Magnifying glass -like trick.

Hi there

I am not sure how this can be done so I turned to answers for some advice.

I have a letter (on a texture) with handwriting on it. Basically what I want to do is move a “magnifying glass” or “loupe” across.

Wherever the loupe is, I want to display beneath the same letter but with type as if typed on a typewriter.

I am trying this with Unity Basic.Thanks!

3710-lenstrick.png

Not there yet - it works with the keyboard now, on to learning how to move it with the finger on screen. I use a separate alpha shader and a script.

The script:

#pragma strict

var scrollspeed : float = 0.3;
private var offsetX : float = 0.0;
private var offsetY : float = 0.0;

function Update() {
 if(Input.GetKey("d"))
 {
   offsetX -= Time.deltaTime * scrollspeed;
   renderer.material.SetTextureOffset("_Alpha", new Vector2(offsetX, offsetY));
 }
 if(Input.GetKey("w"))
 {
   offsetY -= Time.deltaTime * scrollspeed;
   renderer.material.SetTextureOffset("_Alpha", new Vector2(offsetX, offsetY));
 }
 if(Input.GetKey("s"))
 {
   offsetY += Time.deltaTime * scrollspeed;
   renderer.material.SetTextureOffset("_Alpha", new Vector2(offsetX, offsetY));
 }
 if(Input.GetKey("a"))
 {
   offsetX += Time.deltaTime * scrollspeed;
   renderer.material.SetTextureOffset("_Alpha", new Vector2(offsetX, offsetY));
 }

}

and the shader from the unity forums:

    Shader "SeparateAlpha"
{
 Properties 
 {
_Diffuse("_Diffuse", 2D) = "gray" {}
_Alpha("_Alpha", 2D) = "white" {}
_Color("_Color", Color) = (1,1,1,1)

 }

 SubShader 
 {
 Tags
 {
"Queue"="Transparent"
"IgnoreProjector"="False"
"RenderType"="Opaque"

 }


Cull Back
ZWrite On
ZTest LEqual
ColorMask RGBA
Fog{
}


 CGPROGRAM
#pragma surface surf BlinnPhongEditor  alpha decal:blend vertex:vert
#pragma target 2.0


sampler2D _Diffuse;
sampler2D _Alpha;
float4 _Color;

 struct EditorSurfaceOutput {
 half3 Albedo;
 half3 Normal;
 half3 Emission;
 half3 Gloss;
 half Specular;
 half Alpha;
 half4 Custom;
 };

 inline half4 LightingBlinnPhongEditor_PrePass (EditorSurfaceOutput s, half4 light)
 {
half3 spec = light.a * s.Gloss;
half4 c;
c.rgb = (s.Albedo * light.rgb + light.rgb * spec);
c.a = s.Alpha;
return c;

 }

 inline half4 LightingBlinnPhongEditor (EditorSurfaceOutput s, half3 lightDir, half3 viewDir, half atten)
 {
 half3 h = normalize (lightDir + viewDir);

 half diff = max (0, dot ( lightDir, s.Normal ));

 float nh = max (0, dot (s.Normal, h));
 float spec = pow (nh, s.Specular*128.0);

 half4 res;
 res.rgb = _LightColor0.rgb * diff;
 res.w = spec * Luminance (_LightColor0.rgb);
 res *= atten * 2.0;

 return LightingBlinnPhongEditor_PrePass( s, res );
 }

 struct Input {
 float2 uv_Diffuse;
float2 uv_Alpha;

 };

 void vert (inout appdata_full v, out Input o) {
float4 VertexOutputMaster0_0_NoInput = float4(0,0,0,0);
float4 VertexOutputMaster0_1_NoInput = float4(0,0,0,0);
float4 VertexOutputMaster0_2_NoInput = float4(0,0,0,0);
float4 VertexOutputMaster0_3_NoInput = float4(0,0,0,0);


 }


 void surf (Input IN, inout EditorSurfaceOutput o) {
 o.Normal = float3(0.0,0.0,1.0);
 o.Alpha = 1.0;
 o.Albedo = 0.0;
 o.Emission = 0.0;
 o.Gloss = 0.0;
 o.Specular = 0.0;
 o.Custom = 0.0;

float4 Tex2D1=tex2D(_Diffuse,(IN.uv_Diffuse.xyxy).xy);
float4 Add0=_Color + Tex2D1;
float4 Tex2D0=tex2D(_Alpha,(IN.uv_Alpha.xyxy).xy);
float4 Master0_1_NoInput = float4(0,0,1,1);
float4 Master0_2_NoInput = float4(0,0,0,0);
float4 Master0_3_NoInput = float4(0,0,0,0);
float4 Master0_4_NoInput = float4(0,0,0,0);
float4 Master0_7_NoInput = float4(0,0,0,0);
float4 Master0_6_NoInput = float4(1,1,1,1);
o.Albedo = Add0;
o.Alpha = Tex2D0.aaaa;

 o.Normal = normalize(o.Normal);
 }
 ENDCG
 }
 Fallback "Diffuse"
}