shadow volume vp.txt

it is a visual c++ file

!!ARBvp1.0
# Vertex Program for shadow volume extrusion

# Parameters
PARAM mvp[4]		= { state.matrix.mvp };		#modelview projection matrix
PARAM lightPosition = program.env[0];			#object space light position

PARAM zero			= {0.0, 0.0, 0.0, 0.0};
PARAM one			= {1.0, 1.0, 1.0, 1.0};		#useful constants


# Per vertex inputs
ATTRIB iPos			= vertex.position;			#position
ATTRIB iNorm		= vertex.normal;			#normal

# Temporaries
TEMP lightVector;		#light vector
TEMP lightDotNorm;		#light vector dot normal
TEMP toSubtract;		#What to subtract from the vertex position
TEMP position;			#Computed position (object space)
TEMP toMult;			#What to multiply position by to set w=0

# Outputs
OUTPUT oPos			= result.position;			#position




# Calculate light vector
SUB lightVector, lightPosition, iPos;

# lightDotNorm = light vector dot normal(object space)
DP3 lightDotNorm, lightVector, iNorm;

# toSubtract= (1, 1, 1, 0) if l.n<0
#			= (0, 0, 0, 0) if l.n>0
MOV toSubtract, zero;
SLT toSubtract.xyz, lightDotNorm, zero;

# toSubtract= (Lx, Ly, Lz, 0)	if l.n<0 (light position)
#			= (0, 0, 0, 0)		if l.n>0
MUL toSubtract, toSubtract, lightPosition;

# position  = (Vx-Lx, Vy-Ly, Vz-Lz, Vw) if l.n<0
#			= (Vx, Vy, Vz, Vw)			if l.n>0
MOV position, iPos;
SUB position, position, toSubtract;

# toMult= (1, 1, 1, 0) if l.n<0
#		= (1, 1, 1, 1) if l.n>0
MOV toMult, one;
SGE toMult.w, lightDotNorm, zero;

# position  = (Vx-Lx, Vy-Ly, Vz-Lz, 0) if l.n<0
#			= (Vx, Vy, Vz, Vw)			if l.n>0
MUL position, position, toMult;

# project to clip coords
DP4 oPos.x, mvp[0], position;
DP4 oPos.y, mvp[1], position;
DP4 oPos.z, mvp[2], position;
DP4 oPos.w, mvp[3], position;

END