don't use blitFramebuffer to initialize FBO layer

Author: codeanticode

core/src/processing/opengl/PGL.java

@@ -923,45 +923,12 @@ private void createFBOLayer() {
     clear(DEPTH_BUFFER_BIT | STENCIL_BUFFER_BIT | COLOR_BUFFER_BIT);
 
     bindFramebufferImpl(FRAMEBUFFER, 0);
-
-    if (0 < sketch.frameCount) {
-      // Copy the contents of the front and back screen buffers to the textures
-      // of the FBO, so they are properly initialized. Note that the front buffer
-      // of the default framebuffer (the screen) contains the previous frame:
-      // https://www.opengl.org/wiki/Default_Framebuffer
-      // so it is copied to the front texture of the FBO layer:
-      if (pclearColor || 0 < pgeomCount || !sketch.isLooping()) {
-        readBuffer(FRONT);
-      } else {
-        // ...except when the previous frame has not been cleared and nothing was
-        // renderered while looping. In this case the back buffer, which holds the
-        // initial state of the previous frame, still contains the most up-to-date
-        // screen state.
-        readBuffer(BACK);
-      }
-      bindFramebufferImpl(DRAW_FRAMEBUFFER, glColorFbo.get(0));
-      framebufferTexture2D(FRAMEBUFFER, COLOR_ATTACHMENT0,
-                           TEXTURE_2D, glColorTex.get(frontTex), 0);
-      drawBuffer(COLOR_ATTACHMENT0);
-      blitFramebuffer(0, 0, fboWidth, fboHeight,
-                      0, 0, fboWidth, fboHeight,
-                      COLOR_BUFFER_BIT, NEAREST);
-
-      readBuffer(BACK);
-      bindFramebufferImpl(DRAW_FRAMEBUFFER, glColorFbo.get(0));
-      framebufferTexture2D(FRAMEBUFFER, COLOR_ATTACHMENT0,
-                           TEXTURE_2D, glColorTex.get(backTex), 0);
-      drawBuffer(COLOR_ATTACHMENT0);
-      blitFramebuffer(0, 0, fboWidth, fboHeight,
-                      0, 0, fboWidth, fboHeight,
-                      COLOR_BUFFER_BIT, NEAREST);
-
-      bindFramebufferImpl(FRAMEBUFFER, 0);
-    }
+    initFBOLayer();
 
     fboLayerCreated = true;
   }
 
+  protected abstract void initFBOLayer();
 
   protected void destroyFBOLayer() {
     if (threadIsCurrent() && fboLayerCreated) {

core/src/processing/opengl/PGLES.java

@@ -227,6 +227,41 @@ protected int getGLSLVersion() {
   }
 
 
+  @Override
+  protected void initFBOLayer() {
+    if (0 < sketch.frameCount) {
+      IntBuffer buf = null;
+      buf = allocateDirectIntBuffer(fboWidth * fboHeight);
+
+      // Copy the contents of the front and back screen buffers to the textures
+      // of the FBO, so they are properly initialized. Note that the front buffer
+      // of the default framebuffer (the screen) contains the previous frame:
+      // https://www.opengl.org/wiki/Default_Framebuffer
+      // so it is copied to the front texture of the FBO layer:
+      if (pclearColor || 0 < pgeomCount || !sketch.isLooping()) {
+        readBuffer(FRONT);
+      } else {
+        // ...except when the previous frame has not been cleared and nothing was
+        // renderered while looping. In this case the back buffer, which holds the
+        // initial state of the previous frame, still contains the most up-to-date
+        // screen state.
+        readBuffer(BACK);
+      }
+      readPixelsImpl(0, 0, fboWidth, fboHeight, RGBA, UNSIGNED_BYTE, buf);
+      bindTexture(TEXTURE_2D, glColorTex.get(frontTex));
+      texSubImage2D(TEXTURE_2D, 0, 0, 0, fboWidth, fboHeight, RGBA, UNSIGNED_BYTE, buf);
+
+      readBuffer(BACK);
+      readPixelsImpl(0, 0, fboWidth, fboHeight, RGBA, UNSIGNED_BYTE, buf);
+      bindTexture(TEXTURE_2D, glColorTex.get(backTex));
+      texSubImage2D(TEXTURE_2D, 0, 0, 0, fboWidth, fboHeight, RGBA, UNSIGNED_BYTE, buf);
+
+      bindTexture(TEXTURE_2D, 0);
+      bindFramebufferImpl(FRAMEBUFFER, 0);
+    }
+  }
+
+
   ///////////////////////////////////////////////////////////
 
   // Android specific classes (Renderer, ConfigChooser)