using UnityEngine;

// Sets up transformation matrices to scale&scroll water waves
// for the case where graphics card does not support vertex programs.

[ExecuteInEditMode]
public class WaterSimple : MonoBehaviour
{
    void Update()
    {
        if (!renderer)
            return;
        Material mat = renderer.sharedMaterial;
        if (!mat)
            return;

        Vector4 waveSpeed = mat.GetVector("WaveSpeed");
        float waveScale = mat.GetFloat("_WaveScale");
        float t = Time.time / 20.0f;

        Vector4 offset4 = waveSpeed * (t * waveScale);
        Vector4 offsetClamped = new Vector4(Mathf.Repeat(offset4.x, 1.0f), Mathf.Repeat(offset4.y, 1.0f), Mathf.Repeat(offset4.z, 1.0f), Mathf.Repeat(offset4.w, 1.0f));
        mat.SetVector("_WaveOffset", offsetClamped);

        Vector3 scale = new Vector3(1.0f / waveScale, 1.0f / waveScale, 1);
        Matrix4x4 scrollMatrix = Matrix4x4.TRS(new Vector3(offsetClamped.x, offsetClamped.y, 0), Quaternion.identity, scale);
        mat.SetMatrix("_WaveMatrix", scrollMatrix);

        scrollMatrix = Matrix4x4.TRS(new Vector3(offsetClamped.z, offsetClamped.w, 0), Quaternion.identity, scale * 0.45f);
        mat.SetMatrix("_WaveMatrix2", scrollMatrix);
    }
}