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| |
| #include "openglrenderer.h" |
| #include <QQuickItem> |
| |
| #if QT_CONFIG(opengl) |
| |
| #include <QOpenGLShaderProgram> |
| #include <QOpenGLBuffer> |
| #include <QOpenGLFunctions> |
| |
| //! [1] |
| OpenGLRenderNode::~OpenGLRenderNode() |
| { |
| releaseResources(); |
| } |
| |
| void OpenGLRenderNode::releaseResources() |
| { |
| delete m_program; |
| m_program = nullptr; |
| delete m_vbo; |
| m_vbo = nullptr; |
| } |
| //! [1] |
| |
| void OpenGLRenderNode::init() |
| { |
| m_program = new QOpenGLShaderProgram; |
| |
| 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" |
| "uniform lowp float opacity;\n" |
| "void main() {\n" |
| " gl_FragColor = col * opacity;\n" |
| "}\n"; |
| |
| m_program->addCacheableShaderFromSourceCode(QOpenGLShader::Vertex, vertexShaderSource); |
| m_program->addCacheableShaderFromSourceCode(QOpenGLShader::Fragment, fragmentShaderSource); |
| m_program->bindAttributeLocation("posAttr", 0); |
| m_program->bindAttributeLocation("colAttr", 1); |
| m_program->link(); |
| |
| m_matrixUniform = m_program->uniformLocation("matrix"); |
| m_opacityUniform = m_program->uniformLocation("opacity"); |
| |
| const int VERTEX_SIZE = 6 * sizeof(GLfloat); |
| |
| static GLfloat colors[] = { |
| 1.0f, 0.0f, 0.0f, |
| 0.0f, 1.0f, 0.0f, |
| 0.0f, 0.0f, 1.0f |
| }; |
| |
| m_vbo = new QOpenGLBuffer; |
| m_vbo->create(); |
| m_vbo->bind(); |
| m_vbo->allocate(VERTEX_SIZE + sizeof(colors)); |
| m_vbo->write(VERTEX_SIZE, colors, sizeof(colors)); |
| m_vbo->release(); |
| } |
| |
| //! [2] |
| void OpenGLRenderNode::render(const RenderState *state) |
| { |
| if (!m_program) |
| init(); |
| |
| QOpenGLFunctions *f = QOpenGLContext::currentContext()->functions(); |
| m_program->bind(); |
| m_program->setUniformValue(m_matrixUniform, *state->projectionMatrix() * *matrix()); |
| m_program->setUniformValue(m_opacityUniform, float(inheritedOpacity())); |
| //! [2] |
| |
| m_vbo->bind(); |
| |
| //! [5] |
| QPointF p0(m_width - 1, m_height - 1); |
| QPointF p1(0, 0); |
| QPointF p2(0, m_height - 1); |
| |
| GLfloat vertices[6] = { GLfloat(p0.x()), GLfloat(p0.y()), |
| GLfloat(p1.x()), GLfloat(p1.y()), |
| GLfloat(p2.x()), GLfloat(p2.y()) }; |
| m_vbo->write(0, vertices, sizeof(vertices)); |
| //! [5] |
| |
| m_program->setAttributeBuffer(0, GL_FLOAT, 0, 2); |
| m_program->setAttributeBuffer(1, GL_FLOAT, sizeof(vertices), 3); |
| m_program->enableAttributeArray(0); |
| m_program->enableAttributeArray(1); |
| |
| // We are prepared both for the legacy (direct OpenGL) and the modern |
| // (abstracted by RHI) OpenGL scenegraph. So set all the states that are |
| // important to us. |
| |
| //! [3] |
| f->glColorMask(GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE); |
| |
| f->glEnable(GL_BLEND); |
| f->glBlendFunc(GL_ONE, GL_ONE_MINUS_SRC_ALPHA); |
| |
| // Clip support. |
| if (state->scissorEnabled()) { |
| f->glEnable(GL_SCISSOR_TEST); |
| const QRect r = state->scissorRect(); // already bottom-up |
| f->glScissor(r.x(), r.y(), r.width(), r.height()); |
| } |
| if (state->stencilEnabled()) { |
| f->glEnable(GL_STENCIL_TEST); |
| f->glStencilFunc(GL_EQUAL, state->stencilValue(), 0xFF); |
| f->glStencilOp(GL_KEEP, GL_KEEP, GL_KEEP); |
| } |
| |
| f->glDrawArrays(GL_TRIANGLES, 0, 3); |
| //! [3] |
| } |
| |
| //! [4] |
| QSGRenderNode::StateFlags OpenGLRenderNode::changedStates() const |
| { |
| return BlendState | ScissorState | StencilState; |
| } |
| |
| QSGRenderNode::RenderingFlags OpenGLRenderNode::flags() const |
| { |
| return BoundedRectRendering | DepthAwareRendering; |
| } |
| |
| QRectF OpenGLRenderNode::rect() const |
| { |
| return QRect(0, 0, m_width, m_height); |
| } |
| //! [4] |
| |
| void OpenGLRenderNode::sync(QQuickItem *item) |
| { |
| m_width = item->width(); |
| m_height = item->height(); |
| } |
| |
| #endif // opengl |