I recently found the need to spruce up the water in a new 2D game that I am working on, so I decided to have a play around with Unity shaders again. Here’s the code to the shader:<\/p>\n
[sourcecode language=”js”]
\nShader "Unlit\/WaterTexture"
\n{
\n\tProperties
\n\t{
\n\t\t_MainTex ("Texture", 2D) = "white" {}
\n\t\t_ScrollX ("X Scroll Speed", Range(-10, 10)) = 0
\n\t\t_WaveSpeed("WaveSpeed", Range(0, 100)) = 10
\n\t\t_FrequencyX("X Axis Frequency", Range(0, 100)) = 34
\n\t\t_AmplitudeX("X Axis Amplitude", Range(0, 100)) = 0.005
\n\t}
\n\tSubShader
\n\t{
\n\t\tTags { "RenderType"="Opaque" }
\n\t\tLOD 100<\/p>\n
\t\tPass
\n\t\t{
\n\t\t\tCGPROGRAM
\n\t\t\t#pragma vertex vert
\n\t\t\t#pragma fragment frag<\/p>\n
\t\t\t#include "UnityCG.cginc"<\/p>\n
\t\t\tstruct appdata
\n\t\t\t{
\n\t\t\t\tfloat4 vertex : POSITION;
\n\t\t\t\tfloat2 uv : TEXCOORD0;
\n\t\t\t};<\/p>\n
\t\t\tstruct v2f
\n\t\t\t{
\n\t\t\t\tfloat2 uv : TEXCOORD0;
\n\t\t\t\tfloat4 vertex : SV_POSITION;
\n\t\t\t};<\/p>\n
\t\t\tsampler2D _MainTex;
\n\t\t\tfloat4 _MainTex_ST;
\n\t\t\tfixed _ScrollX;
\n\t\t\tfixed _FrequencyX;
\n\t\t\tfixed _AmplitudeX;
\n\t\t\tfixed _WaveSpeed;<\/p>\n
\t\t\tv2f vert (appdata v)
\n\t\t\t{
\n\t\t\t\tv2f o;
\n\t\t\t\to.vertex = mul(UNITY_MATRIX_MVP, v.vertex);
\n\t\t\t\to.uv = TRANSFORM_TEX(v.uv, _MainTex);
\n\t\t\t\treturn o;
\n\t\t\t}<\/p>\n
\t\t\tfixed4 frag(v2f i) : SV_Target
\n\t\t\t{
\n\t\t\t\tfixed time = _Time * _WaveSpeed;
\n\t\t\t\tfixed2 uvs = i.uv;
\n\t\t\t\tfixed offset = (_ScrollX * _Time);
\n\t\t\t\tuvs.x += offset;
\n\t\t\t\tuvs.x = fmod(uvs.x, 1);
\n\t\t\t\tuvs.x += sin(uvs.y * _FrequencyX + time) * _AmplitudeX;
\n\t\t\t\tfixed2 uvs2 = i.uv;
\n\t\t\t\tuvs2.x -= offset;
\n\t\t\t\tuvs2.x = fmod(uvs2.x, 1);
\n\t\t\t\tif (uvs2.x < 0)
\n\t\t\t\t\tuvs2.x += 1;
\n\t\t\t\tuvs2.y = 1 – i.uv.y;
\n\t\t\t\tuvs2.x += sin(uvs2.y * _FrequencyX + time) * _AmplitudeX;
\n\t\t\t\tfixed4 col = tex2D(_MainTex, uvs);
\n\t\t\t\tfixed4 col2 = tex2D(_MainTex, uvs2);
\n\t\t\t\tcol = (col + col2) \/ 2;
\n\t\t\t\treturn col;
\n\t\t\t}<\/p>\n
\t\t\tENDCG
\n\t\t}
\n\t}
\n}
\n[\/sourcecode]<\/p>\n
The main section of the code is the fragment shader, it plays with the textures U coordinates by applying a sine wave to them, it then does the same with the pixel on the opposite side of the V axis then merges them both together, it also scrolls the textures, this produces a nice running water effect.<\/p>\n