add: shader-study-201910.frag

update: Refactor some codes, Exapmles.md, .gitignore(for local dev)

Author: DBC-Works

.gitignore

@@ -6,4 +6,5 @@ application.windows32
 application.windows64
 application.macosx
 .vscode
+.data-workplace
 img

SoundVisualShaderBase.pde

@@ -54,6 +54,9 @@ void draw() {
             recorder.finish();
             recorder = null;
           }
+          if (0 < frameDropCount) {
+            println("Frame drop count: ",  frameDropCount, " / ", frameCount, "(", (frameDropCount * 100.0 / frameCount) ,"%)");
+          }
           exit();
           return;
         }
@@ -66,9 +69,9 @@ void draw() {
   provider.update();
   final float progress = provider.getProgressPercentage();
 
-  if (0 <= startFrameCount && 0.0 < progress) {
-    println("Leading frame count: " + (frameCount - startFrameCount));
-    startFrameCount = -1;
+  if (startFrameCount == 0 && 0.0 < progress) {
+    println("Leading frame count: ", frameCount);
+    startFrameCount = frameCount;
   }
 
   if (onlyInitialization == false) {

data/shader-study-201910.frag

@@ -0,0 +1,58 @@
+/*
+ * shader: ray marching study 201910
+ * references:
+ * - [GLSL SandBoxで手軽にレイマーチングで遊ぼう](https://hackerslab.aktsk.jp/2018/12/01/131928)
+ * - [魔法使いになりたい人のためのシェーダーライブコーディング入門](https://qiita.com/kaneta1992/items/21149c78159bd27e0860)
+ * - [Phantom Mode](https://www.shadertoy.com/view/MtScWW)
+ * - [Live Coding Using Phantom Mode](https://www.shadertoy.com/view/wl2GWG)
+ * - [distance functions](https://iquilezles.org/www/articles/distfunctions/distfunctions.htm)
+ */
+
+uniform ivec2 resolution;
+uniform float time;
+uniform float progress;
+uniform vec3 soundLevel;
+
+uniform float kick;
+
+const float PI = acos(-1);
+const float TWO_PI = PI * 2;
+
+vec3 hsb2rgb(float h, float s, float v) {
+    // [[汎用関数]HSV2RGB 関数](https://qiita.com/keim_at_si/items/c2d1afd6443f3040e900)
+    return ((clamp(abs(fract(h + vec3(0, 2, 1) / 3.) * 6. - 3.) - 1., 0., 1.) - 1.) * s + 1.) * v;
+}
+
+float sdTriPrism( vec3 p, vec2 h ) {
+    vec3 q = abs(p);
+    return max(q.z-h.y,max(q.x*0.866025+p.y*0.5,-p.y)-h.x*0.5);
+}
+
+vec3 repeat(vec3 p, float interval) {
+  return mod(p, interval) - 2.0;
+}
+
+float dist(vec3 p) {
+  vec3 pos = repeat(p - 2.0, 4.0);
+  return sdTriPrism(pos, vec2(0.5, 2.0 * progress));
+}
+
+void main() {
+  vec2 uv = (gl_FragCoord.xy * 2.0 - resolution.xy) / min(resolution.x, resolution.y);
+
+  vec3 cameraUp = normalize(vec3(sin(progress * 5 * TWO_PI), cos(progress * 5 * TWO_PI), 0.0));
+  vec3 cameraDir = vec3(0.0, 0.0, 1.0 * progress);
+  vec3 cameraSite = normalize(cross(cameraUp, cameraDir));
+  vec3 rayDir = normalize((uv.x * cameraSite + uv.y * cameraUp) + cameraDir);
+
+  float t = 0.01;
+  float ac = 0.0;
+  for (int i = 0; i < 48; ++i) {
+    float d = dist(rayDir * t);
+    d = max(abs(d), 0.02);
+    ac += exp(-d * 3.0);
+    t += d * 0.5;
+  }
+
+  gl_FragColor = vec4(hsb2rgb(soundLevel.z * ac * 0.2, ac * 0.01 * kick, ac * 0.02), 1.0);
+}

doc/Examples.md

@@ -1,6 +1,11 @@
 Examples
 ======
 
+[shader-study-201910.frag](../data/shader-study-201910.frag)
+------
+
+[![With impatient heart by Sad Juno](https://i.ytimg.com/vi/ILZz3aaolQ0/sddefault.jpg "With impatient heart by Sad Juno")](https://www.youtube.com/ILZz3aaolQ0)
+
 [shader-study-201909.frag](../data/shader-study-201909.frag)
 ------