1 files changed, 233 insertions, 0 deletions
diff --git a/src/classes/javax/media/nwi/DefaultNWCapabilitiesChooser.java b/src/classes/javax/media/nwi/DefaultNWCapabilitiesChooser.java
new file mode 100644
index 000000000..1318ea419
--- /dev/null
+++ b/src/classes/javax/media/nwi/DefaultNWCapabilitiesChooser.java
@@ -0,0 +1,233 @@
+/*
+ * Copyright (c) 2003 Sun Microsystems, Inc. All Rights Reserved.
+ * 
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ * 
+ * - Redistribution of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ * 
+ * - Redistribution 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 Sun Microsystems, Inc. or the names of
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ * 
+ * This software is provided "AS IS," without a warranty of any kind. ALL
+ * EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES,
+ * INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A
+ * PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN
+ * MICROSYSTEMS, INC. ("SUN") AND ITS LICENSORS SHALL NOT BE LIABLE FOR
+ * ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR
+ * DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES. IN NO EVENT WILL SUN OR
+ * ITS LICENSORS BE LIABLE FOR ANY LOST REVENUE, PROFIT OR DATA, OR FOR
+ * DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL, INCIDENTAL OR PUNITIVE
+ * DAMAGES, HOWEVER CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY,
+ * ARISING OUT OF THE USE OF OR INABILITY TO USE THIS SOFTWARE, EVEN IF
+ * SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
+ * 
+ * You acknowledge that this software is not designed or intended for use
+ * in the design, construction, operation or maintenance of any nuclear
+ * facility.
+ * 
+ * Sun gratefully acknowledges that this software was originally authored
+ * and developed by Kenneth Bradley Russell and Christopher John Kline.
+ */
+
+package javax.media.nwi;
+
+/** <P> The default implementation of the {@link
+    NWCapabilitiesChooser} interface, which provides consistent visual
+    selection behavior across platforms. The precise algorithm is
+    deliberately left loosely specified. Some properties are: </P>
+
+    <UL>
+
+    <LI> As long as there is at least one available non-null
+    NWCapabilities which matches the "stereo" option, will return a
+    valid index.
+
+    <LI> Attempts to match as closely as possible the given
+    NWCapabilities, but will select one with fewer capabilities (i.e.,
+    lower color depth) if necessary.
+
+    <LI> Prefers hardware-accelerated visuals to
+    non-hardware-accelerated.
+
+    <LI> If there is no exact match, prefers a more-capable visual to
+    a less-capable one.
+
+    <LI> If there is more than one exact match, chooses an arbitrary
+    one.
+
+    <LI> May select the opposite of a double- or single-buffered
+    visual (based on the user's request) in dire situations.
+
+    <LI> Color depth (including alpha) mismatches are weighted higher
+    than depth buffer mismatches, which are in turn weighted higher
+    than accumulation buffer (including alpha) and stencil buffer
+    depth mismatches.
+
+    <LI> If a valid windowSystemRecommendedChoice parameter is
+    supplied, chooses that instead of using the cross-platform code.
+
+    </UL>
+*/
+
+public class DefaultNWCapabilitiesChooser implements NWCapabilitiesChooser {
+  private static final boolean DEBUG = false; // FIXME: Debug.debug("DefaultNWCapabilitiesChooser");
+
+  public int chooseCapabilities(NWCapabilities desired,
+                                NWCapabilities[] available,
+                                int windowSystemRecommendedChoice) {
+    if (DEBUG) {
+      System.err.println("Desired: " + desired);
+      for (int i = 0; i < available.length; i++) {
+        System.err.println("Available " + i + ": " + available[i]);
+      }
+      System.err.println("Window system's recommended choice: " + windowSystemRecommendedChoice);
+    }
+
+    if (windowSystemRecommendedChoice >= 0 &&
+        windowSystemRecommendedChoice < available.length &&
+        available[windowSystemRecommendedChoice] != null) {
+      if (DEBUG) {
+        System.err.println("Choosing window system's recommended choice of " + windowSystemRecommendedChoice);
+        System.err.println(available[windowSystemRecommendedChoice]);
+      }
+      return windowSystemRecommendedChoice;
+    }
+
+    // Create score array
+    int[] scores = new int[available.length];
+    int NO_SCORE = -9999999;
+    int DOUBLE_BUFFER_MISMATCH_PENALTY = 1000;
+    int STENCIL_MISMATCH_PENALTY = 500;
+    // Pseudo attempt to keep equal rank penalties scale-equivalent
+    // (e.g., stencil mismatch is 3 * accum because there are 3 accum
+    // components)
+    int COLOR_MISMATCH_PENALTY_SCALE     = 36;
+    int DEPTH_MISMATCH_PENALTY_SCALE     = 6;
+    int ACCUM_MISMATCH_PENALTY_SCALE     = 1;
+    int STENCIL_MISMATCH_PENALTY_SCALE   = 3;
+    for (int i = 0; i < scores.length; i++) {
+      scores[i] = NO_SCORE;
+    }
+    // Compute score for each
+    for (int i = 0; i < scores.length; i++) {
+      NWCapabilities cur = available[i];
+      if (cur == null) {
+        continue;
+      }
+      if (desired.getStereo() != cur.getStereo()) {
+        continue;
+      }
+      int score = 0;
+      // Compute difference in color depth
+      // (Note that this decides the direction of all other penalties)
+      score += (COLOR_MISMATCH_PENALTY_SCALE *
+                ((cur.getRedBits() + cur.getGreenBits() + cur.getBlueBits() + cur.getAlphaBits()) -
+                 (desired.getRedBits() + desired.getGreenBits() + desired.getBlueBits() + desired.getAlphaBits())));
+      // Compute difference in depth buffer depth
+      score += (DEPTH_MISMATCH_PENALTY_SCALE * sign(score) * 
+                Math.abs(cur.getDepthBits() - desired.getDepthBits()));
+      // Compute difference in accumulation buffer depth
+      score += (ACCUM_MISMATCH_PENALTY_SCALE * sign(score) *
+                Math.abs((cur.getAccumRedBits() + cur.getAccumGreenBits() + cur.getAccumBlueBits() + cur.getAccumAlphaBits()) -
+                         (desired.getAccumRedBits() + desired.getAccumGreenBits() + desired.getAccumBlueBits() + desired.getAccumAlphaBits())));
+      // Compute difference in stencil bits
+      score += STENCIL_MISMATCH_PENALTY_SCALE * sign(score) * (cur.getStencilBits() - desired.getStencilBits());
+      if (cur.getDoubleBuffered() != desired.getDoubleBuffered()) {
+        score += sign(score) * DOUBLE_BUFFER_MISMATCH_PENALTY;
+      }
+      if ((desired.getStencilBits() > 0) && (cur.getStencilBits() == 0)) {
+        score += sign(score) * STENCIL_MISMATCH_PENALTY;
+      }
+      scores[i] = score;
+    }
+    // Now prefer hardware-accelerated visuals by pushing scores of
+    // non-hardware-accelerated visuals out
+    boolean gotHW = false;
+    int maxAbsoluteHWScore = 0;
+    for (int i = 0; i < scores.length; i++) {
+      int score = scores[i];
+      if (score == NO_SCORE) {
+        continue;
+      }
+      NWCapabilities cur = available[i];
+      if (cur.getHardwareAccelerated()) {
+        int absScore = Math.abs(score);
+        if (!gotHW ||
+            (absScore > maxAbsoluteHWScore)) {
+          gotHW = true;
+          maxAbsoluteHWScore = absScore;
+        }
+      }
+    }
+    if (gotHW) {
+      for (int i = 0; i < scores.length; i++) {
+        int score = scores[i];
+        if (score == NO_SCORE) {
+          continue;
+        }
+        NWCapabilities cur = available[i];
+        if (!cur.getHardwareAccelerated()) {
+          if (score <= 0) {
+            score -= maxAbsoluteHWScore;
+          } else if (score > 0) {
+            score += maxAbsoluteHWScore;
+          }
+          scores[i] = score;
+        }
+      }
+    }
+
+    if (DEBUG) {
+      System.err.print("Scores: [");
+      for (int i = 0; i < available.length; i++) {
+        if (i > 0) {
+          System.err.print(",");
+        }
+        System.err.print(" " + scores[i]);
+      }
+      System.err.println(" ]");
+    }
+
+    // Ready to select. Choose score closest to 0. 
+    int scoreClosestToZero = NO_SCORE;
+    int chosenIndex = -1;
+    for (int i = 0; i < scores.length; i++) {
+      int score = scores[i];
+      if (score == NO_SCORE) {
+        continue;
+      }
+      // Don't substitute a positive score for a smaller negative score
+      if ((scoreClosestToZero == NO_SCORE) ||
+          (Math.abs(score) < Math.abs(scoreClosestToZero) &&
+	   ((sign(scoreClosestToZero) < 0) || (sign(score) > 0)))) {
+        scoreClosestToZero = score;
+        chosenIndex = i;
+      }
+    }
+    if (chosenIndex < 0) {
+      throw new NativeWindowException("Unable to select one of the provided NWCapabilities");
+    }
+    if (DEBUG) {
+      System.err.println("Chosen index: " + chosenIndex);
+      System.err.println("Chosen capabilities:");
+      System.err.println(available[chosenIndex]);
+    }
+
+    return chosenIndex;
+  }
+
+  private static int sign(int score) {
+    if (score < 0) {
+      return -1;
+    }
+    return 1;
+  }
+}