32 matrices is just a feeeeew two many for ATI cards, but of course

their drivers can't do anything useful like report an error; they just 
silently screw up.  Limiting it to 31 makes it work, but there's still a 
strange slowdown issue (and it's not that the shaders are being run in 
software, but it's worth checking for that anyway).


git-svn-id: svn+ssh://src.earth.threerings.net/nenya/trunk@243 ed5b42cb-e716-0410-a449-f6a68f950b19

src/java/com/threerings/jme/model/SkinMesh.java

@@ -71,7 +71,7 @@ import com.threerings.jme.util.ShaderConfig;
 public class SkinMesh extends ModelMesh
 {
     /** The maximum number of bone matrices that we can use for hardware skinning. */
-    public static final int MAX_SHADER_BONE_COUNT = 32;
+    public static final int MAX_SHADER_BONE_COUNT = 31;
 
     /** The maximum number of bones influencing a single vertex for hardware skinning. */
     public static final int MAX_SHADER_BONES_PER_VERTEX = 4;

src/java/com/threerings/jme/util/ShaderCache.java

@@ -26,7 +26,9 @@ import java.io.IOException;
 import java.io.InputStream;
 import java.io.InputStreamReader;
 
+import java.nio.ByteBuffer;
 import java.nio.IntBuffer;
+import java.nio.charset.Charset;
 
 import java.util.Collections;
 import java.util.HashMap;
@@ -152,10 +154,22 @@ public class ShaderCache
             (frag == null) ? null : getSource(frag, defs));
 
         // check its link status
-        IntBuffer linked = BufferUtils.createIntBuffer(1);
+        IntBuffer ibuf = BufferUtils.createIntBuffer(1);
         ARBShaderObjects.glGetObjectParameterARB(sstate.getProgramID(),
-            ARBShaderObjects.GL_OBJECT_LINK_STATUS_ARB, linked);
-        return (linked.get() == 0) ? null : sstate;
+            ARBShaderObjects.GL_OBJECT_LINK_STATUS_ARB, ibuf);
+        if (ibuf.get(0) == 0) {
+            return null; // failed to link
+        }
+
+        // check the info log
+        ARBShaderObjects.glGetObjectParameterARB(sstate.getProgramID(),
+            ARBShaderObjects.GL_OBJECT_INFO_LOG_LENGTH_ARB, ibuf);
+        ByteBuffer bbuf = BufferUtils.createByteBuffer(ibuf.get(0));
+        ARBShaderObjects.glGetInfoLogARB(sstate.getProgramID(), ibuf, bbuf);
+        String log = Charset.forName("US-ASCII").decode(bbuf).toString();
+
+        // if it runs in software mode, that counts as a failure
+        return (log.indexOf("software") == -1) ? sstate : null;
     }
 
     /**