/* -*- Mode: c++; c-basic-offset: 4; indent-tabs-mode: nil; tab-width: 40; -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef GLTEXTUREIMAGE_H_
#define GLTEXTUREIMAGE_H_

#include "nsRegion.h"
#include "nsTArray.h"
#include "gfxTypes.h"
#include "GLContextTypes.h"
#include "mozilla/gfx/Rect.h"
#include "mozilla/RefPtr.h"

class gfxASurface;

namespace mozilla {
namespace gfx {
class DataSourceSurface;
class DrawTarget;
} // namespace gfx
} // namespace mozilla

namespace mozilla {
namespace gl {
class GLContext;

/**
 * A TextureImage encapsulates a surface that can be drawn to by a
 * Thebes gfxContext and (hopefully efficiently!) synchronized to a
 * texture in the server.  TextureImages are associated with one and
 * only one GLContext.
 *
 * Implementation note: TextureImages attempt to unify two categories
 * of backends
 *
 *  (1) proxy to server-side object that can be bound to a texture;
 *      e.g. Pixmap on X11.
 *
 *  (2) efficient manager of texture memory; e.g. by having clients draw
 *      into a scratch buffer which is then uploaded with
 *      glTexSubImage2D().
 */
class TextureImage
{
    NS_INLINE_DECL_REFCOUNTING(TextureImage)
public:
    enum TextureState
    {
      Created, // Texture created, but has not had glTexImage called to initialize it.
      Allocated,  // Texture memory exists, but contents are invalid.
      Valid  // Texture fully ready to use.
    };

    enum Flags {
        NoFlags          = 0x0,
        UseNearestFilter = 0x1,
        OriginBottomLeft = 0x2,
        DisallowBigImage = 0x4
    };

    typedef gfxContentType ContentType;
    typedef gfxImageFormat ImageFormat;

    static already_AddRefed<TextureImage> Create(
                       GLContext* gl,
                       const gfx::IntSize& aSize,
                       TextureImage::ContentType aContentType,
                       GLenum aWrapMode,
                       TextureImage::Flags aFlags = TextureImage::NoFlags);

    /**
     * Returns a gfxASurface for updating |aRegion| of the client's
     * image if successul, nullptr if not.  |aRegion|'s bounds must fit
     * within Size(); its coordinate space (if any) is ignored.  If
     * the update begins successfully, the returned gfxASurface is
     * owned by this.  Otherwise, nullptr is returned.
     *
     * |aRegion| is an inout param: the returned region is what the
     * client must repaint.  Category (1) regions above can
     * efficiently handle repaints to "scattered" regions, while (2)
     * can only efficiently handle repaints to rects.
     *
     * Painting the returned surface outside of |aRegion| results
     * in undefined behavior.
     *
     * BeginUpdate() calls cannot be "nested", and each successful
     * BeginUpdate() must be followed by exactly one EndUpdate() (see
     * below).  Failure to do so can leave this in a possibly
     * inconsistent state.  Unsuccessful BeginUpdate()s must not be
     * followed by EndUpdate().
     */
    virtual gfx::DrawTarget* BeginUpdate(nsIntRegion& aRegion) = 0;
    /**
     * Retrieves the region that will require updating, given a
     * region that needs to be updated. This can be used for
     * making decisions about updating before calling BeginUpdate().
     *
     * |aRegion| is an inout param.
     */
    virtual void GetUpdateRegion(nsIntRegion& aForRegion) {
    }
    /**
     * Finish the active update and synchronize with the server, if
     * necessary.
     *
     * BeginUpdate() must have been called exactly once before
     * EndUpdate().
     */
    virtual void EndUpdate() = 0;

    /**
     * The Image may contain several textures for different regions (tiles).
     * These functions iterate over each sub texture image tile.
     */
    virtual void BeginBigImageIteration() {
    }

    virtual bool NextTile() {
        return false;
    }

    // Function prototype for a tile iteration callback. Returning false will
    // cause iteration to be interrupted (i.e. the corresponding NextTile call
    // will return false).
    typedef bool (* BigImageIterationCallback)(TextureImage* aImage,
                                           int aTileNumber,
                                           void* aCallbackData);

    // Sets a callback to be called every time NextTile is called.
    virtual void SetIterationCallback(BigImageIterationCallback aCallback,
                                      void* aCallbackData) {
    }

    virtual gfx::IntRect GetTileRect();

    virtual GLuint GetTextureID() = 0;

    virtual uint32_t GetTileCount() {
        return 1;
    }

    /**
     * Set this TextureImage's size, and ensure a texture has been
     * allocated.  Must not be called between BeginUpdate and EndUpdate.
     * After a resize, the contents are undefined.
     *
     * If this isn't implemented by a subclass, it will just perform
     * a dummy BeginUpdate/EndUpdate pair.
     */
    virtual void Resize(const gfx::IntSize& aSize) {
        mSize = aSize;
        nsIntRegion r(gfx::IntRect(0, 0, aSize.width, aSize.height));
        BeginUpdate(r);
        EndUpdate();
    }

    /**
     * Mark this texture as having valid contents. Call this after modifying
     * the texture contents externally.
     */
    virtual void MarkValid() {}

    /**
     * aSurf - the source surface to update from
     * aRegion - the region in this image to update
     * aFrom - offset in the source to update from
     */
    virtual bool DirectUpdate(gfx::DataSourceSurface* aSurf, const nsIntRegion& aRegion, const gfx::IntPoint& aFrom = gfx::IntPoint(0,0)) = 0;
    bool UpdateFromDataSource(gfx::DataSourceSurface* aSurf,
                              const nsIntRegion* aDstRegion = nullptr,
                              const gfx::IntPoint* aSrcOffset = nullptr);

    virtual void BindTexture(GLenum aTextureUnit) = 0;

    /**
     * Returns the image format of the texture. Only valid after a matching
     * BeginUpdate/EndUpdate pair have been called.
     */
    virtual gfx::SurfaceFormat GetTextureFormat() {
        return mTextureFormat;
    }

    /** Can be called safely at any time. */

    /**
     * If this TextureImage has a permanent gfxASurface backing,
     * return it.  Otherwise return nullptr.
     */
    virtual already_AddRefed<gfxASurface> GetBackingSurface()
    { return nullptr; }


    gfx::IntSize GetSize() const;
    ContentType GetContentType() const { return mContentType; }
    virtual bool InUpdate() const = 0;
    GLenum GetWrapMode() const { return mWrapMode; }

    void SetSamplingFilter(gfx::SamplingFilter aSamplingFilter) {
      mSamplingFilter = aSamplingFilter;
    }

protected:
    friend class GLContext;

    void UpdateUploadSize(size_t amount);

    /**
     * After the ctor, the TextureImage is invalid.  Implementations
     * must allocate resources successfully before returning the new
     * TextureImage from GLContext::CreateTextureImage().  That is,
     * clients must not be given partially-constructed TextureImages.
     */
    TextureImage(const gfx::IntSize& aSize,
                 GLenum aWrapMode, ContentType aContentType,
                 Flags aFlags = NoFlags);

    // Protected destructor, to discourage deletion outside of Release():
    virtual ~TextureImage() {
        UpdateUploadSize(0);
    }

    virtual gfx::IntRect GetSrcTileRect();

    gfx::IntSize mSize;
    GLenum mWrapMode;
    ContentType mContentType;
    gfx::SurfaceFormat mTextureFormat;
    gfx::SamplingFilter mSamplingFilter;
    Flags mFlags;
    size_t mUploadSize;
};

/**
 * BasicTextureImage is the baseline TextureImage implementation ---
 * it updates its texture by allocating a scratch buffer for the
 * client to draw into, then using glTexSubImage2D() to upload the new
 * pixels.  Platforms must provide the code to create a new surface
 * into which the updated pixels will be drawn, and the code to
 * convert the update surface's pixels into an image on which we can
 * glTexSubImage2D().
 */
class BasicTextureImage
    : public TextureImage
{
public:
    virtual ~BasicTextureImage();

    BasicTextureImage(GLuint aTexture,
                      const gfx::IntSize& aSize,
                      GLenum aWrapMode,
                      ContentType aContentType,
                      GLContext* aContext,
                      TextureImage::Flags aFlags = TextureImage::NoFlags);

    virtual void BindTexture(GLenum aTextureUnit);

    virtual gfx::DrawTarget* BeginUpdate(nsIntRegion& aRegion);
    virtual void GetUpdateRegion(nsIntRegion& aForRegion);
    virtual void EndUpdate();
    virtual bool DirectUpdate(gfx::DataSourceSurface* aSurf, const nsIntRegion& aRegion, const gfx::IntPoint& aFrom = gfx::IntPoint(0,0));
    virtual GLuint GetTextureID() { return mTexture; }
    virtual already_AddRefed<gfx::DrawTarget>
      GetDrawTargetForUpdate(const gfx::IntSize& aSize, gfx::SurfaceFormat aFmt);

    virtual void MarkValid() { mTextureState = Valid; }

    // Call when drawing into the update surface is complete.
    // Returns true if textures should be upload with a relative
    // offset - See UploadSurfaceToTexture.
    virtual bool FinishedSurfaceUpdate();

    // Call after surface data has been uploaded to a texture.
    virtual void FinishedSurfaceUpload();

    virtual bool InUpdate() const { return !!mUpdateDrawTarget; }

    virtual void Resize(const gfx::IntSize& aSize);

protected:
    GLuint mTexture;
    TextureState mTextureState;
    RefPtr<GLContext> mGLContext;
    RefPtr<gfx::DrawTarget> mUpdateDrawTarget;
    nsIntRegion mUpdateRegion;

    // The offset into the update surface at which the update rect is located.
    nsIntPoint mUpdateOffset;
};

/**
 * A container class that complements many sub TextureImages into a big TextureImage.
 * Aims to behave just like the real thing.
 */

class TiledTextureImage final
    : public TextureImage
{
public:
    TiledTextureImage(GLContext* aGL,
                      gfx::IntSize aSize,
                      TextureImage::ContentType,
                      TextureImage::Flags aFlags = TextureImage::NoFlags,
                      TextureImage::ImageFormat aImageFormat = gfx::SurfaceFormat::UNKNOWN);
    ~TiledTextureImage();
    void DumpDiv();
    virtual gfx::DrawTarget* BeginUpdate(nsIntRegion& aRegion);
    virtual void GetUpdateRegion(nsIntRegion& aForRegion);
    virtual void EndUpdate();
    virtual void Resize(const gfx::IntSize& aSize);
    virtual uint32_t GetTileCount();
    virtual void BeginBigImageIteration();
    virtual bool NextTile();
    virtual void SetIterationCallback(BigImageIterationCallback aCallback,
                                      void* aCallbackData);
    virtual gfx::IntRect GetTileRect();
    virtual GLuint GetTextureID() {
        return mImages[mCurrentImage]->GetTextureID();
    }
    virtual bool DirectUpdate(gfx::DataSourceSurface* aSurf, const nsIntRegion& aRegion, const gfx::IntPoint& aFrom = gfx::IntPoint(0,0));
    virtual bool InUpdate() const { return mInUpdate; }
    virtual void BindTexture(GLenum);

protected:
    virtual gfx::IntRect GetSrcTileRect();

    unsigned int mCurrentImage;
    BigImageIterationCallback mIterationCallback;
    void* mIterationCallbackData;
    nsTArray< RefPtr<TextureImage> > mImages;
    bool mInUpdate;
    unsigned int mTileSize;
    unsigned int mRows, mColumns;
    GLContext* mGL;
    // A temporary draw target to faciliate cross-tile updates.
    RefPtr<gfx::DrawTarget> mUpdateDrawTarget;
    // The region of update requested
    nsIntRegion mUpdateRegion;
    TextureState mTextureState;
    TextureImage::ImageFormat mImageFormat;
};

/**
 * Creates a TextureImage of the basic implementation, can be useful in cases
 * where we know we don't want to use platform-specific TextureImage.
 * In doubt, use GLContext::CreateTextureImage instead.
 */
already_AddRefed<TextureImage>
CreateBasicTextureImage(GLContext* aGL,
                        const gfx::IntSize& aSize,
                        TextureImage::ContentType aContentType,
                        GLenum aWrapMode,
                        TextureImage::Flags aFlags);

/**
 * Creates a TiledTextureImage backed by platform-specific or basic TextureImages.
 * In doubt, use GLContext::CreateTextureImage instead.
 */
already_AddRefed<TextureImage>
CreateTiledTextureImage(GLContext* aGL,
                        const gfx::IntSize& aSize,
                        TextureImage::ContentType aContentType,
                        TextureImage::Flags aFlags,
                        TextureImage::ImageFormat aImageFormat);

/**
  * Return a valid, allocated TextureImage of |aSize| with
  * |aContentType|.  If |aContentType| is COLOR, |aImageFormat| can be used
  * to hint at the preferred RGB format, however it is not necessarily
  * respected.  The TextureImage's texture is configured to use
  * |aWrapMode| (usually GL_CLAMP_TO_EDGE or GL_REPEAT) and by
  * default, GL_LINEAR filtering.  Specify
  * |aFlags=UseNearestFilter| for GL_NEAREST filtering. Specify
  * |aFlags=OriginBottomLeft| if the image is origin-bottom-left, instead of the
  * default origin-top-left. Return
  * nullptr if creating the TextureImage fails.
  *
  * The returned TextureImage may only be used with this GLContext.
  * Attempting to use the returned TextureImage after this
  * GLContext is destroyed will result in undefined (and likely
  * crashy) behavior.
  */
already_AddRefed<TextureImage>
CreateTextureImage(GLContext* gl,
                   const gfx::IntSize& aSize,
                   TextureImage::ContentType aContentType,
                   GLenum aWrapMode,
                   TextureImage::Flags aFlags = TextureImage::NoFlags,
                   TextureImage::ImageFormat aImageFormat = gfx::SurfaceFormat::UNKNOWN);

} // namespace gl
} // namespace mozilla

#endif /* GLTEXTUREIMAGE_H_ */
