A Rectangle is a Pixel Vision 8 primitive used for defining the bounds of an object on the display. It contains an X, W, Width and Height property. The Rectangle object class also has some additional methods to aid with collision detection.
NewRect ( x, y, w, h )| Name | Value | Description |
|---|---|---|
| X | int | The x position of the rect as an int. |
| Y | int | The y position of the rect as an int. |
| Width | int | The width value of the rect as an int. |
| Height | int | The height value of the rect as an int. |
| Value | Description |
|---|---|
| Rect | Returns a new instance of a Rect object. |
The Rectangle has three methods you can use to determine if there is a collision.
| Name | Description |
|---|---|
| Contains( x, y ) | Test to see if an X and Y position are inside of the Rectangle. |
| Contains( point ) | Test to see if a point is inside of the Rectangle. |
| Contains( rectangle ) | Test to see if another Rectangle intersects with the Rectangle. |
In this example, we are going to create two rectangles and test to see if they collide with one another. Running this code will output the following:
-- Create a rectangle
local rectA = NewRect(8, 32, 128, 128)
-- This will store the mouse position
local mousePos = NewPoint()
-- This will store the collision state
local collision = false
function Init()
-- Example Title
DrawText("NewRect()", 8, 8, DrawMode.TilemapCache, "large", 15)
DrawText("Lua Example", 8, 16, DrawMode.TilemapCache, "medium", 15, -4)
end
function Update(timeDelta)
-- Get the mouse position
mousePos = MousePosition()
-- Test for the collision
collision = rectA:Contains(mousePos)
end
function Draw()
-- Redraw the display
RedrawDisplay()
-- Draw rectA and change the color if there is a collision
DrawRect(rectA.x, rectA.y, rectA.width, rectA.height, collision and 6 or 5, DrawMode.Sprite)
-- Draw the mouse cursor on the screen
DrawRect(mousePos.x - 1, mousePos.y - 1, 2, 2, 15, DrawMode.Sprite)
endnamespace PixelVision8.Player
{
class NewRectExample : GameChip
{
// Store the rectangle
Rectangle rectA;
// This will store the mouse position
private Point mousePos;
// This will store the collision state
private bool collision = false;
public override void Init()
{
// Example Title
DrawText("NewRect()", 8, 8, DrawMode.TilemapCache, "large", 15);
DrawText("C Sharp Example", 8, 16, DrawMode.TilemapCache, "medium", 15, -4);
// Use the game's NewRect() to create a rectangle instance
rectA = NewRect(8, 32, 128, 128);
}
public override void Update(int timeDelta)
{
// Get the mouse position
mousePos = MousePosition();
// Test for the collision
collision = rectA.Contains(mousePos);
}
public override void Draw()
{
// Redraw the display
RedrawDisplay();
// Draw rectA and change the color if there is a collision
DrawRect(rectA.X, rectA.Y, rectA.Width, rectA.Height, collision ? 6 : 5, DrawMode.Sprite);
// Draw the mouse cursor on the screen
DrawRect(mousePos.X - 1, mousePos.Y - 1, 2, 2, 15, DrawMode.Sprite);
}
}
}