/*
 * Copyright (c) 2007, 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.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * 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
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 */

package sun.java2d.pipe;

import java.awt.AlphaComposite;
import java.awt.Composite;
import sun.java2d.SurfaceData;
import sun.java2d.loops.Blit;
import sun.java2d.loops.CompositeType;
import sun.java2d.loops.MaskBlit;
import sun.java2d.loops.SurfaceType;
import static sun.java2d.pipe.BufferedOpCodes.*;

The MaskBlit operation is expressed as:
  dst = ((src  dst) * pathA) + (dst * (1 - pathA))
The OGL/D3D implementation of the MaskBlit operation differs from the above
equation because it is not possible to perform such a complex operation in
OpenGL/Direct3D (without the use of advanced techniques like fragment
shaders and multitexturing).  Therefore, the BufferedMaskBlit operation
is expressed as:
  dst = (src * pathA)  dst
This simplified formula is only equivalent to the "true" MaskBlit equation
in the following situations:
  -  is SrcOver
  -  is Src, extra alpha == 1.0, and the source surface is opaque
Therefore, we register BufferedMaskBlit primitives for only the SurfaceType
and CompositeType restrictions mentioned above.  In addition for the Src
case, we must override the composite with a SrcOver (no extra alpha)
instance, so that we set up the OpenGL/Direct3D blending mode to match the
BufferedMaskBlit equation.
/**
 * The MaskBlit operation is expressed as:
 *   dst = ((src <MODE> dst) * pathA) + (dst * (1 - pathA))
 *
 * The OGL/D3D implementation of the MaskBlit operation differs from the above
 * equation because it is not possible to perform such a complex operation in
 * OpenGL/Direct3D (without the use of advanced techniques like fragment
 * shaders and multitexturing).  Therefore, the BufferedMaskBlit operation
 * is expressed as:
 *   dst = (src * pathA) <SrcOver> dst
 *
 * This simplified formula is only equivalent to the "true" MaskBlit equation
 * in the following situations:
 *   - <MODE> is SrcOver
 *   - <MODE> is Src, extra alpha == 1.0, and the source surface is opaque
 *
 * Therefore, we register BufferedMaskBlit primitives for only the SurfaceType
 * and CompositeType restrictions mentioned above.  In addition for the Src
 * case, we must override the composite with a SrcOver (no extra alpha)
 * instance, so that we set up the OpenGL/Direct3D blending mode to match the
 * BufferedMaskBlit equation.
 */
public abstract class BufferedMaskBlit extends MaskBlit {

    private static final int ST_INT_ARGB     = 0;
    private static final int ST_INT_ARGB_PRE = 1;
    private static final int ST_INT_RGB      = 2;
    private static final int ST_INT_BGR      = 3;

    private final RenderQueue rq;
    private final int srcTypeVal;
    private Blit blitop;

    protected BufferedMaskBlit(RenderQueue rq,
                               SurfaceType srcType,
                               CompositeType compType,
                               SurfaceType dstType)
    {
        super(srcType, compType, dstType);
        this.rq = rq;
        if (srcType == SurfaceType.IntArgb) {
            this.srcTypeVal = ST_INT_ARGB;
        } else if (srcType == SurfaceType.IntArgbPre) {
            this.srcTypeVal = ST_INT_ARGB_PRE;
        } else if (srcType == SurfaceType.IntRgb) {
            this.srcTypeVal = ST_INT_RGB;
        } else if (srcType == SurfaceType.IntBgr) {
            this.srcTypeVal = ST_INT_BGR;
        } else {
            throw new InternalError("unrecognized source surface type");
        }
    }

    @Override
    public void MaskBlit(SurfaceData src, SurfaceData dst,
                         Composite comp, Region clip,
                         int srcx, int srcy,
                         int dstx, int dsty,
                         int width, int height,
                         byte[] mask, int maskoff, int maskscan)
    {
        if (width <= 0 || height <= 0) {
            return;
        }

        if (mask == null) {
            // no mask involved; delegate to regular blit loop
            if (blitop == null) {
                blitop = Blit.getFromCache(src.getSurfaceType(),
                                           CompositeType.AnyAlpha,
                                           this.getDestType());
            }
            blitop.Blit(src, dst,
                        comp, clip,
                        srcx, srcy, dstx, dsty,
                        width, height);
            return;
        }

        AlphaComposite acomp = (AlphaComposite)comp;
        if (acomp.getRule() != AlphaComposite.SRC_OVER) {
            comp = AlphaComposite.SrcOver;
        }

        rq.lock();
        try {
            validateContext(dst, comp, clip);

            RenderBuffer buf = rq.getBuffer();
            int totalBytesRequired = 20 + (width * height * 4);

            /*
             * REMIND: we should fix this so that it works with tiles that
             *         are larger than the entire buffer, but the native
             *         OGL/D3DMaskBlit isn't even prepared for tiles larger
             *         than 32x32 pixels, so there's no urgency here...
             */
            rq.ensureCapacity(totalBytesRequired);

            // enqueue parameters and tile pixels
            int newpos = enqueueTile(buf.getAddress(), buf.position(),
                                     src, src.getNativeOps(), srcTypeVal,
                                     mask, mask.length, maskoff, maskscan,
                                     srcx, srcy, dstx, dsty,
                                     width, height);

            buf.position(newpos);
        } finally {
            rq.unlock();
        }
    }

    private native int enqueueTile(long buf, int bpos,
                                   SurfaceData srcData,
                                   long pSrcOps, int srcType,
                                   byte[] mask, int masklen,
                                   int maskoff, int maskscan,
                                   int srcx, int srcy, int dstx, int dsty,
                                   int width, int height);

    
Validates the context state using the given destination surface
and composite/clip values.
/**
     * Validates the context state using the given destination surface
     * and composite/clip values.
     */
    protected abstract void validateContext(SurfaceData dstData,
                                            Composite comp, Region clip);
}