It might be a trivial question, but I couldn't come up with a simple solution. I need to create a cube like on the image below in Unity.

enter image description here

As always, I target mobile so it would be nice if it was made on a mobile/diffuse shader.

I was playing with lights a little bit, but in order to achieve this kind of look, I'd need to stack multiple lights because one shadow is not enough. Also, I tried adjusting the angles of the lighting - with no luck.

Do you have any tips, how could I make one in a most efficient way?

  • \$\begingroup\$ Can you cheat with a texture? As in, just make a texture that's yellow on top and dark on the sides? \$\endgroup\$ – MichaelHouse Jun 27 '17 at 21:19
  • \$\begingroup\$ Yep! As long as it stays mobile/diffuse :) \$\endgroup\$ – Jacob Jun 27 '17 at 21:21
  • \$\begingroup\$ Be more specific, ONLY a face pointing TOP should have a color? All others faces are going to be black? Or are we talking about blending these colors, accordingly to the normal of that said face? \$\endgroup\$ – Guilherme Junqueira Coutinho Jun 27 '17 at 23:34

I will be giving you two answers, The one for your actuall problem,and another one with a cube that has faces colored based on how much they are facing top:

To simply create a Cube like that:

  • Create an image, and color it like the left half should be COLOR_X and the other half, COLOR_Y, save it; (paint will do it)
  • create a cube inside blender, and go to UV/Unwrapp;
  • place the face you want to be COLOR_X in the left, the others in the right;
  • Export to Unity;
  • Inside Unity create a simple Unlit/Texture Material;
  • Set the image you created as the Texture;
  • Apply the material to the UV/mapped cube;

Faces should have a color depending of the normal angle;

    Shader "Unlit/NormalColored"
            _NormalColor ("Color facing TOP", Color) = (1,.5,0,1)
                #pragma vertex vert
                #pragma fragment frag
                // include file that contains UnityObjectToWorldNormal helper function
                #include "UnityCG.cginc"

                struct v2f {
                    // we'll output world space normal as one of regular ("texcoord") interpolators
                    half3 worldNormal : TEXCOORD0;
                    float4 pos : SV_POSITION;

                // vertex shader: takes object space normal as input too
                v2f vert (float4 vertex : POSITION, float3 normal : NORMAL)
                    v2f o;
                    o.pos = UnityObjectToClipPos(vertex);
                    // UnityCG.cginc file contains function to transform
                    // normal from object to world space, use that
                    o.worldNormal = UnityObjectToWorldNormal(normal);
                    return o;

                float4 _NormalColor;
                float _ShadeColor;

                fixed4 frag (v2f i) : SV_Target
                    // The Y component is TOP direction
                    float normal_y = (i.worldNormal).y/2 + .5;
                    float normal_y_2 = (i.worldNormal).y;
                    return (normal_y_2 * _NormalColor);
  • only a face pointing EXACTLY TOP should be colored, change the Frag function to this;

    fixed4 frag (v2f i) : SV_Target
                    // The Y component is TOP direction
                    float normal_y = (i.worldNormal).y/2 + .5;
                    if (normal_y >= .999) // THIS VALUE CAN BE SET AS A PROPERTY SO U CAN PLAY AROUND WITH IT
                        return _NormalColor;
                    return 0;
  • \$\begingroup\$ I assume you know how to create a shader and then a material from this shader? If not, create one shader inside unity, then double click it, copy paste my code, then apply it to a material. It will be under Unlit/NormalColored \$\endgroup\$ – Guilherme Junqueira Coutinho Jun 28 '17 at 0:04
  • \$\begingroup\$ Btw, unlit shaders are the most performatic shaders... If this is not what you wanted, be more specific, but upvote my answer because it actually does what u described. \$\endgroup\$ – Guilherme Junqueira Coutinho Jun 28 '17 at 0:05
  • \$\begingroup\$ Yeah, this is what I want, but I need to color 5 other faces with a different one so top is color X and 5 other are color Y. \$\endgroup\$ – Jacob Jun 28 '17 at 13:47
  • \$\begingroup\$ Which frag function are you using? The "EXACTLY TOP should be colored,"? \$\endgroup\$ – Guilherme Junqueira Coutinho Jun 28 '17 at 14:03
  • \$\begingroup\$ The first one, with angles \$\endgroup\$ – Jacob Jun 28 '17 at 14:07

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