|
|
Performs a three-component dot product and uses the result to do a 1D texture lookup.
| texdp3tex dst, src |
|---|
where
| Pixel shader versions | 1_1 | 1_2 | 1_3 | 1_4 | 2_0 | 2_x | 2_sw | 3_0 | 3_sw |
|---|---|---|---|---|---|---|---|---|---|
| texdp3tex | x | x |
Texture registers must use the following sequence.
tex t(n) // Define tn as a standard 3-vector (tn must be
// defined in some way before texdp3tex uses it)
texdp3tex t(m), t(n) // where m > n
// Perform a three-component dot product between t(n) and
// the texture coordinate set m. Use the scalar result to
// do a 1D texture lookup at texturestage m and place
// the result in t(m)
Here is more detail about how the dot product and texture lookup are done.
The texdp3tex instruction performs a three-component dot product.
u' = TextureCoordinates(stage m)UVW • t(n)RGB
The result is used to sample the texture at texture stage m by performing a 1D lookup.
t(m)RGBA = TextureSample(stage m)RGBA using (u',0,0) as coordinates