/*

 * Copyright (c) 2007, 2011, 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.opengl;

import java.awt.GradientPaint;

import java.awt.LinearGradientPaint;

import java.awt.MultipleGradientPaint;

import java.awt.MultipleGradientPaint.ColorSpaceType;

import java.awt.MultipleGradientPaint.CycleMethod;

import java.awt.RadialGradientPaint;

import java.awt.TexturePaint;

import java.awt.image.BufferedImage;

import java.util.HashMap;

import java.util.Map;

import sun.java2d.SunGraphics2D;

import sun.java2d.SurfaceData;

import sun.java2d.loops.CompositeType;

import static sun.java2d.pipe.BufferedPaints.*;

import static sun.java2d.opengl.OGLContext.OGLContextCaps.*;

abstract class OGLPaints {

    /**

     * Holds all registered implementations, using the corresponding

     * SunGraphics2D.PAINT_* constant as the hash key.

     */

    private static Map<Integer, OGLPaints> impls =

        new HashMap<Integer, OGLPaints>(4, 1.0f);

    static {

        impls.put(SunGraphics2D.PAINT_GRADIENT, new Gradient());

        impls.put(SunGraphics2D.PAINT_LIN_GRADIENT, new LinearGradient());

        impls.put(SunGraphics2D.PAINT_RAD_GRADIENT, new RadialGradient());

        impls.put(SunGraphics2D.PAINT_TEXTURE, new Texture());

    }

    /**

     * Attempts to locate an implementation corresponding to the paint state

     * of the provided SunGraphics2D object.  If no implementation can be

     * found, or if the paint cannot be accelerated under the conditions

     * of the SunGraphics2D, this method returns false; otherwise, returns

     * true.

     */

    static boolean isValid(SunGraphics2D sg2d) {

        OGLPaints impl = impls.get(sg2d.paintState);

        return (impl != null && impl.isPaintValid(sg2d));

    }

    /**

     * Returns true if this implementation is able to accelerate the

     * Paint object associated with, and under the conditions of, the

     * provided SunGraphics2D instance; otherwise returns false.

     */

    abstract boolean isPaintValid(SunGraphics2D sg2d);

/************************* GradientPaint support ****************************/

    private static class Gradient extends OGLPaints {

        private Gradient() {}

        /**

         * There are no restrictions for accelerating GradientPaint, so

         * this method always returns true.

         */

        @Override

        boolean isPaintValid(SunGraphics2D sg2d) {

            return true;

        }

    }

/************************** TexturePaint support ****************************/

    private static class Texture extends OGLPaints {

        private Texture() {}

        /**

         * Returns true if the given TexturePaint instance can be used by the

         * accelerated OGLPaints.Texture implementation.  A TexturePaint is

         * considered valid if the following conditions are met:

         *   - the texture image dimensions are power-of-two (or the

         *     GL_ARB_texture_non_power_of_two extension is present)

         *   - the texture image can be (or is already) cached in an OpenGL

         *     texture object

         */

        @Override

        boolean isPaintValid(SunGraphics2D sg2d) {

            TexturePaint paint = (TexturePaint)sg2d.paint;

            OGLSurfaceData dstData = (OGLSurfaceData)sg2d.surfaceData;

            BufferedImage bi = paint.getImage();

            // see if texture-non-pow2 extension is available

            if (!dstData.isTexNonPow2Available()) {

                int imgw = bi.getWidth();

                int imgh = bi.getHeight();

                // verify that the texture image dimensions are pow2

                if ((imgw & (imgw - 1)) != 0 || (imgh & (imgh - 1)) != 0) {

                    return false;

                }

            }

            SurfaceData srcData =

                dstData.getSourceSurfaceData(bi,

                                             SunGraphics2D.TRANSFORM_ISIDENT,

                                             CompositeType.SrcOver, null);

            if (!(srcData instanceof OGLSurfaceData)) {

                // REMIND: this is a hack that attempts to cache the system

                //         memory image from the TexturePaint instance into an

                //         OpenGL texture...

                srcData =

                    dstData.getSourceSurfaceData(bi,

                                                 SunGraphics2D.TRANSFORM_ISIDENT,

                                                 CompositeType.SrcOver, null);

                if (!(srcData instanceof OGLSurfaceData)) {

                    return false;

                }

            }

            // verify that the source surface is actually a texture

            OGLSurfaceData oglData = (OGLSurfaceData)srcData;

            if (oglData.getType() != OGLSurfaceData.TEXTURE) {

                return false;

            }

            return true;

        }

    }

/****************** Shared MultipleGradientPaint support ********************/

    private static abstract class MultiGradient extends OGLPaints {

        protected MultiGradient() {}

        /**

         * Returns true if the given MultipleGradientPaint instance can be

         * used by the accelerated OGLPaints.MultiGradient implementation.

         * A MultipleGradientPaint is considered valid if the following

         * conditions are met:

         *   - the number of gradient "stops" is <= MAX_FRACTIONS

         *   - the destination has support for fragment shaders

         */

        @Override

        boolean isPaintValid(SunGraphics2D sg2d) {

            MultipleGradientPaint paint = (MultipleGradientPaint)sg2d.paint;

            // REMIND: ugh, this creates garbage; would be nicer if

            // we had a MultipleGradientPaint.getNumStops() method...

            if (paint.getFractions().length > MULTI_MAX_FRACTIONS) {

                return false;

            }

            OGLSurfaceData dstData = (OGLSurfaceData)sg2d.surfaceData;

            OGLGraphicsConfig gc = dstData.getOGLGraphicsConfig();

            if (!gc.isCapPresent(CAPS_EXT_GRAD_SHADER)) {

                return false;

            }

            return true;

        }

    }

/********************** LinearGradientPaint support *************************/

    private static class LinearGradient extends MultiGradient {

        private LinearGradient() {}

        @Override

        boolean isPaintValid(SunGraphics2D sg2d) {

            LinearGradientPaint paint = (LinearGradientPaint)sg2d.paint;

            if (paint.getFractions().length == 2 &&

                paint.getCycleMethod() != CycleMethod.REPEAT &&

                paint.getColorSpace() != ColorSpaceType.LINEAR_RGB)

            {

                // we can delegate to the optimized two-color gradient

                // codepath, which does not require fragment shader support

                return true;

            }

            return super.isPaintValid(sg2d);

        }

    }

/********************** RadialGradientPaint support *************************/

    private static class RadialGradient extends MultiGradient {

        private RadialGradient() {}

    }

}