diff --git a/examples/common/OpenGLWidget.cpp b/examples/common/OpenGLWidget.cpp index a83fa70d..f26c2237 100644 --- a/examples/common/OpenGLWidget.cpp +++ b/examples/common/OpenGLWidget.cpp @@ -26,27 +26,32 @@ void OpenGLWidget::setShader(QSharedPointer shader) void OpenGLWidget::setViewableRegion(Region viewableRegion) { m_viewableRegion = viewableRegion; + + // The user has specifed a new viewable region + // so we need to regenerate our camera matrix. setupWorldToCameraMatrix(); } void OpenGLWidget::mousePressEvent(QMouseEvent* event) { + // Initialise these variables which will be used when the mouse actually moves. m_CurrentMousePos = event->pos(); m_LastFrameMousePos = m_CurrentMousePos; - - update(); } void OpenGLWidget::mouseMoveEvent(QMouseEvent* event) { + // Update the x and y rotations based on the mouse movement. m_CurrentMousePos = event->pos(); QPoint diff = m_CurrentMousePos - m_LastFrameMousePos; m_xRotation += diff.x(); m_yRotation += diff.y(); m_LastFrameMousePos = m_CurrentMousePos; + // The camera rotation has changed so we need to regenerate the matrix. setupWorldToCameraMatrix(); + // Re-render. update(); } diff --git a/examples/common/OpenGLWidget.h b/examples/common/OpenGLWidget.h index af660909..d87b4161 100644 --- a/examples/common/OpenGLWidget.h +++ b/examples/common/OpenGLWidget.h @@ -52,11 +52,11 @@ public: // Constructor OpenGLWidget(QWidget *parent); - // Convert a SurfaceMesh to OpenGL index/vertex buffers. Inlined because it's templatised. + // Convert a PolyVox mesh to OpenGL index/vertex buffers. Inlined because it's templatised. template void addMesh(const MeshType& surfaceMesh, const PolyVox::Vector3DInt32& translation = PolyVox::Vector3DInt32(0, 0, 0), float scale = 1.0f) { - //Convienient access to the vertices and indices + // Convienient access to the vertices and indices const auto& vecIndices = surfaceMesh.getIndices(); const auto& vecVertices = surfaceMesh.getVertices(); @@ -64,38 +64,46 @@ public: // to render our mesh. We copy the data from the PolyVox mesh into this structure. OpenGLMeshData meshData; - //Create the VAO for the mesh + // Create the VAO for the mesh glGenVertexArrays(1, &(meshData.vertexArrayObject)); glBindVertexArray(meshData.vertexArrayObject); - //The GL_ARRAY_BUFFER will contain the list of vertex positions + // The GL_ARRAY_BUFFER will contain the list of vertex positions glGenBuffers(1, &(meshData.vertexBuffer)); glBindBuffer(GL_ARRAY_BUFFER, meshData.vertexBuffer); glBufferData(GL_ARRAY_BUFFER, vecVertices.size() * sizeof(MeshType::VertexType), vecVertices.data(), GL_STATIC_DRAW); - //and GL_ELEMENT_ARRAY_BUFFER will contain the indices + // and GL_ELEMENT_ARRAY_BUFFER will contain the indices glGenBuffers(1, &(meshData.indexBuffer)); glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, meshData.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 - glEnableVertexAttribArray(0); //We're talking about shader attribute '0' + // Every surface extractor outputs valid positions for the vertices, so tell OpenGL how these are laid out + glEnableVertexAttribArray(0); // Attrib '0' is the vertex positions glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof(MeshType::VertexType), (GLvoid*)(offsetof(MeshType::VertexType, position))); //take the first 3 floats from every sizeof(decltype(vecVertices)::value_type) - glEnableVertexAttribArray(1); //We're talking about shader attribute '1' + // Some surface extractors also generate normals, so tell OpenGL how these are laid out. If a surface extractor + // does not generate normals then nonsense values are written into the buffer here and sghould be ignored by the + // shader. This is mostly just to simplify this example code - in a real application you will know whether your + // chosen surface extractor generates normals and can skip uploading them if not. + glEnableVertexAttribArray(1); // Attrib '1' is the vertex normals. glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, sizeof(MeshType::VertexType), (GLvoid*)(offsetof(MeshType::VertexType, normal))); + // Finally a surface extractor will probably output additional data. This is highly application dependant. For this example code + // we're just uploading it as a set of bytes which we can read individually, but real code will want to do something specialised here. glEnableVertexAttribArray(2); //We're talking about shader attribute '2' - GLint size = (std::min)(sizeof(MeshType::VertexType::VoxelType), size_t(4)); + GLint size = (std::min)(sizeof(MeshType::VertexType::VoxelType), size_t(4)); // Can't upload more that 4 components (vec4 is GLSL's biggest type) glVertexAttribIPointer(2, size, GL_UNSIGNED_BYTE, sizeof(MeshType::VertexType), (GLvoid*)(offsetof(MeshType::VertexType, material))); + // We're done uploading and can now unbind. glBindVertexArray(0); - meshData.noOfIndices = vecIndices.size(); //Save this for the call to glDrawElements later - + // A few additional properties can be copied across for use during rendering. + meshData.noOfIndices = vecIndices.size(); meshData.translation = QVector3D(translation.getX(), translation.getY(), translation.getZ()); meshData.scale = scale; + // Now add the mesh to the list of meshes to render. mMeshData.push_back(meshData); }