/*
 Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)

 This library is free software; you can redistribute it and/or
 modify it under the terms of the GNU Library General Public
 License as published by the Free Software Foundation; either
 version 2 of the License, or (at your option) any later version.

 This library is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 Library General Public License for more details.

 You should have received a copy of the GNU Library General Public License
 along with this library; see the file COPYING.LIB.  If not, write to
 the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 Boston, MA 02110-1301, USA.
 */

#include "config.h"

#include "TextureMapperGL.h"

#include "GraphicsContext.h"
#include "Image.h"
#include "Timer.h"
#include <wtf/HashMap.h>
#include <wtf/OwnArrayPtr.h>
#include <wtf/PassOwnArrayPtr.h>
#include <wtf/PassRefPtr.h>
#include <wtf/RefCounted.h>

#if PLATFORM(QT)
#include <cairo/OpenGLShims.h>
#elif defined(TEXMAP_OPENGL_ES_2)
#include <GLES2/gl2.h>
#include <GLES2/gl2ext.h>
#elif OS(MAC_OS_X)
#include <gl.h>
#else
#include <GL/gl.h>
#endif

#if !defined(TEXMAP_OPENGL_ES_2) && !PLATFORM(QT)
extern "C" {
    void glUniform1f(GLint, GLfloat);
    void glUniform1i(GLint, GLint);
    void glVertexAttribPointer(GLuint, GLint, GLenum, GLboolean, GLsizei, const GLvoid*);
    void glUniform4f(GLint, GLfloat, GLfloat, GLfloat, GLfloat);
    void glShaderSource(GLuint, GLsizei, const char**, const GLint*);
    GLuint glCreateShader(GLenum);
    void glShaderSource(GLuint, GLsizei, const char**, const GLint*);
    void glCompileShader(GLuint);
    void glDeleteShader(GLuint);
    void glUniformMatrix4fv(GLint, GLsizei, GLboolean, const GLfloat*);
    GLuint glCreateProgram();
    void glAttachShader(GLuint, GLuint);
    void glLinkProgram(GLuint);
    void glUseProgram(GLuint);
    void glDisableVertexAttribArray(GLuint);
    void glEnableVertexAttribArray(GLuint);
    void glBindFramebuffer(GLenum target, GLuint framebuffer);
    void glDeleteFramebuffers(GLsizei n, const GLuint* framebuffers);
    void glGenFramebuffers(GLsizei n, GLuint* framebuffers);
    void glFramebufferTexture2D(GLenum target, GLenum attachment, GLenum textarget, GLuint texture, GLint level);
    void glGetFramebufferAttachmentParameteriv(GLenum target, GLenum attachment, GLenum pname, GLint* params);
    void glBindBuffer(GLenum, GLuint);
    void glDeleteBuffers(GLsizei, const GLuint*);
    void glGenBuffers(GLsizei, GLuint*);
    void glBufferData(GLenum, GLsizeiptr, const GLvoid*, GLenum);
    void glBufferSubData(GLenum, GLsizeiptr, GLsizeiptr, const GLvoid*);
    void glGetProgramInfoLog(GLuint, GLsizei, GLsizei*, GLchar*);
    void glGetShaderInfoLog(GLuint, GLsizei, GLsizei*, GLchar*);
    void glGenRenderbuffers(GLsizei n, GLuint* ids);
    void glDeleteRenderbuffers(GLsizei n, const GLuint* ids);
    void glBindRenderbuffer(GLenum target, GLuint id);
    void glRenderbufferStorage(GLenum target, GLenum internalFormat, GLsizei width, GLsizei height);
    void glFramebufferRenderbuffer(GLenum target, GLenum attachmentPoint, GLenum renderbufferTarget, GLuint renderbufferId);
    GLenum glCheckFramebufferStatus(GLenum target);
    GLint glGetAttribLocation(GLuint program, const GLchar* name);
#if !OS(MAC_OS_X)
    GLint glGetUniformLocation(GLuint, const GLchar*);
    GLint glBindAttribLocation(GLuint, GLuint, const GLchar*);
#endif
}
#endif

namespace WebCore {

inline static void debugGLCommand(const char* command, int line)
{
    const GLenum err = glGetError();
    if (!err)
        return;
    WTFReportError(__FILE__, line, WTF_PRETTY_FUNCTION, "[TextureMapper GL] Command failed: %s (%x)\n", command, err);
    ASSERT_NOT_REACHED();
}

#define DEBUG_GL_COMMANDS

#ifdef DEBUG_GL_COMMANDS
#define GL_CMD(x) {x, debugGLCommand(#x, __LINE__); }
#else
#define GL_CMD(x) x
#endif

struct TextureMapperGLData {
    static struct GlobalGLData {
        enum ShaderProgramIndex {
            NoProgram = -1,
            SimpleProgram,
            OpacityAndMaskProgram,
            ClipProgram,

            ProgramCount
        };

        enum ShaderVariableIndex {
            InMatrixVariable,
            InSourceMatrixVariable,
            InMaskMatrixVariable,
            OpacityVariable,
            SourceTextureVariable,
            MaskTextureVariable,

            VariableCount
        };

        struct ProgramInfo {
            GLuint id;
            GLuint vertexAttrib;
            GLint vars[VariableCount];
        };

        GLint getUniformLocation(ShaderProgramIndex prog, ShaderVariableIndex var, const char* name)
        {
            return programs[prog].vars[var] = glGetUniformLocation(programs[prog].id, name);
        }

        void createShaderProgram(const char* vertexShaderSource, const char* fragmentShaderSource, ShaderProgramIndex index)
        {
            GLuint vertexShader = glCreateShader(GL_VERTEX_SHADER);
            GLuint fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
            GL_CMD(glShaderSource(vertexShader, 1, &vertexShaderSource, 0))
            GL_CMD(glShaderSource(fragmentShader, 1, &fragmentShaderSource, 0))
            GLuint programID = glCreateProgram();
            GL_CMD(glCompileShader(vertexShader))
            GL_CMD(glCompileShader(fragmentShader))
            GL_CMD(glAttachShader(programID, vertexShader))
            GL_CMD(glAttachShader(programID, fragmentShader))
            GL_CMD(glLinkProgram(programID))
            programs[index].vertexAttrib = glGetAttribLocation(programID, "InVertex");
            programs[index].id = programID;
        }

        ProgramInfo programs[ProgramCount];

        int stencilIndex;

        GlobalGLData()
            : stencilIndex(1)
        { }
    } globalGLData;

    struct DirectlyCompositedImageRepository {
        struct Entry {
            GLuint texture;
            int refCount;
        };
        typedef HashMap<ImageUID, Entry> ImageTextureMap;
        ImageTextureMap imageToTexture;

        GLuint findOrCreate(ImageUID image, bool& found)
        {
            ImageTextureMap::iterator it = imageToTexture.find(image);
            found = false;
            if (it != imageToTexture.end()) {
                it->second.refCount++;
                found = true;
                return it->second.texture;
            }
            Entry entry;
            GL_CMD(glGenTextures(1, &entry.texture));
            entry.refCount = 1;
            imageToTexture.add(image, entry);
            return entry.texture;
        }

        bool deref(ImageUID image)
        {
            HashMap<ImageUID, Entry>::iterator it = imageToTexture.find(image);
            if (it != imageToTexture.end()) {
                if (it->second.refCount < 2) {
                    imageToTexture.remove(it);
                    return false;
                }
            }
            return true;
        }

        DirectlyCompositedImageRepository()
        {
        }

        ~DirectlyCompositedImageRepository()
        {
            for (ImageTextureMap::iterator it = imageToTexture.begin(); it != imageToTexture.end(); ++it) {
                GLuint texture = it->second.texture;
                if (texture)
                    GL_CMD(glDeleteTextures(1, &texture));
            }

        }
    } directlyCompositedImages;

    TextureMapperGLData()
        : currentProgram(TextureMapperGLData::GlobalGLData::NoProgram)
    { }

    TransformationMatrix projectionMatrix;
    int currentProgram;
    int previousProgram;
};

TextureMapperGLData::GlobalGLData TextureMapperGLData::globalGLData;

class BitmapTextureGL : public BitmapTexture {
public:
    virtual void destroy();
    virtual IntSize size() const;
    virtual bool isValid() const;
    virtual void reset(const IntSize&, bool opaque);
    void bind();
    virtual PlatformGraphicsContext* beginPaint(const IntRect& dirtyRect);
    virtual void endPaint();
    virtual void setContentsToImage(Image*);
    ~BitmapTextureGL() { destroy(); }
    virtual uint32_t id() const { return m_id; }
    inline bool isOpaque() const { return m_opaque; }
    inline FloatSize relativeSize() const { return m_relativeSize; }
    void setTextureMapper(TextureMapperGL* texmap) { m_textureMapper = texmap; }

    void updateContents(PixelFormat, const IntRect&, void*);
    void pack()
    {
        // This is currently a stub.
        if (isPacked())
            return;
        m_isPacked = true;
    }

    void unpack()
    {
        // This is currently a stub.
        if (!isPacked())
            return;
        m_isPacked = false;
    }

    bool isPacked() const
    {
        return m_isPacked;
    }

private:
    GLuint m_id;
    ImageUID m_imageUID;
    FloatSize m_relativeSize;
    bool m_opaque;
    IntSize m_textureSize;
    OwnPtr<BGRA32PremultimpliedBuffer> m_buffer;
    IntRect m_dirtyRect;
    GLuint m_fbo;
    GLuint m_rbo;
    IntSize m_actualSize;
    bool m_surfaceNeedsReset;
    bool m_isPacked;
    TextureMapperGL* m_textureMapper;
    BitmapTextureGL()
        : m_id(0)
        , m_imageUID(0)
        , m_opaque(false)
        , m_fbo(0)
        , m_rbo(0)
        , m_surfaceNeedsReset(true)
        , m_textureMapper(0)
    {
    }

    friend class TextureMapperGL;
};

#define TEXMAP_GET_SHADER_VAR_LOCATION(prog, var) \
    if (TextureMapperGLData::globalGLData.getUniformLocation(TextureMapperGLData::globalGLData.prog##Program, TextureMapperGLData::globalGLData.var##Variable, #var) < 0) \
            LOG_ERROR("Couldn't find variable "#var" in program "#prog"\n");

#define TEXMAP_BUILD_SHADER(program) \
    TextureMapperGLData::globalGLData.createShaderProgram(vertexShaderSource##program, fragmentShaderSource##program, TextureMapperGLData::globalGLData.program##Program);

TextureMapperGL::TextureMapperGL()
    : m_data(new TextureMapperGLData)
    , m_context(0)
{
}

void TextureMapperGL::initializeShaders()
{
    static bool shadersCompiled = false;
    if (shadersCompiled)
        return;
    shadersCompiled = true;
#ifndef TEXMAP_OPENGL_ES_2
#define OES2_PRECISION_DEFINITIONS \
    "#define lowp\n#define highp\n"
#else
#define OES2_PRECISION_DEFINITIONS
#endif

    const char* fragmentShaderSourceOpacityAndMask =
            OES2_PRECISION_DEFINITIONS
"               uniform sampler2D SourceTexture, MaskTexture;                       \n"
"               uniform lowp float Opacity;                                         \n"
"               varying highp vec2 OutTexCoordSource, OutTexCoordMask;              \n"
"               void main(void)                                                     \n"
"               {                                                                   \n"
"                   lowp vec4 color = texture2D(SourceTexture, OutTexCoordSource);  \n"
"                   lowp vec4 maskColor = texture2D(MaskTexture, OutTexCoordMask);  \n"
"                   lowp float o = Opacity * maskColor.a;                           \n"
"                   gl_FragColor = vec4(color.rgb * o, color.a * o);                \n"
"               }                                                                   \n";

    const char* vertexShaderSourceOpacityAndMask =
            OES2_PRECISION_DEFINITIONS
"               uniform mat4 InMatrix, InSourceMatrix, InMaskMatrix;            \n"
"               attribute vec4 InVertex;                                        \n"
"               varying highp vec2 OutTexCoordSource, OutTexCoordMask;          \n"
"               void main(void)                                                 \n"
"               {                                                               \n"
"                   OutTexCoordSource = vec2(InSourceMatrix * InVertex);        \n"
"                   OutTexCoordMask = vec2(InMaskMatrix * InVertex);            \n"
"                   gl_Position = InMatrix * InVertex;                          \n"
"               }                                                               \n";

    const char* fragmentShaderSourceSimple =
            OES2_PRECISION_DEFINITIONS
"               uniform sampler2D SourceTexture;                                    \n"
"               uniform lowp float Opacity;                                         \n"
"               varying highp vec2 OutTexCoordSource;                               \n"
"               void main(void)                                                     \n"
"               {                                                                   \n"
"                   lowp vec4 color = texture2D(SourceTexture, OutTexCoordSource);  \n"
"                   gl_FragColor = vec4(color.rgb * Opacity, color.a * Opacity);    \n"
"               }                                                                   \n";

    const char* vertexShaderSourceSimple =
            OES2_PRECISION_DEFINITIONS
"               uniform mat4 InMatrix, InSourceMatrix;                      \n"
"               attribute vec4 InVertex;                                    \n"
"               varying highp vec2 OutTexCoordSource;                       \n"
"               void main(void)                                             \n"
"               {                                                           \n"
"                   OutTexCoordSource = vec2(InSourceMatrix * InVertex);    \n"
"                   gl_Position = InMatrix * InVertex;                      \n"
"               }                                                           \n";

    const char* fragmentShaderSourceClip =
"               void main(void) { gl_FragColor = vec4(0.0, 0.0, 0.0, 0.0); }                                ";

    const char* vertexShaderSourceClip =
"               uniform mat4 InMatrix;                                      \n"
"               attribute vec4 InVertex;                                    \n"
"               void main(void) { gl_Position = InMatrix * InVertex; }      ";


    TEXMAP_BUILD_SHADER(Simple)
    TEXMAP_BUILD_SHADER(OpacityAndMask)
    TEXMAP_BUILD_SHADER(Clip)

    TEXMAP_GET_SHADER_VAR_LOCATION(OpacityAndMask, InMatrix)
    TEXMAP_GET_SHADER_VAR_LOCATION(OpacityAndMask, InSourceMatrix)
    TEXMAP_GET_SHADER_VAR_LOCATION(OpacityAndMask, InMaskMatrix)
    TEXMAP_GET_SHADER_VAR_LOCATION(OpacityAndMask, SourceTexture)
    TEXMAP_GET_SHADER_VAR_LOCATION(OpacityAndMask, MaskTexture)
    TEXMAP_GET_SHADER_VAR_LOCATION(OpacityAndMask, Opacity)

    TEXMAP_GET_SHADER_VAR_LOCATION(Simple, InSourceMatrix)
    TEXMAP_GET_SHADER_VAR_LOCATION(Simple, InMatrix)
    TEXMAP_GET_SHADER_VAR_LOCATION(Simple, SourceTexture)
    TEXMAP_GET_SHADER_VAR_LOCATION(Simple, Opacity)

    TEXMAP_GET_SHADER_VAR_LOCATION(Clip, InMatrix)
}

void TextureMapperGL::beginPainting()
{
#if PLATFORM(QT)
    if (!initializeOpenGLShims())
        return;

    glGetIntegerv(GL_CURRENT_PROGRAM, &m_data->previousProgram);
    if (m_context) {
        QPainter* painter = m_context->platformContext();
        painter->save();
        painter->beginNativePainting();
    }
    glClearStencil(0);
    glClear(GL_STENCIL_BUFFER_BIT);
    bindSurface(0);
#endif
    initializeShaders();
}

void TextureMapperGL::endPainting()
{
#if PLATFORM(QT)
    glClearStencil(1);
    glClear(GL_STENCIL_BUFFER_BIT);
    glUseProgram(m_data->previousProgram);
    if (!m_context)
        return;
    QPainter* painter = m_context->platformContext();
    painter->endNativePainting();
    painter->restore();
#endif
}


void TextureMapperGL::drawTexture(const BitmapTexture& texture, const FloatRect& targetRect, const TransformationMatrix& matrix, float opacity, const BitmapTexture* mask)
{
    if (!texture.isValid())
        return;
    const BitmapTextureGL& textureGL = static_cast<const BitmapTextureGL&>(texture);
    drawTexture(textureGL.id(), textureGL.isOpaque(), textureGL.relativeSize(), targetRect, matrix, opacity, mask, false);
}

void TextureMapperGL::drawTexture(uint32_t texture, bool opaque, const FloatSize& relativeSize, const FloatRect& targetRect, const TransformationMatrix& modelViewMatrix, float opacity, const BitmapTexture* maskTexture, bool flip)
{
    TextureMapperGLData::GlobalGLData::ShaderProgramIndex program;
    if (maskTexture)
        program = TextureMapperGLData::GlobalGLData::OpacityAndMaskProgram;
    else
        program = TextureMapperGLData::GlobalGLData::SimpleProgram;

    const TextureMapperGLData::GlobalGLData::ProgramInfo& programInfo = data().globalGLData.programs[program];
    GL_CMD(glUseProgram(programInfo.id))
    data().currentProgram = program;
    GL_CMD(glEnableVertexAttribArray(programInfo.vertexAttrib))
    GL_CMD(glActiveTexture(GL_TEXTURE0))
    GL_CMD(glBindTexture(GL_TEXTURE_2D, texture))
    GL_CMD(glBindBuffer(GL_ARRAY_BUFFER, 0))
    const GLfloat unitRect[] = {0, 0, 1, 0, 1, 1, 0, 1};
    GL_CMD(glVertexAttribPointer(programInfo.vertexAttrib, 2, GL_FLOAT, GL_FALSE, 0, unitRect))

    TransformationMatrix matrix = TransformationMatrix(data().projectionMatrix).multiply(modelViewMatrix).multiply(TransformationMatrix(
            targetRect.width(), 0, 0, 0,
            0, targetRect.height(), 0, 0,
            0, 0, 1, 0,
            targetRect.x(), targetRect.y(), 0, 1));

    const GLfloat m4[] = {
        matrix.m11(), matrix.m12(), matrix.m13(), matrix.m14(),
        matrix.m21(), matrix.m22(), matrix.m23(), matrix.m24(),
        matrix.m31(), matrix.m32(), matrix.m33(), matrix.m34(),
        matrix.m41(), matrix.m42(), matrix.m43(), matrix.m44()
    };
    const GLfloat m4src[] = {relativeSize.width(), 0, 0, 0,
                                     0, relativeSize.height() * (flip ? -1 : 1), 0, 0,
                                     0, 0, 1, 0,
                                     0, flip ? relativeSize.height() : 0, 0, 1};

    GL_CMD(glUniformMatrix4fv(programInfo.vars[TextureMapperGLData::GlobalGLData::InMatrixVariable], 1, GL_FALSE, m4))
    GL_CMD(glUniformMatrix4fv(programInfo.vars[TextureMapperGLData::GlobalGLData::InSourceMatrixVariable], 1, GL_FALSE, m4src))
    GL_CMD(glUniform1i(programInfo.vars[TextureMapperGLData::GlobalGLData::SourceTextureVariable], 0))
    GL_CMD(glUniform1f(programInfo.vars[TextureMapperGLData::GlobalGLData::OpacityVariable], opacity))

    if (maskTexture && maskTexture->isValid()) {
        const BitmapTextureGL* maskTextureGL = static_cast<const BitmapTextureGL*>(maskTexture);
        GL_CMD(glActiveTexture(GL_TEXTURE1))
        GL_CMD(glBindTexture(GL_TEXTURE_2D, maskTextureGL->id()))
        const GLfloat m4mask[] = {maskTextureGL->relativeSize().width(), 0, 0, 0,
                                         0, maskTextureGL->relativeSize().height(), 0, 0,
                                         0, 0, 1, 0,
                                         0, 0, 0, 1};
        GL_CMD(glUniformMatrix4fv(programInfo.vars[TextureMapperGLData::GlobalGLData::InMaskMatrixVariable], 1, GL_FALSE, m4mask));
        GL_CMD(glUniform1i(programInfo.vars[TextureMapperGLData::GlobalGLData::MaskTextureVariable], 1))
        GL_CMD(glActiveTexture(GL_TEXTURE0))
    }

    if (opaque && opacity > 0.99 && !maskTexture)
        GL_CMD(glDisable(GL_BLEND))
    else {
        GL_CMD(glBlendFunc(GL_ONE, GL_ONE_MINUS_SRC_ALPHA))
        GL_CMD(glEnable(GL_BLEND))
    }

    GL_CMD(glDisable(GL_DEPTH_TEST))
    GL_CMD(glDrawArrays(GL_TRIANGLE_FAN, 0, 4))
    GL_CMD(glDisableVertexAttribArray(programInfo.vertexAttrib))
}

const char* TextureMapperGL::type() const
{
    return "OpenGL";
}

// This function is similar with GraphicsContext3D::texImage2DResourceSafe.
static void texImage2DResourceSafe(size_t width, size_t height)
{
    const int pixelSize = 4; // RGBA
    OwnArrayPtr<unsigned char> zero;
    if (width && height) {
        unsigned int size = width * height * pixelSize;
        zero = adoptArrayPtr(new unsigned char[size]);
        memset(zero.get(), 0, size);
    }
    GL_CMD(glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, zero.get()))
}

void BitmapTextureGL::reset(const IntSize& newSize, bool opaque)
{
    BitmapTexture::reset(newSize, opaque);
    m_imageUID = 0;
    IntSize newTextureSize = nextPowerOfTwo(newSize);
    bool justCreated = false;
    if (!m_id) {
        GL_CMD(glGenTextures(1, &m_id))
        justCreated = true;
    }

    if (justCreated || newTextureSize.width() > m_textureSize.width() || newTextureSize.height() > m_textureSize.height()) {
        m_textureSize = newTextureSize;
        GL_CMD(glBindTexture(GL_TEXTURE_2D, m_id))
        GL_CMD(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR))
        GL_CMD(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR))
        GL_CMD(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE))
        GL_CMD(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE))
        texImage2DResourceSafe(m_textureSize.width(), m_textureSize.height());
    }
    m_actualSize = newSize;
    m_relativeSize = FloatSize(float(newSize.width()) / m_textureSize.width(), float(newSize.height()) / m_textureSize.height());
    m_opaque = opaque;
    m_surfaceNeedsReset = true;
}

PlatformGraphicsContext* BitmapTextureGL::beginPaint(const IntRect& dirtyRect)
{
    m_buffer = BGRA32PremultimpliedBuffer::create();
    m_dirtyRect = dirtyRect;
    return m_buffer->beginPaint(dirtyRect, m_opaque);
}

void BitmapTextureGL::endPaint()
{
    if (!m_buffer)
        return;
    m_buffer->endPaint();
    updateContents(BGRAFormat, m_dirtyRect, m_buffer->data());
    GL_CMD(glBindTexture(GL_TEXTURE_2D, m_id))
    m_buffer.clear();
}

#ifdef TEXMAP_OPENGL_ES_2
static void swizzleBGRAToRGBA(uint32_t* data, const IntSize& size)
{
    int width = size.width();
    int height = size.height();
    for (int y = 0; y < height; ++y) {
        uint32_t* p = data + y * width;
        for (int x = 0; x < width; ++x)
            p[x] = ((p[x] << 16) & 0xff0000) | ((p[x] >> 16) & 0xff) | (p[x] & 0xff00ff00);
    }
}
#endif

void BitmapTextureGL::updateContents(PixelFormat pixelFormat, const IntRect& rect, void* bits)
{
    GL_CMD(glBindTexture(GL_TEXTURE_2D, m_id))
#ifdef TEXMAP_OPENGL_ES_2
    bool shouldSwizzle = false;
#endif

    GLint glFormat = GL_RGBA;
    switch (pixelFormat) {
    case RGBAFormat:
        glFormat = GL_RGBA;
        break;
    case RGBFormat:
        glFormat = GL_RGB;
        break;
    case BGRAFormat:
#ifdef TEXMAP_OPENGL_ES_2
        shouldSwizzle = true;
        glFormat = GL_RGBA;
#else
        glFormat = GL_BGRA;
#endif
        break;
    case BGRFormat:
#ifdef TEXMAP_OPENGL_ES_2
        shouldSwizzle = true;
        glFormat = GL_RGB;
#else
        glFormat = GL_BGR;
#endif
         break;
    }

#ifdef TEXMAP_OPENGL_ES_2
    if (shouldSwizzle)
        swizzleBGRAToRGBA(static_cast<uint32_t*>(bits), rect.size());
#endif
    GL_CMD(glTexSubImage2D(GL_TEXTURE_2D, 0, rect.x(), rect.y(), rect.width(), rect.height(), glFormat, GL_UNSIGNED_BYTE, bits))
}

void BitmapTextureGL::setContentsToImage(Image* image)
{
    ImageUID uid = image ? uidForImage(image) : 0;
    if (!image || !uid) {
        if (m_imageUID)
            destroy();
        return;
    }

    if (uid == m_imageUID)
        return;
    bool found = false;
    GLuint newTextureID = m_textureMapper->data().directlyCompositedImages.findOrCreate(uid, found);
    if (newTextureID != m_id) {
        m_imageUID = uid;
        destroy();
        m_id = newTextureID;
        reset(image->size(), false);
        if (!found) {
            GraphicsContext context(beginPaint(IntRect(0, 0, m_textureSize.width(), m_textureSize.height())));
            context.drawImage(image, ColorSpaceDeviceRGB, IntPoint(0, 0), CompositeCopy);
            endPaint();
        }
    }
}

static inline TransformationMatrix createProjectionMatrix(const IntSize& size, bool flip)
{
    const float near = 9999999;
    const float far = -99999;

    return TransformationMatrix(2.0 / float(size.width()), 0, 0, 0,
                                0, (flip ? -2.0 : 2.0) / float(size.height()), 0, 0,
                                0, 0, -2.f / (far - near), 0,
                                -1, flip ? 1 : -1, -(far + near) / (far - near), 1);
}

void BitmapTextureGL::bind()
{
    int& stencilIndex = TextureMapperGLData::globalGLData.stencilIndex;
    if (m_surfaceNeedsReset || !m_fbo) {
        if (!m_fbo)
            GL_CMD(glGenFramebuffers(1, &m_fbo))
        if (!m_rbo)
            GL_CMD(glGenRenderbuffers(1, &m_rbo));
        GL_CMD(glBindRenderbuffer(GL_RENDERBUFFER, m_rbo))
#ifdef TEXMAP_OPENGL_ES_2
        GL_CMD(glRenderbufferStorage(GL_RENDERBUFFER, GL_STENCIL_INDEX8, m_textureSize.width(), m_textureSize.height()))
#else
        GL_CMD(glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_STENCIL, m_textureSize.width(), m_textureSize.height()))
#endif
        GL_CMD(glBindFramebuffer(GL_FRAMEBUFFER, m_fbo))
        GL_CMD(glBindTexture(GL_TEXTURE_2D, 0))
        GL_CMD(glBindRenderbuffer(GL_RENDERBUFFER, 0))
        GL_CMD(glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, id(), 0))
        GL_CMD(glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_STENCIL_ATTACHMENT, GL_RENDERBUFFER, m_rbo))
#ifndef TEXMAP_OPENGL_ES_2
        GL_CMD(glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, m_rbo));
#endif
        GL_CMD(glClearColor(0, 0, 0, 0))
        GL_CMD(glClearStencil(stencilIndex - 1))
        GL_CMD(glClear(GL_STENCIL_BUFFER_BIT | GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT))
        m_surfaceNeedsReset = false;
    } else
        GL_CMD(glBindFramebuffer(GL_FRAMEBUFFER, m_fbo))

    glStencilOp(GL_KEEP, GL_KEEP, GL_KEEP);
    glStencilFunc(stencilIndex > 1 ? GL_GEQUAL : GL_ALWAYS, stencilIndex - 1, stencilIndex - 1);
    GL_CMD(glViewport(0, 0, size().width(), size().height()))
    m_textureMapper->data().projectionMatrix = createProjectionMatrix(size(), false);
    glDisable(GL_SCISSOR_TEST);
}

void BitmapTextureGL::destroy()
{
    if (m_id && (!m_imageUID || !m_textureMapper->data().directlyCompositedImages.deref(m_imageUID)))
        GL_CMD(glDeleteTextures(1, &m_id))

    if (m_fbo)
        GL_CMD(glDeleteFramebuffers(1, &m_fbo))

    if (m_rbo)
        GL_CMD(glDeleteRenderbuffers(1, &m_rbo))

    m_fbo = 0;
    m_id = 0;
    m_textureSize = IntSize();
    m_relativeSize = FloatSize(1, 1);
}

bool BitmapTextureGL::isValid() const
{
    return m_id;
}

IntSize BitmapTextureGL::size() const
{
    return m_textureSize;
}

TextureMapperGL::~TextureMapperGL()
{
    delete m_data;
}

void TextureMapperGL::bindSurface(BitmapTexture *surfacePointer)
{
    BitmapTextureGL* surface = static_cast<BitmapTextureGL*>(surfacePointer);

    if (!surface) {
        GL_CMD(glBindFramebuffer(GL_FRAMEBUFFER, 0))
        data().projectionMatrix = createProjectionMatrix(viewportSize(), true).multiply(transform());
        GL_CMD(glStencilFunc(data().globalGLData.stencilIndex > 1 ? GL_EQUAL : GL_ALWAYS, data().globalGLData.stencilIndex - 1, data().globalGLData.stencilIndex - 1))
        GL_CMD(glStencilOp(GL_KEEP, GL_KEEP, GL_KEEP))
        GL_CMD(glViewport(0, 0, viewportSize().width(), viewportSize().height()))
        return;
    }

    surface->bind();
}

void TextureMapperGL::beginClip(const TransformationMatrix& modelViewMatrix, const FloatRect& targetRect)
{
    TextureMapperGLData::GlobalGLData::ShaderProgramIndex program = TextureMapperGLData::GlobalGLData::ClipProgram;
    const TextureMapperGLData::GlobalGLData::ProgramInfo& programInfo = data().globalGLData.programs[program];
    GL_CMD(glUseProgram(programInfo.id))
    GL_CMD(glEnableVertexAttribArray(programInfo.vertexAttrib))
    const GLfloat unitRect[] = {0, 0, 1, 0, 1, 1, 0, 1};
    GL_CMD(glVertexAttribPointer(programInfo.vertexAttrib, 2, GL_FLOAT, GL_FALSE, 0, unitRect))

    TransformationMatrix matrix = TransformationMatrix(data().projectionMatrix)
            .multiply(modelViewMatrix)
            .multiply(TransformationMatrix(targetRect.width(), 0, 0, 0,
                0, targetRect.height(), 0, 0,
                0, 0, 1, 0,
                targetRect.x(), targetRect.y(), 0, 1));

    const GLfloat m4[] = {
        matrix.m11(), matrix.m12(), matrix.m13(), matrix.m14(),
        matrix.m21(), matrix.m22(), matrix.m23(), matrix.m24(),
        matrix.m31(), matrix.m32(), matrix.m33(), matrix.m34(),
        matrix.m41(), matrix.m42(), matrix.m43(), matrix.m44()
    };

    int& stencilIndex = data().globalGLData.stencilIndex;

    GL_CMD(glUniformMatrix4fv(programInfo.vars[TextureMapperGLData::GlobalGLData::InMatrixVariable], 1, GL_FALSE, m4))
    GL_CMD(glEnable(GL_STENCIL_TEST))
    GL_CMD(glStencilFunc(GL_NEVER, stencilIndex, stencilIndex))
    GL_CMD(glStencilOp(GL_REPLACE, GL_REPLACE, GL_REPLACE))
    GL_CMD(glStencilMask(0xff & ~(stencilIndex - 1)))
    GL_CMD(glDrawArrays(GL_TRIANGLE_FAN, 0, 4))
    GL_CMD(glStencilOp(GL_KEEP, GL_KEEP, GL_KEEP))
    stencilIndex <<= 1;
    glStencilFunc(stencilIndex > 1 ? GL_EQUAL : GL_ALWAYS, stencilIndex - 1, stencilIndex - 1);
    GL_CMD(glDisableVertexAttribArray(programInfo.vertexAttrib))
}

void TextureMapperGL::endClip()
{
    data().globalGLData.stencilIndex >>= 1;
    glStencilFunc(data().globalGLData.stencilIndex > 1 ? GL_EQUAL : GL_ALWAYS, data().globalGLData.stencilIndex - 1, data().globalGLData.stencilIndex - 1);
}

PassRefPtr<BitmapTexture> TextureMapperGL::createTexture()
{
    BitmapTextureGL* texture = new BitmapTextureGL();
    texture->setTextureMapper(this);
    return adoptRef(texture);
}

};
