How to use uniforms on Unity shaders?

Hi there,
I am quite new on Shaders.

I would like to know how to declare uniforms.
I am following the famous Bookofshaders. Where we have the following code:

Code (CSharp):

1. #ifdef GL_ES
2. precision mediump float;
3. #endif
4.  
5. uniform vec2 u_resolution;
6. uniform float u_time;
7.  
8. vec3 colorA = vec3(0.149,0.141,0.912);
9. vec3 colorB = vec3(1.000,0.833,0.224);
10.  
11. void main() {
12.     vec3 color = vec3(0.0);
13.  
14.     float pct = abs(sin(u_time));
15.  
16.     // Mix uses pct (a value from 0-1) to
17.     // mix the two colors
18.     color = mix(colorA, colorB, pct);
19.  
20.     gl_FragColor = vec4(color,1.0);
21. }

However when I try to do the same in Unity I get an error coming from the declaration of the uniform:

Code (CSharp):

1.  
2. Shader "ColorShader00" { // defines the name of the shader
3.    SubShader { // Unity chooses the subshader that fits the GPU best
4.       Pass { // some shaders require multiple passes
5.          GLSLPROGRAM // here begins the part in Unity's GLSL
6.  
7.          #ifdef VERTEX // here begins the vertex shader
8.          
9.  
10.          void main() // all vertex shaders define a main() function
11.          {
12.                 gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex;
13.                
14.          }
15.  
16.          #endif // here ends the definition of the vertex shader
17.  
18.  
19.          #ifdef FRAGMENT // here begins the fragment shader
20.          uniform vec4 _SinTime
21.  
22.          void main() // all fragment shaders define a main() function
23.          {
24.        
25.             vec3 colorA = vec3(0.149,0.141,0.912);
26.             vec3 colorB = vec3(1.000,0.833,0.224);
27.  
28.             float pct = abs(_SinTime.y));
29.  
30.             // Mix uses pct (a value from 0-1) to
31.             // mix the two colors
32.             color = mix(colorA, colorB, pct);
33.  
34.             gl_FragColor = vec4(color, 1.0);
35.                
36.          }
37.  
38.          #endif // here ends the definition of the fragment shader
39.  
40.          ENDGLSL // here ends the part in GLSL
41.       }
42.    }
43. }
44.  

What am I doing wrong?

 

You're missing a semi-colon at the end of that line...

 

Thats true, my bad. Thanks!
Anyway the main problem is not there.
I want it to change color over time but it remains cyan. all the time.

 

If that's not working, I honestly don't know. I don't ever write GLSL shaders for Unity. The only guess I have is I usually see the uniform defined outside of the #ifdef blocks.