working 6-stage fragments

shaders/frag1.glsl

@@ -0,0 +1,25 @@
+#version 460
+
+uniform float iTime;
+uniform vec2 iResolution;
+
+uniform sampler2D frame0;
+uniform sampler2D frame1;
+
+in vec2 vUV;
+layout(location = 3) out vec3 fragColor;
+
+
+// SRC A
+// ---------
+// IN: 0 / 1
+// OUT: 3
+
+void main() {
+    vec2 uv0 = vUV.st;
+    float ratio = iResolution.x / iResolution.y;
+    vec2 uv1 = (uv0 - .5) * vec2(ratio, 1);
+    vec3 color = vec3(vUV, sin(iTime * 0.5) * 0.5 + 0.5);
+    color *= 1 - step(cos(iTime) * 0.1 + 0.4, length(uv1));
+    fragColor = color + texture(frame0, vUV - 0.04).xyz * 0.5;
+}