Drawing Shapes

Believe it or not, MonoGame doesn't include any methods for drawing shapes. But you can still use one of many techniques to draw shapes, this will focus on textures and will ignore primitives.

Using Textures

Much easier than drawing primitives, we can use a texture to draw each point of the shape, the texture is generated using 1 x 1 pixels:

Filled Rectangle

// Make a 1x1 texture named pixel.  
Texture2D pixel = new Texture2D(graphicsDeviceReferenceHere, 1, 1);  
 
// Create a 1D array of color data to fill the pixel texture with.  
Color[] colorData = {  
                        Color.White,   
                    };  
 
// Set the texture data with our color information.  
pixel.SetData<Color>(colorData);  
 
// Draw a fancy purple rectangle.  
spriteBatch.Draw(pixel, new Rectangle(0, 0, 300, 300), Color.Purple);

Outline Only

// In LoadContent() 
Texture2D pixel = new Texture2D(GraphicsDevice, 1, 1, false, SurfaceFormat.Color); 
pixel.SetData(new[] { Color.White }); // so that we can draw whatever color we want on top of it 

// In Draw() 
spriteBatch.Begin(); 
Rectangle titleSafeRectangle = GraphicsDevice.Viewport.TitleSafeArea; 
DrawBorder(titleSafeRectangle, 5, Color.Red); // can draw any rectangle here 
spriteBatch.End(); 

private void DrawBorder(Rectangle rectangleToDraw, int thicknessOfBorder, Color borderColor) 
{ 
// Draw top line 
spriteBatch.Draw(_pixel, new Rectangle(rectangleToDraw.X, rectangleToDraw.Y, rectangleToDraw.Width, thicknessOfBorder), borderColor); 

// Draw left line 
spriteBatch.Draw(pixel, new Rectangle(rectangleToDraw.X, rectangleToDraw.Y, thicknessOfBorder, rectangleToDraw.Height), borderColor); 

// Draw right line 
spriteBatch.Draw(pixel, new Rectangle((rectangleToDraw.X + rectangleToDraw.Width - thicknessOfBorder), 
rectangleToDraw.Y, 
thicknessOfBorder, 
rectangleToDraw.Height), borderColor);
 
// Draw bottom line 
spriteBatch.Draw(pixel, new Rectangle(rectangleToDraw.X, 
rectangleToDraw.Y + rectangleToDraw.Height - thicknessOfBorder, 
rectangleToDraw.Width, 
thicknessOfBorder), borderColor); 
}

Drawing Other Shapes

Adding new methods

You need to have a working MonoGame project, so from the project tab choose new class. Give the class a name and copy the code below (remember to keep the same namespace as your project):

using System;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Graphics;

namespace DrawingShapes
{
    public static class DrawShapes
    {
        private static Texture2D _blankTexture;

        public static void LoadContent(GraphicsDevice graphicsDevice)
        {
            _blankTexture = new Texture2D(graphicsDevice, 1, 1, false, SurfaceFormat.Color);
            _blankTexture.SetData(new[] { Color.White });
        }

        public static void LoadContent(Texture2D blankTexture)
        {
            _blankTexture = blankTexture;
        }

        public static void DrawLineSegment(this SpriteBatch spriteBatch, Vector2 point1, Vector2 point2, Color color, int lineWidth)
        {

            float angle = (float)Math.Atan2(point2.Y - point1.Y, point2.X - point1.X);
            float length = Vector2.Distance(point1, point2);

            spriteBatch.Draw(_blankTexture, point1, null, color,
                       angle, Vector2.Zero, new Vector2(length, lineWidth),
                       SpriteEffects.None, 0);
        }

        public static void DrawPolygon(this SpriteBatch spriteBatch, Vector2[] vertex, int count, Color color, int lineWidth)
        {
            if (count > 0)
            {
                for (int i = 0; i < count - 1; i++)
                {
                    DrawLineSegment(spriteBatch, vertex[i], vertex[i + 1], color, lineWidth);
                }
                DrawLineSegment(spriteBatch, vertex[count - 1], vertex[0], color, lineWidth);
            }
        }

        public static void DrawRectangle(this SpriteBatch spriteBatch, Rectangle rectangle, Color color, int lineWidth)
        {
            Vector2[] vertex = new Vector2[4];
            vertex[0] = new Vector2(rectangle.Left, rectangle.Top);
            vertex[1] = new Vector2(rectangle.Right, rectangle.Top);
            vertex[2] = new Vector2(rectangle.Right, rectangle.Bottom);
            vertex[3] = new Vector2(rectangle.Left, rectangle.Bottom);

            DrawPolygon(spriteBatch, vertex, 4, color, lineWidth);
        }

        public static void DrawCircle(this SpriteBatch spritbatch, Vector2 center, float radius, Color color, int lineWidth, int segments = 16)
        {

            Vector2[] vertex = new Vector2[segments];

            double increment = Math.PI * 2.0 / segments;
            double theta = 0.0;

            for (int i = 0; i < segments; i++)
            {
                vertex[i] = center + radius * new Vector2((float)Math.Cos(theta), (float)Math.Sin(theta));
                theta += increment;
            }

            DrawPolygon(spritbatch, vertex, segments, color, lineWidth);
        }
    }
}

Initialize You Shape Class

Now in your Game1.cs, you need to add the code below into the Initialize method:

DrawShapes.LoadContent(GraphicsDevice);

Draw Method

Now in the Draw method you can use the methods to draw a shape, for example:

spriteBatch.Begin();
spriteBatch.DrawRectangle(new Rectangle(0, 0, 200, 200), Color.White, 5);
spriteBatch.End();

Remember DrawRectangle, DrawPolygon, DrawCircle, and DrawLineSegment methods can be used to draw the appropriate shapes.