/*
 * Copyright (C) 2010 Google 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 AND ITS CONTRIBUTORS "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 OR ITS 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 "config.h"

#if USE(ACCELERATED_COMPOSITING)

#include "PluginLayerChromium.h"

#include "GraphicsContext3D.h"
#include "LayerRendererChromium.h"
#include <GLES2/gl2.h>

namespace WebCore {

PluginLayerChromium::SharedValues::SharedValues(GraphicsContext3D* context)
    : m_context(context)
    , m_shaderProgram(0)
    , m_shaderSamplerLocation(-1)
    , m_shaderMatrixLocation(-1)
    , m_shaderAlphaLocation(-1)
    , m_initialized(false)
{
    char vertexShaderString[] =
        "attribute vec4 a_position;   \n"
        "attribute vec2 a_texCoord;   \n"
        "uniform mat4 matrix;         \n"
        "varying vec2 v_texCoord;     \n"
        "void main()                  \n"
        "{                            \n"
        "  gl_Position = matrix * a_position; \n"
        "  v_texCoord = a_texCoord;   \n"
        "}                            \n";

    char fragmentShaderString[] =
        "precision mediump float;                            \n"
        "varying vec2 v_texCoord;                            \n"
        "uniform sampler2D s_texture;                        \n"
        "uniform float alpha;                                \n"
        "void main()                                         \n"
        "{                                                   \n"
        "  vec4 texColor = texture2D(s_texture, vec2(v_texCoord.x, v_texCoord.y)); \n"
        "  gl_FragColor = vec4(texColor.x, texColor.y, texColor.z, texColor.w) * alpha; \n"
        "}                                                   \n";

    m_shaderProgram = createShaderProgram(m_context, vertexShaderString, fragmentShaderString);
    if (!m_shaderProgram) {
        LOG_ERROR("PluginLayerChromium: Failed to create shader program");
        return;
    }

    m_shaderSamplerLocation = m_context->getUniformLocation(m_shaderProgram, "s_texture");
    m_shaderMatrixLocation = m_context->getUniformLocation(m_shaderProgram, "matrix");
    m_shaderAlphaLocation = m_context->getUniformLocation(m_shaderProgram, "alpha");
    ASSERT(m_shaderSamplerLocation != -1);
    ASSERT(m_shaderMatrixLocation != -1);
    ASSERT(m_shaderAlphaLocation != -1);

    m_initialized = true;
}

PluginLayerChromium::SharedValues::~SharedValues()
{
    if (m_shaderProgram)
        GLC(m_context, m_context->deleteProgram(m_shaderProgram));
}

PassRefPtr<PluginLayerChromium> PluginLayerChromium::create(GraphicsLayerChromium* owner)
{
    return adoptRef(new PluginLayerChromium(owner));
}

PluginLayerChromium::PluginLayerChromium(GraphicsLayerChromium* owner)
    : LayerChromium(owner)
{
}

void PluginLayerChromium::setTextureId(unsigned id)
{
    m_textureId = id;
}

void PluginLayerChromium::updateContentsIfDirty()
{
}

void PluginLayerChromium::draw()
{
    ASSERT(layerRenderer());
    const PluginLayerChromium::SharedValues* sv = layerRenderer()->pluginLayerSharedValues();
    ASSERT(sv && sv->initialized());
    GraphicsContext3D* context = layerRendererContext();
    GLC(context, context->activeTexture(GL_TEXTURE0));
    GLC(context, context->bindTexture(GL_TEXTURE_2D, m_textureId));
    
    // FIXME: setting the texture parameters every time is redundant. Move this code somewhere
    // where it will only happen once per texture.
    GLC(context, context->texParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR));
    GLC(context, context->texParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR));
    GLC(context, context->texParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE));
    GLC(context, context->texParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE));
    
    layerRenderer()->useShader(sv->shaderProgram());
    GLC(context, context->uniform1i(sv->shaderSamplerLocation(), 0));
    drawTexturedQuad(context, layerRenderer()->projectionMatrix(), drawTransform(),
                     bounds().width(), bounds().height(), drawOpacity(),
                     sv->shaderMatrixLocation(), sv->shaderAlphaLocation());
}

}
#endif // USE(ACCELERATED_COMPOSITING)