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| |
| #include "openglwindow.h" |
| |
| #include <QtGui/QGuiApplication> |
| #include <QtGui/QMatrix4x4> |
| #include <QtGui/QOpenGLShaderProgram> |
| #include <QtGui/QScreen> |
| |
| #include <QtCore/qmath.h> |
| |
| //! [1] |
| class TriangleWindow : public OpenGLWindow |
| { |
| public: |
| TriangleWindow(); |
| |
| void initialize() override; |
| void render() override; |
| |
| private: |
| GLuint m_posAttr; |
| GLuint m_colAttr; |
| GLuint m_matrixUniform; |
| |
| QOpenGLShaderProgram *m_program; |
| int m_frame; |
| }; |
| |
| TriangleWindow::TriangleWindow() |
| : m_program(0) |
| , m_frame(0) |
| { |
| } |
| //! [1] |
| |
| //! [2] |
| int main(int argc, char **argv) |
| { |
| QGuiApplication app(argc, argv); |
| |
| QSurfaceFormat format; |
| format.setSamples(16); |
| |
| TriangleWindow window; |
| window.setFormat(format); |
| window.resize(640, 480); |
| window.show(); |
| |
| window.setAnimating(true); |
| |
| return app.exec(); |
| } |
| //! [2] |
| |
| |
| //! [3] |
| static const char *vertexShaderSource = |
| "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 *fragmentShaderSource = |
| "varying lowp vec4 col;\n" |
| "void main() {\n" |
| " gl_FragColor = col;\n" |
| "}\n"; |
| //! [3] |
| |
| //! [4] |
| void TriangleWindow::initialize() |
| { |
| m_program = new QOpenGLShaderProgram(this); |
| m_program->addShaderFromSourceCode(QOpenGLShader::Vertex, vertexShaderSource); |
| m_program->addShaderFromSourceCode(QOpenGLShader::Fragment, fragmentShaderSource); |
| m_program->link(); |
| m_posAttr = m_program->attributeLocation("posAttr"); |
| m_colAttr = m_program->attributeLocation("colAttr"); |
| m_matrixUniform = m_program->uniformLocation("matrix"); |
| } |
| //! [4] |
| |
| //! [5] |
| void TriangleWindow::render() |
| { |
| const qreal retinaScale = devicePixelRatio(); |
| glViewport(0, 0, width() * retinaScale, height() * retinaScale); |
| |
| glClear(GL_COLOR_BUFFER_BIT); |
| |
| m_program->bind(); |
| |
| QMatrix4x4 matrix; |
| matrix.perspective(60.0f, 4.0f/3.0f, 0.1f, 100.0f); |
| matrix.translate(0, 0, -2); |
| matrix.rotate(100.0f * m_frame / screen()->refreshRate(), 0, 1, 0); |
| |
| m_program->setUniformValue(m_matrixUniform, matrix); |
| |
| GLfloat vertices[] = { |
| 0.0f, 0.707f, |
| -0.5f, -0.5f, |
| 0.5f, -0.5f |
| }; |
| |
| GLfloat colors[] = { |
| 1.0f, 0.0f, 0.0f, |
| 0.0f, 1.0f, 0.0f, |
| 0.0f, 0.0f, 1.0f |
| }; |
| |
| glVertexAttribPointer(m_posAttr, 2, GL_FLOAT, GL_FALSE, 0, vertices); |
| glVertexAttribPointer(m_colAttr, 3, GL_FLOAT, GL_FALSE, 0, colors); |
| |
| glEnableVertexAttribArray(0); |
| glEnableVertexAttribArray(1); |
| |
| glDrawArrays(GL_TRIANGLES, 0, 3); |
| |
| glDisableVertexAttribArray(1); |
| glDisableVertexAttribArray(0); |
| |
| m_program->release(); |
| |
| ++m_frame; |
| } |
| //! [5] |