So, I successfully implemented picking/selection by rendering with a unique color each part I want to be selectable.
This works for geometry, but what about the text? I searched the Web a lot, but I didn't find anything connected to color picking and text.
The solution I thought was rendering some custom geometry instead of a text in the back buffer. Problem is that my scene can have different rotations (global X + local Z), so I would need to calculate every time the right position and rotation of this geometry since I need to match the position/rotation of the text, that is rendered automatically horizontal and perpendicular to the user with the glut.glutStrokeString(font, string) call.
I wonder if there is a trick also regarding text selection.
Ps: sry, I was wrong, I am not using the stroke but the glutBitmapString..
You can calculate a bounding rectangle in screen space for your text and on a click event check if the cursor position lies in any of active bounding rectangles. Something like this:
struct brect_t { float x, y, w, h; };
struct string_t {
void *fontID;
const unsigned char *data;
brect_t rect;
};
static string_t strings[MAX_STRINGS];
int stringsCount = 0;
// add new string to render queue
int stringsAdd(float x, float y, void *fontID, const unsigned char *str) {
if (stringsCount >= MAX_STRINGS)
return 0;
string_t *string = strings + stringsCount++;
string->rect.x = x;
string->rect.y = y;
string->rect.w = glutStrokeLength(fontID, str);
string->rect.h = glutStrokeHeight(fontID);
strings->fontID = fontID;
string->data = str;
return 1;
}
// render all strings
void stringsRender(float r, float g, float b) {
glColor3f(r, g, b);
for (int i = 0; i < stringsCount; ++i) {
const string_t *string = strings + i;
glPushMatrix();
glLoadIdentity();
glTranslatef(string->rect.x, string->rect.y, 0.0f);
glutStrokeString(string->fontID, string->data);
glPopMatrix();
}
}
// x,y - in model space coordinates
const string_t* stringsPick(float x, float y) {
for (int i = 0; i < stringsCount; ++i) {
const string_t *string = strings + i;
const rect_t *rect = &string->rect;
if (x >= rect->x &&
y >= rect->y &&
x <= (rect->x + rect->w) &&
y <= (rect->y + rect->h)) {
return string;
}
}
return NULL;
}
I'm researching UI's as a portfolio project and I ran into a little bit of trouble when it comes to inheritance. The problem I'm facing is this: I have two classes, R_GUI, in which I draw the form, and Button, where I draw the buttons. I want the Buttons to be positioned inside the FORM. I store the FORM position as form_x, and form_y. Here are my two classes:
class R_GUI
{
private:
bool get_pos_only_once;
bool move_form;
public:
int form_x, form_y;
int form_height, form_width;
int handle_bar_y;
inline void Form(int pos_x, int pos_y, int height, int width);
//inline void Button(int id, string ButtonText, int pos_x, int pos_y);
inline void Update_form(void);
inline void UPDATE(void);
inline ~R_GUI( );
inline R_GUI( )
{
d3dInit();
get_pos_only_once = false;
move_form = false;
form_x = 0;
form_y = 0;
handle_bar_y = 40;
}
};
and the Button class:
class Button: public R_GUI
{
private:
int b_form_x, b_form_y;
int b_handle_y;
int button_width, button_height;
public:
inline void Draw(string ButtonText, int b_pos_x, int b_pos_y);
Button()
{
b_form_x = R_GUI::form_x;
b_form_y = R_GUI::form_y;
b_handle_y = 20;
button_width = 90;
button_height = 35;
}
~Button();
};
As you can see, I'm trying to give b_form_x the value of form_x (which is a variable from R_GUI). form_x has a value, given in Form( );:
inline void R_GUI::Form(int pos_x, int pos_y, int height, int width)
{
if(get_pos_only_once == false)
{
form_x = pos_x;
form_y = pos_y;
form_height = height;
form_width = width;
get_pos_only_once = true;
}
//Create the form outline
d3dLine(pos_x,pos_y,pos_x+width,pos_y,dbRGB(50,50,50));
d3dLine(pos_x,pos_y,pos_x,pos_y+height,dbRGB(50,50,50));
d3dLine(pos_x+width,pos_y,pos_x+width,pos_y+height,dbRGB(50,50,50));
d3dLine(pos_x,pos_y+height,pos_x+width,pos_y+height,dbRGB(50,50,50));
//Create the handle bar
d3dLine(pos_x,pos_y+handle_bar_y,pos_x+width,pos_y+handle_bar_y,dbRGB(50,50,50));
//Fill the Handlebar;
d3dBox(pos_x,pos_y,pos_x+width,pos_y+handle_bar_y,dbRGB(3,3,3),dbRGB(3,3,3),dbRGB(3,3,3),dbRGB(3,3,3));
}
Yet, when I update the Form's Position, R_GUI::form_x value doesn't change. Any idea what I am doing wrong?
You don't want to have a second variable in your subclass (b_form_x). Eliminate it entirely. Instead, you want to use this->form_x, which in the Button will be inherited from R_GUI. The same applies for b_form_y.
this refers to the current instance of an object, and contains not only your local member variables but also any member variables inherited from classes all the way up the hierarchy as well.
I've read a bunch of tutorials involving XNA (and it's various versions) and I still am a little confused on drawing primitives. Everything seems to be really convoluted.
Can someone show me, using code, the simplest XNA implementation of drawing one or two lines on to the screen? Perhaps with a brief explanation (including the boilerplate)?
I'm not a games programmer and I have little XNA experience. My ultimate goal is to draw some lines onto the screen which I will eventually transform with rotations, etc (by hand). However, for this first step.. I need to simply draw the lines! I remember back in my ancient OpenGL days it was fairly straightforward when drawing a line with a few method calls. Should I simply revert to using unmanaged directx calls?
When working with XNA, everything (even 2d primitives) have to be expressed in a way that a 3d card can understand, which means that a line is just a set of vertices.
MSDN has a pretty good walkthrough here:
http://msdn.microsoft.com/en-us/library/bb196414.aspx#ID2EEF
You'll find that it takes more code to render a primitive line than it would take to just setup a textured quad and rotate that, since in essence, your doing the same thing when rendering a line.
Following NoHayProblema's answer (I cannot comment yet).
That answer, although the correct one for this old question, is incomplete. Texture2D constructor returns an uninitialized texture, which is never painted on screen.
In order to use that approach, you need to set the texture's data like this:
Texture2D SimpleTexture = new Texture2D(GraphicsDevice, 1, 1, false,
SurfaceFormat.Color);
Int32[] pixel = {0xFFFFFF}; // White. 0xFF is Red, 0xFF0000 is Blue
SimpleTexture.SetData<Int32> (pixel, 0, SimpleTexture.Width * SimpleTexture.Height);
// Paint a 100x1 line starting at 20, 50
this.spriteBatch.Draw(SimpleTexture, new Rectangle(20, 50, 100, 1), Color.Blue);
Take into account that the way you write the data into pixel must be consistent with the texture's SurfaceFormat. The example works because the texture is being formatted as RGB.
Rotations can be applied in spriteBatch.Draw like this:
this.spriteBatch.Draw (SimpleTexture, new Rectangle(0, 0, 100, 1), null,
Color.Blue, -(float)Math.PI/4, new Vector2 (0f, 0f), SpriteEffects.None, 1f);
found a tutorial for that
http://www.bit-101.com/blog/?p=2832
its using a BasicEffect (shader)
and the built in draw user primitive in XNA 4.0
some code samples i find helpful:
load content method
basicEffect = new BasicEffect(GraphicsDevice);
basicEffect.VertexColorEnabled = true;
basicEffect.Projection = Matrix.CreateOrthographicOffCenter
(0, GraphicsDevice.Viewport.Width, // left, right
GraphicsDevice.Viewport.Height, 0, // bottom, top
0, 1);
draw method
basicEffect.CurrentTechnique.Passes[0].Apply();
var vertices = new VertexPositionColor[4];
vertices[0].Position = new Vector3(100, 100, 0);
vertices[0].Color = Color.Black;
vertices[1].Position = new Vector3(200, 100, 0);
vertices[1].Color = Color.Red;
vertices[2].Position = new Vector3(200, 200, 0);
vertices[2].Color = Color.Black;
vertices[3].Position = new Vector3(100, 200, 0);
vertices[3].Color = Color.Red;
GraphicsDevice.DrawUserPrimitives<VertexPositionColor>(PrimitiveType.LineList, vertices, 0, 2);
have fun and vote up if this helped you. also pay a visit to the tutorial i got this from.
Well, you can do it in a very simple way without getting into the 3D horrible vector stuff.
Just create a quick texture, for example:
Texture2D SimpleTexture = new Texture2D(GraphicsDevice, 1, 1, false, SurfaceFormat.Color);
And then just draw a line using that texture:
this.spriteBatch.Draw(SimpleTexture, new Rectangle(100, 100, 100, 1), Color.Blue);
I hope this helps
The simplest best way, I think, is to get the image of just a white pixel then stretch that pixel in a rectangle to look like a line
I made a Line class,
class Line
{
Texture pixel = ((set this to a texture of a white pixel with no border));
Vector2 p1, p2; //this will be the position in the center of the line
int length, thickness; //length and thickness of the line, or width and height of rectangle
Rectangle rect; //where the line will be drawn
float rotation; // rotation of the line, with axis at the center of the line
Color color;
//p1 and p2 are the two end points of the line
public Line(Vector2 p1, Vector2 p2, int thickness, Color color)
{
this.p1 = p1;
this.p2 = p2;
this.thickness = thickness;
this.color = color;
}
public void Update(GameTime gameTime)
{
length = (int)Vector2.Distance(p1, p2); //gets distance between the points
rotation = getRotation(p1.X, p1.Y, p2.X, p2.Y); //gets angle between points(method on bottom)
rect = new Rectangle((int)p1.X, (int)p1.Y, length, thickness)
//To change the line just change the positions of p1 and p2
}
public void Draw(SpriteBatch spriteBatch, GameTime gameTime)
{
spriteBatch.Draw(pixel, rect, null, color, rotation, new Vector2.Zero, SpriteEffects.None, 0.0f);
}
//this returns the angle between two points in radians
private float getRotation(float x, float y, float x2, float y2)
{
float adj = x - x2;
float opp = y - y2;
float tan = opp / adj;
float res = MathHelper.ToDegrees((float)Math.Atan2(opp, adj));
res = (res - 180) % 360;
if (res < 0) { res += 360; }
res = MathHelper.ToRadians(res);
return res;
}
Hope this helps
There is also the "round line" code that "manders" has released on CodePlex:
http://roundline.codeplex.com/
Here is the blog post about it:
XNA RoundLine Code Released on CodePlex
Just stretch a white pixel.
point = game.Content.Load<Texture2D>("ui/point");
public void DrawLine(Vector2 start, Vector2 end, Color color)
{
Vector2 edge = end - start;
float angle = (float)Math.Atan2(edge.Y, edge.X);
spriteBatch.Begin();
spriteBatch.Draw(point,
new Rectangle((int)start.X, (int)start.Y, (int)edge.Length(), 1),
null,
color,
angle,
new Vector2(0, 0),
SpriteEffects.None,
0);
spriteBatch.End();
}
I wanted to draw rays so that I could debug rays created by explosions and where they intersect objects. This will draw a single pixel thin line between two points. This is what I did:
Class to store some simple ray data. The XNA default ray class could work, but it doesn't store the length of the ray to intersection.
public class myRay
{
public Vector3 position, direction;
public float length;
}
A list to store the rays that are to be drawn:
List<myRay> DebugRays= new List<myRay>();
Create a BasicEffect and pass it a "Matrix.CreateOrthographicOffCenter" projection with your desired resolution in the LoadContent method.
Then run this in the draw method:
private void DrawRays()
{
spriteBatch.Begin();
foreach (myRay ray in DebugRays)
{
//An array of 2 vertices - a start and end position
VertexPositionColor[] Vertices = new VertexPositionColor[2];
int[] Indices = new int[2];
//Starting position of the ray
Vertices[0] = new VertexPositionColor()
{
Color = Color.Orange,
Position = ray.position
};
//End point of the ray
Vertices[1] = new VertexPositionColor()
{
Color = Color.Orange,
Position = ray.position + (ray.direction * ray.length)
};
Indices[0] = 0;
Indices[1] = 1;
foreach (EffectPass pass in BasicEffect.CurrentTechnique.Passes)
{
pass.Apply();
GraphicsDevice.DrawUserIndexedPrimitives(PrimitiveType.LineStrip, Vertices, 0, 2, Indices, 0, 1, VertexPositionColorTexture.VertexDeclaration);
}
}
spriteBatch.End();
}
So when an explosion happens in my game it does this (Psuedocode):
OnExplosionHappened()
{
DebugRays.Clear()
myRay ray = new myRay()
{
position = explosion.Position,
direction = GetDirection(explosion, solid),
//Used GetValueOrDefault here to prevent null value errors
length = explosionRay.Intersects(solid.BoundingBox).GetValueOrDefault()
};
DebugRays.Add(ray);
}
It's pretty simple (It possibly looks way more complicated than it is) and it'd be easy to put it into a separate class that you never have to think about again. It also lets you draw a whole lot of lines at once.
I encountered this problem my self and decided to make a class called LineBatch.
LineBatch will draw lines without needing a spriteBatch or dots.
The class is below.
public class LineBatch
{
bool cares_about_begin_without_end;
bool began;
GraphicsDevice GraphicsDevice;
List<VertexPositionColor> verticies = new List<VertexPositionColor>();
BasicEffect effect;
public LineBatch(GraphicsDevice graphics)
{
GraphicsDevice = graphics;
effect = new BasicEffect(GraphicsDevice);
Matrix world = Matrix.Identity;
Matrix view = Matrix.CreateTranslation(-GraphicsDevice.Viewport.Width / 2, -GraphicsDevice.Viewport.Height / 2, 0);
Matrix projection = Matrix.CreateOrthographic(GraphicsDevice.Viewport.Width, -GraphicsDevice.Viewport.Height, -10, 10);
effect.World = world;
effect.View = view;
effect.VertexColorEnabled = true;
effect.Projection = projection;
effect.DiffuseColor = Color.White.ToVector3();
cares_about_begin_without_end = true;
}
public LineBatch(GraphicsDevice graphics, bool cares_about_begin_without_end)
{
this.cares_about_begin_without_end = cares_about_begin_without_end;
GraphicsDevice = graphics;
effect = new BasicEffect(GraphicsDevice);
Matrix world = Matrix.Identity;
Matrix view = Matrix.CreateTranslation(-GraphicsDevice.Viewport.Width / 2, -GraphicsDevice.Viewport.Height / 2, 0);
Matrix projection = Matrix.CreateOrthographic(GraphicsDevice.Viewport.Width, -GraphicsDevice.Viewport.Height, -10, 10);
effect.World = world;
effect.View = view;
effect.VertexColorEnabled = true;
effect.Projection = projection;
effect.DiffuseColor = Color.White.ToVector3();
}
public void DrawAngledLineWithRadians(Vector2 start, float length, float radians, Color color)
{
Vector2 offset = new Vector2(
(float)Math.Sin(radians) * length, //x
-(float)Math.Cos(radians) * length //y
);
Draw(start, start + offset, color);
}
public void DrawOutLineOfRectangle(Rectangle rectangle, Color color)
{
Draw(new Vector2(rectangle.X, rectangle.Y), new Vector2(rectangle.X + rectangle.Width, rectangle.Y), color);
Draw(new Vector2(rectangle.X, rectangle.Y), new Vector2(rectangle.X, rectangle.Y + rectangle.Height), color);
Draw(new Vector2(rectangle.X + rectangle.Width, rectangle.Y), new Vector2(rectangle.X + rectangle.Width, rectangle.Y + rectangle.Height), color);
Draw(new Vector2(rectangle.X, rectangle.Y + rectangle.Height), new Vector2(rectangle.X + rectangle.Width, rectangle.Y + rectangle.Height), color);
}
public void DrawOutLineOfTriangle(Vector2 point_1, Vector2 point_2, Vector2 point_3, Color color)
{
Draw(point_1, point_2, color);
Draw(point_1, point_3, color);
Draw(point_2, point_3, color);
}
float GetRadians(float angleDegrees)
{
return angleDegrees * ((float)Math.PI) / 180.0f;
}
public void DrawAngledLine(Vector2 start, float length, float angleDegrees, Color color)
{
DrawAngledLineWithRadians(start, length, GetRadians(angleDegrees), color);
}
public void Draw(Vector2 start, Vector2 end, Color color)
{
verticies.Add(new VertexPositionColor(new Vector3(start, 0f), color));
verticies.Add(new VertexPositionColor(new Vector3(end, 0f), color));
}
public void Draw(Vector3 start, Vector3 end, Color color)
{
verticies.Add(new VertexPositionColor(start, color));
verticies.Add(new VertexPositionColor(end, color));
}
public void End()
{
if (!began)
if (cares_about_begin_without_end)
throw new ArgumentException("Please add begin before end!");
else
Begin();
if (verticies.Count > 0)
{
VertexBuffer vb = new VertexBuffer(GraphicsDevice, typeof(VertexPositionColor), verticies.Count, BufferUsage.WriteOnly);
vb.SetData<VertexPositionColor>(verticies.ToArray());
GraphicsDevice.SetVertexBuffer(vb);
foreach (EffectPass pass in effect.CurrentTechnique.Passes)
{
pass.Apply();
GraphicsDevice.DrawPrimitives(PrimitiveType.LineList, 0, verticies.Count / 2);
}
}
began = false;
}
public void Begin()
{
if (began)
if (cares_about_begin_without_end)
throw new ArgumentException("You forgot end.");
else
End();
verticies.Clear();
began = true;
}
}
Here is a simple way that I use to make lines by specifying a start coordinate, an end coordinate, width, and color of them:
NOTE: you must add a file named "dot" to the content directory (the line will be made out of these).
using System;
using System.Collections.Generic;
using System.Linq;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Audio;
using Microsoft.Xna.Framework.Content;
using Microsoft.Xna.Framework.GamerServices;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Input;
using Microsoft.Xna.Framework.Media;
namespace Xna.LineHelper
{
public class LineManager
{
int loopCounter;
int lineLegnth;
Vector2 lineDirection;
Vector2 _position;
Color dotColor;
Rectangle _rectangle;
List<Texture2D> _dots = new List<Texture2D>();
FunctionsLibrary functions = new FunctionsLibrary();
public void CreateLineFiles(Vector2 startPosition, Vector2 endPosition, int width, Color color, ContentManager content)
{
dotColor = color;
_position.X = startPosition.X;
_position.Y = startPosition.Y;
lineLegnth = functions.Distance((int)startPosition.X, (int)endPosition.X, (int)startPosition.Y, (int)endPosition.Y);
lineDirection = new Vector2((endPosition.X - startPosition.X) / lineLegnth, (endPosition.Y - startPosition.Y) / lineLegnth);
_dots.Clear();
loopCounter = 0;
_rectangle = new Rectangle((int)startPosition.X, (int)startPosition.Y, width, width);
while (loopCounter < lineLegnth)
{
Texture2D dot = content.Load<Texture2D>("dot");
_dots.Add(dot);
loopCounter += 1;
}
}
public void DrawLoadedLine(SpriteBatch sb)
{
foreach (Texture2D dot in _dots)
{
_position.X += lineDirection.X;
_position.Y += lineDirection.Y;
_rectangle.X = (int)_position.X;
_rectangle.Y = (int)_position.Y;
sb.Draw(dot, _rectangle, dotColor);
}
}
}
public class FunctionsLibrary
{
//Random for all methods
Random Rand = new Random();
#region math
public int TriangleArea1(int bottom, int height)
{
int answer = (bottom * height / 2);
return answer;
}
public double TriangleArea2(int A, int B, int C)
{
int s = ((A + B + C) / 2);
double answer = (Math.Sqrt(s * (s - A) * (s - B) * (s - C)));
return answer;
}
public int RectangleArea(int side1, int side2)
{
int answer = (side1 * side2);
return answer;
}
public int SquareArea(int side)
{
int answer = (side * side);
return answer;
}
public double CircleArea(int diameter)
{
double answer = (((diameter / 2) * (diameter / 2)) * Math.PI);
return answer;
}
public int Diference(int A, int B)
{
int distance = Math.Abs(A - B);
return distance;
}
#endregion
#region standardFunctions
public int Distance(int x1, int x2, int y1, int y2)
{
return (int)(Math.Sqrt((x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2)));
}
#endregion
}
}