api clear

Clearing the display removes all of the existing pixel data, replacing it with the default background color. By calling Clear(), it automatically clears the entire display. The Clear() can only be used once at the beginning of the the draw phase no matter how many times you use it or where you put it in your code.

Usage

Clear ()

Example

In this example, we are going to use a simple timer to clear the entire screen. Running this code will output the following:

Lua

local display = Display()

-- Create a delay and time value
local delay = 2000
local time = 0

-- This flag will toggle between a full or partial clear
local clearFlag = false

-- Store random integers for drawing a random character to the screen
local char, x, y, colorID = 0

function Update(timeDelta)

  -- Increase the time value base on the timeDelta between the last frame
  time = time + timeDelta

  -- Text to see if time is greater than the delay
  if(time > delay) then

    -- Toggle the clear flag
    clearFlag = true

    -- Reset the timer
    time = 0

  end

end

function Draw()

  -- Test the clear flag and do a full or partial clear based on the value
  if(clearFlag == true) then
    
    Clear()

    clearFlag= false
  end

  -- Perform the next block of code 10 times
  for i = 1, 10 do

    -- Assign random values to each of these variable
    char = math.random(32, 126)
    x = math.random(0, display.x)
    y = math.random(0, display.y)
    colorID = math.random(1, 15)

    -- Draw a random character at a random position on the screen with a random color
    DrawText( string.char(char), x, y, DrawMode.Sprite, "large", colorID)

  end

  -- Example Title
  DrawText("Clear()", 8, 8, DrawMode.Sprite, "large", 15)
  DrawText("Lua Example", 8, 16, DrawMode.Sprite, "medium", 15, -4)

end

C#

using System;

namespace PixelVision8.Player
{
    class ClearExample : GameChip
    {
        // Create a new random generator
        Random random = new Random();

        // We'll store the display's boundaries here
        private Point display;

        // Create a delay and time value
        private int delay = 2000;
        private int time = 0;

        // This flag will toggle between a full or partial clear
        private bool clearFlag = false;

        // Store random integers for drawing a random character to the screen
        private int charID, x, y, colorID;

        public override void Init()
        {
            // Save the display's boundaries when the game starts up
            display = Display();
        }

        public override void Update(int timeDelta)
        {
            // Increase the time value base on the timeDelta between the last frame
            time = time + timeDelta;

            // Text to see if time is greater than the delay
            if (time > delay)
            {

                // Toggle the clear flag
                clearFlag = true;

                // Reset the timer
                time = 0;

            }
        }

        public override void Draw()
        {
            // Test the clear flag and do a full or partial clear based on the value
            if (clearFlag == true)
            {
                Clear();

                clearFlag = false;

            }
            
            // Perform the next block of code 10 times
            for (int i = 0; i < 10; i++)
            {

                // Assign random values to each of these variable
                charID = random.Next(32, 126);
                x = random.Next(0, display.X);
                y = random.Next(0, display.Y);
                colorID = random.Next(1, 15);

                // Draw a random charIDacter at a random position on the screen with a random color
                DrawText(Convert.ToChar(charID).ToString(), x, y, DrawMode.Sprite, "large", colorID);

            }

            // Example Title
            DrawText("Clear()", 8, 8, DrawMode.Sprite, "large", 15);
            DrawText("C Sharp Example", 8, 16, DrawMode.Sprite, "medium", 15, -4);
        }
    }
}