/*
 * Copyright 2003-2006 Sun Microsystems, Inc.  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.  Sun designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
 * CA 95054 USA or visit www.sun.com if you need additional information or
 * have any questions.
 */

package sun.java2d.opengl;

import java.awt.AlphaComposite;
import java.awt.Composite;
import java.nio.ByteBuffer;
import sun.java2d.SunGraphics2D;
import sun.java2d.SurfaceData;
import sun.java2d.loops.Blit;
import sun.java2d.loops.CompositeType;
import sun.java2d.loops.GraphicsPrimitive;
import sun.java2d.loops.GraphicsPrimitiveMgr;
import sun.java2d.loops.MaskBlit;
import sun.java2d.loops.SurfaceType;
import sun.java2d.pipe.Region;
import sun.java2d.pipe.RenderBuffer;
import sun.java2d.pipe.RenderQueue;
import static sun.java2d.pipe.BufferedOpCodes.*;

/**
 * The MaskBlit operation is expressed as:
 *   dst = ((src <MODE> dst) * pathA) + (dst * (1 - pathA))
 *
 * The OGL implementation of the MaskBlit operation differs from the above
 * equation because it is not possible to perform such a complex operation in
 * OpenGL (without the use of advanced techniques like fragment shaders and
 * multitexturing).  Therefore, the OGLMaskBlit 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 OGLMaskBlit 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 blending mode to match the
 * OGLMaskBlit equation.
 */
class OGLMaskBlit extends MaskBlit {

    static void register() {
        GraphicsPrimitive[] primitives = {
            new OGLMaskBlit(SurfaceType.IntArgb,
                            CompositeType.SrcOver,
                            OGLSurfaceData.PF_INT_ARGB),
            new OGLMaskBlit(SurfaceType.IntRgb,
                            CompositeType.SrcOver,
                            OGLSurfaceData.PF_INT_RGB),
            new OGLMaskBlit(SurfaceType.IntRgb,
                            CompositeType.SrcNoEa,
                            OGLSurfaceData.PF_INT_RGB),
            new OGLMaskBlit(SurfaceType.IntBgr,
                            CompositeType.SrcOver,
                            OGLSurfaceData.PF_INT_BGR),
            new OGLMaskBlit(SurfaceType.IntBgr,
                            CompositeType.SrcNoEa,
                            OGLSurfaceData.PF_INT_BGR),
        };
        GraphicsPrimitiveMgr.register(primitives);
    }

    private int typeval;
    private Blit blitop;

    private OGLMaskBlit(SurfaceType srcType,
                        CompositeType compType,
                        int typeval)
    {
        super(srcType, compType, OGLSurfaceData.OpenGLSurface);
        this.typeval = typeval;
    }

    @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 (mask == null) {
            // no mask involved; delegate to regular blit loop
            if (blitop == null) {
                blitop = Blit.getFromCache(src.getSurfaceType(),
                                           CompositeType.AnyAlpha,
                                           OGLSurfaceData.OpenGLSurface);
            }
            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;
        }

        OGLRenderQueue rq = OGLRenderQueue.getInstance();
        rq.lock();
        try {
            // make sure the RenderQueue keeps a hard reference to the
            // source (sysmem) SurfaceData to prevent it from being
            // disposed while the operation is processed on the QFT
            rq.addReference(src);

            OGLSurfaceData oglDst = (OGLSurfaceData)dst;
            OGLContext.validateContext(oglDst, oglDst,
                                       clip, comp, null, null, null,
                                       OGLContext.NO_CONTEXT_FLAGS);

            RenderBuffer buf = rq.getBuffer();
            // we adjust the mask length so that the mask ends on a
            // 4-byte boundary
            int maskBytesRequired = (mask.length + 3) & (~3);
            int padding = maskBytesRequired - mask.length;
            int totalBytesRequired = 52 + maskBytesRequired;

            /*
             * REMIND: we should fix this so that it works with tiles that
             *         are larger than the entire buffer, but the native
             *         OGLMaskBlit isn't even prepared for tiles larger than
             *         1024 bytes, so there's no urgency here...
             */
            rq.ensureCapacityAndAlignment(totalBytesRequired, 4);
            buf.putInt(MASK_BLIT);
            // enqueue parameters
            buf.putLong(src.getNativeOps());
            buf.putInt(typeval);
            buf.putInt(srcx).putInt(srcy);
            buf.putInt(dstx).putInt(dsty);
            buf.putInt(width).putInt(height);
            buf.putInt(maskoff);
            buf.putInt(maskscan);
            buf.putInt(maskBytesRequired);
            // enqueue the mask
            buf.put(mask);
            if (padding != 0) {
                buf.position(buf.position() + padding);
            }

            // always flush immediately, since we (currently) have no means
            // of tracking changes to the source surface
            rq.flushNow();
        } finally {
            rq.unlock();
        }
    }
}