BCA 4th Sem Notes-Midpoint Subdivision Algorithm

• UNIT-I 

~The Advantages of Interactive Graphics
~Representative Uses of Computer Graphics 
~Classification of Application Development of Hardware and software for computer Graphics
~Overview, Scan:
~Converting Lines
~Scan Converting Circles
~Scan Converting Ellipses

UNIT-II 

~Hardcopy Technologies
~Display Technologies
~Raster-Scan Display System
~Video Controller
~Random-Scan Display processor
~Input Devices for Operator Interaction
~Image Scanners
~Working exposure on graphics tools like Dream Weaver, 3D Effects etc
~Clipping
~Southland- Cohen Algorithm
~Cyrus-Beck Algorithm
~Midpoint Subdivision Algorithm

UNIT-III 

~Geometrical Transformation
~2D Transformation
~Homogeneous Coordinates and Matrix Representation of 2DTransformations 
~composition of 2D Transformations
~The Window-to-Viewport
Transformations

~Introduction to 3D Transformations Matrix

UNIT-IV 

Representing Curves & Surfaces----

Polygon meshes parametric

Cubic Curves

Quadric Surface

Solid Modeling   Representing Solids

Regularized Boolean Set Operation primitive Instancing Sweep   Representation
Boundary Representations
Spatial Partitioning Representations
Constructive Solid Geometry Comparison of Representations

UNIT-V                           

~Multimedia Definition
~CD-ROM and the multimedia highway
~Computer Animation
(Design, types of animation, using different functions)

UNIT-VI  

~Uses of Multimedia
~Introduction to making multimedia –
~The stage of Project
~hardware & software requirements to make good multimedia skills
~Training opportunities in Multimedia Motivation for Multimedia usage

Midpoint Subdivision Algorithm

It is utilized for cutting lines. The line is isolated in two sections. Mid purposes of line is acquired by partitioning it in two short fragments. Again division is done, by discovering midpoint. This procedure has proceeded until line of noticeable and imperceptible classification is acquired. Let (xi,yi) are midpoint

x₅lie on point of intersection of boundary of window.

Advantage of midpoint subdivision Line Clipping:

It is suitable for machines in which multiplication and division operation is not possible. Because it can be performed by introducing clipping divides in hardware.

Algorithm of midpoint subdivision Line Clipping:

Step1: Calculate the position of both endpoints of the line
Step2: Perform OR operation on both of these endpoints
Step3: If the OR operation gives 0000
            then
                    Line is guaranteed to be visible
          else
                  Perform AND operation on both endpoints.
                  If AND ≠ 0000
            then the line is invisible
      else
            AND=6000
            then the line is clipped case.
Step4: For the line to be clipped. Find midpoint
            X_m=(x₁+x₂)/2
            Y_m=(y₁+y₂)/2
        X_mis midpoint of X coordinate.
                  Y_mis midpoint of Y coordinate.
Step5: Check each midpoint, whether it nearest to the boundary of a window or not.
Step6: If the line is totally visible or totally rejected not found then repeat step 1 to 5.
Step7: Stop algorithm.
Example: Window size is (-3, 1) to (2, 6). A line AB is given having co-ordinates of A (-4, 2) and B (-1, 7). Does this line visible. Find the visible portion of the line using midpoint subdivision?
Solution:
Step1: Fix point A (-4, 2)

Step2: Find b"=mid of b'and b

So (-1, 5) is better than (2, 4)
Find b"&bb"(-1, 5) b (-1, 7)

   




 So B""to B length of line will be clipped from upper side
            Now considered left-hand side portion.
      A and B""are now endpoints
            Find mid of A and B""
      A (-4, 2) B ""(-1, 6)

 

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