/*
 * Copyright (C) 2009-2017 Apple 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:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions 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.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
 */

#include "config.h"

#if ENABLE(WEBGL)
#import "WebGLLayer.h"

#import "GraphicsContext3D.h"
#import "GraphicsContextCG.h"
#import "GraphicsLayer.h"
#import "GraphicsLayerCA.h"
#import "PlatformCALayer.h"
#import <pal/spi/cocoa/QuartzCoreSPI.h>
#import <wtf/FastMalloc.h>
#import <wtf/RetainPtr.h>

#if USE(OPENGL)
#import <OpenGL/OpenGL.h>
#import <OpenGL/gl.h>
#endif

using namespace WebCore;

@implementation WebGLLayer

@synthesize context=_context;

-(id)initWithGraphicsContext3D:(GraphicsContext3D*)context
{
    _context = context;
    self = [super init];
    _devicePixelRatio = context->getContextAttributes().devicePixelRatio;
#if USE(OPENGL)
    self.contentsOpaque = !context->getContextAttributes().alpha;
    self.transform = CATransform3DIdentity;
    self.contentsScale = _devicePixelRatio;
#else
    self.opaque = !context->getContextAttributes().alpha;
#endif
    return self;
}

#if USE(OPENGL)
// When using an IOSurface as layer contents, we need to flip the
// layer to take into account that the IOSurface provides content
// in Y-up. This means that any incoming transform (unlikely, since
// this is a contents layer) and anchor point must add a Y scale of
// -1 and make sure the transform happens from the top.

- (void)setTransform:(CATransform3D)t
{
    [super setTransform:CATransform3DScale(t, 1, -1, 1)];
}

- (void)setAnchorPoint:(CGPoint)p
{
    [super setAnchorPoint:CGPointMake(p.x, 1.0 - p.y)];
}

static void freeData(void *, const void *data, size_t /* size */)
{
    fastFree(const_cast<void *>(data));
}
#endif

-(CGImageRef)copyImageSnapshotWithColorSpace:(CGColorSpaceRef)colorSpace
{
    if (!_context)
        return nullptr;

#if USE(OPENGL)
    CGLSetCurrentContext(_context->platformGraphicsContext3D());

    RetainPtr<CGColorSpaceRef> imageColorSpace = colorSpace;
    if (!imageColorSpace)
        imageColorSpace = sRGBColorSpaceRef();

    CGRect layerBounds = CGRectIntegral([self bounds]);

    size_t width = layerBounds.size.width * _devicePixelRatio;
    size_t height = layerBounds.size.height * _devicePixelRatio;

    size_t rowBytes = (width * 4 + 15) & ~15;
    size_t dataSize = rowBytes * height;
    void* data = fastMalloc(dataSize);
    if (!data)
        return nullptr;

    glPixelStorei(GL_PACK_ROW_LENGTH, rowBytes / 4);
    glReadPixels(0, 0, width, height, GL_BGRA, GL_UNSIGNED_INT_8_8_8_8_REV, data);

    CGDataProviderRef provider = CGDataProviderCreateWithData(0, data, dataSize, freeData);
    CGImageRef image = CGImageCreate(width, height, 8, 32, rowBytes, imageColorSpace.get(),
        kCGImageAlphaPremultipliedFirst | kCGBitmapByteOrder32Host, provider, 0, true, kCGRenderingIntentDefault);
    CGDataProviderRelease(provider);
    return image;
#else
    UNUSED_PARAM(colorSpace);
    return nullptr;
#endif
}

- (void)display
{
    if (!_context)
        return;

#if USE(OPENGL)
    _context->prepareTexture();
    if (_drawingBuffer) {
        std::swap(_contentsBuffer, _drawingBuffer);
        self.contents = _contentsBuffer->asLayerContents();
        [self reloadValueForKeyPath:@"contents"];
        [self bindFramebufferToNextAvailableSurface];
    }
#else
    _context->presentRenderbuffer();
#endif

    _context->markLayerComposited();
    PlatformCALayer* layer = PlatformCALayer::platformCALayer(self);
    if (layer && layer->owner())
        layer->owner()->platformCALayerLayerDidDisplay(layer);
}

#if USE(OPENGL)
- (void)allocateIOSurfaceBackingStoreWithSize:(IntSize)size usingAlpha:(BOOL)usingAlpha
{
    _bufferSize = size;
    _usingAlpha = usingAlpha;
    _contentsBuffer = WebCore::IOSurface::create(size, sRGBColorSpaceRef());
    _drawingBuffer = WebCore::IOSurface::create(size, sRGBColorSpaceRef());
    _spareBuffer = WebCore::IOSurface::create(size, sRGBColorSpaceRef());

    ASSERT(_contentsBuffer);
    ASSERT(_drawingBuffer);
    ASSERT(_spareBuffer);

    _contentsBuffer->migrateColorSpaceToProperties();
    _drawingBuffer->migrateColorSpaceToProperties();
    _spareBuffer->migrateColorSpaceToProperties();
}

- (void)bindFramebufferToNextAvailableSurface
{
    GC3Denum texture = _context->platformTexture();
    glBindTexture(GL_TEXTURE_RECTANGLE_ARB, texture);

    if (_drawingBuffer && _drawingBuffer->isInUse())
        std::swap(_drawingBuffer, _spareBuffer);

    IOSurfaceRef ioSurface = _drawingBuffer->surface();
    GC3Denum internalFormat = _usingAlpha ? GL_RGBA : GL_RGB;

    // Link the IOSurface to the texture.
    CGLError error = CGLTexImageIOSurface2D(_context->platformGraphicsContext3D(), GL_TEXTURE_RECTANGLE_ARB, internalFormat, _bufferSize.width(), _bufferSize.height(), GL_BGRA, GL_UNSIGNED_INT_8_8_8_8_REV, ioSurface, 0);
    ASSERT_UNUSED(error, error == kCGLNoError);
}
#endif

@end

#endif // ENABLE(WEBGL)