Added simple 'TFT effect' shader

Author: Greger Olsson

tft.glsl

@@ -0,0 +1,23 @@
+/** Size of TFT "pixels" */
+float resolution = 4.0;
+
+/** Strength of effect */
+float strength = 0.5;
+
+void _scanline(inout vec3 color, vec2 uv)
+{
+    float scanline = step(1.2, mod(uv.y * iResolution.y, resolution));
+    float grille   = step(1.2, mod(uv.x * iResolution.x, resolution));
+    color *= max(1.0 - strength, scanline * grille);
+}
+
+void mainImage(out vec4 fragColor, in vec2 fragCoord)
+{
+    vec2 uv = fragCoord.xy / iResolution.xy;
+    vec3 color = texture(iChannel0, uv).rgb;
+
+    _scanline(color, uv);
+
+    fragColor.xyz = color;
+    fragColor.w   = 1.0;
+}