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#include "qglshaderprogram.h"

#include "qglextensions_p.h"

#include "qgl_p.h"

#include <QtCore/qdebug.h>

#include <QtCore/qfile.h>

#include <QtCore/qvarlengtharray.h>

#include <QtCore/qvector.h>

QT_BEGIN_NAMESPACE

#if !defined(QT_OPENGL_ES_1_CL) && !defined(QT_OPENGL_ES_1)

/*!

    \class QGLShaderProgram

    \brief The QGLShaderProgram class allows OpenGL shader programs to be linked and used.

    \since 4.6

    \ingroup painting-3D

    \section1 Introduction

    This class supports shader programs written in the OpenGL Shading

    Language (GLSL) and in the OpenGL/ES Shading Language (GLSL/ES).

    QGLShader and QGLShaderProgram shelter the programmer from the details of

    compiling and linking vertex and fragment shaders.

    The following example creates a vertex shader program using the

    supplied source \c{code}.  Once compiled and linked, the shader

    program is activated in the current QGLContext by calling

    \snippet doc/src/snippets/code/src_opengl_qglshaderprogram.cpp 0

    \section1 Writing portable shaders

    Shader programs can be difficult to reuse across OpenGL implementations

    because of varying levels of support for standard vertex attributes and

    uniform variables.  In particular, GLSL/ES lacks all of the

    standard variables that are present on desktop OpenGL systems:

    \c{gl_Vertex}, \c{gl_Normal}, \c{gl_Color}, and so on.  Desktop OpenGL

    lacks the variable qualifiers \c{highp}, \c{mediump}, and \c{lowp}.

    The QGLShaderProgram class makes the process of writing portable shaders

    easier by prefixing all shader programs with the following lines on

    desktop OpenGL:

    \code

    #define highp

    #define mediump

    #define lowp

    \endcode

    This makes it possible to run most GLSL/ES shader programs

    on desktop systems.  The programmer should restrict themselves

    to just features that are present in GLSL/ES, and avoid

    standard variable names that only work on the desktop.

    \section1 Simple shader example

    \snippet doc/src/snippets/code/src_opengl_qglshaderprogram.cpp 1

    With the above shader program active, we can draw a green triangle

    as follows:

    \snippet doc/src/snippets/code/src_opengl_qglshaderprogram.cpp 2

    \sa QGLShader

*/

/*!

    \class QGLShader

    \brief The QGLShader class allows OpenGL shaders to be compiled.

    \since 4.6

    \ingroup painting-3D

    This class supports shaders written in the OpenGL Shading Language (GLSL)

    and in the OpenGL/ES Shading Language (GLSL/ES).

    QGLShader and QGLShaderProgram shelter the programmer from the details of

    compiling and linking vertex and fragment shaders.

    \sa QGLShaderProgram

*/

/*!

    This enum specifies the type of QGLShader that is being created.

*/

#ifndef GL_FRAGMENT_SHADER

#define GL_FRAGMENT_SHADER 0x8B30

#endif

#ifndef GL_VERTEX_SHADER

#define GL_VERTEX_SHADER 0x8B31

#endif

#ifndef GL_COMPILE_STATUS

#define GL_COMPILE_STATUS 0x8B81

#endif

#ifndef GL_LINK_STATUS

#define GL_LINK_STATUS 0x8B82

#endif

#ifndef GL_INFO_LOG_LENGTH

#define GL_INFO_LOG_LENGTH 0x8B84

#endif

#ifndef GL_ACTIVE_UNIFORMS

#define GL_ACTIVE_UNIFORMS 0x8B86

#endif

#ifndef GL_ACTIVE_UNIFORM_MAX_LENGTH

#define GL_ACTIVE_UNIFORM_MAX_LENGTH 0x8B87

#endif

#ifndef GL_ACTIVE_ATTRIBUTES

#define GL_ACTIVE_ATTRIBUTES 0x8B89

#endif

#ifndef GL_ACTIVE_ATTRIBUTE_MAX_LENGTH

#define GL_ACTIVE_ATTRIBUTE_MAX_LENGTH 0x8B8A

#endif

#ifndef GL_CURRENT_VERTEX_ATTRIB

#define GL_CURRENT_VERTEX_ATTRIB 0x8626

#endif

#ifndef GL_SHADER_SOURCE_LENGTH

#define GL_SHADER_SOURCE_LENGTH 0x8B88

#endif

#ifndef GL_SHADER_BINARY_FORMATS

#define GL_SHADER_BINARY_FORMATS          0x8DF8

#endif

#ifndef GL_NUM_SHADER_BINARY_FORMATS

#define GL_NUM_SHADER_BINARY_FORMATS      0x8DF9

#endif

{

public:

    QGLShaderPrivate(const QGLContext *context, QGLShader::ShaderType type)

        : shaderGuard(context)

        , shaderType(type)

        , compiled(false)

    {

    }

    QGLSharedResourceGuard shaderGuard;

    QGLShader::ShaderType shaderType;

    bool compiled;

    QString log;

    bool create();

    bool compile(QGLShader *q);

    void deleteShader();

};

#define ctx shaderGuard.context()

bool QGLShaderPrivate::create()

{

    const QGLContext *context = shaderGuard.context();

    if (!context)

        return false;

    if (qt_resolve_glsl_extensions(const_cast<QGLContext *>(context))) {

        GLuint shader;

            shader = glCreateShader(GL_VERTEX_SHADER);

        else

            shader = glCreateShader(GL_FRAGMENT_SHADER);

        if (!shader) {

            qWarning() << "QGLShader: could not create shader";

            return false;

        }

        shaderGuard.setId(shader);

        return true;

    } else {

        return false;

    }

}

bool QGLShaderPrivate::compile(QGLShader *q)

{

    GLuint shader = shaderGuard.id();

    if (!shader)

        return false;

    glCompileShader(shader);

    GLint value = 0;

    glGetShaderiv(shader, GL_COMPILE_STATUS, &value);

    compiled = (value != 0);

    value = 0;

    glGetShaderiv(shader, GL_INFO_LOG_LENGTH, &value);

    if (!compiled && value > 1) {

        char *logbuf = new char [value];

        GLint len;

        glGetShaderInfoLog(shader, value, &len, logbuf);

        log = QString::fromLatin1(logbuf);

        QString name = q->objectName();

        if (name.isEmpty())

            qWarning() << "QGLShader::compile:" << log;

        else

            qWarning() << "QGLShader::compile[" << name << "]:" << log;

        delete [] logbuf;

    }

    return compiled;

}

void QGLShaderPrivate::deleteShader()

{

    if (shaderGuard.id()) {

        glDeleteShader(shaderGuard.id());

        shaderGuard.setId(0);

    }

}

#undef ctx

#define ctx d->shaderGuard.context()

/*!

    Constructs a new QGLShader object of the specified \a type

    and attaches it to \a parent.  If shader programs are not supported,

    The shader will be associated with the current QGLContext.

*/

QGLShader::QGLShader(QGLShader::ShaderType type, QObject *parent)

{

    d->create();

}

/*!

    Constructs a new QGLShader object of the specified \a type

    and attaches it to \a parent.  If shader programs are not supported,

    The shader will be associated with \a context.

*/

QGLShader::QGLShader(QGLShader::ShaderType type, const QGLContext *context, QObject *parent)

{

#ifndef QT_NO_DEBUG

    if (context && !QGLContext::areSharing(context, QGLContext::currentContext())) {

        return;

    }

#endif

    d->create();

}

/*!

    Deletes this shader.  If the shader has been attached to a

    QGLShaderProgram object, then the actual shader will stay around

    until the QGLShaderProgram is destroyed.

*/

QGLShader::~QGLShader()

{

}

/*!

    Returns the type of this shader.

*/

QGLShader::ShaderType QGLShader::shaderType() const

{

    return d->shaderType;

}

// The precision qualifiers are useful on OpenGL/ES systems,

// but usually not present on desktop systems.  Define the

// keywords to empty strings on desktop systems.

#ifndef QT_OPENGL_ES

#define QGL_DEFINE_QUALIFIERS 1

static const char qualifierDefines[] =

    "#define lowp\n"

    "#define mediump\n"

    "#define highp\n";

#endif

// The "highp" qualifier doesn't exist in fragment shaders

// on all ES platforms.  When it doesn't exist, use "mediump".

#ifdef QT_OPENGL_ES

#define QGL_REDEFINE_HIGHP 1

static const char redefineHighp[] =

    "#ifndef GL_FRAGMENT_PRECISION_HIGH\n"

    "#define highp mediump\n"

    "#endif\n";

#endif

/*!

    Sets the \a source code for this shader and compiles it.

    Returns true if the source was successfully compiled, false otherwise.

*/

{

        int headerLen = 0;

        while (source && source[headerLen] == '#') {

            // Skip #version and #extension directives at the start of

            // the shader code.  We need to insert the qualifierDefines

            // and redefineHighp just after them.

            if (qstrncmp(source + headerLen, "#version", 8) != 0 &&

                    qstrncmp(source + headerLen, "#extension", 10) != 0) {

                break;

            }

            while (source[headerLen] != '\0' && source[headerLen] != '\n')

                ++headerLen;

            if (source[headerLen] == '\n')

                ++headerLen;

        }

        if (headerLen > 0) {

        }

#ifdef QGL_DEFINE_QUALIFIERS

        src.append(qualifierDefines);

#endif

#ifdef QGL_REDEFINE_HIGHP

            src.append(redefineHighp);

#endif

        src.append(source + headerLen);

        return d->compile(this);

    } else {

        return false;

    }

}

/*!

    \overload

    Sets the \a source code for this shader and compiles it.

    Returns true if the source was successfully compiled, false otherwise.

*/

{

}

/*!

    \overload

    Sets the \a source code for this shader and compiles it.

    Returns true if the source was successfully compiled, false otherwise.

*/

{

}

/*!

    Sets the source code for this shader to the contents of \a fileName

    and compiles it.  Returns true if the file could be opened and the

    source compiled, false otherwise.

*/

{

    QFile file(fileName);

    if (!file.open(QFile::ReadOnly)) {

        qWarning() << "QGLShader: Unable to open file" << fileName;

        return false;

    }

    QByteArray contents = file.readAll();

}

/*!

    Returns the source code for this shader.

*/

QByteArray QGLShader::sourceCode() const

{

    GLuint shader = d->shaderGuard.id();

    if (!shader)

        return QByteArray();

    GLint size = 0;

    glGetShaderiv(shader, GL_SHADER_SOURCE_LENGTH, &size);

    if (size <= 0)

        return QByteArray();

    GLint len = 0;

    char *source = new char [size];

    glGetShaderSource(shader, size, &len, source);

    QByteArray src(source);

    delete [] source;

    return src;

}

/*!

    Returns true if this shader has been compiled; false otherwise.

*/

bool QGLShader::isCompiled() const

{

    return d->compiled;

}

/*!

    Returns the errors and warnings that occurred during the last compile.

*/

QString QGLShader::log() const

{

    return d->log;

}

/*!

    Returns the OpenGL identifier associated with this shader.

    \sa QGLShaderProgram::programId()

*/

GLuint QGLShader::shaderId() const

{

    return d->shaderGuard.id();

}

#undef ctx

#define ctx programGuard.context()

{

public:

    QGLShaderProgramPrivate(const QGLContext *context)

        : programGuard(context)

        , linked(false)

        , inited(false)

        , removingShaders(false)

        , vertexShader(0)

        , fragmentShader(0)

    {

    }

    ~QGLShaderProgramPrivate();

    QGLSharedResourceGuard programGuard;

    bool linked;