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#include "paintedwindow.h"
#include <QOpenGLContext>
#include <QOpenGLFunctions>
#include <QPainter>
#include <QTimer>
#include <qmath.h>
PaintedWindow::PaintedWindow()
: m_fbo(0)
{
QSurfaceFormat format;
format.setStencilBufferSize(8);
setSurfaceType(QWindow::OpenGLSurface);
setWindowFlags(Qt::Window | Qt::WindowTitleHint | Qt::WindowMinMaxButtonsHint | Qt::WindowCloseButtonHint);
setFormat(format);
create();
m_context = new QOpenGLContext(this);
m_context->setFormat(format);
m_context->create();
QTimer *timer = new QTimer(this);
timer->setInterval(16);
connect(timer, SIGNAL(timeout()), this, SLOT(paint()));
timer->start();
m_context->makeCurrent(this);
QOpenGLShader *vshader = new QOpenGLShader(QOpenGLShader::Vertex, this);
const char *vsrc =
"attribute highp vec2 vertexCoordsInput;\n"
"attribute mediump vec2 texCoordsInput;\n"
"varying mediump vec2 texCoords;\n"
"void main(void)\n"
"{\n"
" texCoords = texCoordsInput;\n"
" gl_Position = vec4(vertexCoordsInput, 0, 1);\n"
"}\n";
vshader->compileSourceCode(vsrc);
QOpenGLShader *fshader = new QOpenGLShader(QOpenGLShader::Fragment, this);
const char *fsrc =
"uniform sampler2D tex;\n"
"varying mediump vec2 texCoords;\n"
"void main(void)\n"
"{\n"
" gl_FragColor = texture2D(tex, texCoords);\n"
"}\n";
fshader->compileSourceCode(fsrc);
m_program = new QOpenGLShaderProgram;
m_program->addShader(vshader);
m_program->addShader(fshader);
m_program->link();
m_vertexAttribute = m_program->attributeLocation("vertexCoordsInput");
m_texCoordsAttribute = m_program->attributeLocation("texCoordsInput");
}
void PaintedWindow::resizeEvent(QResizeEvent *)
{
m_context->makeCurrent(this);
delete m_fbo;
m_fbo = new QOpenGLFramebufferObject(size());
}
void PaintedWindow::paint()
{
if (!m_fbo)
return;
m_context->makeCurrent(this);
QPainterPath path;
path.addEllipse(0, 0, m_fbo->width(), m_fbo->height());
QPainter painter;
painter.begin(m_fbo);
painter.fillRect(0, 0, m_fbo->width(), m_fbo->height(), Qt::white);
painter.setRenderHint(QPainter::Antialiasing);
painter.fillPath(path, Qt::blue);
painter.end();
glViewport(0, 0, width(), height());
glDisable(GL_DEPTH_TEST);
glDisable(GL_STENCIL_TEST);
glDisable(GL_BLEND);
glClearColor(0.1f, 0.1f, 0.2f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
GLfloat texCoords[] = { 0, 0, 1, 0, 0, 1,
1, 0, 1, 1, 0, 1 };
GLfloat vertexCoords[] = { -1, -1, 1, -1, -1, 1,
1, -1, 1, 1, -1, 1 };
m_program->bind();
m_context->functions()->glEnableVertexAttribArray(m_vertexAttribute);
m_context->functions()->glEnableVertexAttribArray(m_texCoordsAttribute);
m_context->functions()->glVertexAttribPointer(m_vertexAttribute, 2, GL_FLOAT, GL_FALSE, 0, vertexCoords);
m_context->functions()->glVertexAttribPointer(m_texCoordsAttribute, 2, GL_FLOAT, GL_FALSE, 0, texCoords);
glBindTexture(GL_TEXTURE_2D, m_fbo->texture());
glDrawArrays(GL_TRIANGLES, 0, 6);
glBindTexture(GL_TEXTURE_2D, 0);
m_context->functions()->glDisableVertexAttribArray(m_vertexAttribute);
m_context->functions()->glDisableVertexAttribArray(m_texCoordsAttribute);
m_program->release();
m_context->swapBuffers(this);
}
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