//
// Copyright 2016 The ANGLE Project Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//
// RenderTargetVk:
//   Wrapper around a Vulkan renderable resource, using an ImageView.
//

#ifndef LIBANGLE_RENDERER_VULKAN_RENDERTARGETVK_H_
#define LIBANGLE_RENDERER_VULKAN_RENDERTARGETVK_H_

#include "common/vulkan/vk_headers.h"
#include "libANGLE/FramebufferAttachment.h"
#include "libANGLE/renderer/renderer_utils.h"
#include "libANGLE/renderer/vulkan/vk_helpers.h"

namespace rx
{
namespace vk
{
struct Format;
class FramebufferHelper;
class ImageHelper;
class ImageView;
class Resource;
class RenderPassDesc;
}  // namespace vk

class ContextVk;
class TextureVk;

// This is a very light-weight class that does not own to the resources it points to.
// It's meant only to copy across some information from a FramebufferAttachment to the
// business rendering logic. It stores Images and ImageViews by pointer for performance.
class RenderTargetVk final : public FramebufferAttachmentRenderTarget
{
  public:
    RenderTargetVk();
    ~RenderTargetVk() override;

    // Used in std::vector initialization.
    RenderTargetVk(RenderTargetVk &&other);

    void init(vk::ImageHelper *image,
              vk::ImageViewHelper *imageViews,
              vk::ImageHelper *resolveImage,
              vk::ImageViewHelper *resolveImageViews,
              uint32_t levelIndexGL,
              uint32_t layerIndex,
              bool isImageTransient);
    void reset();

    vk::ImageViewSubresourceSerial getDrawSubresourceSerial() const;
    vk::ImageViewSubresourceSerial getResolveSubresourceSerial() const;

    // Note: RenderTargets should be called in order, with the depth/stencil onRender last.
    angle::Result onColorDraw(ContextVk *contextVk);
    angle::Result onDepthStencilDraw(ContextVk *contextVk);

    vk::ImageHelper &getImageForRenderPass();
    const vk::ImageHelper &getImageForRenderPass() const;

    vk::ImageHelper &getResolveImageForRenderPass();
    const vk::ImageHelper &getResolveImageForRenderPass() const;

    vk::ImageHelper &getImageForCopy() const;
    vk::ImageHelper &getImageForWrite() const;

    // For cube maps we use single-level single-layer 2D array views.
    angle::Result getImageView(ContextVk *contextVk, const vk::ImageView **imageViewOut) const;
    angle::Result getResolveImageView(ContextVk *contextVk,
                                      const vk::ImageView **imageViewOut) const;

    // For 3D textures, the 2D view created for render target is invalid to read from.  The
    // following will return a view to the whole image (for all types, including 3D and 2DArray).
    angle::Result getAndRetainCopyImageView(ContextVk *contextVk,
                                            const vk::ImageView **imageViewOut) const;

    const vk::Format &getImageFormat() const;
    gl::Extents getExtents() const;
    uint32_t getLevelIndex() const { return mLevelIndexGL; }
    uint32_t getLayerIndex() const { return mLayerIndex; }

    gl::ImageIndex getImageIndex() const;

    // Special mutator for Surface RenderTargets. Allows the Framebuffer to keep a single
    // RenderTargetVk pointer.
    void updateSwapchainImage(vk::ImageHelper *image,
                              vk::ImageViewHelper *imageViews,
                              vk::ImageHelper *resolveImage,
                              vk::ImageViewHelper *resolveImageViews);

    angle::Result flushStagedUpdates(ContextVk *contextVk,
                                     vk::ClearValuesArray *deferredClears,
                                     uint32_t deferredClearIndex);

    void retainImageViews(ContextVk *contextVk) const;

    bool hasDefinedContent() const { return mContentDefined; }
    // Mark content as undefined so that certain optimizations are possible such as using DONT_CARE
    // as loadOp of the render target in the next renderpass.
    void invalidateEntireContent() { mContentDefined = false; }

    // See the description of mIsImageTransient for details of how the following two can
    // interact.
    bool hasResolveAttachment() const { return mResolveImage != nullptr; }
    bool isImageTransient() const { return mIsImageTransient; }

  private:
    angle::Result getImageViewImpl(ContextVk *contextVk,
                                   const vk::ImageHelper &image,
                                   vk::ImageViewHelper *imageViews,
                                   const vk::ImageView **imageViewOut) const;

    vk::ImageViewSubresourceSerial getSubresourceSerialImpl(vk::ImageViewHelper *imageViews) const;

    bool isResolveImageOwnerOfData() const;

    // The color or depth/stencil attachment of the framebuffer and its view.
    vk::ImageHelper *mImage;
    vk::ImageViewHelper *mImageViews;

    // If present, this is the corresponding resolve attachment and its view.  This is used to
    // implement GL_EXT_multisampled_render_to_texture, so while the rendering is done on mImage
    // during the renderpass, the resolved image is the one that actually holds the data.  This
    // means that data uploads and blit are done on this image, copies are done out of this image
    // etc.  This means that if there is no clear, and hasDefinedContent(), the contents of
    // mResolveImage must be copied to mImage since the loadOp of the attachment must be set to
    // LOAD.
    vk::ImageHelper *mResolveImage;
    vk::ImageViewHelper *mResolveImageViews;

    // Which subresource of the image is used as render target.
    uint32_t mLevelIndexGL;
    uint32_t mLayerIndex;

    // Whether the render target has been invalidated.  If so, DONT_CARE is used instead of LOAD for
    // loadOp of this attachment.
    bool mContentDefined;

    // If resolve attachment exists, |mIsImageTransient| is true if the multisampled results need to
    // be discarded.
    //
    // - GL_EXT_multisampled_render_to_texture: this is true for render targets created for this
    //   extension's usage.  Only color attachments use this optimization at the moment.
    // - GL_EXT_multisampled_render_to_texture2: this is true for depth/stencil textures per this
    //   extension, even though a resolve attachment is not even provided.
    // - Multisampled swapchain: TODO(syoussefi) this is true for the multisampled color attachment.
    //   http://anglebug.com/4836
    // - glBlitFramebuffer optimization: TODO(timvp) this is **false** in this case, as the
    //   multisampled attachment and the resolve attachments belong to independent framebuffers.
    //   http://anglebug.com/4753
    //
    // Based on the above, we have:
    //
    //                   mResolveImage == nullptr        |       mResolveImage != nullptr
    //                                                   |
    //                      Normal rendering             |          Blit optimization
    // !IsTransient            No resolve                |               Resolve
    //                       storeOp = STORE             |           storeOp = STORE
    //                    Owner of data: mImage          |        Owner of data: mImage
    //                                                   |
    //      ---------------------------------------------+---------------------------------------
    //                                                   |
    //               EXT_multisampled_render_to_texture2 | GL_EXT_multisampled_render_to_texture
    //                                                   | or multisampled Swapchain optimization
    // IsTransient             No resolve                |               Resolve
    //                      storeOp = DONT_CARE          |         storeOp = DONT_CARE
    //                Owner of data: None (not stored)   |     Owner of data: mResolveImage
    //
    // In the above, storeOp of the resolve attachment is always STORE.  if !IsTransient, storeOp is
    // affected by a framebuffer invalidate call.
    bool mIsImageTransient;
};

// A vector of rendertargets
using RenderTargetVector = std::vector<RenderTargetVk>;
}  // namespace rx

#endif  // LIBANGLE_RENDERER_VULKAN_RENDERTARGETVK_H_
