/*
 * Copyright (C) 2009 Apple Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "modules/webgl/WebGLTexture.h"

#include "gpu/command_buffer/client/gles2_interface.h"
#include "modules/webgl/WebGLRenderingContextBase.h"

namespace blink {

WebGLTexture* WebGLTexture::create(WebGLRenderingContextBase* ctx)
{
    return new WebGLTexture(ctx);
}

WebGLTexture::WebGLTexture(WebGLRenderingContextBase* ctx)
    : WebGLSharedPlatform3DObject(ctx)
    , m_target(0)
{
    GLuint texture;
    ctx->contextGL()->GenTextures(1, &texture);
    setObject(texture);
}

WebGLTexture::~WebGLTexture()
{
    // See the comment in WebGLObject::detachAndDeleteObject().
    detachAndDeleteObject();
}

void WebGLTexture::setTarget(GLenum target)
{
    if (!object())
        return;
    // Target is finalized the first time bindTexture() is called.
    if (m_target)
        return;
    m_target = target;
}

void WebGLTexture::deleteObjectImpl(gpu::gles2::GLES2Interface* gl)
{
    gl->DeleteTextures(1, &m_object);
    m_object = 0;
}

int WebGLTexture::mapTargetToIndex(GLenum target) const
{
    if (m_target == GL_TEXTURE_2D) {
        if (target == GL_TEXTURE_2D)
            return 0;
    } else if (m_target == GL_TEXTURE_CUBE_MAP) {
        switch (target) {
        case GL_TEXTURE_CUBE_MAP_POSITIVE_X:
            return 0;
        case GL_TEXTURE_CUBE_MAP_NEGATIVE_X:
            return 1;
        case GL_TEXTURE_CUBE_MAP_POSITIVE_Y:
            return 2;
        case GL_TEXTURE_CUBE_MAP_NEGATIVE_Y:
            return 3;
        case GL_TEXTURE_CUBE_MAP_POSITIVE_Z:
            return 4;
        case GL_TEXTURE_CUBE_MAP_NEGATIVE_Z:
            return 5;
        }
    } else if (m_target == GL_TEXTURE_3D) {
        if (target == GL_TEXTURE_3D)
            return 0;
    } else if (m_target == GL_TEXTURE_2D_ARRAY) {
        if (target == GL_TEXTURE_2D_ARRAY)
            return 0;
    }
    return -1;
}

GLint WebGLTexture::computeLevelCount(GLsizei width, GLsizei height, GLsizei depth)
{
    // return 1 + log2Floor(std::max(width, height));
    GLsizei n = std::max(std::max(width, height), depth);
    if (n <= 0)
        return 0;
    GLint log = 0;
    GLsizei value = n;
    for (int ii = 4; ii >= 0; --ii) {
        int shift = (1 << ii);
        GLsizei x = (value >> shift);
        if (x) {
            value = x;
            log += shift;
        }
    }
    ASSERT(value == 1);
    return log + 1;
}

} // namespace blink