GetSpriteVertexY - Learn To Code - PlayBASIC Documentation

GetSpriteVertexY

Ypos# = GetSpriteVertexY(SpriteIndex, VertexIndex)

Parameters:

SpriteIndex = The Sprite you wish to query
VertexIndex = The vertex you wish to read ranges between (0 and 3)

Returns:

Ypos# = The Y position of this vertex

The GetSpriteVertexY function returns the position of a sprite corner vertex. This position is post rotation & scaling.

The corner vertex of a sprite are ordered in a clock wise fashion. Vertex zero being the Top-Left, Vertex One is the Top-Right, Vertex three is the bottom/right and Vertex four is the Bottom-Left

So if the image isn't rotated, they'd look like this.


         (0)-----(1)
          |       |
          |       |
          |       |
          |       |
         (3)-----(2)

FACTS:

* GetSpriteVertexY returns the position of the vertex after rotation and scaling have been applied to the sprite.

* Also see PositionSprite, ScaleSprite, RotateSprite

Mini Tutorial:

This example creates a random image, creates 10 randomly positioned sprites on the screen using this image.

The main loop rotates the sprites and draws the bounding egdes via reading the sprites vertex positions.

; Make a Blue image, with circle on it
  Cls RGB(0,0,255)
  For lp =0 To 100
     CircleC Rnd(100),Rnd(100),Rnd(5),1,RndRGB()
  Next
  GetImage 1,0,0,100,100
  PrepareFXImage 1

; Make 10 sprites
  For spr=1 To 10

   ; Create the sprite
     CreateSprite Spr

   ; psition the spriotye randomly on the screen
     x=Rnd(GetScreenWidth())
     y=Rnd(GetScreenHeight())
     PositionSprite Spr,x,y

   ; assign this sprite Image #1
     SpriteImage Spr,1

   ; Set Sprite Drawmode to rotated
     SpriteDrawMode Spr,2


     CenterSpriteHandle spr
     SpriteCollision spr,on

   ; Set sprite collision to Rotated rectangles
     SpriteCollisionMode Spr,1
  Next



  Do
     Cls RGB(0,0,0)


     DrawAllSprites

   ; start for/next loop from 1 to 10
     For spr=1 To 10

      ; Turn this sprite
        TurnSprite spr,spr*0.33

      ; Read the Sprites Vertex positions
        X1#=GetSpriteVertexX(spr,0)
        Y1#=GetSpriteVertexY(spr,0)

        X2#=GetSpriteVertexX(spr,1)
        Y2#=GetSpriteVertexY(spr,1)

        X3#=GetSpriteVertexX(spr,2)
        Y3#=GetSpriteVertexY(spr,2)

        X4#=GetSpriteVertexX(spr,3)
        Y4#=GetSpriteVertexY(spr,3)

      ; Draw lines to connect the edges
        Line x1#,y1#,x2#,y2#
        Line x2#,y2#,x3#,y3#
        Line x3#,y3#,x4#,y4#
        Line x4#,y4#,x1#,y1#

     Next

     Sync
  Loop


Related Info:	GetSpriteOldX \| GetSpriteOldY \| GetSpriteOldZ \| GetSpriteVertexX \| GetSpriteX \| GetSpriteY \| GetSpriteZ :