Added circle module, demonstration, changed default configuration values

shaders/circle/1.frag

@@ -0,0 +1,83 @@
+layout(pixel_center_integer) in vec4 gl_FragCoord;
+
+#request uniform "screen" screen
+uniform ivec2 screen;
+
+#request uniform "audio_sz" audio_sz
+uniform int audio_sz;
+
+#include ":util/smooth.glsl"
+#include ":circle.glsl"
+
+#request uniform "audio_l" audio_l
+#request transform audio_l "window"
+#request transform audio_l "fft"
+#request transform audio_l "gravity"
+#request transform audio_l "avg"
+uniform sampler1D audio_l;
+
+#request uniform "audio_r" audio_r
+#request transform audio_r "window"
+#request transform audio_r "fft"
+#request transform audio_r "gravity"
+#request transform audio_r "avg"
+uniform sampler1D audio_r;
+
+out vec4 fragment;
+
+#define TWOPI 6.28318530718
+#define PI 3.14159265359
+
+/* This shader is based on radial.glsl, refer to it for more commentary */
+
+float apply_smooth(float theta) {
+    
+    float idx = theta + ROTATE;
+    float dir = mod(abs(idx), TWOPI);
+    if (dir > PI)
+        idx = -sign(idx) * (TWOPI - dir);
+    if (INVERT > 0)
+        idx = -idx;
+    
+    float pos = abs(idx) / (PI + 0.001F);
+    #define smooth_f(tex) smooth_audio(tex, audio_sz, pos)
+    float v;
+    if (idx > 0) v = smooth_f(audio_l);
+    else         v = smooth_f(audio_r);
+    v *= AMPLIFY;      
+    #undef smooth_f
+    return v;
+}
+
+void main() {
+    float
+        dx = gl_FragCoord.x - (screen.x / 2),
+        dy = gl_FragCoord.y - (screen.y / 2);
+    float theta = atan(dy, dx);
+    float d = sqrt((dx * dx) + (dy * dy));
+    float adv = (1.0F / d) * (C_LINE * 0.5);
+    float
+        adj0 = theta + adv,
+        adj1 = theta - adv;
+    d -= C_RADIUS;
+    if (d >= -(float(C_LINE) / 2.0F)) {
+        float v = apply_smooth(theta);
+        
+        adj0 = apply_smooth(adj0) - v;
+        adj1 = apply_smooth(adj1) - v;
+        
+        float
+            dmax = max(adj0, adj1),
+            dmin = min(adj0, adj1);
+        
+        d -= v;
+        #if C_FILL > 0
+        #define BOUNDS (d < (float(C_LINE) / 2.0F))
+        #else
+        #define BOUNDS (d > -(float(C_LINE) / 2.0F) && d < (float(C_LINE) / 2.0F)) || (d <= dmax && d >= dmin)
+        #endif
+        if (BOUNDS)  {
+            fragment = OUTLINE;
+        }
+    }
+}

shaders/circle/2.frag

@@ -0,0 +1,30 @@
+
+in vec4 gl_FragCoord;
+
+#request uniform "prev" tex
+uniform sampler2D tex;    /* screen texture    */
+
+out vec4 fragment; /* output */
+
+#include ":circle.glsl"
+
+void main() {
+    fragment = texelFetch(tex, ivec2(gl_FragCoord.x, gl_FragCoord.y), 0);
+    #if C_SMOOTH > 0
+    vec4
+        a0 = texelFetch(tex, ivec2((gl_FragCoord.x + 1), (gl_FragCoord.y + 0)), 0),
+        a1 = texelFetch(tex, ivec2((gl_FragCoord.x + 1), (gl_FragCoord.y + 1)), 0),
+        a2 = texelFetch(tex, ivec2((gl_FragCoord.x + 0), (gl_FragCoord.y + 1)), 0),
+        a3 = texelFetch(tex, ivec2((gl_FragCoord.x + 1), (gl_FragCoord.y + 0)), 0),
+    
+        a4 = texelFetch(tex, ivec2((gl_FragCoord.x - 1), (gl_FragCoord.y - 0)), 0),
+        a5 = texelFetch(tex, ivec2((gl_FragCoord.x - 1), (gl_FragCoord.y - 1)), 0),
+        a6 = texelFetch(tex, ivec2((gl_FragCoord.x - 0), (gl_FragCoord.y - 1)), 0),
+        a7 = texelFetch(tex, ivec2((gl_FragCoord.x - 1), (gl_FragCoord.y - 0)), 0);
+
+    vec4 avg = (a0 + a1 + a2 + a3 + a4 + a5 + a6 + a7) / 8.0;
+    if (fragment.a == 0) {
+        fragment = avg;
+    }
+    #endif
+}