);
@@ -2311,7 +2325,7 @@ public Vector2f[] getFrameBufferSamplePositions(FrameBuffer fb) {
     @Override
     public void setMainFrameBufferOverride(FrameBuffer fb) {
         mainFbOverride = null;
-        if (context.boundFBO == 0) {
+        if (context.isFrameBufferBindingValid() && context.boundFBO == 0) {
             // Main FB is now set to fb, make sure its bound
             setFrameBuffer(fb);
         }
@@ -2385,7 +2399,14 @@ public void setFrameBuffer(FrameBuffer fb) {
             fb = mainFbOverride;
         }
 
-        if (context.boundFB == fb) {
+        if (fb == null && !caps.contains(Caps.FrameBuffer)) {
+            // Selecting the screen does not require framebuffer-object support.
+            toggleFramebufferSrgb(null);
+            return;
+        }
+
+        if (context.isFrameBufferBindingValid() && context.boundFB == fb
+                && context.boundFBO == (fb == null ? defaultFBO : fb.getId())) {
             if (fb == null || !fb.isUpdateNeeded()) {
                 toggleFramebufferSrgb(fb);
                 return;
@@ -2443,7 +2464,7 @@ && isMipmapGenerationSupported(tex.getImage().getFormat(),
             assert fb.getId() > 0;
             assert context.boundFBO == fb.getId();
 
-            context.boundFB = fb;
+            context.setFrameBufferBinding(fb, fb.getId());
             if (debug && caps.contains(Caps.GLDebug)) {
                 if (fb.getName() != null) glext.glObjectLabel(GL3.GL_FRAMEBUFFER, fb.getId(), fb.getName());
             }
@@ -2488,9 +2509,9 @@ private void deleteRenderBuffer(FrameBuffer fb, RenderBuffer rb) {
     @Override
     public void deleteFrameBuffer(FrameBuffer fb) {
         if (fb.getId() != -1) {
-            if (context.boundFBO == fb.getId()) {
+            if (context.isFrameBufferBindingValid() && context.boundFBO == fb.getId()) {
                 glfbo.glBindFramebufferEXT(GLFbo.GL_FRAMEBUFFER_EXT, 0);
-                context.boundFBO = 0;
+                context.setFrameBufferBinding(null, 0);
             }
 
             if (fb.getDepthTarget() != null) {
@@ -3838,7 +3859,8 @@ public void setMainFrameBufferSrgb(boolean enableSrgb) {
         }
 
         mainFrameBufferSrgb = enableSrgb;
-        if (context.boundFB == null) {
+        if (context.isFrameBufferBindingValid() && context.boundFB == null
+                && context.boundFBO == defaultFBO) {
             toggleFramebufferSrgb(null);
         }
     }

jme3-core/src/test/java/com/jme3/renderer/RenderContextBindingTest.java

@@ -0,0 +1,113 @@
+/*
+ * Copyright (c) 2009-2026 jMonkeyEngine
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ *
+ * * Redistributions in binary form must reproduce the above copyright
+ *   notice, this list of conditions and the following disclaimer in the
+ *   documentation and/or other materials provided with the distribution.
+ *
+ * * Neither the name of 'jMonkeyEngine' nor the names of its contributors
+ *   may be used to endorse or promote products derived from this software
+ *   without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+package com.jme3.renderer;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertSame;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import com.jme3.texture.FrameBuffer;
+import com.jme3.texture.Image;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Verifies the distinction between fresh defaults and externally changed bindings.
+ */
+public class RenderContextBindingTest {
+
+    @Test
+    public void bindingInvalidationClearsTextureReferencesWithoutAssumingNativeDefaults() {
+        RenderContext context = new RenderContext();
+        Image image = new Image();
+        context.boundTextures[0] = image.getWeakRef();
+        context.boundTextures[3] = image.getWeakRef();
+        context.textureIndexList.moveToNew(3);
+        context.textureIndexList.copyNewToOld();
+        context.boundTextureUnit = 3;
+        context.boundFBO = 12;
+        context.boundFB = new FrameBuffer(4, 4, 1);
+
+        context.invalidateBindings();
+
+        assertEquals(-1, context.boundTextureUnit);
+        assertEquals(12, context.boundFBO);
+        assertNull(context.boundFB);
+        assertFalse(context.isFrameBufferBindingValid());
+        for (int unit = 0; unit < context.boundTextures.length; unit++) {
+            assertNull(context.boundTextures[unit]);
+        }
+        assertEquals(0, context.textureIndexList.oldLen);
+        assertEquals(0, context.textureIndexList.newLen);
+    }
+
+    @Test
+    public void resetReturnsBindingsToKnownFreshDefaults() {
+        RenderContext context = new RenderContext();
+        context.boundFBO = 12;
+        context.boundTextureUnit = 3;
+        context.invalidateBindings();
+        context.reset();
+        assertDefaults(context);
+    }
+
+    @Test
+    public void framebufferOnlyInvalidationPreservesTextureKnowledgeAndUntrustedName() {
+        RenderContext context = new RenderContext();
+        FrameBuffer framebuffer = new FrameBuffer(4, 4, 1);
+        context.setFrameBufferBinding(framebuffer, 12);
+        Image image = new Image();
+        context.boundTextures[3] = image.getWeakRef();
+        context.boundTextureUnit = 3;
+        context.textureIndexList.moveToNew(3);
+        context.textureIndexList.copyNewToOld();
+        context.textureIndexList.moveToNew(0);
+
+        context.invalidateFrameBufferBinding();
+
+        assertNull(context.boundFB);
+        assertFalse(context.isFrameBufferBindingValid());
+        assertEquals(12, context.boundFBO);
+        assertEquals(3, context.boundTextureUnit);
+        assertSame(image.getWeakRef(), context.boundTextures[3]);
+        assertEquals(1, context.textureIndexList.oldLen);
+        assertEquals(1, context.textureIndexList.newLen);
+    }
+
+    private static void assertDefaults(RenderContext context) {
+        assertEquals(0, context.boundTextureUnit);
+        assertEquals(0, context.boundFBO);
+        assertNull(context.boundFB);
+        assertTrue(context.isFrameBufferBindingValid());
+    }
+}