//
// 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.
//
// FramebufferNULL.cpp:
//    Implements the class methods for FramebufferNULL.
//

#include "libANGLE/renderer/null/FramebufferNULL.h"

#include "common/debug.h"
#include "libANGLE/Context.h"
#include "libANGLE/formatutils.h"
#include "libANGLE/renderer/null/BufferNULL.h"
#include "libANGLE/renderer/null/ContextNULL.h"

namespace rx
{

FramebufferNULL::FramebufferNULL(const gl::FramebufferState &state) : FramebufferImpl(state) {}

FramebufferNULL::~FramebufferNULL() {}

angle::Result FramebufferNULL::discard(const gl::Context *context,
                                       size_t count,
                                       const GLenum *attachments)
{
    return angle::Result::Continue;
}

angle::Result FramebufferNULL::invalidate(const gl::Context *context,
                                          size_t count,
                                          const GLenum *attachments)
{
    return angle::Result::Continue;
}

angle::Result FramebufferNULL::invalidateSub(const gl::Context *context,
                                             size_t count,
                                             const GLenum *attachments,
                                             const gl::Rectangle &area)
{
    return angle::Result::Continue;
}

angle::Result FramebufferNULL::clear(const gl::Context *context, GLbitfield mask)
{
    return angle::Result::Continue;
}

angle::Result FramebufferNULL::clearBufferfv(const gl::Context *context,
                                             GLenum buffer,
                                             GLint drawbuffer,
                                             const GLfloat *values)
{
    return angle::Result::Continue;
}

angle::Result FramebufferNULL::clearBufferuiv(const gl::Context *context,
                                              GLenum buffer,
                                              GLint drawbuffer,
                                              const GLuint *values)
{
    return angle::Result::Continue;
}

angle::Result FramebufferNULL::clearBufferiv(const gl::Context *context,
                                             GLenum buffer,
                                             GLint drawbuffer,
                                             const GLint *values)
{
    return angle::Result::Continue;
}

angle::Result FramebufferNULL::clearBufferfi(const gl::Context *context,
                                             GLenum buffer,
                                             GLint drawbuffer,
                                             GLfloat depth,
                                             GLint stencil)
{
    return angle::Result::Continue;
}

angle::Result FramebufferNULL::readPixels(const gl::Context *context,
                                          const gl::Rectangle &origArea,
                                          GLenum format,
                                          GLenum type,
                                          void *ptrOrOffset)
{
    const gl::PixelPackState &packState = context->getState().getPackState();
    gl::Buffer *packBuffer = context->getState().getTargetBuffer(gl::BufferBinding::PixelPack);

    // Get the pointer to write to from the argument or the pack buffer
    GLubyte *pixels = nullptr;
    if (packBuffer != nullptr)
    {
        BufferNULL *packBufferGL = GetImplAs<BufferNULL>(packBuffer);
        pixels                   = reinterpret_cast<GLubyte *>(packBufferGL->getDataPtr());
        pixels += reinterpret_cast<intptr_t>(ptrOrOffset);
    }
    else
    {
        pixels = reinterpret_cast<GLubyte *>(ptrOrOffset);
    }

    // Clip read area to framebuffer.
    const gl::Extents fbSize = getState().getReadPixelsAttachment(format)->getSize();
    const gl::Rectangle fbRect(0, 0, fbSize.width, fbSize.height);
    gl::Rectangle area;
    if (!ClipRectangle(origArea, fbRect, &area))
    {
        // nothing to read
        return angle::Result::Continue;
    }

    // Compute size of unclipped rows and initial skip
    const gl::InternalFormat &glFormat = gl::GetInternalFormatInfo(format, type);

    ContextNULL *contextNull = GetImplAs<ContextNULL>(context);

    GLuint rowBytes = 0;
    ANGLE_CHECK_GL_MATH(contextNull,
                        glFormat.computeRowPitch(type, origArea.width, packState.alignment,
                                                 packState.rowLength, &rowBytes));

    GLuint skipBytes = 0;
    ANGLE_CHECK_GL_MATH(contextNull,
                        glFormat.computeSkipBytes(type, rowBytes, 0, packState, false, &skipBytes));
    pixels += skipBytes;

    // Skip OOB region up to first in bounds pixel
    int leftClip = area.x - origArea.x;
    int topClip  = area.y - origArea.y;
    pixels += leftClip * glFormat.pixelBytes + topClip * rowBytes;

    // Write the in-bounds readpixels data with non-zero values
    for (GLint y = area.y; y < area.y + area.height; ++y)
    {
        memset(pixels, 42, glFormat.pixelBytes * area.width);
        pixels += rowBytes;
    }

    return angle::Result::Continue;
}

angle::Result FramebufferNULL::blit(const gl::Context *context,
                                    const gl::Rectangle &sourceArea,
                                    const gl::Rectangle &destArea,
                                    GLbitfield mask,
                                    GLenum filter)
{
    return angle::Result::Continue;
}

bool FramebufferNULL::checkStatus(const gl::Context *context) const
{
    return true;
}

angle::Result FramebufferNULL::syncState(const gl::Context *context,
                                         GLenum binding,
                                         const gl::Framebuffer::DirtyBits &dirtyBits)
{
    return angle::Result::Continue;
}

angle::Result FramebufferNULL::getSamplePosition(const gl::Context *context,
                                                 size_t index,
                                                 GLfloat *xy) const
{
    return angle::Result::Continue;
}

}  // namespace rx