I have the following problem:
I have my mouse coordinates and I have a Model (Data Points) and I want the 3d Coordinates of my mouse coordinates and my lookAt Vector of this coordinates, so that I can make a raycast with the object, so that I can see the 3d values of the data points. So I want to click with the mouse and then I want to see the coordinates of the datapoint I clicked at.
I have the following from a tutorial, but it doesn't work. The ray origin and ray direction are not correct (I draw I line from ray origin in the ray direction and the ray origin isn't right:
Can anyone help me? Here is the code:
// Move the mouse cursor coordinates into the -1 to +1 range.
pointX = ((2.0f * (float)mouseX) / (float) screen_width) - 1.0f;
pointY = (((2.0f * (float)mouseY) / (float) screen_height) - 1.0f) * -1.0f;
m_D3D->GetProjectionMatrix(projectionMatrix);
pointX = pointX / projectionMatrix._11;
pointY = pointY / projectionMatrix._22;
// Get the inverse of the view matrix.
m_Camera->GetViewMatrix(viewMatrix);
D3DXMatrixInverse(&inverseViewMatrix, NULL, &viewMatrix);
// Calculate the direction of the picking ray in view space.
direction.x = (pointX * inverseViewMatrix._11) + (pointY * inverseViewMatrix._21)+
inverseViewMatrix._31;
direction.y = (pointX * inverseViewMatrix._12) + (pointY * inverseViewMatrix._22)
+ inverseViewMatrix._32;
direction.z = (pointX * inverseViewMatrix._13) + (pointY * inverseViewMatrix._23)
+ inverseViewMatrix._33;
// Get the origin of the picking ray which is the position of the camera.
origin = m_Camera->GetPosition();
// Get the world matrix and translate to the location of the sphere.
m_Impact->GetWorldMatrix(worldMatrix);
//D3DXMatrixTranslation(&translateMatrix, -5.0f, 1.0f, 5.0f);
//D3DXMatrixMultiply(&worldMatrix, &worldMatrix, &translateMatrix);
// Now get the inverse of the translated world matrix.
D3DXMatrixInverse(&inverseWorldMatrix, NULL, &worldMatrix);
D3DXVec3TransformCoord(&rayOrigin, &origin, &inverseWorldMatrix);
D3DXVec3TransformNormal(&rayDirection, &direction, &inverseWorldMatrix);
// Normalize the ray direction.
D3DXVec3Normalize(&rayDirection, &rayDirection);
//collision_object->setTransform(col_matrix);
collision_model->setTransform(col_matrix);
float collision_point[3];
//bool collision_result = collision_object ->rayCollision(rayOrigin,
rayDirection, true);
bool collision_result = collision_model ->rayCollision(rayOrigin,
rayDirection, true);
if(collision_result == true)
{
intersect = true;
//collision_object->getCollisionPoint(collision_point, true);
collision_model->getCollisionPoint(collision_point, false);
*coordX = collision_point[0];
*coordY = collision_point[1];
*coordZ = collision_point[2];
}
One simple way to build a ray from mouse is as follow (pseudo code)
Get mouse coords to -1 -> 1 range (as you already do)
Create view projection matrix (view*projection)
Invert it.
Create 2 mouse vectors:
near = Vector3(mousex,mousey,0);
far = Vector3(mousex,mousey,1);
rayorigin = transformcoord(near, inverseviewprojection);
rayend = transformcoord(far, inverseviewprojection);
raydir = normalize(rayend-rayorigin);
Related
I have a problem and although I serached everywhere I couldn't find a solution.
I have a stacked sprite and I'm rotating this sprite around the center of the screen. So I iterate over a list of sprites (stacked) and increase the y-coordinate by 2 every loop (rotation is increased step by step by 0.01f outside of the loop):
foreach(var s in stacked)
{
Vector2 origin = new Vector2(Basic.width / 2, Basic.height / 2);
Rectangle newPosition = new Rectangle(position.X, position.Y - y, position.Width, position.Height);
float angle = 0f;
Matrix transform = Matrix.CreateTranslation(-origin.X, -origin.Y, 0f) *
Matrix.CreateRotationZ(rotation) *
Matrix.CreateTranslation(origin.X, origin.Y, 0f);
Vector2 pos = new Vector2(newPosition.X, newPosition.Y);
pos = Vector2.Transform(pos, transform);
newPosition.X = (int)pos.X;
newPosition.Y = (int)pos.Y;
angle += rotation;
s.Draw(newPosition, origin, angle, Color.White);
y += 2;
}
This works fine. But now my problem. I want not only to rotate the sprite around the center of the screen but also around itself. How to achieve this? I can only set one origin and one rotation per Draw. I would like to rotate the sprite around the origin 'Basic.width / 2, Basic.height / 2' and while it rotates, around 'position.Width / 2, position.Height / 2'. With different rotation speed each. How is this possible?
Thank you in advance!
Just to be clear:
When using SpriteBatch.Draw() with origin and angle, there is only one rotation: the final angle of the sprite.
The other rotations are positional offsets.
The origin in the Draw() call is a translation, rotation, translate back. Your transform matrix shows this quite well:
Matrix transform = Matrix.CreateTranslation(-origin.X, -origin.Y, 0f) *
Matrix.CreateRotationZ(rotation) *
Matrix.CreateTranslation(origin.X, origin.Y, 0f);
//Class level variables:
float ScreenRotation, ScreenRotationSpeed;
float ObjectRotation, ObjectRotationSpeed;
Vector2 ScreenOrigin, SpriteOrigin;
// ...
// In constructor and resize events:
ScreenOrigin = new Vector2(Basic.width <<1, Basic.height <<1);
// shifts are faster for `int` type. If "Basic.width" is `float`:
//ScreenOrigin = new Vector2(Basic.width, Basic.height) * 0.5f;
// In Update():
ScreenRotation += ScreenRotationSpeed; // * gameTime.ElapsedGameTime.Seconds; // for FPS invariant speed where speed = 60 * single frame speed
ObjectRotation+= ObjectRotationSpeed;
//Calculate the screen center rotation once per step
Matrix baseTransform = Matrix.CreateTranslation(-ScreenOrigin.X, -ScreenOrigin.Y, 0f) *
Matrix.CreateRotationZ(ScreenRotation) *
Matrix.CreateTranslation(ScreenOrigin.X, ScreenOrigin.Y, 0f);
// In Draw() at the start of your code snippet posted:
// moved outside of the loop for a translationally invariant vertical y interpretation
// or move it inside the loop and apply -y to position.Y for an elliptical effect
Vector2 ObjectOrigin = new Vector2(position.X, position.Y);
Matrix transform = baseTransform *
Matrix.CreateTranslation(-ObjectOrigin.X, -ObjectOrigin.Y, 0f) *
Matrix.CreateRotationZ(ObjectRotation) *
Matrix.CreateTranslation(ObjectOrigin.X, ObjectOrigin.Y, 0f);
foreach(var s in stacked)
{
Vector2 pos = new Vector2(ObjectOrigin.X, ObjectOrigin.Y - y);
pos = Vector2.Transform(pos, transform);
float DrawAngle = ObjectRotation;
// or float DrawAngle = ScreenRotation;
// or float DrawAngle = ScreenRotation + ObjectRotation;
// or float DrawAngle = 0;
s.Draw(pos, SpriteOrigin, DrawAngle, Color.White);
}
I suggest moving the Draw() parameter away from destinationRectangle and use the Vector2 position directly with scaling. Rotations within square rectangles can differ up to SQRT(2) in aspect ratio, i.e. stretching/squashing. Using Vector2 incurs a cost of higher collision complexity.
I am sorry for the ors, but without complete knowledge of the problem...YMMV
In my 2D projects, I use the vector form of polar coordinates.
The Matrix class requires more calculations than the polar equivalents in 2D. Matrix operates in 3D, wasting cycles calculating Z components.
With normalized direction vectors (cos t,sin t) and a radius(vector length),in many cases I use Vector2.LengthSquared() to avoid the square root when possible.
The only time I have used Matrices in 2D is display projection matrix(entire SpriteBatch) and Mouse and TouchScreen input deprojection(times the inverse of the projection matrix)
video game link
I'm trying to make a game (see link above) , and I need to have the stick rotate around himself to maintain the orientation face to center of the circle.
this is how I declare the Sprite, and how I move it around the circle:
declaration:
line = new Sprite(new Texture(Gdx.files.internal("drawable/blockLine.png")));
line.setSize(140, 20);
lineX = Gdx.graphics.getWidth()/2 - line.getWidth()/2;
lineY = (Gdx.graphics.getHeight()/2 - line.getHeight()/2) + circle.getHeight()/2;
movement:
Point point = rotatePoint(new Point(lineX, lineY), new Point(Gdx.graphics.getWidth()/2, Gdx.graphics.getHeight()/2), angle+= Gdx.graphics.getDeltaTime() * lineSpeed);
line.setPosition(point.x, point.y);
rotatePoint function:
Point rotatePoint(Point point, Point center, double angle){
angle = (angle ) * (Math.PI/180); // Convert to radians
float rotatedX = (int) (Math.cos(angle) * (point.x - center.x) - Math.sin(angle) * (point.y-center.y) + center.x);
float rotatedY = (int) (Math.sin(angle) * (point.x - center.x) + Math.cos(angle) * (point.y - center.y) + center.y);
return new Point(rotatedX,rotatedY);
}
Any sugestions ?
I can't test right now but I think the rotation of the line should simply be:
Math.atan2(rotatedPoint.getOriginX() - middlePoint.getOriginX(), rotatedPoint.getOriginY() - middlePoint.getOriginY()));
Then you'll have to adjust rad to degrees or whatever you'll use. Tell me if it doesn't work!
I would take a different approach, I just created a method that places n Buttons around a click on the screen. I am using something that looks like this:
float rotation; // in degree's
float distance; //Distance from origin (radius of circle).
vector2 originOfRotation; //Center of circle
vector2 originOfSprite; //Origin of rotation sprite we are calculating
Vector2 direction = new vector2(0, 1); //pointing up
//rotate the direction
direction.rotate(rotation);
// add distance based of the direction. Warning: originOfRotation will change because of chaining method.
// use originOfRotation.cpy() if you do not want to init each frame
originOfSprite = originOfRotation.add(direction.scl(distance));
Now you have the position of your sprite. You need to increment rotation by x each frame to have it rotate. If you want the orientation of the sprite to change you can use the direction vector, probably rotated by 180 again. Efficiency wise I'm not sure what the difference would be.
I'm using jsc3d to load and display some 3d objects on a canvas. The viewer has already a built-in feature that allows to rotate the "view coordinates" (correct me if i'm wrong) about the Y axis by dragging the mouse.
The rotation is performed through a classic rotation matrix, and finally the trasformation matrix is multiplied by this rotation matrix.
The totation about the Y axis is calculated in a way that resembles a circular movement around the whole scene of loaded objects:
JSC3D.Matrix3x4.prototype.rotateAboutYAxis = function(angle) {
if(angle != 0) {
angle *= Math.PI / 180;
var c = Math.cos(angle);
var s = Math.sin(angle);
var m00 = c * this.m00 + s * this.m20;
var m01 = c * this.m01 + s * this.m21;
var m02 = c * this.m02 + s * this.m22;
var m03 = c * this.m03 + s * this.m23;
var m20 = c * this.m20 - s * this.m00;
var m21 = c * this.m21 - s * this.m01;
var m22 = c * this.m22 - s * this.m02;
var m23 = c * this.m23 - s * this.m03;
this.m00 = m00; this.m01 = m01; this.m02 = m02; this.m03 = m03;
this.m20 = m20; this.m21 = m21; this.m22 = m22; this.m23 = m23;
}
};
Now, dragging the mouse will apply this rotation about the Y axis on the whole world, like on the left side in the picture below. Is there a way, to apply a rotation about the Up vector to keep it in the initial position, like it appear on the right side?
I tried something like that:
var rotY = (x - viewer.mouseX) * 360 / viewer.canvas.height;
var rotMat = new JSC3D.Matrix3x4; // identity
rotMat.rotateAboutYAxis(rotY);
viewer.rotMatrix.multiply(rotMat);
but it has no effect.
What operations shall be applied to my rotation matrix to achieve a rotation about the Up vector?
Sample: https://jsfiddle.net/4xzjnnar/1/
This 3D library has already some built-in functions to allow scene rotation about X,Y,and Z axis, so there is no need to implement new matrix operations for that, we can use the existing functions rotateAboutXAyis, rotateAboutYAxis and rotateAboutZAxis, which apply an in-place matrix multiplication of the desired rotation angle in degrees.
The scene in JSC3D is transformed by a 3x4 matrix where the rotation is stored in the first 3 values of each row.
After applying a scene rotation and/or translation, applying a subsequent rotation about the Up vector, is a problem of calculate a rotation about an arbitrary axis.
A very clean and didactic explanation how to solve this problem is described here: http://ami.ektf.hu/uploads/papers/finalpdf/AMI_40_from175to186.pdf
Translate the P 0 (x 0 ,y 0 ,z 0 ) axis point to the origin of the coordinate system.
Perform appropriate rotations to make the axis of rotation coincident with
z-coordinate axis.
Rotate about the z-axis by the angle θ.
Perform the inverse of the combined rotation transformation.
Perform the inverse of the translation.
Now, its easy to write a function for that, because we use the functions already available in JSC3D (translation part is omitted here).
JSC3D.Viewer.prototype.rotateAboutUpVector = function(angle) {
angle %= 360;
/* pitch, counter-clockwise rotation about the Y axis */
var degX = this.rpy[0], degZ = this.rpy[2];
this.rotMatrix.rotateAboutXAxis(-degX);
this.rotMatrix.rotateAboutZAxis(-degZ);
this.rotMatrix.rotateAboutYAxis(angle);
this.rotMatrix.rotateAboutZAxis(degZ);
this.rotMatrix.rotateAboutXAxis(degX);
}
Because all above mentioned functions are using degrees, we need to get back the actual Euler angles from the rotation matrix (simplified):
JSC3D.Viewer.prototype.calcRollPitchYaw = function() {
var m = this.rotMatrix;
var radians = 180 / Math.PI;
var angleX = Math.atan2(-m.m12, m.m22) * radians;
var angleY = Math.asin(m.m01) * radians;
var angleZ = Math.atan2(-m.m01, m.m00) * radians;
this.rpy[0] = angleX;
this.rpy[1] = angleY;
this.rpy[2] = angleZ;
}
The tricky part here, is that we need always to get back the current rotation angles, as they results from the applied rotations, so a separate function must be used to store the current Euler angles every time that a rotation is applied to the scene.
For that, we can use a very simple structure:
JSC3D.Viewer.prototype.rpy = [0, 0, 0];
This will be the final result:
I am trying to implement transform methods to rotate and resize a movieclip at runtime and I have a problem when recalculating the rotation to follow the mouse.
I have a squared movieclip and a rotator object (a circle) at the right bottom corner of the square where I am listening for mouse events and on mouse move I do this:
_rotation = -(Math.atan2((event.stageX - this.x ), (event.stageY - this.y ))) * 180/Math.PI;
this.rotation = rotation + 45;//this is because my rotator object is on right,bottom corner
this works perfect as long as I don´t modify the width or height of the object but if I do modify then there is a small "jump" on the rotation of the object that I am not able of avoid.
I know this is due event.stageX and even.stageY are different as the rotator object, the one with the mouse listener, has moved after the resize event but no clue how to avoid the "jump".
Please excuse my bad English
You need to rotate the object around its center.
/**
* Rotates the object based on its center
* Parameters: #obj => the object to rotate
* # rotation => angle to rotate
* */
public function RotateAroundCenter(obj:Object, rotation:Number):void
{
var bound:Rectangle = new Rectangle();
// get the bounded rectangle of objects
bound = obj.getRect(this);
// calculate mid poits
var midx1:Number = bound.x + bound.width/2;
var midy1:Number = bound.y + bound.height/2;
// assign the rotation
obj.rotation = rotation;
// assign the previous mid point as (x,y)
obj.x = midx1;
obj.y = midy1;
// get the new bounded rectangle of objects
bound = obj.getRect(this);
// calculate new mid points
var midx2:Number = bound.x + bound.width/2;
var midy2:Number = bound.y + bound.height/2;
// calculate differnece between the current mid and (x,y) and subtract
//it to position the object in the previous bound.
var diff:Number = midx2 - obj.x;
obj.x -= diff;
diff = midy2 - obj.y;
obj.y -= diff;
}
Usage:
_rotation = -(Math.atan2((event.stageX - this.x ), (event.stageY - this.y ))) * 180/Math.PI;
RotateAroundCenter(this, rotation + 45);
Check this link
I'm struggling with some quaternion code in iOS. I have an open cube, which i've rotated into an isometric view. i am able to rotate the cube with touch and rotate about its axis and also zoom in/out. I also have labels associated with the cube - which also need to rotate with the cube. Again, i've managed to do this.
However, i'm now trying to implement being able to drag the label (ie. translate it) from one position, to another. If we look at the image below, what i've tried to illustrate is that i want to be able to translate the label from "label from" to the position "label to". Then, when i come to rotating the cube, the label should stay in its new position and rotate with the cube. However, i'm making a cock-up of this translation and when i try rotating the cube, the label jumps to a new position since i've not set the label coordinates properly.
I have the quaternion associated with the cube.
With the following code, i have been able to translate the label properly when the quaternion is set to [0, 0, 0, 1] (so that the cube is front-on - looks like a square from this position).
- (void) rotateWithAngle:(float) radians andVector:(GLKVector3) axis andScale:(float) scale
{
if (radians != self.lastRadians
|| (axis.v[0] != self.lastAxis.v[0] || axis.v[1] != self.lastAxis.v[1] || axis.v[2] != self.lastAxis.v[2])
|| scale != self.lastScale)
{
GLKMatrix4 m = GLKMatrix4MakeTranslation(self.normX, self.normY, self.normZ);
if (radians != 0)
m = GLKMatrix4Rotate(m, radians, axis.x, -axis.y, axis.z);
m = GLKMatrix4Scale(m, scale, scale, scale);
float x = (m.m00 * m.m30) + (m.m01 * m.m31) + (m.m02 * m.m32) + (m.m03 * m.m33);
float y = (m.m10 * m.m30) + (m.m11 * m.m31) + (m.m12 * m.m32) + (m.m13 * m.m33);
float z = (m.m20 * m.m30) + (m.m21 * m.m31) + (m.m22 * m.m32) + (m.m23 * m.m33);
x /= m.m33;
y /= m.m33;
z /= m.m33;
float w = (((x+self.winSz) / (self.winSz * 2.0)) * self.parentFrame.size.width) + self.parentFrame.origin.x;
float h = (((y+self.winSz) / (self.winSz * 2.0)) * self.parentFrame.size.height) + self.parentFrame.origin.y;
self.lastRadians = radians;
self.lastAxis = axis;
self.lastScale = scale;
[self setCenter:CGPointMake(w,h)];
}
}
- (void) translateFromTouch:(UIPanGestureRecognizer *) pan
{
CGPoint translation = [pan translationInView:self];
CGPoint imageViewPosition = self.center;
GLKVector3 axis = GLKQuaternionAxis(*_quaternion);
float rot = GLKQuaternionAngle(*_quaternion);
CGFloat h = self.parentFrame.size.height;
CGFloat w = self.parentFrame.size.width;
imageViewPosition.x += translation.x;
imageViewPosition.y += translation.y;
self.center = imageViewPosition;
// recalculate the norm position
float x = ((2.0 * self.winSz * (imageViewPosition.x - self.parentFrame.origin.x)) / w) - self.winSz;
float y = ((2.0 * self.winSz * (imageViewPosition.y - self.parentFrame.origin.y)) / h) - self.winSz;
self.normX = x;
self.normY = y;
[pan setTranslation:CGPointZero inView:self];
}
These methods are hit if a label (based on a UILabel) is either dragged or the cube (or the opengl scene) is rotated.
This works when we are looking front-on, so that the x,y values can easily be converted from pixel coords into normal or world coords.
However, when the axis is not front-on, i'm struggling to figure it out. For instance, we we have the quaternion set at (0, sqrt(2)/2, 0, sqrt(2)/2) then all x translations correspond to z world coords. So how do i make this connection/calculation? I'm sure it's fairly easy but i've hit a wall with this.
(winSz i have set to 1.5. model coords very between -1 and 1)