02b7ec05d5
Use M_PI (and friends), where possible, in favor of hand-coded approximations of various (in)accuracies. Where that's not available (e.g. fragment shaders), use the same value that qmath.h uses for M_PI, for consistency. Replaced math.h with qmath.h in places that defined a fall-back in case math.h omits it (it's not in the C++ standard, although M_PI is in POSIX); or removed this entirely where it wasn't used. Reworked some code to reduce the amount of arithmetic needed, in the process; e.g. pulling common factors out of loops. Revised an example's doc to not waste time talking about using a six-sig-fig value for pi (which we no longer do) - it really wasn't relevant, or anything to be proud of; nor did the doc mention its later use. Task-number: QTBUG-58083 Change-Id: I5a31e3a2b6a823b97a43209bed61a37b9aa6c05f Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
258 lines
8.1 KiB
C++
258 lines
8.1 KiB
C++
/****************************************************************************
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**
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** Copyright (C) 2016 The Qt Company Ltd.
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** Contact: https://www.qt.io/licensing/
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**
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** This file is part of the examples of the Qt Toolkit.
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**
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** $QT_BEGIN_LICENSE:BSD$
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** Commercial License Usage
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** Licensees holding valid commercial Qt licenses may use this file in
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** accordance with the commercial license agreement provided with the
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** Software or, alternatively, in accordance with the terms contained in
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** a written agreement between you and The Qt Company. For licensing terms
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** and conditions see https://www.qt.io/terms-conditions. For further
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** information use the contact form at https://www.qt.io/contact-us.
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**
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** BSD License Usage
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** Alternatively, you may use this file under the terms of the BSD license
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** as follows:
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**
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** "Redistribution and use in source and binary forms, with or without
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** modification, are permitted provided that the following conditions are
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** met:
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** * Redistributions of source code must retain the above copyright
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** notice, this list of conditions and the following disclaimer.
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** * Redistributions in binary form must reproduce the above copyright
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** notice, this list of conditions and the following disclaimer in
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** the documentation and/or other materials provided with the
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** distribution.
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** * Neither the name of The Qt Company Ltd nor the names of its
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** contributors may be used to endorse or promote products derived
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** from this software without specific prior written permission.
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**
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**
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** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
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**
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** $QT_END_LICENSE$
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**
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****************************************************************************/
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#include "glwidget.h"
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#include <QtGui/QImage>
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#include <qmath.h>
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static GLint cubeArray[][3] = {
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{0, 0, 0}, {0, 1, 0}, {1, 1, 0}, {1, 0, 0},
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{0, 0, 1}, {1, 0, 1}, {1, 1, 1}, {0, 1, 1},
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{0, 0, 0}, {1, 0, 0}, {1, 0, 1}, {0, 0, 1},
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{0, 1, 0}, {0, 1, 1}, {1, 1, 1}, {1, 1, 0},
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{0, 1, 0}, {0, 0, 0}, {0, 0, 1}, {0, 1, 1},
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{1, 0, 0}, {1, 1, 0}, {1, 1, 1}, {1, 0, 1}
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};
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static GLint cubeTextureArray[][2] = {
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{0, 0}, {1, 0}, {1, 1}, {0, 1},
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{0, 0}, {0, 1}, {1, 1}, {1, 0},
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{0, 0}, {1, 0}, {1, 1}, {0, 1},
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{1, 0}, {0, 0}, {0, 1}, {1, 1},
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{0, 0}, {1, 0}, {1, 1}, {0, 1},
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{1, 0}, {0, 0}, {0, 1}, {1, 1}
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};
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static GLint faceArray[][2] = {
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{1, -1}, {1, 1}, {-1, 1}, {-1, -1}
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};
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static GLubyte colorArray[][4] = {
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{102, 176, 54, 255},
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{81, 141, 41, 255},
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{62, 108, 32, 255},
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{45, 79, 23, 255}
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};
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GLWidget::GLWidget(QWidget *parent)
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: QGLWidget(QGLFormat(QGL::SampleBuffers), parent)
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{
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// create the framebuffer object - make sure to have a current
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// context before creating it
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makeCurrent();
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fbo = new QGLFramebufferObject(512, 512);
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timerId = startTimer(20);
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setWindowTitle(tr("OpenGL framebuffer objects 2"));
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}
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GLWidget::~GLWidget()
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{
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glDeleteLists(pbufferList, 1);
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delete fbo;
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}
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void GLWidget::initializeGL()
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{
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glMatrixMode(GL_MODELVIEW);
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glEnable(GL_CULL_FACE);
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glEnableClientState(GL_VERTEX_ARRAY);
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glEnableClientState(GL_TEXTURE_COORD_ARRAY);
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glVertexPointer(3, GL_INT, 0, cubeArray);
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glTexCoordPointer(2, GL_INT, 0, cubeTextureArray);
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glColorPointer(4, GL_UNSIGNED_BYTE, 0, colorArray);
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glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
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glEnable(GL_BLEND);
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glEnable(GL_TEXTURE_2D);
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glEnable(GL_DEPTH_TEST);
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glClearColor(1.0f, 1.0f, 1.0f, 1.0f);
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pbufferList = glGenLists(1);
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glNewList(pbufferList, GL_COMPILE);
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{
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glClear(GL_DEPTH_BUFFER_BIT | GL_COLOR_BUFFER_BIT);
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// draw cube background
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glPushMatrix();
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glLoadIdentity();
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glTranslatef(0.5f, 0.5f, -2.0f);
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glDisable(GL_TEXTURE_2D);
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glEnableClientState(GL_COLOR_ARRAY);
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glVertexPointer(2, GL_INT, 0, faceArray);
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glDrawArrays(GL_QUADS, 0, 4);
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glVertexPointer(3, GL_INT, 0, cubeArray);
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glDisableClientState(GL_COLOR_ARRAY);
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glEnable(GL_TEXTURE_2D);
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glPopMatrix();
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// draw cube
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glTranslatef(0.5f, 0.5f, 0.5f);
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glRotatef(3.0f, 1.0f, 1.0f, 1.0f);
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glTranslatef(-0.5f, -0.5f, -0.5f);
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glColor4f(0.9f, 0.9f, 0.9f, 1.0f);
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glDrawArrays(GL_QUADS, 0, 24);
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glPushMatrix(); // this state is popped back in the paintGL() function
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}
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glEndList();
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for (int i = 0; i < 3; ++i) {
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yOffs[i] = 0.0f;
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xInc[i] = 0.005f;
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rot[i] = 0.0f;
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}
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xOffs[0]= 0.0f;
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xOffs[1]= 0.5f;
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xOffs[2]= 1.0f;
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cubeTexture = bindTexture(QImage(":res/cubelogo.png"));
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glPushMatrix(); // push to avoid stack underflow in the first paintGL() call
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}
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void GLWidget::resizeGL(int w, int h)
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{
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glViewport(0, 0, w, h);
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glMatrixMode(GL_PROJECTION);
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glLoadIdentity();
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float aspect = w/(float)(h ? h : 1);
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glFrustum(-aspect, aspect, -1, 1, 10, 100);
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glTranslatef(-0.5f, -0.5f, -0.5f);
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glTranslatef(0.0f, 0.0f, -15.0f);
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}
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void GLWidget::paintGL()
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{
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glPopMatrix(); // pop the matrix pushed in the pbuffer list
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// push the projection matrix and the entire GL state before
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// doing any rendering into our framebuffer object
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glPushAttrib(GL_ALL_ATTRIB_BITS);
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glMatrixMode(GL_PROJECTION);
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glPushMatrix();
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glViewport(0, 0, fbo->size().width(), fbo->size().height());
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glMatrixMode(GL_PROJECTION);
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glLoadIdentity();
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glOrtho(-1, 1, -1, 1, -99, 99);
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glTranslatef(-0.5f, -0.5f, 0.0f);
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glMatrixMode(GL_MODELVIEW);
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// render to the framebuffer object
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fbo->bind();
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glBindTexture(GL_TEXTURE_2D, cubeTexture);
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glCallList(pbufferList);
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fbo->release();
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// pop the projection matrix and GL state back for rendering
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// to the actual widget
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glPopAttrib();
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glMatrixMode(GL_PROJECTION);
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glPopMatrix();
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glBindTexture(GL_TEXTURE_2D, fbo->texture());
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glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
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// draw the background
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glMatrixMode(GL_MODELVIEW);
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glPushMatrix();
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glLoadIdentity();
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glMatrixMode(GL_PROJECTION);
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glPushMatrix();
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glLoadIdentity();
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glVertexPointer(2, GL_INT, 0, faceArray);
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glTranslatef(-1.2f, -0.8f, 0.0f);
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glScalef(0.2f, 0.2f, 0.2f);
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for (int y = 0; y < 5; ++y) {
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for (int x = 0; x < 5; ++x) {
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glTranslatef(2.0f, 0, 0);
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glColor4f(0.8f, 0.8f, 0.8f, 1.0f);
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glDrawArrays(GL_QUADS, 0, 4);
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}
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glTranslatef(-10.0f, 2.0f, 0);
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}
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glVertexPointer(3, GL_INT, 0, cubeArray);
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glPopMatrix();
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glMatrixMode(GL_MODELVIEW);
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// draw the bouncing cubes
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drawCube(0, 0.0f, 1.5f, 2.5f, 1.5f);
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drawCube(1, 1.0f, 2.0f, 2.5f, 2.0f);
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drawCube(2, 2.0f, 3.5f, 2.5f, 2.5f);
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glPopMatrix();
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}
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void GLWidget::drawCube(int i, GLfloat z, GLfloat rotation, GLfloat jmp, GLfloat amp)
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{
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glMatrixMode(GL_MODELVIEW);
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glLoadIdentity();
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glTranslatef(xOffs[i], yOffs[i], z);
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glTranslatef(0.5f, 0.5f, 0.5f);
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GLfloat scale = 0.75 + i*(0.25f/2);
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glScalef(scale, scale, scale);
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glRotatef(rot[i], 1.0f, 1.0f, 1.0f);
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glTranslatef(-0.5f, -0.5f, -0.5f);
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glColor4f(1.0f, 1.0f, 1.0f, 0.8f);
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glDrawArrays(GL_QUADS, 0, 24);
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if (xOffs[i] > 1.0f || xOffs[i] < -1.0f) {
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xInc[i] = -xInc[i];
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xOffs[i] = xOffs[i] > 1.0f ? 1.0f : -1.0f;
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}
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xOffs[i] += xInc[i];
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yOffs[i] = qAbs(cos((-GLfloat(M_PI) * jmp) * xOffs[i]) * amp) - 1;
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rot[i] += rotation;
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}
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