vs.1.1              // version instruction

// Scale the vertex position by the heightmap dimensions
mul r0, v0, c[8]

// Transform the vertex position
dp4 oPos.x, r0, c[0]      	// Matrix multiply row 0
dp4 oPos.y, r0, c[1]      	// Matrix multiply row 1
dp4 oPos.z, r0, c[2]      	// Matrix multiply row 2
dp4 oPos.w, r0, c[3]      	// Matrix multiply row 3

mul r1, v0.xzww, c[9]       // Convert the vertex's XZ position into a UV coordinate
sub r1.y, c[9].y, r1.y      // Flip the V coordinate

mov oT0, r1                 // Set up UV stage 0
mov oT1, r1                 // Set up UV stage 1
mov oT2, r1                 // Set up UV stage 2
mov oT3, r1                 // Set up UV stage 3

// Generate a greyscale color for this vertex. Black means Y==0, White means
// Y==the highest point on the heightmap. Since our vertex position is passed
// in to v0 normalized from 0..1, all we need to do is copy its Y coordinate
// into the Diffuse's RGB values.
mov oD0, v0.yyyw