out and monitor in defined shaders

shaders/frag8.glsl

@@ -0,0 +1,23 @@
+// MONITOR
+// ---
+
+in vec2 vUV;
+out vec4 fragColor;
+
+float s(vec2 uv, float x0, float y0) {
+    return step(x0, uv.x) * step(-x0 - 1, -uv.x) * step(y0, uv.y) *
+step(-y0 - 1, -uv.y);
+}
+
+void main() {
+    vec2 uv = vUV * 3;
+    fragColor = vec4(0);
+    fragColor += s(uv,0,2) * texture(tex1, uv);
+    fragColor += s(uv,1,2) * texture(tex2, uv);
+    fragColor += s(uv,2,2) * texture(tex3, uv);
+    fragColor += s(uv,0,1) * texture(tex4, uv);
+    fragColor += s(uv,1,1) * texture(tex5, uv);
+    fragColor += s(uv,2,1) * texture(tex6, uv);
+    fragColor += s(uv,0.5,0) * texture(tex7, uv-vec2(0.5,0));
+    fragColor += s(uv,1.5,0) * texture(tex0, uv-vec2(0.5,0));
+}