I'm trying to make a basic ripple effect in HLSL. So I'm using the following equation(please correct me if I'm wrong)
Current Vertex Height = A * sin( kr - wt)
with this equation , i am able to generate basic sin waves along x and z axes.
For generating ripples i replaced r with
r = sqrt(x2 + z2) , where x and z are the respective x & z coordinates of the point.
The problem is that when i use this value of r (ie the sqrt one), im getting strange random oscillations which clearly do not look like circular waves , but when i remove the sqrt and instead write this
r = x2 + z2
i get, with some adjustment to the value k , perfect circular waves , although now i have to adjust the value of k with a increment/decrement factor of 0.000001 !!!!(earlier with sqrt it was 0.0001)
the values that i use are(all floats)
A = 25
K = 8
w = pi/2
and one more thing , im incrementing the time t by 0.01 every iteration
and heres the code outline (using HLSL ,by the way)
..... ConvertToradians(t); float term = input.position.x * input.position.x + input.position.z * input.position.z; float amp = 25.0f; input.position.y = amp * sin(k*term - (w * t)); output.position = multiply(input.position,ViewProjectionMatrix); ..... Can anyone please explain why is this happening? I've seen a similar example in the DX SDK Samples and in there they have used the length() function , which i think still calculates squareroot.Even in many other samples that i checked on the net , sqrt is used.
Is this due to the values that I've used??
thanks!
