I can't seem to figure out how to make this simple animation work, where i have user control over a red square, and it shouldn't overlap/intersect with a black square (e.g. a wall sprite)

My best effort is to have stack data structure of keys pressed and if there is an intersection, then we look at (peek) last key pressed and assign a speed of -1. (See line 67 of code) But this doesn't prevent an overlap. Is there a way that I can make it so the user's red rectangle can't overlap with black?

 using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Collections;

namespace Movement
{
    public partial class Form1 : Form
    {
        bool moveRight, moveLeft, moveUp, moveDown;
        Keys currentInput;
        Keys lastInput;
        Stack pressedKeys = new Stack();
        int speed = 5;
        bool collision = false;
        public Form1()
        {
            InitializeComponent();
            this.CenterToScreen();
            
        }

        private void pbRed_Click(object sender, EventArgs e)
        {

        }

        
        private void moveTimeEvent(object sender, EventArgs e)
        {
            currentInput = Keys.KeyCode;
            //moving left
            if (moveLeft == true && pbRed.Left > 7 )
            {
                pbRed.Left -= speed;
            }
            //moving right
            if (moveRight == true && pbRed.Left < 750)
            {
                pbRed.Left  = speed;
            }
            //moving up
            if(moveUp == true && pbRed.Top > 7)
            {
                pbRed.Top -= speed;
            }    
            //moving down
            if(moveDown == true && pbRed.Top < 400)
            {
                pbRed.Top  = speed;
            }
            if (moveLeft == true || moveRight == true || moveUp == true || moveDown == true)
            {
                pressedKeys.Push(currentInput);
                
            }
            Collision();
            

        }
         private void Collision()
        {
            
            //collision detection
            if(pbRed.Bounds.IntersectsWith(pbBlack.Bounds))
            { 
                collision = true;
                if(collision)
                {
                    lastInput = (Keys)pressedKeys.Peek();
                    if(currentInput == lastInput)
                    {
                        speed = -1;
                    }
                }                
            }
        }

        private void keyisdown(object sender, KeyEventArgs e)
        {
            if(e.KeyCode == Keys.Left)
            {
                moveLeft = true;
                
            }
            if (e.KeyCode == Keys.Right)
            {
                moveRight = true;
                
            }
            if (e.KeyCode == Keys.Up)
            {
                moveUp = true;
                
            }
            if (e.KeyCode == Keys.Down)
            {
                moveDown = true;
                
            }
        }

        private void keyisup(object sender, KeyEventArgs e)
        {
            if (e.KeyCode == Keys.Left)
            {
                moveLeft = false;
            }
            if (e.KeyCode == Keys.Right)
            {
                moveRight = false;
            }
            if (e.KeyCode == Keys.Up)
            {
                moveUp = false;
            }
            if (e.KeyCode == Keys.Down)
            {
                moveDown = false;
            }
        }
    }
}

CodePudding user response：

When your speed is 5, don't apply a movement of 5 pixels in one go, but apply the 5 steps separately. Before each step, so before actually moving the rectangle, decide whether that one step movement is allowed. Also look at vertical and horizontal movement separately.

using System;
using System.Drawing;
using System.Windows.Forms;

namespace Movement
{
    public partial class Form1 : Form
    {
        bool moveRight, moveLeft, moveUp, moveDown;
        int speed = 5;

        public Form1()
        {
            InitializeComponent();
            this.CenterToScreen();
        }


        private void moveTimeEvent(object sender, EventArgs e)
        {
            // Get movement vector
            Point movement = new Point(0, 0);
            if (moveLeft) movement.X -= 1;
            if (moveRight) movement.X  = 1;
            if (moveUp) movement.Y -= 1;
            if (moveDown) movement.Y  = 1;

            // Speed defines how many steps we move
            for (int i=1; i<= speed; i  )
            {
                // Check vertical movement allowed
                if (movement.X != 0)
                {
                    Rectangle newPosition = pbRed.Bounds;
                    newPosition.X  = movement.X;
                    if (!CheckCollision(newPosition))
                    {
                        movement.X = 0;
                    }
                }

                // Check horizontal movement allowed
                if (movement.Y != 0)
                {
                    Rectangle newPosition = pbRed.Bounds;
                    newPosition.X  = movement.X;
                    newPosition.Y  = movement.Y;
                    if (!CheckCollision(newPosition))
                    {
                        movement.Y = 0;
                    }
                }

                // Apply Actual movement
                if (!movement.IsEmpty)
                {
                    Rectangle newPosition = pbRed.Bounds;
                    newPosition.X  = movement.X;
                    newPosition.Y  = movement.Y;
                    pbRed.Bounds = newPosition;
                }

            }
        }

        // Returns true when movingRecht is allowed position
        private bool CheckCollision(Rectangle movingRect)
        {
            bool lResult = true;

            //collision detection
            lResult = lResult && !pbBlack.Bounds.IntersectsWith(movingRect);


            // Check we remain inside the form
            lResult = lResult && movingRect.Left >= 0;
            lResult = lResult && movingRect.Top >= 0;
            lResult = lResult && movingRect.Right <= ClientRectangle.Right;
            lResult = lResult && movingRect.Bottom <= ClientRectangle.Bottom;

            return lResult;

        }

        private void keyisdown(object sender, KeyEventArgs e)
        {
            if (e.KeyCode == Keys.Left)
            {
                moveLeft = true;

            }
            if (e.KeyCode == Keys.Right)
            {
                moveRight = true;

            }
            if (e.KeyCode == Keys.Up)
            {
                moveUp = true;

            }
            if (e.KeyCode == Keys.Down)
            {
                moveDown = true;

            }
        }

        private void keyisup(object sender, KeyEventArgs e)
        {
            if (e.KeyCode == Keys.Left)
            {
                moveLeft = false;
            }
            if (e.KeyCode == Keys.Right)
            {
                moveRight = false;
            }
            if (e.KeyCode == Keys.Up)
            {
                moveUp = false;
            }
            if (e.KeyCode == Keys.Down)
            {
                moveDown = false;
            }
        }

    }
}