View source for Default DX9Settings.ini

 <nowiki>
[General]

// UseRenderedShaders=true is nearly always useful, because it trims the 
// list of shaders seen while hunting down to just those active in the 
// current scene.  Disable this only if you get crashes during hunting.
UseRenderedShaders=true

// DumpAll will generate ASM text files for every shader seen by the game.
// This is usually worth doing once, but not useful for every run.
DumpAll=false

// Constant registers that will arrive in Vertex and Pixel Shaders, as
// c250.  The constants below will be assigned, based on the key preset.
DefVSConst1 = 250  		
DefPSConst1 = 250

// The PresetKeysList specifies which KEYs will be used.
// Multiple keys lists are supported.
PresetsKeysList = 1;

// For this single key example, we only need one keylist, KEY1. This specifies
// that the Numpad 0 keyboard key (Key=96) should act as a toggle. And toggle
// between the two Presets of PRES1, PRES2.  Which will change the Const1 being 
// passed to the shader code from 1.0 to 0.0 as floating point numbers.
// Type=1 is toggle, Type=2 is momentary.
[KEY1]
Key = 96
Presets = 1;2;
Type = 1

// Constants that will be sent to every shader through constant register c250.
// The Const1 tells us that we'll need to use c250.x to compare against these
// values.  Const2 would be seen as c250.y.
// 0x3f800000 is 1.0 in floating point hex, 0x00000000 is 0.0 in hex
[PRES1]
Const1 = 0x3f800000
[PRES2]
Const1 = 0x00000000
</nowiki>


To use these constants in the shader add code like:

 <nowiki>
//def c250, Const1, Const2, Const3, Const4
def c200, 0, 1, 0.0625, 0	// x=0 for comparison to Const1

// if Const1 = 0 turn effect off, else leave it on
mov r30.x, c200.x
if_eq r30.x, c200.x
   mov oC0.xyzw, c200.wwww
endif
</nowiki>

----
'''References''':

Microsoft virtual keycodes for ''Key='' use. Especially helpful for those odd keys like Insert, or Pause or F-Keys or Numpad. Must be converted from Hexadecimal to Decimal. [http://msdn.microsoft.com/en-us/library/ms927178.aspx keycodes]

ASCII table for normal keyboard keys. Use the Dec column. [http://www.asciitable.com/ ASCII]

Floating point to Hex converter, to make floating point hex constants.  At shader runtime, constants are always float. [http://gregstoll.dyndns.org/~gregstoll/floattohex/ FloatToHex]