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// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
#include "renderwindow.h"
#include <QTimer>
#include <QMatrix4x4>
#include <QOpenGLContext>
#include <QtOpenGL/QOpenGLShaderProgram>
#include <QOpenGLFunctions>
RenderWindow::RenderWindow(const QSurfaceFormat &format)
: m_context(nullptr),
m_initialized(false),
m_forceGLSL110(false),
m_angle(0.0f)
{
setSurfaceType(QWindow::OpenGLSurface);
setFormat(format);
m_context = new QOpenGLContext(this);
m_context->setFormat(requestedFormat());
if (!m_context->create()) {
delete m_context;
m_context = nullptr;
}
}
void RenderWindow::exposeEvent(QExposeEvent *)
{
if (isExposed())
render();
}
// ES needs the precision qualifiers.
// On desktop GL QOpenGLShaderProgram inserts dummy defines for highp/mediump/lowp.
static const char *vertexShaderSource110 =
"attribute highp vec4 posAttr;\n"
"attribute lowp vec4 colAttr;\n"
"varying lowp vec4 col;\n"
"uniform highp mat4 matrix;\n"
"void main() {\n"
" col = colAttr;\n"
" gl_Position = matrix * posAttr;\n"
"}\n";
static const char *fragmentShaderSource110 =
"varying lowp vec4 col;\n"
"void main() {\n"
" gl_FragColor = col;\n"
"}\n";
static const char *vertexShaderSource =
"#version 150\n"
"in vec4 posAttr;\n"
"in vec4 colAttr;\n"
"out vec4 col;\n"
"uniform mat4 matrix;\n"
"void main() {\n"
" col = colAttr;\n"
" gl_Position = matrix * posAttr;\n"
"}\n";
static const char *fragmentShaderSource =
"#version 150\n"
"in vec4 col;\n"
"out vec4 fragColor;\n"
"void main() {\n"
" fragColor = col;\n"
"}\n";
static GLfloat vertices[] = {
0.0f, 0.707f,
-0.5f, -0.5f,
0.5f, -0.5f
};
static GLfloat colors[] = {
1.0f, 0.0f, 0.0f,
0.0f, 1.0f, 0.0f,
0.0f, 0.0f, 1.0f
};
void RenderWindow::init()
{
m_program = new QOpenGLShaderProgram(this);
QSurfaceFormat format = m_context->format();
bool useNewStyleShader = format.profile() == QSurfaceFormat::CoreProfile;
// Try to handle 3.0 & 3.1 that do not have the core/compatibility profile concept 3.2+ has.
// This may still fail since version 150 (3.2) is specified in the sources but it's worth a try.
if (format.renderableType() == QSurfaceFormat::OpenGL && format.majorVersion() == 3 && format.minorVersion() <= 1)
useNewStyleShader = !format.testOption(QSurfaceFormat::DeprecatedFunctions);
if (m_forceGLSL110)
useNewStyleShader = false;
const char *vsrc = useNewStyleShader ? vertexShaderSource : vertexShaderSource110;
const char *fsrc = useNewStyleShader ? fragmentShaderSource : fragmentShaderSource110;
qDebug("Using version %s shader", useNewStyleShader ? "150" : "110");
if (!m_program->addShaderFromSourceCode(QOpenGLShader::Vertex, vsrc)) {
emit error(m_program->log());
return;
}
if (!m_program->addShaderFromSourceCode(QOpenGLShader::Fragment, fsrc)) {
emit error(m_program->log());
return;
}
if (!m_program->link()) {
emit error(m_program->log());
return;
}
m_posAttr = m_program->attributeLocation("posAttr");
m_colAttr = m_program->attributeLocation("colAttr");
m_matrixUniform = m_program->uniformLocation("matrix");
m_vbo.create();
m_vbo.bind();
m_vbo.allocate(vertices, sizeof(vertices) + sizeof(colors));
m_vbo.write(sizeof(vertices), colors, sizeof(colors));
m_vbo.release();
QOpenGLVertexArrayObject::Binder vaoBinder(&m_vao);
if (m_vao.isCreated()) // have VAO support, use it
setupVertexAttribs();
}
void RenderWindow::setupVertexAttribs()
{
m_vbo.bind();
m_program->setAttributeBuffer(m_posAttr, GL_FLOAT, 0, 2);
m_program->setAttributeBuffer(m_colAttr, GL_FLOAT, sizeof(vertices), 3);
m_program->enableAttributeArray(m_posAttr);
m_program->enableAttributeArray(m_colAttr);
m_vbo.release();
}
bool RenderWindow::event(QEvent *ev)
{
if (ev->type() == QEvent::UpdateRequest)
render();
return QWindow::event(ev);
}
void RenderWindow::render()
{
if (!m_context->makeCurrent(this)) {
emit error(tr("makeCurrent() failed"));
return;
}
QOpenGLFunctions *f = m_context->functions();
if (!m_initialized) {
m_initialized = true;
f->glEnable(GL_DEPTH_TEST);
f->glClearColor(0, 0, 0, 1);
init();
emit ready();
}
if (!m_vbo.isCreated()) // init() failed, don't bother with trying to render
return;
const qreal retinaScale = devicePixelRatio();
f->glViewport(0, 0, width() * retinaScale, height() * retinaScale);
f->glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
m_program->bind();
QMatrix4x4 matrix;
matrix.perspective(60.0f, 4.0f / 3.0f, 0.1f, 100.0f);
matrix.translate(0.0f, 0.0f, -2.0f);
matrix.rotate(m_angle, 0.0f, 1.0f, 0.0f);
m_program->setUniformValue(m_matrixUniform, matrix);
if (m_vao.isCreated())
m_vao.bind();
else // no VAO support, set the vertex attribute arrays now
setupVertexAttribs();
f->glDrawArrays(GL_TRIANGLES, 0, 3);
m_vao.release();
m_program->release();
// swapInterval is 1 by default which means that swapBuffers() will (hopefully) block
// and wait for vsync.
m_context->swapBuffers(this);
m_angle += 1.0f;
requestUpdate();
}
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