From acd56d4e6b4c4522abc515b48357213fbe3be88a Mon Sep 17 00:00:00 2001
From: Daniel Bulant <danbulant@gmail.com>
Date: Sun, 1 Jan 2023 11:01:45 +0100
Subject: [PATCH] some basic shaders

---
 src/lib/shaders/basic.vert           |  3 +++
 src/lib/shaders/utils/brickTile.frag | 10 ++++++++++
 src/lib/shaders/utils/circle.frag    |  8 ++++++++
 src/lib/shaders/utils/cog.frag       | 17 +++++++++++++++++
 src/lib/shaders/utils/move.frag      |  5 +++++
 src/lib/shaders/utils/polygon.frag   | 21 +++++++++++++++++++++
 src/lib/shaders/utils/random.frag    | 27 +++++++++++++++++++++++++++
 src/lib/shaders/utils/repeat.frag    |  9 +++++++++
 src/lib/shaders/utils/rotate2d.frag  | 14 ++++++++++++++
 src/lib/shaders/utils/scale.frag     | 14 ++++++++++++++
 10 files changed, 128 insertions(+)
 create mode 100644 src/lib/shaders/basic.vert
 create mode 100644 src/lib/shaders/utils/brickTile.frag
 create mode 100644 src/lib/shaders/utils/circle.frag
 create mode 100644 src/lib/shaders/utils/cog.frag
 create mode 100644 src/lib/shaders/utils/move.frag
 create mode 100644 src/lib/shaders/utils/polygon.frag
 create mode 100644 src/lib/shaders/utils/random.frag
 create mode 100644 src/lib/shaders/utils/repeat.frag
 create mode 100644 src/lib/shaders/utils/rotate2d.frag
 create mode 100644 src/lib/shaders/utils/scale.frag

diff --git a/src/lib/shaders/basic.vert b/src/lib/shaders/basic.vert
new file mode 100644
index 0000000..89c5662
--- /dev/null
+++ b/src/lib/shaders/basic.vert
@@ -0,0 +1,3 @@
+void main() {
+    gl_Position = vec4( position, 1.0 );
+}
\ No newline at end of file
diff --git a/src/lib/shaders/utils/brickTile.frag b/src/lib/shaders/utils/brickTile.frag
new file mode 100644
index 0000000..783a120
--- /dev/null
+++ b/src/lib/shaders/utils/brickTile.frag
@@ -0,0 +1,10 @@
+precision mediump float;
+
+vec2 brickTile(vec2 _st, float _zoom){
+    _st *= _zoom;
+
+    // Here is where the offset is happening
+    _st.x += step(1., mod(_st.y,2.0)) * 0.5;
+
+    return fract(_st);
+}
\ No newline at end of file
diff --git a/src/lib/shaders/utils/circle.frag b/src/lib/shaders/utils/circle.frag
new file mode 100644
index 0000000..e01a083
--- /dev/null
+++ b/src/lib/shaders/utils/circle.frag
@@ -0,0 +1,8 @@
+precision mediump float;
+
+mediump float circle(in vec2 _st, in float _radius){
+    vec2 dist = _st-vec2(0.5);
+	return 1.-smoothstep(_radius-(_radius*0.01),
+        _radius+(_radius*0.01),
+        dot(dist,dist)*4.0);
+}
\ No newline at end of file
diff --git a/src/lib/shaders/utils/cog.frag b/src/lib/shaders/utils/cog.frag
new file mode 100644
index 0000000..432a1fb
--- /dev/null
+++ b/src/lib/shaders/utils/cog.frag
@@ -0,0 +1,17 @@
+precision mediump float;
+
+mediump float cog(in vec2 st){
+    vec2 pos = vec2(0.5)-st;
+
+    float r = length(pos)*2.0;
+    float a = atan(pos.y,pos.x);
+
+    return smoothstep(
+        -1.2, // lower cog part
+        1.5,  // upper cog part
+        cos(
+            a * 10. // number of teeth
+        ))
+    *0.5 // inner size
+    + 0.5; // outer size
+}
\ No newline at end of file
diff --git a/src/lib/shaders/utils/move.frag b/src/lib/shaders/utils/move.frag
new file mode 100644
index 0000000..909b270
--- /dev/null
+++ b/src/lib/shaders/utils/move.frag
@@ -0,0 +1,5 @@
+precision mediump float;
+
+vec2 move(in vec2 st, in vec2 move) {
+    return st + move;
+}
\ No newline at end of file
diff --git a/src/lib/shaders/utils/polygon.frag b/src/lib/shaders/utils/polygon.frag
new file mode 100644
index 0000000..cdddd90
--- /dev/null
+++ b/src/lib/shaders/utils/polygon.frag
@@ -0,0 +1,21 @@
+precision mediump float;
+
+#define PI 3.14159265359
+#define TWO_PI 6.28318530718
+
+// sides should probably be an integer, but it can be abused for morphin effects
+mediump float polygon(in vec2 st, in float sides){
+    vec3 color = vec3(0.0);
+
+    // Remap the space to -1. to 1.
+    st = st *2. -1.;
+
+    // Angle and radius from the current pixel
+    float a = atan(st.x,st.y)+PI;
+    float r = TWO_PI/float(sides);
+
+    // Shaping function that modulate the distance
+    return cos(floor(0.500+a/r)*r-a)*length(st);
+    // when it's not 0.5 exactly, the triangles will not match perfectly for the polygon to take shape. Can be abused for cool effects
+    // (possibly transitions)
+}
diff --git a/src/lib/shaders/utils/random.frag b/src/lib/shaders/utils/random.frag
new file mode 100644
index 0000000..dfb1713
--- /dev/null
+++ b/src/lib/shaders/utils/random.frag
@@ -0,0 +1,27 @@
+precision mediump float;
+
+float random (vec2 st) {
+    return fract(sin(dot(st.xy,
+        vec2(12.9898,78.233)))*
+        43758.5453123);
+}
+
+vec2 random2(vec2 st){
+    st = vec2( dot(st,vec2(127.1,311.7)),
+              dot(st,vec2(269.5,183.3)) );
+    return -1.0 + 2.0*fract(sin(st)*43758.5453123);
+}
+
+// Gradient Noise by Inigo Quilez - iq/2013
+// https://www.shadertoy.com/view/XdXGW8
+float noise(vec2 st) {
+    vec2 i = floor(st);
+    vec2 f = fract(st);
+
+    vec2 u = f*f*(3.0-2.0*f);
+
+    return mix( mix( dot( random2(i + vec2(0.0,0.0) ), f - vec2(0.0,0.0) ),
+                     dot( random2(i + vec2(1.0,0.0) ), f - vec2(1.0,0.0) ), u.x),
+                mix( dot( random2(i + vec2(0.0,1.0) ), f - vec2(0.0,1.0) ),
+                     dot( random2(i + vec2(1.0,1.0) ), f - vec2(1.0,1.0) ), u.x), u.y);
+}
\ No newline at end of file
diff --git a/src/lib/shaders/utils/repeat.frag b/src/lib/shaders/utils/repeat.frag
new file mode 100644
index 0000000..627371d
--- /dev/null
+++ b/src/lib/shaders/utils/repeat.frag
@@ -0,0 +1,9 @@
+precision mediump float;
+
+vec2 repeat(in vec2 st, in float repeat) {
+    return st * repeat;
+}
+
+vec2 repeat(in vec2 st, in vec2 repeat) {
+    return vec2(st.x * repeat.x, st.y * repeat.y);
+}
\ No newline at end of file
diff --git a/src/lib/shaders/utils/rotate2d.frag b/src/lib/shaders/utils/rotate2d.frag
new file mode 100644
index 0000000..1a6f1f6
--- /dev/null
+++ b/src/lib/shaders/utils/rotate2d.frag
@@ -0,0 +1,14 @@
+precision mediump float;
+
+mat2 mat_rotate2d(in float angle){
+    return mat2(cos(angle),-sin(angle),
+        sin(angle),cos(angle));
+}
+
+vec2 rotate2d(in vec2 _st, in float angle) {
+    vec2 st = _st;
+    st -= 0.5;
+    st *= mat_rotate2d(angle);
+    st += 0.5;
+    return st;
+}
\ No newline at end of file
diff --git a/src/lib/shaders/utils/scale.frag b/src/lib/shaders/utils/scale.frag
new file mode 100644
index 0000000..45d0f96
--- /dev/null
+++ b/src/lib/shaders/utils/scale.frag
@@ -0,0 +1,14 @@
+precision mediump float;
+
+mat2 mat_scale(vec2 _scale){
+    return mat2(_scale.x,0.0,
+                0.0,_scale.y);
+}
+
+vec2 scale(in vec2 _st, in vec2 _scale) {
+    vec2 st = _st;
+    st -= 0.5;
+    st *= mat_scale(_scale);
+    st += 0.5;
+    return st;
+}
\ No newline at end of file