I'm trying to develop a game in cocos2d-x and want one image on the scene to be repeated 10 times in one row. Can a do it in a function and call it again using setPosition wherever I want that image?
Suppose the function name is point() where I have defeinition:
auto sprite = Sprite::create("point.png");
and function returns the sprite.
So can I create a sprite in it using that function and call it like
point()->setPosition(40, 40);
Sprite* GenerateScene::point()
{
auto sprite6 = Sprite::create("point.png");
sprite6->setAnchorPoint(Vec2(0.0, 0.0));
return sprite6;
}
bool GenerateScene::init()
{
auto sprite = Sprite::create("bkgnd.png");
sprite->setAnchorPoint(Vec2(0.0, 0.0));
sprite->addChild(point());
sprite->setPosition(0, 0);
point()->setPosition(120, 480);
}
This piece of code here only generates an "point.png" at (0, 0) location of the background image i.e. bottom left corner. It is not considering
point()->setPosition(120, 480);
statement.
Thanks
The purpose of a Sprite is to repeat an image on the screen.
If you looked at the Sprite::create source you would see that creating 10 sprites with the same image does not create and load 10 images. Instead there is a SpriteFrameCache that caches the actual image. Each of the 10 Sprites would be just a lighweight reference to an instance of that one image in the Scene.
Related
I am currently working on a project that I use C++, OpenGL, Qt 5.9.2 and Microsoft Visual Studio Professional 2015 on a 64 bit Operating System, Windows 10 Pro.
I have a user interface that I have created and in that user interface, there is a QGLWidget, that I am using for draw processes, with other widgets like push buttons and a dockWidget. I have a class Ball and it has variables(distance(double) and angle(int)) that determines where an instance of that Ball is going to be drawn inside the QGLWidget. Ball class has got 2 more variables that is, id(int), model(String) and year(int) Every other draw process draws lines except Ball drawings.
Drawings are 2 dimensional.
Every Ball has the same color(rgb)!
First problem: I want to left click to one of the Ball instances and I want to display it's id, model and year at The dockWidget.
Second Problem: While doing the stuff that I have mentioned at the First Problem section. I want the cursor image to change while hovering above any of the Ball instances, and change back to default Windows mouse cursor while not.
I have created a function that checks if the MouseEvent is LeftClick:
void DisplayManager::mousePressEvent(QMouseEvent* ev) {
if (ev->buttons() & Qt::LeftButton) { // Balls Are Green
if(// CHECK IF THERE IS A BALL AT THE CLICKED COORDINATES) {
// DISPLAY THE X and Y OF THE BALL AT THE DOCK WIDGET
}
}
}
This is my initializeGL function: (DisplayManager is the name of my QGLWidget)
void DisplayManager::initializeGL() {
glEnable(GL_COLOR_MATERIAL); // Enables the changing of the draw color with glColor() functions
glColor3f(0.0, 1.0, 0.0);
glEnable(GL_DEPTH_TEST);
glClearColor(0, 0, 0, 1); //sets a black background 1 0 0 1
}
On the basis this is a Picking problem and there are several information about it at the internet but I am not using GLUT and I am not using any shader. So in the light of all these I was unable to find any effective solution or clue about how can I accomplish all that I want.
I would be really glad if someone could help me with at least one of these problems.
I have currently finished working with the project. I thought that I should provide an answer to my question in case someone with a similar problem comes across with my question in the future.
void DisplayManager::mousePressEvent(QMouseEvent* ev) {
// The processes that are being executed after a left mouse button click on the DisplayManager.
if (ev->buttons() & Qt::LeftButton) {
double aspectRatio = openGLWidgetWidth / openGLWidgetHeight;
int xOfClicked = ev->x() - (openGLWidgetWidth / 2);
int yOfClicked = - (ev->y() - (openGLWidgetHeight / 2));
// The variable to be used for calculating fault tolerance of the click event.
int distanceBetweenPressAndDraw = 0;
// Executes the processes inside for every ball in vector.
for (int i = 0; i < ballVector.length(); i++) {
// Calculates the screen coordinates of the i'th ball.
int rangeOfBallInScreenDistance = rangeToScreenDistance(ballVector.at(i).range);
double screenXOfBall = rangeOfBallInScreenDistance * sin(ballVector.at(i).degree * DEGTORAD);
double screenYOfBall = rangeOfBallInScreenDistance * cos(ballVector.at(i).degree * DEGTORAD);
// Calculates the distance between pressed position and the i'th ball according to the screen coordinates.
distanceBetweenPressAndDraw = sqrt(pow((screenXOfBall - xOfClicked), 2) + pow((screenYOfBall - yOfClicked), 2));
// Decides if the clicked position is a ball (considering the fault tolerance).
if (distanceBetweenPressAndDraw < 10) {
emit printXY(QPointF(xOfClicked, yOfClicked)); // Prints the screen coordinates of the clicked positions (At the Dock Widget inside Main Window).
}
}
}
}
This was the solution for my First Problem. I would be glad though if someone could answer my Second problem in a comment or answer somehow.
I have a function that draws triangles through OpenGL
I draw two triangles by pressing a button (function on_drawMapPushButton_clicked()).
Then i draw a sphere that placed above these triangles. And now i see, that sphere is drawed correctly over first triangle, but second triangle drawed over the sphere and not vice versa.
If i press the button second time, then spehere is drawed correctly over first and second triangles.
When i press the button third time, then second triangle drawed over the sphere again.
When i press the button fourth time, then spehere is drawed correctly over first and second triangles and so on.
If i use in sphereMesh QPhongMaterial instead of QPhongAlphaMaterial, then spehere is drawed correctly over first and second triangles always. Like it must to be.
I can't understand what i do wrong to get my sphere is drawed always over the triangles.
Code, that draws transparent sphere:
selectModel_ = new Qt3DExtras::QSphereMesh(selectEntity_);
selectModel_->setRadius(75);
selectModel_->setSlices(150);
selectMaterial_ = new Qt3DExtras::QPhongAlphaMaterial(selectEntity_);
selectMaterial_->setAmbient(QColor(28, 61, 136));
selectMaterial_->setDiffuse(QColor(11, 56, 159));
selectMaterial_->setSpecular(QColor(10, 67, 199));
selectMaterial_->setShininess(0.8f);
selectEntity_->addComponent(selectModel_);
selectEntity_->addComponent(selectMaterial_);
Function drawTriangles:
void drawTriangles(QPolygonF triangles, QColor color){
int numOfVertices = triangles.size();
// Create and fill vertex buffer
QByteArray bufferBytes;
bufferBytes.resize(3 * numOfVertices * static_cast<int>(sizeof(float)));
float *positions = reinterpret_cast<float*>(bufferBytes.data());
for(auto point : triangles){
*positions++ = static_cast<float>(point.x());
*positions++ = 0.0f; //We need to drow only on the surface
*positions++ = static_cast<float>(point.y());
}
geometry_ = new Qt3DRender::QGeometry(mapEntity_);
auto *buf = new Qt3DRender::QBuffer(geometry_);
buf->setData(bufferBytes);
positionAttribute_ = new Qt3DRender::QAttribute(mapEntity_);
positionAttribute_->setName(Qt3DRender::QAttribute::defaultPositionAttributeName());
positionAttribute_->setVertexBaseType(Qt3DRender::QAttribute::Float); //In our buffer we will have only floats
positionAttribute_->setVertexSize(3); // Size of a vertex
positionAttribute_->setAttributeType(Qt3DRender::QAttribute::VertexAttribute); // Attribute type
positionAttribute_->setByteStride(3 * sizeof(float));
positionAttribute_->setBuffer(buf);
geometry_->addAttribute(positionAttribute_); // Add attribute to ours Qt3DRender::QGeometry
// Create and fill an index buffer
QByteArray indexBytes;
indexBytes.resize(numOfVertices * static_cast<int>(sizeof(unsigned int))); // start to end
unsigned int *indices = reinterpret_cast<unsigned int*>(indexBytes.data());
for(unsigned int i = 0; i < static_cast<unsigned int>(numOfVertices); ++i) {
*indices++ = i;
}
auto *indexBuffer = new Qt3DRender::QBuffer(geometry_);
indexBuffer->setData(indexBytes);
indexAttribute_ = new Qt3DRender::QAttribute(geometry_);
indexAttribute_->setVertexBaseType(Qt3DRender::QAttribute::UnsignedInt); //In our buffer we will have only unsigned ints
indexAttribute_->setAttributeType(Qt3DRender::QAttribute::IndexAttribute); // Attribute type
indexAttribute_->setBuffer(indexBuffer);
indexAttribute_->setCount(static_cast<unsigned int>(numOfVertices)); // Set count of our vertices
geometry_->addAttribute(indexAttribute_); // Add the attribute to ours Qt3DRender::QGeometry
shape_ = new Qt3DRender::QGeometryRenderer(mapEntity_);
shape_->setPrimitiveType(Qt3DRender::QGeometryRenderer::Triangles);
shape_->setGeometry(geometry_);
//Create material
material_ = new Qt3DExtras::QPhongMaterial(mapEntity_);
material_->setAmbient(color);
trianglesEntity_ = new Qt3DCore::QEntity(mapEntity_);
trianglesEntity_->addComponent(shape_);
trianglesEntity_->addComponent(material_);
}
Press button handler on_drawMapPushButton_clicked():
void on_drawMapPushButton_clicked()
{
clearMap(); //Implementation is above
QPolygonF triangle1;
triangle1 << QPointF( 0 ,-1000) << QPointF(0 ,1000) << QPointF(1000, -1000);
drawTriangles(triangle1, Qt::black);
QPolygonF triangle2;
triangle2 << QPointF(-1000,-1000) << QPointF(-100,1000) << QPointF(-100,-1000);
drawTriangles(triangle2, Qt::red);
}
Map clearing function clearMap():
void clearMap()
{
if(mapEntity_){
delete mapEntity_;
mapEntity_ = nullptr;
mapEntity_ = new Qt3DCore::QEntity(view3dRootEntity_);
}
}
Ok here comes the extend answer.
The reason why this sometimes happens and sometimes not depends on the order of your entities. If you experiment with two simple spheres, one transparent and one not, you will see that when the sphere that is transparent is added later it will be drawn above the opaque object - just like you want it to.
This happens because the opaque object will be drawn first (it comes first in the scene graph) and the transparent object later which will give you the result you want. In the other case where the transparent object gets drawn first, the opaque object is drawn above because the QPhongAlphaMaterial has a QNoDepthMask render state which tells it not to write to the depth buffer. Thus, the opaque object always passes the depth test, where the transparent object actually already drew to. You have to do some more work to properly draw transparent objects for arbitrary scene graphs and camera positions.
The Qt3D Rendering Graph
To understand what you have to do you should understand how the Qt3D rendering graph is laid out. If you know this already you can skip this part.
Italic words reference items in the graph image in the following text.
If you use a Qt3DWindow, you can't access the root node of rendering graph. It is maintained by the window. You can access the QRenderSettings and root node of your framegraph through the functions activeFramegraph() and renderSettings() which you can both call on the window. You can also set the root node of scene graph through the setRootEntity() function of Qt3DWindow. The window internally has a QAspectEngine, where it sets the root node of the whole graph, which is the root node of the rendering graph in the graph image above.
If you want to insert a framegraph node to the existing framegraph of the 3D window, you have to add it as the parent of the active framegraph which I will explain in the next section. If you have your own custom framegraph which you set on the window through setActiveFramegraph() then just append it to the end, this should suffice.
Using QSortPolicy
As you already found out according to you other questions, you can use QSortPolicy in your framegraph to sort the entities by distance to camera. You can add a sort policy as follows (assuming that view is your Qt3DWindow and scene is your root entity of the scene graph, although I don't understand why it has to be):
Qt3DRender::QFrameGraphNode *framegraph = view.activeFrameGraph();
Qt3DRender::QSortPolicy *sortPolicy = new Qt3DRender::QSortPolicy(scene);
framegraph->setParent(sortPolicy);
QVector<Qt3DRender::QSortPolicy::SortType> sortTypes =
QVector<Qt3DRender::QSortPolicy::SortType>() << Qt3DRender::QSortPolicy::BackToFront;
sortPolicy->setSortTypes(sortTypes);
view.setActiveFrameGraph(framegraph);
The issue with this code is that this sort policy sorts the entities by the distance of their centers to the camera. If one of the opaque objects is closer to the camera than the transparent object it gets drawn later anyways and occludes the transparent object. See the images below for a graphical explanation.
The red and black sphere are further away from the camera than the torus, that's why they get drawn first and they don't occlude the torus.
No the center of the red sphere is closer to the camera than the center of the torus. It gets rendered later than the torus and occludes it.
Using Two Framegraph Branches
You can tackle the issue above if you use two framegraph branches. One which draws all opaque entities and one which draws all transparent ones. To achieve this you have to make use of QLayer and QLayerFilter. You can attach layers to entities and then add layer filters to your framegraph. This way you can exclude entities from entering a certain branch of your framegraph.
Let's say you create two layers, one for opaque objects and one for transparents ones:
Qt3DRender::QLayer *transparentLayer = new Qt3DRender::QLayer;
Qt3DRender::QLayer *opaqueLayer = new Qt3DRender::QLayer;
You have to attach the transparent layer to each transparent object and the opaque layer to each opaque object as a component (using addComponent()).
Unfortunately, you need a special framegraph tree to include the two corresponding layer filters (again, assuming that view is your Qt3DWindow):
Qt3DRender::QRenderSurfaceSelector *renderSurfaceSelector
= new Qt3DRender::QRenderSurfaceSelector();
renderSurfaceSelector->setSurface(&view);
Qt3DRender::QClearBuffers *clearBuffers
= new Qt3DRender::QClearBuffers(renderSurfaceSelector);
clearBuffers->setBuffers(Qt3DRender::QClearBuffers::AllBuffers);
clearBuffers->setClearColor(Qt::white);
This is the first branch to clear the buffers. Now you add the following code:
Qt3DRender::QViewport *viewport = new Qt3DRender::QViewport(renderSurfaceSelector);
Qt3DRender::QCameraSelector *cameraSelector = new Qt3DRender::QCameraSelector(viewport);
Qt3DRender::QCamera *camera = new Qt3DRender::QCamera(cameraSelector);
// set your camera parameters here
cameraSelector->setCamera(camera);
Since you create the QViewport as a child of the QRenderSurfaceSelector it is now a sibling in your framegraph with respect to the QClearBuffers. You can see an illustration of the example framegraphs here.
Now you have to create the two leaf nodes that contain the layer filters. The Qt3D engine always executes a whole branch when it reaches a leaf. This means that first the opaque objects are drawn and then the transparent ones.
// not entirely sure why transparent filter has to go first
// I would have expected the reversed order of the filters but this works...
Qt3DRender::QLayerFilter *transparentFilter = new Qt3DRender::QLayerFilter(camera);
transparentFilter->addLayer(transparentLayer);
Qt3DRender::QLayerFilter *opaqueFilter = new Qt3DRender::QLayerFilter(camera);
opaqueFilter->addLayer(opaqueLayer);
The two layer filters are now leaf nodes in your framegraph branch and Qt3D will first draw the opaque objects and then afterwards, since it uses the same viewport and everything, will draw the transparent objects above. It will draw them correctly (i.e. not in front of parts of opaque objects that the transparent object actually lies behind, because we did not clear the depth buffers again -> Splitting the framegraph happens only on the camera node).
Now set the new framegaph on your Qt3DWindow:
view.setActiveFrameGraph(renderSurfaceSelector);
Result:
Edit (26.03.21): As Patrick B. pointed out correctly, using the suggested solution with two layers you will have to add both layers as components to any lights in the scene. You can get around this by setting the filter mode on the QLayerFilters to QLayerFilter::FilterMode::DiscardAnyMatching and then reverse the order of the filters. This way, the transparentFilter discards any entities with the transparentLayer attached - but not the lights because they don't have the transparentLayer. Vice versa for the opaqueFilter.
My mistake was that i did wrong order of creating and deletion of Triangles and Sphere entities.
In pseudo code right order is as follows:
clearTriangles();
clearSphere();
drawTriangles();
drawSphere();
If you are using Qt3d with QML and want to control the order elements are drawn you can control it by the order of layers in your QML file.
Something like:
{
objectName: "firstLayer"
id : firstLayer
}
Layer {
objectName: "secondLayer"
id: secondLayer
}
The order you add them to layer filters will then control which is drawn first:
RenderSurfaceSelector {
CameraSelector {
id : cameraSelector
camera: mainCamera
FrustumCulling {
ClearBuffers {
buffers : ClearBuffers.AllBuffers
clearColor: "#04151c"
NoDraw {}
}
LayerFilter
{
objectName: "firstLayerFilter"
id: firstLayerFilter
layers: [firstLayer]
}
LayerFilter
{
id: secondLayerFilter
objectName: "secondLayerFilter"
layers: [secondLayer]
}
Then anything you add to the secondLayer will get drawn over-top of the first layer. I used this to make sure text always showed up in front of shapes, but it can be used similarly with transparencies.
I have a function that draws triangles through OpenGL
I draw two triangles by pressing a button (function on_drawMapPushButton_clicked()).
Then i draw a sphere that placed above these triangles. And now i see, that sphere is drawed correctly over first triangle, but second triangle drawed over the sphere and not vice versa.
If i press the button second time, then spehere is drawed correctly over first and second triangles.
When i press the button third time, then second triangle drawed over the sphere again.
When i press the button fourth time, then spehere is drawed correctly over first and second triangles and so on.
If i use in sphereMesh QPhongMaterial instead of QPhongAlphaMaterial, then spehere is drawed correctly over first and second triangles always. Like it must to be.
I can't understand what i do wrong to get my sphere is drawed always over the triangles.
Code, that draws transparent sphere:
selectModel_ = new Qt3DExtras::QSphereMesh(selectEntity_);
selectModel_->setRadius(75);
selectModel_->setSlices(150);
selectMaterial_ = new Qt3DExtras::QPhongAlphaMaterial(selectEntity_);
selectMaterial_->setAmbient(QColor(28, 61, 136));
selectMaterial_->setDiffuse(QColor(11, 56, 159));
selectMaterial_->setSpecular(QColor(10, 67, 199));
selectMaterial_->setShininess(0.8f);
selectEntity_->addComponent(selectModel_);
selectEntity_->addComponent(selectMaterial_);
Function drawTriangles:
void drawTriangles(QPolygonF triangles, QColor color){
int numOfVertices = triangles.size();
// Create and fill vertex buffer
QByteArray bufferBytes;
bufferBytes.resize(3 * numOfVertices * static_cast<int>(sizeof(float)));
float *positions = reinterpret_cast<float*>(bufferBytes.data());
for(auto point : triangles){
*positions++ = static_cast<float>(point.x());
*positions++ = 0.0f; //We need to drow only on the surface
*positions++ = static_cast<float>(point.y());
}
geometry_ = new Qt3DRender::QGeometry(mapEntity_);
auto *buf = new Qt3DRender::QBuffer(geometry_);
buf->setData(bufferBytes);
positionAttribute_ = new Qt3DRender::QAttribute(mapEntity_);
positionAttribute_->setName(Qt3DRender::QAttribute::defaultPositionAttributeName());
positionAttribute_->setVertexBaseType(Qt3DRender::QAttribute::Float); //In our buffer we will have only floats
positionAttribute_->setVertexSize(3); // Size of a vertex
positionAttribute_->setAttributeType(Qt3DRender::QAttribute::VertexAttribute); // Attribute type
positionAttribute_->setByteStride(3 * sizeof(float));
positionAttribute_->setBuffer(buf);
geometry_->addAttribute(positionAttribute_); // Add attribute to ours Qt3DRender::QGeometry
// Create and fill an index buffer
QByteArray indexBytes;
indexBytes.resize(numOfVertices * static_cast<int>(sizeof(unsigned int))); // start to end
unsigned int *indices = reinterpret_cast<unsigned int*>(indexBytes.data());
for(unsigned int i = 0; i < static_cast<unsigned int>(numOfVertices); ++i) {
*indices++ = i;
}
auto *indexBuffer = new Qt3DRender::QBuffer(geometry_);
indexBuffer->setData(indexBytes);
indexAttribute_ = new Qt3DRender::QAttribute(geometry_);
indexAttribute_->setVertexBaseType(Qt3DRender::QAttribute::UnsignedInt); //In our buffer we will have only unsigned ints
indexAttribute_->setAttributeType(Qt3DRender::QAttribute::IndexAttribute); // Attribute type
indexAttribute_->setBuffer(indexBuffer);
indexAttribute_->setCount(static_cast<unsigned int>(numOfVertices)); // Set count of our vertices
geometry_->addAttribute(indexAttribute_); // Add the attribute to ours Qt3DRender::QGeometry
shape_ = new Qt3DRender::QGeometryRenderer(mapEntity_);
shape_->setPrimitiveType(Qt3DRender::QGeometryRenderer::Triangles);
shape_->setGeometry(geometry_);
//Create material
material_ = new Qt3DExtras::QPhongMaterial(mapEntity_);
material_->setAmbient(color);
trianglesEntity_ = new Qt3DCore::QEntity(mapEntity_);
trianglesEntity_->addComponent(shape_);
trianglesEntity_->addComponent(material_);
}
Press button handler on_drawMapPushButton_clicked():
void on_drawMapPushButton_clicked()
{
clearMap(); //Implementation is above
QPolygonF triangle1;
triangle1 << QPointF( 0 ,-1000) << QPointF(0 ,1000) << QPointF(1000, -1000);
drawTriangles(triangle1, Qt::black);
QPolygonF triangle2;
triangle2 << QPointF(-1000,-1000) << QPointF(-100,1000) << QPointF(-100,-1000);
drawTriangles(triangle2, Qt::red);
}
Map clearing function clearMap():
void clearMap()
{
if(mapEntity_){
delete mapEntity_;
mapEntity_ = nullptr;
mapEntity_ = new Qt3DCore::QEntity(view3dRootEntity_);
}
}
Ok here comes the extend answer.
The reason why this sometimes happens and sometimes not depends on the order of your entities. If you experiment with two simple spheres, one transparent and one not, you will see that when the sphere that is transparent is added later it will be drawn above the opaque object - just like you want it to.
This happens because the opaque object will be drawn first (it comes first in the scene graph) and the transparent object later which will give you the result you want. In the other case where the transparent object gets drawn first, the opaque object is drawn above because the QPhongAlphaMaterial has a QNoDepthMask render state which tells it not to write to the depth buffer. Thus, the opaque object always passes the depth test, where the transparent object actually already drew to. You have to do some more work to properly draw transparent objects for arbitrary scene graphs and camera positions.
The Qt3D Rendering Graph
To understand what you have to do you should understand how the Qt3D rendering graph is laid out. If you know this already you can skip this part.
Italic words reference items in the graph image in the following text.
If you use a Qt3DWindow, you can't access the root node of rendering graph. It is maintained by the window. You can access the QRenderSettings and root node of your framegraph through the functions activeFramegraph() and renderSettings() which you can both call on the window. You can also set the root node of scene graph through the setRootEntity() function of Qt3DWindow. The window internally has a QAspectEngine, where it sets the root node of the whole graph, which is the root node of the rendering graph in the graph image above.
If you want to insert a framegraph node to the existing framegraph of the 3D window, you have to add it as the parent of the active framegraph which I will explain in the next section. If you have your own custom framegraph which you set on the window through setActiveFramegraph() then just append it to the end, this should suffice.
Using QSortPolicy
As you already found out according to you other questions, you can use QSortPolicy in your framegraph to sort the entities by distance to camera. You can add a sort policy as follows (assuming that view is your Qt3DWindow and scene is your root entity of the scene graph, although I don't understand why it has to be):
Qt3DRender::QFrameGraphNode *framegraph = view.activeFrameGraph();
Qt3DRender::QSortPolicy *sortPolicy = new Qt3DRender::QSortPolicy(scene);
framegraph->setParent(sortPolicy);
QVector<Qt3DRender::QSortPolicy::SortType> sortTypes =
QVector<Qt3DRender::QSortPolicy::SortType>() << Qt3DRender::QSortPolicy::BackToFront;
sortPolicy->setSortTypes(sortTypes);
view.setActiveFrameGraph(framegraph);
The issue with this code is that this sort policy sorts the entities by the distance of their centers to the camera. If one of the opaque objects is closer to the camera than the transparent object it gets drawn later anyways and occludes the transparent object. See the images below for a graphical explanation.
The red and black sphere are further away from the camera than the torus, that's why they get drawn first and they don't occlude the torus.
No the center of the red sphere is closer to the camera than the center of the torus. It gets rendered later than the torus and occludes it.
Using Two Framegraph Branches
You can tackle the issue above if you use two framegraph branches. One which draws all opaque entities and one which draws all transparent ones. To achieve this you have to make use of QLayer and QLayerFilter. You can attach layers to entities and then add layer filters to your framegraph. This way you can exclude entities from entering a certain branch of your framegraph.
Let's say you create two layers, one for opaque objects and one for transparents ones:
Qt3DRender::QLayer *transparentLayer = new Qt3DRender::QLayer;
Qt3DRender::QLayer *opaqueLayer = new Qt3DRender::QLayer;
You have to attach the transparent layer to each transparent object and the opaque layer to each opaque object as a component (using addComponent()).
Unfortunately, you need a special framegraph tree to include the two corresponding layer filters (again, assuming that view is your Qt3DWindow):
Qt3DRender::QRenderSurfaceSelector *renderSurfaceSelector
= new Qt3DRender::QRenderSurfaceSelector();
renderSurfaceSelector->setSurface(&view);
Qt3DRender::QClearBuffers *clearBuffers
= new Qt3DRender::QClearBuffers(renderSurfaceSelector);
clearBuffers->setBuffers(Qt3DRender::QClearBuffers::AllBuffers);
clearBuffers->setClearColor(Qt::white);
This is the first branch to clear the buffers. Now you add the following code:
Qt3DRender::QViewport *viewport = new Qt3DRender::QViewport(renderSurfaceSelector);
Qt3DRender::QCameraSelector *cameraSelector = new Qt3DRender::QCameraSelector(viewport);
Qt3DRender::QCamera *camera = new Qt3DRender::QCamera(cameraSelector);
// set your camera parameters here
cameraSelector->setCamera(camera);
Since you create the QViewport as a child of the QRenderSurfaceSelector it is now a sibling in your framegraph with respect to the QClearBuffers. You can see an illustration of the example framegraphs here.
Now you have to create the two leaf nodes that contain the layer filters. The Qt3D engine always executes a whole branch when it reaches a leaf. This means that first the opaque objects are drawn and then the transparent ones.
// not entirely sure why transparent filter has to go first
// I would have expected the reversed order of the filters but this works...
Qt3DRender::QLayerFilter *transparentFilter = new Qt3DRender::QLayerFilter(camera);
transparentFilter->addLayer(transparentLayer);
Qt3DRender::QLayerFilter *opaqueFilter = new Qt3DRender::QLayerFilter(camera);
opaqueFilter->addLayer(opaqueLayer);
The two layer filters are now leaf nodes in your framegraph branch and Qt3D will first draw the opaque objects and then afterwards, since it uses the same viewport and everything, will draw the transparent objects above. It will draw them correctly (i.e. not in front of parts of opaque objects that the transparent object actually lies behind, because we did not clear the depth buffers again -> Splitting the framegraph happens only on the camera node).
Now set the new framegaph on your Qt3DWindow:
view.setActiveFrameGraph(renderSurfaceSelector);
Result:
Edit (26.03.21): As Patrick B. pointed out correctly, using the suggested solution with two layers you will have to add both layers as components to any lights in the scene. You can get around this by setting the filter mode on the QLayerFilters to QLayerFilter::FilterMode::DiscardAnyMatching and then reverse the order of the filters. This way, the transparentFilter discards any entities with the transparentLayer attached - but not the lights because they don't have the transparentLayer. Vice versa for the opaqueFilter.
My mistake was that i did wrong order of creating and deletion of Triangles and Sphere entities.
In pseudo code right order is as follows:
clearTriangles();
clearSphere();
drawTriangles();
drawSphere();
If you are using Qt3d with QML and want to control the order elements are drawn you can control it by the order of layers in your QML file.
Something like:
{
objectName: "firstLayer"
id : firstLayer
}
Layer {
objectName: "secondLayer"
id: secondLayer
}
The order you add them to layer filters will then control which is drawn first:
RenderSurfaceSelector {
CameraSelector {
id : cameraSelector
camera: mainCamera
FrustumCulling {
ClearBuffers {
buffers : ClearBuffers.AllBuffers
clearColor: "#04151c"
NoDraw {}
}
LayerFilter
{
objectName: "firstLayerFilter"
id: firstLayerFilter
layers: [firstLayer]
}
LayerFilter
{
id: secondLayerFilter
objectName: "secondLayerFilter"
layers: [secondLayer]
}
Then anything you add to the secondLayer will get drawn over-top of the first layer. I used this to make sure text always showed up in front of shapes, but it can be used similarly with transparencies.
I'm trying to create a node that is simply a rectangle with a number in it. And this is how I'm doing it now:
int size = 100, fontSize = 64;
auto node = DrawNode::create();
Vec2 vertices[] =
{
Vec2(0,size),
Vec2(size,size),
Vec2(size,0),
Vec2(0,0)
};
node->drawPolygon(vertices, 4, Color4F(1.0f,0.3f,0.3f,1), 0, Color4F(1.0f,1.0f,1.0f,1));
auto texture = new Texture2D();
int numberToDisplay = 2000;
std::string s = std::to_string(numberToDisplay);
texture -> initWithString(s.c_str(), "fonts/Marker Felt.ttf", fontSize, Size(size, size), TextHAlignment::CENTER, TextVAlignment::CENTER);
auto textSprite = Sprite::createWithTexture(texture);
node -> addChild(textSprite);
textSprite -> setPosition(size/2, size/2);
Every time I want to change the number I have to re-create a textureSprite, remove the current child and add the new one. Is there a better way to do it?
i wonder whether you want some special features, so why not use LayerColor and labelTTF?
LayerColor* node = LayerColor::create(Color4B(255, 85, 85, 255), 100, 100);
LabelTTF* label = LabelTTF::create(s, "fonts/Marker Felt.ttf", fontSize);
node->addChild(label);
just change content of labelttf,no need to create sprite
You could use two different techniques for achieve this, to me both of them are good
1:- Use texture cache to cache texture and change image texture at run time(good if u know how many exact textures are there and texture has same Size). in your .h file define no of textures like:-
Texture2D *startTexture, *endTexture, *midTexture;
in you .cpp file do it like:-
startTexture = Director::getInstance()->getTextureCache()->addImage(
"start.png");
endTexture = Director::getInstance()->getTextureCache()->addImage(
"end.png");
middleTexture = Director::getInstance()->getTextureCache()->addImage(
"middle.png");
after that when you want to change texture of any Sprite, simply do it like:-
textSprite->setTexture(startTexture);
for this to work with you, declare "textSprite" in your .h file aswell for quick access.
Pit-fall:- changing texture doesn't change sprite initial bounding box, if initial sprite texture was 32*32 and changed texture was 50*50, then extra texture of 20*20 will be cropped automatically starting from origin point, which might look bad. to over come this you need to change rect also using
textSprite->setTextureRect(
Rect(0, 0, startTexture->getContentSize().width,
startTexture->getContentSize().height));
2:- Using Sprite Frame Cache, put all your texture in a spriteframe, load it into memory like :-
SpriteFrameCache *spriteCache = SpriteFrameCache::getInstance();
spriteCache->addSpriteFramesWithFile("test.plist", "test.png");
now when ever you want to change you texture do it like this
testSprite->setSpriteFrame(
(SpriteFrameCache::getInstance())->getSpriteFrameByName(
"newImage.png"));
this will first check sprite cache for a image named "newImage.png", if it found it in memory then it will return that texture or else it will return nullptr.
I created a renderer2D so the user can click and pick the centre of a lesion. I want to show the user where he clicked. Currently my idea is to freeze the renderer (so the slice will be the same and the zoom too) and then use the canvas to draw a circle.
Here is my code:
centerpick2D = new X.renderer2D();
centerpick2D.container = 'pick_center_segment';
centerpick2D.orientation = 'Z';
centerpick2D.init();
centerpick2D.add(volumeT1DCM);
centerpick2D.render();
centerpick2D.interactor.onMouseDown = function(){
tumorCenter=centerpick2D.xy2ijk(centerpick2D.interactor.mousePosition[0],centerpick2D.interactor.mousePosition[1]);
centerpick2D.interactor.config.MOUSEWHEEL_ENABLED = false;
centerpick2D.interactor.config.MOUSECLICKS_ENABLED = false;
$('canvas').attr('id', 'xtkCanvas');
var myCanvas = document.getElementById("xtkCanvas");
var ctx=myCanvas.getContext("2d");
ctx.fillStyle="#FF0000";
ctx.beginPath();
ctx.arc(centerpick2D.interactor.mousePosition[0],centerpick2D.interactor.mousePosition[1],20,0,Math.PI*2,true);
ctx.closePath();
ctx.fill();
};
I have two problems:
The MOUSEWHEEL_ENABLED=false and MOUSECLICKS_ENABLED = false do not work. I tried adding a centerpick2D.init() which works but add a second canvas on top of the previous one.
My circle does not appear anywhere.
Any help would be greatly appreciated. :-D
Sorry took me a while to get this uploaded. Here's a quick overview of how I am copying the XTK canvas' contents into my own canvas and then do my own custom drawing on top of it. The actual code for my project is all over the place, so am just pasting formatted snippets here. Again there's a definite drawback in terms of performance here (due to the copying of pixels), so I think it would be better to introduce all this into the XTK Code in the first place and do all the drawing in one Canvas element.
// initialise animation loop with requestAnimationFrame
startDraw:function(){
var _this = this;
var time = new Date().getTime();
function draw() {
//update time
var now = new Date().getTime();
//only draw the frame if 25 milliseconds have passed!
if(now > (time + 25)){
// call drawing function here
drawFrame();
time = now;
}
requestAnimationFrame(draw);
}
requestAnimationFrame(draw);
};
//...
// actual drawing function, for each frame copy the pixel contents from a XTK canvas
// into custom canvas and do custom drawing on top of it, so drawing is actually at each
// frame
drawFrame:function(){
//...
// this.ctx is the context of my own custom canvas element
// I use drawImage() function to copy the pixels from this.srcCanvasA
// this.srcCanvasA is a predefined XTKCanvas
this.ctx.drawImage(this.srcCanvas, 1, 1)
// custom func to draw on top of this same canvas (ie. this.ctx) with standard
// HTML Canvas functionality, so this is where you could draw your own circle based
// on the user mouse coords
this.drawAnnotation();
//...
}
Let me know if you have any more questions. The full code is available here:
https://github.com/davidbasalla/IndividualProject