/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* 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 WEBGLTYPES_H_
#define WEBGLTYPES_H_

// Most WebIDL typedefs are identical to their OpenGL counterparts.
#include "GLTypes.h"

// Manual reflection of WebIDL typedefs that are different from their
// OpenGL counterparts.
typedef int64_t WebGLsizeiptr;
typedef int64_t WebGLintptr;
typedef bool WebGLboolean;

namespace mozilla {
namespace gl {
class GLContext;  // This is going to be needed a lot.
}  // namespace gl

/*
 * WebGLTextureFakeBlackStatus is an enum to track what needs to use a dummy 1x1
 * black texture, which we refer to as a 'fake black' texture.
 *
 * There are two things that can cause us to use such 'fake black' textures:
 *
 *   (1) OpenGL ES rules on sampling incomplete textures specify that they
 *       must be sampled as RGBA(0, 0, 0, 1) (opaque black). We have to
 * implement these rules ourselves, if only because we do not always run on
 * OpenGL ES, and also because this is dangerously close to the kind of
 * case where we don't want to trust the driver with corner cases of
 * texture memory accesses.
 *
 *   (2) OpenGL has cases where a renderbuffer, or a texture image, can contain
 *       uninitialized image data. See below the comment about
 * WebGLImageDataStatus. WebGL must never have access to uninitialized image
 * data. The WebGL 1 spec, section 4.1 'Resource Restrictions', specifies
 * that in any such case, the uninitialized image data must be exposed to
 * WebGL as if it were filled with zero bytes, which means it's either
 * opaque or transparent black depending on whether the image format has
 * alpha.
 */

enum class FakeBlackType : uint8_t {
  None,
  RGBA0001,  // Incomplete textures and uninitialized no-alpha color textures.
  RGBA0000,  // Uninitialized with-alpha color textures.
};

/*
 * Implementing WebGL (or OpenGL ES 2.0) on top of desktop OpenGL requires
 * emulating the vertex attrib 0 array when it's not enabled. Indeed,
 * OpenGL ES 2.0 allows drawing without vertex attrib 0 array enabled, but
 * desktop OpenGL does not allow that.
 */
enum class WebGLVertexAttrib0Status : uint8_t {
  Default,                     // default status - no emulation needed
  EmulatedUninitializedArray,  // need an artificial attrib 0 array, but
                               // contents may be left uninitialized
  EmulatedInitializedArray  // need an artificial attrib 0 array, and contents
                            // must be initialized
};

/*
 * Enum to track the status of image data (renderbuffer or texture image)
 * presence and initialization.
 *
 * - NoImageData is the initial state before any image data is allocated.
 * - InitializedImageData is the state after image data is allocated and
 * initialized.
 * - UninitializedImageData is an intermediate state where data is allocated but
 * not initialized. It is the state that renderbuffers are in after a
 * renderbufferStorage call, and it is the state that texture images are in
 * after a texImage2D call with null data.
 */
enum class WebGLImageDataStatus : uint8_t {
  NoImageData,
  UninitializedImageData,
  InitializedImageData
};

/*
 * The formats that may participate, either as source or destination formats,
 * in WebGL texture conversions. This includes:
 *  - all the formats accepted by WebGL.texImage2D, e.g. RGBA4444
 *  - additional formats provided by extensions, e.g. RGB32F
 *  - additional source formats, depending on browser details, used when
 * uploading textures from DOM elements. See gfxImageSurface::Format().
 */
enum class WebGLTexelFormat : uint8_t {
  // returned by SurfaceFromElementResultToImageSurface to indicate absence of
  // image data
  None,
  // common value for formats for which format conversions are not supported
  FormatNotSupportingAnyConversion,
  // dummy pseudo-format meaning "use the other format".
  // For example, if SrcFormat=Auto and DstFormat=RGB8, then the source
  // is implicitly treated as being RGB8 itself.
  Auto,
  // 1-channel formats
  A8,
  A16F,  // OES_texture_half_float
  A32F,  // OES_texture_float
  R8,
  R16F,  // OES_texture_half_float
  R32F,  // OES_texture_float
  // 2-channel formats
  RA8,
  RA16F,  // OES_texture_half_float
  RA32F,  // OES_texture_float
  RG8,
  RG16F,
  RG32F,
  // 3-channel formats
  RGB8,
  RGB565,
  RGB11F11F10F,
  RGB16F,  // OES_texture_half_float
  RGB32F,  // OES_texture_float
  // 4-channel formats
  RGBA8,
  RGBA5551,
  RGBA4444,
  RGBA16F,  // OES_texture_half_float
  RGBA32F,  // OES_texture_float
  // DOM element source only formats.
  RGBX8,
  BGRX8,
  BGRA8
};

enum class WebGLTexImageFunc : uint8_t {
  TexImage,
  TexSubImage,
  CopyTexImage,
  CopyTexSubImage,
  CompTexImage,
  CompTexSubImage,
};

enum class WebGLTexDimensions : uint8_t { Tex2D, Tex3D };

// Please keep extensions in alphabetic order.
enum class WebGLExtensionID : uint8_t {
  ANGLE_instanced_arrays,
  EXT_blend_minmax,
  EXT_color_buffer_float,
  EXT_color_buffer_half_float,
  EXT_frag_depth,
  EXT_sRGB,
  EXT_shader_texture_lod,
  EXT_texture_filter_anisotropic,
  EXT_disjoint_timer_query,
  MOZ_debug,
  OES_element_index_uint,
  OES_standard_derivatives,
  OES_texture_float,
  OES_texture_float_linear,
  OES_texture_half_float,
  OES_texture_half_float_linear,
  OES_vertex_array_object,
  WEBGL_color_buffer_float,
  WEBGL_compressed_texture_astc,
  WEBGL_compressed_texture_atc,
  WEBGL_compressed_texture_etc,
  WEBGL_compressed_texture_etc1,
  WEBGL_compressed_texture_pvrtc,
  WEBGL_compressed_texture_s3tc,
  WEBGL_compressed_texture_s3tc_srgb,
  WEBGL_debug_renderer_info,
  WEBGL_debug_shaders,
  WEBGL_depth_texture,
  WEBGL_draw_buffers,
  WEBGL_lose_context,
  Max,
  Unknown
};

class UniqueBuffer {
  // Like UniquePtr<>, but for void* and malloc/calloc/free.
  void* mBuffer;

 public:
  UniqueBuffer() : mBuffer(nullptr) {}

  MOZ_IMPLICIT UniqueBuffer(void* buffer) : mBuffer(buffer) {}

  ~UniqueBuffer() { free(mBuffer); }

  UniqueBuffer(UniqueBuffer&& other) {
    this->mBuffer = other.mBuffer;
    other.mBuffer = nullptr;
  }

  UniqueBuffer& operator=(UniqueBuffer&& other) {
    free(this->mBuffer);
    this->mBuffer = other.mBuffer;
    other.mBuffer = nullptr;
    return *this;
  }

  UniqueBuffer& operator=(void* newBuffer) {
    free(this->mBuffer);
    this->mBuffer = newBuffer;
    return *this;
  }

  explicit operator bool() const { return bool(mBuffer); }

  void* get() const { return mBuffer; }

  UniqueBuffer(const UniqueBuffer& other) = delete;  // construct using Move()!
  void operator=(const UniqueBuffer& other) = delete;  // assign using Move()!
};

}  // namespace mozilla

#endif