7181438: [OGL] Incorrect alpha used, during blit from SW to the texture.

Reviewed-by: prr, campbell

src/share/native/sun/java2d/opengl/OGLBlitLoops.c

@@ -393,7 +393,16 @@ OGLBlitSwToTexture(SurfaceDataRasInfo *srcInfo, OGLPixelFormat *pf,
                    OGLSDOps *dstOps,
                    jint dx1, jint dy1, jint dx2, jint dy2)
 {
+    jboolean adjustAlpha = (pf != NULL && !pf->hasAlpha);
     j2d_glBindTexture(dstOps->textureTarget, dstOps->textureID);
+
+    if (adjustAlpha) {
+        // if the source surface does not have an alpha channel,
+        // we need to ensure that the alpha values are forced to 1.0f
+        j2d_glPixelTransferf(GL_ALPHA_SCALE, 0.0f);
+        j2d_glPixelTransferf(GL_ALPHA_BIAS, 1.0f);
+    }
+
     // in case pixel stride is not a multiple of scanline stride the copy
     // has to be done line by line (see 6207877)
     if (srcInfo->scanStride % srcInfo->pixelStride != 0) {
@@ -413,6 +422,11 @@ OGLBlitSwToTexture(SurfaceDataRasInfo *srcInfo, OGLPixelFormat *pf,
                             dx1, dy1, dx2-dx1, dy2-dy1,
                             pf->format, pf->type, srcInfo->rasBase);
     }
+    if (adjustAlpha) {
+        // restore scale/bias to their original values
+        j2d_glPixelTransferf(GL_ALPHA_SCALE, 1.0f);
+        j2d_glPixelTransferf(GL_ALPHA_BIAS, 0.0f);
+    }
 }
 
 /**

test/sun/java2d/OpenGL/bug7181438.java

+/*
+ * Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+import java.awt.Color;
+import java.awt.Graphics;
+import java.awt.GraphicsConfiguration;
+import java.awt.GraphicsEnvironment;
+import java.awt.Transparency;
+import java.awt.image.BufferedImage;
+import java.awt.image.VolatileImage;
+
+/**
+ * @test
+ * @bug 7181438
+ * @summary Verifies that we get correct alpha, when we draw opaque
+ * BufferedImage to non opaque VolatileImage via intermediate opaque texture.
+ * @author Sergey Bylokhov
+ * @run main/othervm -Dsun.java2d.accthreshold=0 bug7181438
+ */
+public final class bug7181438 {
+
+    private static final int SIZE = 500;
+
+    public static void main(final String[] args) {
+
+        final BufferedImage bi = createBufferedImage();
+        final VolatileImage vi = createVolatileImage();
+        final Graphics s2dVi = vi.getGraphics();
+
+        //sw->texture->surface blit
+        s2dVi.drawImage(bi, 0, 0, null);
+
+        final BufferedImage results = vi.getSnapshot();
+        for (int i = 0; i < SIZE; ++i) {
+            for (int j = 0; j < SIZE; ++j) {
+                //Image should be opaque: (black color and alpha = 255)
+                if (results.getRGB(i, j) != 0xFF000000) {
+                    throw new RuntimeException("Failed: Wrong alpha");
+                }
+            }
+        }
+        System.out.println("Passed");
+    }
+
+
+    private static VolatileImage createVolatileImage() {
+        final GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
+        final GraphicsConfiguration gc = ge.getDefaultScreenDevice().getDefaultConfiguration();
+        return gc.createCompatibleVolatileImage(SIZE, SIZE,
+                                                Transparency.TRANSLUCENT);
+    }
+
+    private static BufferedImage createBufferedImage() {
+        final BufferedImage bi = new BufferedImage(SIZE, SIZE,
+                                                   BufferedImage.TYPE_INT_RGB);
+        final Graphics bg = bi.getGraphics();
+        //Black color and alpha = 0
+        bg.setColor(new Color(0, 0, 0, 0));
+        bg.fillRect(0, 0, SIZE, SIZE);
+        bg.dispose();
+        return bi;
+    }
+}