1 files changed, 286 insertions, 0 deletions
diff --git a/examples/hellooffscreen_opengl/window.cpp b/examples/hellooffscreen_opengl/window.cpp
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+++ b/examples/hellooffscreen_opengl/window.cpp
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+/****************************************************************************
+**
+** Copyright (C) 2016 The Qt Company Ltd.
+** Contact: http://www.qt.io/licensing/
+**
+** This file is part of the examples of the QtD3D12Window module
+**
+** $QT_BEGIN_LICENSE:BSD$
+** You may use this file under the terms of the BSD license as follows:
+**
+** "Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions are
+** met:
+**   * Redistributions of source code must retain the above copyright
+**     notice, this list of conditions and the following disclaimer.
+**   * 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.
+**   * Neither the name of The Qt Company Ltd nor the names of its
+**     contributors may be used to endorse or promote products derived
+**     from this software without specific prior written permission.
+**
+**
+** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND 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 THE COPYRIGHT
+** OWNER OR 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."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "window.h"
+#include <QFileDialog>
+#include <QMessageBox>
+#include <QOpenGLFramebufferObject>
+#include <QOpenGLShaderProgram>
+#include <QOpenGLFunctions>
+#include <QOpenGLBuffer>
+#include <QOpenGLVertexArrayObject>
+
+static const int OFFSCREEN_WIDTH = 512;
+static const int OFFSCREEN_HEIGHT = 512;
+
+static const float offscreenClearColor[] = { 0.0f, 0.2f, 0.4f, 1.0f };
+static const float onscreenClearColor[] = { 0.4f, 0.5f, 0.5f, 1.0f };
+
+Window::Window()
+{
+    QSurfaceFormat fmt;
+    fmt.setDepthBufferSize(24);
+    setFormat(fmt);
+}
+
+Window::~Window()
+{
+    makeCurrent();
+
+    delete offscreen.fbo;
+    delete offscreen.prog;
+    delete offscreen.vbo;
+    delete offscreen.vao;
+
+    delete onscreen.prog;
+    delete onscreen.vbo;
+    delete onscreen.vao;
+}
+
+void Window::initializeGL()
+{
+    initializeOffscreen();
+    initializeOnscreen();
+
+    QOpenGLFunctions *f = context()->functions();
+    f->glEnable(GL_DEPTH_TEST);
+    f->glEnable(GL_CULL_FACE);
+}
+
+void Window::initializeOffscreen()
+{
+    offscreen.fbo = new QOpenGLFramebufferObject(OFFSCREEN_WIDTH, OFFSCREEN_HEIGHT, QOpenGLFramebufferObject::CombinedDepthStencil);
+
+    offscreen.prog = new QOpenGLShaderProgram;
+    offscreen.prog->addShaderFromSourceFile(QOpenGLShader::Vertex, QStringLiteral(":/shader_offscreen.vert"));
+    offscreen.prog->addShaderFromSourceFile(QOpenGLShader::Fragment, QStringLiteral(":/shader_offscreen.frag"));
+    offscreen.prog->bindAttributeLocation("position", 0);
+    offscreen.prog->bindAttributeLocation("color", 1);
+    offscreen.prog->link();
+
+    offscreen.modelviewLoc = offscreen.prog->uniformLocation("modelview");
+    offscreen.projectionLoc = offscreen.prog->uniformLocation("projection");
+
+    offscreen.vao = new QOpenGLVertexArrayObject;
+    offscreen.vao->create();
+    QOpenGLVertexArrayObject::Binder vaoBinder(offscreen.vao);
+
+    offscreen.vbo = new QOpenGLBuffer;
+    offscreen.vbo->create();
+    offscreen.vbo->bind();
+
+    const float vertices[] = {
+        0.0f, 0.707f, 0.0f, /* color */ 1.0f, 0.0f, 0.0f, 1.0f,
+        -0.5f, -0.5f, 0.0f,             0.0f, 1.0f, 0.0f, 1.0f,
+        0.5f, -0.5f, 0.0f,              0.0f, 0.0f, 1.0f, 1.0f
+    };
+
+    const int vertexCount = 3;
+    offscreen.vbo->allocate(sizeof(GLfloat) * vertexCount * 7);
+    offscreen.vbo->write(0, vertices, sizeof(GLfloat) * vertexCount * 7);
+
+    if (offscreen.vao->isCreated())
+        setupOffscreenVertexAttribs();
+
+    offscreen.projection.perspective(60.0f, OFFSCREEN_WIDTH / float(OFFSCREEN_HEIGHT), 0.1f, 100.0f);
+}
+
+void Window::initializeOnscreen()
+{
+    onscreen.prog = new QOpenGLShaderProgram;
+    onscreen.prog->addShaderFromSourceFile(QOpenGLShader::Vertex, QStringLiteral(":/shader_onscreen.vert"));
+    onscreen.prog->addShaderFromSourceFile(QOpenGLShader::Fragment, QStringLiteral(":/shader_onscreen.frag"));
+    onscreen.prog->bindAttributeLocation("position", 0);
+    onscreen.prog->bindAttributeLocation("texcoord", 1);
+    onscreen.prog->link();
+
+    onscreen.modelviewLoc = onscreen.prog->uniformLocation("modelview");
+    onscreen.projectionLoc = onscreen.prog->uniformLocation("projection");
+
+    onscreen.vao = new QOpenGLVertexArrayObject;
+    onscreen.vao->create();
+    QOpenGLVertexArrayObject::Binder vaoBinder(onscreen.vao);
+
+    onscreen.vbo = new QOpenGLBuffer;
+    onscreen.vbo->create();
+    onscreen.vbo->bind();
+
+    GLfloat v[] = {
+        -0.5, 0.5, 0.5, 0.5,-0.5,0.5,-0.5,-0.5,0.5,
+        0.5, -0.5, 0.5, -0.5,0.5,0.5,0.5,0.5,0.5,
+        -0.5, -0.5, -0.5, 0.5,-0.5,-0.5,-0.5,0.5,-0.5,
+        0.5, 0.5, -0.5, -0.5,0.5,-0.5,0.5,-0.5,-0.5,
+
+        0.5, -0.5, -0.5, 0.5,-0.5,0.5,0.5,0.5,-0.5,
+        0.5, 0.5, 0.5, 0.5,0.5,-0.5,0.5,-0.5,0.5,
+        -0.5, 0.5, -0.5, -0.5,-0.5,0.5,-0.5,-0.5,-0.5,
+        -0.5, -0.5, 0.5, -0.5,0.5,-0.5,-0.5,0.5,0.5,
+
+        0.5, 0.5,  -0.5, -0.5, 0.5,  0.5,  -0.5,  0.5,  -0.5,
+        -0.5,  0.5,  0.5,  0.5,  0.5,  -0.5, 0.5, 0.5,  0.5,
+        -0.5,  -0.5, -0.5, -0.5, -0.5, 0.5,  0.5, -0.5, -0.5,
+        0.5, -0.5, 0.5,  0.5,  -0.5, -0.5, -0.5,  -0.5, 0.5
+    };
+    GLfloat texCoords[] = {
+        0.0f,0.0f, 1.0f,1.0f, 1.0f,0.0f,
+        1.0f,1.0f, 0.0f,0.0f, 0.0f,1.0f,
+        1.0f,1.0f, 1.0f,0.0f, 0.0f,1.0f,
+        0.0f,0.0f, 0.0f,1.0f, 1.0f,0.0f,
+
+        1.0f,1.0f, 1.0f,0.0f, 0.0f,1.0f,
+        0.0f,0.0f, 0.0f,1.0f, 1.0f,0.0f,
+        0.0f,0.0f, 1.0f,1.0f, 1.0f,0.0f,
+        1.0f,1.0f, 0.0f,0.0f, 0.0f,1.0f,
+
+        0.0f,1.0f, 1.0f,0.0f, 1.0f,1.0f,
+        1.0f,0.0f, 0.0f,1.0f, 0.0f,0.0f,
+        1.0f,0.0f, 1.0f,1.0f, 0.0f,0.0f,
+        0.0f,1.0f, 0.0f,0.0f, 1.0f,1.0f
+    };
+
+    const int vertexCount = 36;
+    onscreen.vbo->allocate(sizeof(GLfloat) * vertexCount * 5);
+    onscreen.vbo->write(0, v, sizeof(GLfloat) * vertexCount * 3);
+    onscreen.vbo->write(sizeof(GLfloat) * vertexCount * 3, texCoords, sizeof(GLfloat) * vertexCount * 2);
+
+    if (onscreen.vao->isCreated())
+        setupOnscreenVertexAttribs();
+
+    onscreen.projection.perspective(60.0f, width() / float(height()), 0.1f, 100.0f);
+}
+
+void Window::resizeGL(int, int)
+{
+    onscreen.projection.setToIdentity();
+    onscreen.projection.perspective(60.0f, width() / float(height()), 0.1f, 100.0f);
+}
+
+void Window::paintGL()
+{
+    paintOffscreen();
+    paintOnscreen();
+
+    update();
+}
+
+void Window::setupOffscreenVertexAttribs()
+{
+    QOpenGLFunctions *f = context()->functions();
+    offscreen.vbo->bind();
+    offscreen.prog->enableAttributeArray(0);
+    offscreen.prog->enableAttributeArray(1);
+    f->glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 7 * sizeof(GLfloat), 0);
+    f->glVertexAttribPointer(1, 4, GL_FLOAT, GL_FALSE, 7 * sizeof(GLfloat), (const void *)(3 * sizeof(GLfloat)));
+    offscreen.vbo->release();
+}
+
+void Window::paintOffscreen()
+{
+    QOpenGLFunctions *f = context()->functions();
+
+    offscreen.fbo->bind();
+    offscreen.prog->bind();
+    QOpenGLVertexArrayObject::Binder vaoBinder(offscreen.vao);
+    if (!offscreen.vao->isCreated())
+        setupOffscreenVertexAttribs();
+
+    QMatrix4x4 modelview;
+    modelview.translate(0, 0, -2);
+    modelview.rotate(offscreen.rotationAngle, 0, 0, 1);
+    offscreen.rotationAngle += 1;
+    offscreen.prog->setUniformValue(offscreen.modelviewLoc, modelview);
+    offscreen.prog->setUniformValue(offscreen.projectionLoc, offscreen.projection);
+
+    f->glViewport(0, 0, OFFSCREEN_WIDTH, OFFSCREEN_HEIGHT);
+    f->glClearColor(offscreenClearColor[0], offscreenClearColor[1], offscreenClearColor[2], offscreenClearColor[3]);
+    f->glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+
+    f->glFrontFace(GL_CCW);
+    f->glDrawArrays(GL_TRIANGLES, 0, 3);
+
+    offscreen.fbo->release();
+}
+
+void Window::setupOnscreenVertexAttribs()
+{
+    QOpenGLFunctions *f = context()->functions();
+    onscreen.vbo->bind();
+    onscreen.prog->enableAttributeArray(0);
+    onscreen.prog->enableAttributeArray(1);
+    f->glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, 0);
+    f->glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 0, (const void *)(36 * 3 * sizeof(GLfloat)));
+    onscreen.vbo->release();
+}
+
+void Window::paintOnscreen()
+{
+    QOpenGLFunctions *f = context()->functions();
+
+    onscreen.prog->bind();
+    QOpenGLVertexArrayObject::Binder vaoBinder(onscreen.vao);
+    if (!onscreen.vao->isCreated())
+        setupOnscreenVertexAttribs();
+
+    f->glBindTexture(GL_TEXTURE_2D, offscreen.fbo->texture());
+
+    QMatrix4x4 modelview;
+    modelview.translate(0, 0, -2);
+    modelview.rotate(onscreen.rotationAngle, 1, 0.5, 0);
+    onscreen.rotationAngle += 1;
+    onscreen.prog->setUniformValue(onscreen.modelviewLoc, modelview);
+    onscreen.prog->setUniformValue(onscreen.projectionLoc, onscreen.projection);
+
+    f->glViewport(0, 0, width(), height());
+    f->glClearColor(onscreenClearColor[0], onscreenClearColor[1], onscreenClearColor[2], onscreenClearColor[3]);
+    f->glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+
+    f->glFrontFace(GL_CW);
+    f->glDrawArrays(GL_TRIANGLES, 0, 36);
+}
+
+void Window::readbackAndSave()
+{
+    QImage img = offscreen.fbo->toImage();
+    QString fn = QFileDialog::getSaveFileName(Q_NULLPTR, QStringLiteral("Save PNG"), QString(), QStringLiteral("PNG files (*.png)"));
+    if (!fn.isEmpty()) {
+        img.save(fn);
+        QMessageBox::information(Q_NULLPTR, QStringLiteral("Saved"), QStringLiteral("Offscreen render target read back and saved to ") + fn);
+    }
+}