//
// Copyright 2013 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.
//
// Helper structures about Generic Vertex Attribute.
//

#ifndef LIBANGLE_VERTEXATTRIBUTE_H_
#define LIBANGLE_VERTEXATTRIBUTE_H_

#include "libANGLE/Buffer.h"
#include "libANGLE/angletypes.h"
#include "libANGLE/renderer/Format.h"

namespace gl
{
class VertexArray;

//
// Implementation of Generic Vertex Attribute Bindings for ES3.1. The members are intentionally made
// private in order to hide implementation details. Shared object like gl::Buffer should not be
// stored here since this data structure will be accessed without shared context lock.
//
class VertexBinding final : angle::NonCopyable
{
  public:
    VertexBinding();
    explicit VertexBinding(GLuint boundAttribute);
    VertexBinding(VertexBinding &&binding);
    ~VertexBinding();
    VertexBinding &operator=(VertexBinding &&binding);

    GLuint getStride() const { return mStride; }
    void setStride(GLuint strideIn) { mStride = strideIn; }

    GLuint getDivisor() const { return mDivisor; }
    void setDivisor(GLuint divisorIn) { mDivisor = divisorIn; }

    GLintptr getOffset() const { return mOffset; }
    void setOffset(GLintptr offsetIn) { mOffset = offsetIn; }

    const AttributesMask &getBoundAttributesMask() const { return mBoundAttributesMask; }

    void setBoundAttribute(size_t index) { mBoundAttributesMask.set(index); }

    void resetBoundAttribute(size_t index) { mBoundAttributesMask.reset(index); }

  private:
    GLuint mStride;
    GLuint mDivisor;
    GLintptr mOffset;

    // Mapping from this binding to all of the attributes that are using this binding.
    AttributesMask mBoundAttributesMask;
};

//
// Implementation of Generic Vertex Attributes for ES3.1
//
struct VertexAttribute final : private angle::NonCopyable
{
    explicit VertexAttribute(GLuint bindingIndex);
    VertexAttribute(VertexAttribute &&attrib);
    VertexAttribute &operator=(VertexAttribute &&attrib);

    // Called from VertexArray.
    void updateCachedElementLimit(const VertexBinding &binding, GLint64 bufferSize);
    GLint64 getCachedElementLimit() const { return mCachedElementLimit; }

    bool enabled;  // For glEnable/DisableVertexAttribArray
    const angle::Format *format;

    const void *pointer;
    GLuint relativeOffset;

    GLuint vertexAttribArrayStride;  // ONLY for queries of VERTEX_ATTRIB_ARRAY_STRIDE
    GLuint bindingIndex;

    // Special value for the cached element limit on the integer overflow case.
    static constexpr GLint64 kIntegerOverflow = std::numeric_limits<GLint64>::min();

  private:
    // This is kept in sync by the VertexArray. It is used to optimize draw call validation.
    // |mCachedElementLimit| defines the number of elements in the vertex attribute that are
    // accessible in a draw call.  For instanced attributes in instanced draw calls, the number of
    // possible instances is |VertexBinding::mDivisor| times this limit.
    GLint64 mCachedElementLimit;
};

ANGLE_INLINE size_t ComputeVertexAttributeTypeSize(const VertexAttribute &attrib)
{
    ASSERT(attrib.format);
    return attrib.format->pixelBytes;
}

// Warning: you should ensure binding really matches attrib.bindingIndex before using this function.
size_t ComputeVertexAttributeStride(const VertexAttribute &attrib, const VertexBinding &binding);

// Warning: you should ensure binding really matches attrib.bindingIndex before using this function.
GLintptr ComputeVertexAttributeOffset(const VertexAttribute &attrib, const VertexBinding &binding);

size_t ComputeVertexBindingElementCount(GLuint divisor, uint64_t drawCount, size_t instanceCount);

struct VertexAttribCurrentValueData
{
    union
    {
        GLfloat FloatValues[4];
        GLint IntValues[4];
        GLuint UnsignedIntValues[4];
    } Values;
    VertexAttribType Type;

    VertexAttribCurrentValueData();

    void setFloatValues(const GLfloat floatValues[4]);
    void setIntValues(const GLint intValues[4]);
    void setUnsignedIntValues(const GLuint unsignedIntValues[4]);
};

bool operator==(const VertexAttribCurrentValueData &a, const VertexAttribCurrentValueData &b);
bool operator!=(const VertexAttribCurrentValueData &a, const VertexAttribCurrentValueData &b);

}  // namespace gl

#include "VertexAttribute.inc"

#endif  // LIBANGLE_VERTEXATTRIBUTE_H_