71 lines
2.3 KiB
C++
71 lines
2.3 KiB
C++
#include "svpointcloudviewer.h"
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#include <QtGui/QOpenGLShaderProgram>
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#include <QtGui/QOpenGLContext>
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SvPointCloudViewer::SvPointCloudViewer(QQuickItem *parent) :
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QQuickPaintedItem(parent)
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{
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setRenderTarget(QQuickPaintedItem::FramebufferObject);
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}
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void SvPointCloudViewer::paint(QPainter *painter)
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{
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painter->beginNativePainting();
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if (!m_program) {
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m_program = new QOpenGLShaderProgram();
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m_program->addShaderFromSourceCode(QOpenGLShader::Vertex,
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"attribute highp vec4 vertices;"
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"varying highp vec2 coords;"
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"void main() {"
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" gl_Position = vertices;"
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" coords = vertices.xy;"
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"}");
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m_program->addShaderFromSourceCode(QOpenGLShader::Fragment,
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"uniform lowp float t;"
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"varying highp vec2 coords;"
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"void main() {"
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" lowp float i = 1. - (pow(abs(coords.x), 4.) + pow(abs(coords.y), 4.));"
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" i = smoothstep(t - 0.8, t + 0.8, i);"
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" i = floor(i * 20.) / 20.;"
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" gl_FragColor = vec4(coords * .5 + .5, i, i);"
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"}");
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m_program->bindAttributeLocation("vertices", 0);
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m_program->link();
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}
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m_program->bind();
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m_program->enableAttributeArray(0);
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float values[] = {
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-1, -1,
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1, -1,
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-1, 1,
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1, 1
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};
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m_program->setAttributeArray(0, GL_FLOAT, values, 2);
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m_program->setUniformValue("t", (float) 1);
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glViewport(0, 0, width(), height());
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glDisable(GL_DEPTH_TEST);
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glClearColor(0, 0, 0, 1);
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glClear(GL_COLOR_BUFFER_BIT);
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glEnable(GL_BLEND);
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glBlendFunc(GL_SRC_ALPHA, GL_ONE);
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glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
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m_program->disableAttributeArray(0);
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m_program->release();
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painter->endNativePainting();
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}
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