Hello Mali developers!
I have Samsung Galaxy J7(2016) device with Mali-T830 GPU.
The simple code with drawing of line list causes some graphics artifacts, i changed code from QT example hellogl2.
Code:
static const char *vertexShaderSource =
"attribute vec4 vertex;\n"
"uniform mat4 projMatrix;\n"
"uniform mat4 mvMatrix;\n"
"void main() {\n"
"gl_Position = projMatrix * mvMatrix * vertex;\n"
"}\n";
static const char *fragmentShaderSource = "void main() {\n"
"gl_FragColor = vec4(0.0, 1.0, 0.0, 1.0);\n"
void GLWidget::initializeGL()
{
...
m_program = new QOpenGLShaderProgram;
m_program->addShaderFromSourceCode(QOpenGLShader::Vertex, vertexShaderSource);
m_program->addShaderFromSourceCode(QOpenGLShader::Fragment, fragmentShaderSource);
m_program->bindAttributeLocation("vertex", 0);
m_program->link();
m_program->bind();
m_projMatrixLoc = m_program->uniformLocation("projMatrix");
m_mvMatrixLoc = m_program->uniformLocation("mvMatrix");
}
void GLWidget::CreateBuffer(const void* data, size_t size, uint& vb)
glGenBuffers(1, &vb);
glBindBuffer(GL_ARRAY_BUFFER, vb);
CheckOpenGLErrorImpl();
glBufferData(GL_ARRAY_BUFFER, size, data, GL_STATIC_DRAW);
void GLWidget::DrawLines(const VertexData& gridData)
glBindBuffer(GL_ARRAY_BUFFER, gridData.vb);
glEnableVertexAttribArray(0);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(GLfloat), 0);
glDrawArrays(GL_LINES, 0, gridData.numVertices);
void GLWidget::paintGL()
m_program->setUniformValue(m_projMatrixLoc, m_proj);
m_program->setUniformValue(m_mvMatrixLoc, m_camera * m_world);
DrawLines(gridData);
I attached the simple project with Qt, apk file and some screeenshots. The last screenshot shows correct image from Samsung Galaxy Tab 4 7.0(Vivante GC1000 GPU, OpenGL ES 2.0)
OpenGL ES Info from Mali-T830 GPU:
glGetString(GL_RENDERER): Mali-T830
glGetString(GL_VENDOR): ARM
glGetString(GL_VERSION): OpenGL ES 3.1 v1.r7p0-03rel0.dec36ba15c3f1bc697cb53aefb95b03e
On other devices it working without artefacts(Nexus 7, Samsung Galaxy Tab 4), also it working on IOS(IPhone 6+, IPod 6).
May be this is depth buffer problem or invalid clipping of the line between screen coords ?
Thanks for the bug report and the reproducer; we're investigating and will let you know when we have an update.
Cheers, Pete
Hello Peter,
Thanks for your responce!
Note, if try to comment the code of rendering of QT Logo:
//m_logoVbo.bind();
//setupVertexAttribs();
//glDrawArrays(GL_TRIANGLES, 0, m_logo.vertexCount());
//m_logoVbo.release();
Then lines won't be shown on the screen, but other devices shows lines, also i have no any OpenGL errors...
Thanks!
Hello, i found the same problem on Mali T720:
glGetString(GL_RENDERER): Mali-T720
glGetString(GL_VERSION): OpenGL ES 3.1 v1.r7p0-02rel0.4ea33e6671ff828e33c99c982634cd65
Any update ?