show demo mode

project/frag7.glsl

@@ -10,11 +10,15 @@ out vec4 fragColor;
 
 uniform sampler2D iTex0;
 uniform int iFPS;
+uniform int iDemo;
+
+const int[] demoStr = int[5](0x44, 0x45, 0x4D, 0x4F, 0x00);
 
 void main() {
     // vec2 uv = 1 - vUV;
     vec2 uv = vUV;
     vec3 c = texture(iTex0, uv).xyz;
-    c = mix(c, 1 - c, write_int(uv * 20, vec2(1.), iFPS, 2));
+    c = mix(c, 1 - c, iDemo * write_int(uv * 20, vec2(1.), iFPS, 2));
+    c = mix(c, 1 - c, iDemo * write_5(uv * 20, vec2(1., 19.), demoStr));
     fragColor = vec4(c, 1);
 }