12. Effect

Following code clip demostrates the use of effect.

• In the shader class declares an effect variable effect

  variable effect

• In InitDeviceObjects method of the shader class inserts lines

  set effect [$app effect $filename $userid]

You may set fixed file name string without using the open file dialog box. The $app graph command creates a graph object gh with filename and userid. The userid is a 32-bit integer.

• In the RestoreDeviceObjects method inserts below line to restore the effect.

  $effect restore

• In the InvalidateDeviceObjects method inserts below line to invalidate the effect.

  $effect invalidate

• In the DeleteDeviceObjects method inserts below line to delete the effect.

  $effect release

• In the Render method the regular use of effect looks like

  $effect setMatrix "matView" $mView
  $vb stream 0 0 [$vertice size]
  $ib indices 0
  set uPass [$effect begin 0]
  for {set i 0} {i < uPass} {incr i} {
    $effect pass $i
    $app drawIndexedPrimitive trianglelist 0 \
           0 $nNumVertices 0 $nNumFaces
  }
  $effect end

The $effect setMatrix sets a matrix used in the effect. $effect begin id starts the effect. In the for loop $effect pass $i enables the i-th pass in the effect. After showing all the effect, $effect end closes the rendering.