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#include "glwidget.h"

#include <QtGui/QImage>

#include <math.h>

static GLint cubeArray[][3] = {

    {0, 0, 0}, {0, 1, 0}, {1, 1, 0}, {1, 0, 0},

    {0, 0, 1}, {1, 0, 1}, {1, 1, 1}, {0, 1, 1},

    {0, 0, 0}, {1, 0, 0}, {1, 0, 1}, {0, 0, 1},

    {0, 1, 0}, {0, 1, 1}, {1, 1, 1}, {1, 1, 0},

    {0, 1, 0}, {0, 0, 0}, {0, 0, 1}, {0, 1, 1},

    {1, 0, 0}, {1, 1, 0}, {1, 1, 1}, {1, 0, 1}

};

static GLint cubeTextureArray[][2] = {

    {0, 0}, {1, 0}, {1, 1}, {0, 1},

    {0, 0}, {0, 1}, {1, 1}, {1, 0},

    {0, 0}, {1, 0}, {1, 1}, {0, 1},

    {1, 0}, {0, 0}, {0, 1}, {1, 1},

    {0, 0}, {1, 0}, {1, 1}, {0, 1},

    {1, 0}, {0, 0}, {0, 1}, {1, 1}

};

static GLint faceArray[][2] = {

    {1, -1}, {1, 1}, {-1, 1}, {-1, -1}

};

static GLubyte colorArray[][4] = {

    {102, 176, 54, 255},

    {81, 141, 41, 255},

    {62, 108, 32, 255},

    {45, 79, 23, 255}

};

GLWidget::GLWidget(QWidget *parent)

  : QGLWidget(QGLFormat(QGL::SampleBuffers), parent)

{

    // create the framebuffer object - make sure to have a current

    // context before creating it

    makeCurrent();

    fbo = new QGLFramebufferObject(512, 512);

    timerId = startTimer(20);

    setWindowTitle(tr("OpenGL framebuffer objects 2"));

}

GLWidget::~GLWidget()

{

    glDeleteLists(pbufferList, 1);

    delete fbo;

}

void GLWidget::initializeGL()

{

    glMatrixMode(GL_MODELVIEW);

    glEnable(GL_CULL_FACE);

    glEnableClientState(GL_VERTEX_ARRAY);

    glEnableClientState(GL_TEXTURE_COORD_ARRAY);

    glVertexPointer(3, GL_INT, 0, cubeArray);

    glTexCoordPointer(2, GL_INT, 0, cubeTextureArray);

    glColorPointer(4, GL_UNSIGNED_BYTE, 0, colorArray);

    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

    glEnable(GL_BLEND);

    glEnable(GL_TEXTURE_2D);

    glEnable(GL_DEPTH_TEST);

    glClearColor(1.0f, 1.0f, 1.0f, 1.0f);

    pbufferList = glGenLists(1);

    glNewList(pbufferList, GL_COMPILE);

    {

        glClear(GL_DEPTH_BUFFER_BIT | GL_COLOR_BUFFER_BIT);

	// draw cube background

        glPushMatrix();

        glLoadIdentity();

        glTranslatef(0.5f, 0.5f, -2.0f);

	glDisable(GL_TEXTURE_2D);

	glEnableClientState(GL_COLOR_ARRAY);

	glVertexPointer(2, GL_INT, 0, faceArray);

	glDrawArrays(GL_QUADS, 0, 4);

	glVertexPointer(3, GL_INT, 0, cubeArray);

	glDisableClientState(GL_COLOR_ARRAY);

	glEnable(GL_TEXTURE_2D);

        glPopMatrix();

	// draw cube

        glTranslatef(0.5f, 0.5f, 0.5f);

        glRotatef(3.0f, 1.0f, 1.0f, 1.0f);

        glTranslatef(-0.5f, -0.5f, -0.5f);

        glColor4f(0.9f, 0.9f, 0.9f, 1.0f);

        glDrawArrays(GL_QUADS, 0, 24);

        glPushMatrix(); // this state is popped back in the paintGL() function

    }

    glEndList();

    for (int i = 0; i < 3; ++i) {

        yOffs[i] = 0.0f;

        xInc[i] = 0.005f;

        rot[i] = 0.0f;

    }

    xOffs[0]= 0.0f;

    xOffs[1]= 0.5f;

    xOffs[2]= 1.0f;

    cubeTexture = bindTexture(QImage(":res/cubelogo.png"));

    glPushMatrix(); // push to avoid stack underflow in the first paintGL() call

}

void GLWidget::resizeGL(int w, int h)

{

    glViewport(0, 0, w, h);

    glMatrixMode(GL_PROJECTION);

    glLoadIdentity();

    float aspect = w/(float)(h ? h : 1);

    glFrustum(-aspect, aspect, -1, 1, 10, 100);

    glTranslatef(-0.5f, -0.5f, -0.5f);

    glTranslatef(0.0f, 0.0f, -15.0f);

}

void GLWidget::paintGL()

{

    glPopMatrix(); // pop the matrix pushed in the pbuffer list

    // push the projection matrix and the entire GL state before

    // doing any rendering into our framebuffer object

    glPushAttrib(GL_ALL_ATTRIB_BITS);

    glMatrixMode(GL_PROJECTION);

    glPushMatrix();

    glViewport(0, 0, fbo->size().width(), fbo->size().height());

    glMatrixMode(GL_PROJECTION);

    glLoadIdentity();

    glOrtho(-1, 1, -1, 1, -99, 99);

    glTranslatef(-0.5f, -0.5f, 0.0f);

    glMatrixMode(GL_MODELVIEW);

    // render to the framebuffer object

    fbo->bind();

    glBindTexture(GL_TEXTURE_2D, cubeTexture);

    glCallList(pbufferList);

    fbo->release();

    // pop the projection matrix and GL state back for rendering

    // to the actual widget

    glPopAttrib();

    glMatrixMode(GL_PROJECTION);

    glPopMatrix();

    glBindTexture(GL_TEXTURE_2D, fbo->texture());

    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    // draw the background

    glMatrixMode(GL_MODELVIEW);

    glPushMatrix();

    glLoadIdentity();

    glMatrixMode(GL_PROJECTION);

    glPushMatrix();

    glLoadIdentity();

    glVertexPointer(2, GL_INT, 0, faceArray);

    glTranslatef(-1.2f, -0.8f, 0.0f);

    glScalef(0.2f, 0.2f, 0.2f);

    for (int y = 0; y < 5; ++y) {

	for (int x = 0; x < 5; ++x) {

	    glTranslatef(2.0f, 0, 0);

	    glColor4f(0.8f, 0.8f, 0.8f, 1.0f);

	    glDrawArrays(GL_QUADS, 0, 4);

	}

 	glTranslatef(-10.0f, 2.0f, 0);

    }

    glVertexPointer(3, GL_INT, 0, cubeArray);

    glPopMatrix();

    glMatrixMode(GL_MODELVIEW);

    // draw the bouncing cubes

    drawCube(0, 0.0f, 1.5f, 2.5f, 1.5f);

    drawCube(1, 1.0f, 2.0f, 2.5f, 2.0f);

    drawCube(2, 2.0f, 3.5f, 2.5f, 2.5f);

    glPopMatrix();

}

void GLWidget::drawCube(int i, GLfloat z, GLfloat rotation, GLfloat jmp, GLfloat amp)

{

    glMatrixMode(GL_MODELVIEW);

    glLoadIdentity();

    glTranslatef(xOffs[i], yOffs[i], z);

    glTranslatef(0.5f, 0.5f, 0.5f);

    GLfloat scale = 0.75 + i*(0.25f/2);

    glScalef(scale, scale, scale);

    glRotatef(rot[i], 1.0f, 1.0f, 1.0f);

    glTranslatef(-0.5f, -0.5f, -0.5f);

    glColor4f(1.0f, 1.0f, 1.0f, 0.8f);

    glDrawArrays(GL_QUADS, 0, 24);

    if (xOffs[i] > 1.0f || xOffs[i] < -1.0f) {

        xInc[i] = -xInc[i];

        xOffs[i] = xOffs[i] > 1.0f ? 1.0f : -1.0f;

    }

    xOffs[i] += xInc[i];

    yOffs[i] = qAbs(cos((-3.141592f * jmp) * xOffs[i]) * amp) - 1;

    rot[i] += rotation;

}