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Remove usage of QOpenGLFunctions and use GLEW instead.

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Qt's OpenGL interface was causing problems on Windows since it doesn't mix
well with ANGLE.

Relates to issue #50.
This commit is contained in:
Matt Williams
2014-03-23 12:16:02 +00:00
parent ac16dfd325
commit 464d713c2a
3 changed files with 43 additions and 49 deletions
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79
examples/Basic/OpenGLWidget.cpp
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@ -11,7 +11,6 @@ OpenGLWidget::OpenGLWidget(QWidget *parent)
:QGLWidget(parent)
,m_xRotation(0)
,m_yRotation(0)
,gl(nullptr)
{
}
@ -22,63 +21,57 @@ void OpenGLWidget::setSurfaceMeshToRender(const PolyVox::SurfaceMesh<PositionMat
const auto& vecVertices = surfaceMesh.getVertices();
//Create the VAO for the mesh
gl->glGenVertexArrays(1, &vertexArrayObject);
gl->glBindVertexArray(vertexArrayObject);
glGenVertexArrays(1, &vertexArrayObject);
glBindVertexArray(vertexArrayObject);
//The GL_ARRAY_BUFFER will contain the list of vertex positions
gl->glGenBuffers(1, &vertexBuffer);
gl->glBindBuffer(GL_ARRAY_BUFFER, vertexBuffer);
gl->glBufferData(GL_ARRAY_BUFFER, vecVertices.size() * sizeof(PositionMaterial), vecVertices.data(), GL_STATIC_DRAW);
glGenBuffers(1, &vertexBuffer);
glBindBuffer(GL_ARRAY_BUFFER, vertexBuffer);
glBufferData(GL_ARRAY_BUFFER, vecVertices.size() * sizeof(PositionMaterial), vecVertices.data(), GL_STATIC_DRAW);
//and GL_ELEMENT_ARRAY_BUFFER will contain the indices
gl->glGenBuffers(1, &indexBuffer);
gl->glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, indexBuffer);
gl->glBufferData(GL_ELEMENT_ARRAY_BUFFER, vecIndices.size() * sizeof(uint32_t), vecIndices.data(), GL_STATIC_DRAW);
glGenBuffers(1, &indexBuffer);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, indexBuffer);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, vecIndices.size() * sizeof(uint32_t), vecIndices.data(), GL_STATIC_DRAW);
//We need to tell OpenGL how to understand the format of the vertex data
gl->glEnableVertexAttribArray(0); //We're talking about shader attribute '0'
gl->glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof(PositionMaterial), 0); //take the first 3 floats from every sizeof(decltype(vecVertices)::value_type)
glEnableVertexAttribArray(0); //We're talking about shader attribute '0'
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof(PositionMaterial), 0); //take the first 3 floats from every sizeof(decltype(vecVertices)::value_type)
gl->glBindVertexArray(0);
glBindVertexArray(0);
noOfIndices = vecIndices.size(); //Save this for the call to glDrawElements later
}
void OpenGLWidget::initializeGL()
{
//'gl' will give us access to all the OpenGL functions
gl = context()->contextHandle()->versionFunctions<QOpenGLFunctions_3_1>();
if(!gl)
GLenum err = glewInit();
if (GLEW_OK != err)
{
std::cerr << "Could not obtain required OpenGL context version" << std::endl;
exit(EXIT_FAILURE);
}
if(!gl->initializeOpenGLFunctions())
{
std::cerr << "Could not initialise OpenGL functions" << std::endl;
exit(EXIT_FAILURE);
/* Problem: glewInit failed, something is seriously wrong. */
std::cout << "GLEW Error: " << glewGetErrorString(err) << std::endl;
}
//Print out some information about the OpenGL implementation.
std::cout << "OpenGL Implementation Details:" << std::endl;
if(gl->glGetString(GL_VENDOR))
std::cout << "\tGL_VENDOR: " << gl->glGetString(GL_VENDOR) << std::endl;
if(gl->glGetString(GL_RENDERER))
std::cout << "\tGL_RENDERER: " << gl->glGetString(GL_RENDERER) << std::endl;
if(gl->glGetString(GL_VERSION))
std::cout << "\tGL_VERSION: " << gl->glGetString(GL_VERSION) << std::endl;
if(gl->glGetString(GL_SHADING_LANGUAGE_VERSION))
std::cout << "\tGL_SHADING_LANGUAGE_VERSION: " << gl->glGetString(GL_SHADING_LANGUAGE_VERSION) << std::endl;
if(glGetString(GL_VENDOR))
std::cout << "\tGL_VENDOR: " << glGetString(GL_VENDOR) << std::endl;
if(glGetString(GL_RENDERER))
std::cout << "\tGL_RENDERER: " << glGetString(GL_RENDERER) << std::endl;
if(glGetString(GL_VERSION))
std::cout << "\tGL_VERSION: " << glGetString(GL_VERSION) << std::endl;
if(glGetString(GL_SHADING_LANGUAGE_VERSION))
std::cout << "\tGL_SHADING_LANGUAGE_VERSION: " << glGetString(GL_SHADING_LANGUAGE_VERSION) << std::endl;
//Set up the clear colour
gl->glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
gl->glClearDepth(1.0f);
glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
glClearDepth(1.0f);
gl->glEnable(GL_CULL_FACE);
gl->glEnable(GL_DEPTH_TEST);
gl->glDepthMask(GL_TRUE);
gl->glDepthFunc(GL_LEQUAL);
gl->glDepthRange(0.0, 1.0);
glEnable(GL_CULL_FACE);
glEnable(GL_DEPTH_TEST);
glDepthMask(GL_TRUE);
glDepthFunc(GL_LEQUAL);
glDepthRange(0.0, 1.0);
if(!shader.addShaderFromSourceCode(QOpenGLShader::Vertex, R"(
#version 140
@ -144,7 +137,7 @@ void OpenGLWidget::initializeGL()
void OpenGLWidget::resizeGL(int w, int h)
{
//Setup the viewport
gl->glViewport(0, 0, w, h);
glViewport(0, 0, w, h);
auto aspectRatio = w / (float)h;
float zNear = 1.0;
@ -161,7 +154,7 @@ void OpenGLWidget::resizeGL(int w, int h)
void OpenGLWidget::paintGL()
{
//Clear the screen
gl->glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
QMatrix4x4 modelToWorldMatrix{};
modelToWorldMatrix.rotate(m_xRotation, 0, 1, 0); //rotate around y-axis
@ -172,15 +165,15 @@ void OpenGLWidget::paintGL()
shader.setUniformValue("modelToWorldMatrix", modelToWorldMatrix); //Update to the latest camera matrix
gl->glBindVertexArray(vertexArrayObject);
glBindVertexArray(vertexArrayObject);
gl->glDrawElements(GL_TRIANGLES, noOfIndices, GL_UNSIGNED_INT, 0);
glDrawElements(GL_TRIANGLES, noOfIndices, GL_UNSIGNED_INT, 0);
gl->glBindVertexArray(0);
glBindVertexArray(0);
shader.release();
GLenum errCode = gl->glGetError();
GLenum errCode = glGetError();
if(errCode != GL_NO_ERROR)
{
std::cerr << "OpenGL Error: " << errCode << std::endl;