Cardboard Box and Stealth Components (#11569)

Resources/Textures/Shaders/stealth.swsl

@@ -0,0 +1,37 @@
+light_mode unshaded;
+
+uniform sampler2D SCREEN_TEXTURE;
+uniform highp float visibility; // number between -1 and 1
+uniform mediump vec2 reference;
+
+const mediump float time_scale = 0.25;
+const mediump float distance_scale = 0.125;
+
+void fragment() {
+
+    vec4 sprite = zTexture(UV);
+
+    if (sprite.a == 0.0) {
+        discard;
+    }
+
+    // get distortion magnitude. hand crafted from a random jumble of trig functions
+    vec2 coords = (FRAGCOORD.xy + reference) * distance_scale;
+    float w = sin(TIME + (coords.x + coords.y + 2.0*sin(TIME*time_scale) * sin(TIME*time_scale + coords.x - coords.y)) );
+
+    // visualize distortion via:
+    // COLOR = vec4(w,w,w,1);
+
+    w *= (3 + visibility * 2);
+
+    vec4 background = zTextureSpec(SCREEN_TEXTURE, ( FRAGCOORD.xy + vec2(w) ) * SCREEN_PIXEL_SIZE );
+
+    float alpha;
+    if (visibility>0)
+      alpha = sprite.a * visibility;
+    else
+      alpha = 0;
+
+    COLOR.xyz = mix(background.xyz, sprite.xyz, alpha);
+    COLOR.a = 1.0;
+}