/
buffers.html
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/
buffers.html
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<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>GlslCanvas</title>
<script type="text/javascript" src="dist/GlslCanvas.js"></script>
<style>
body {
background: #101515;
}
#glslCanvas {
position: absolute;
top: 50%;
left: 50%;
transform: translate(-50%, -50%);
}
</style>
</head>
<body>
<canvas id="glslCanvas" data-fragment="
#ifdef GL_ES
precision mediump float;
#endif
uniform vec2 u_resolution;
uniform vec2 u_mouse;
uniform float u_time;
uniform sampler2D u_tex0; // data/moon.jpg
uniform vec2 u_tex0Resolution;
uniform sampler2D u_buffer0;
uniform sampler2D u_buffer1;
vec2 scale(vec2 st, float s) {
return (st-.5)*s+.5;
}
vec2 ratio(in vec2 st, in vec2 s) {
return mix( vec2((st.x*s.x/s.y)-(s.x*.5-s.y*.5)/s.y,st.y),
vec2(st.x,st.y*(s.y/s.x)-(s.y*.5-s.x*.5)/s.x),
step(s.x,s.y));
}
float circleSDF(vec2 st) {
return length(st - 0.5) * 2.0;
}
vec2 sphereCoords(vec2 _st, float _scale){
float maxFactor = sin(1.570796327);
vec2 uv = vec2(0.0);
vec2 xy = 2.0 * _st.xy - 1.0;
float d = length(xy);
if (d < (2.0-maxFactor)){
d = length(xy * maxFactor);
float z = sqrt(1.0 - d * d);
float r = atan(d, z) / 3.1415926535 * _scale;
float phi = atan(xy.y, xy.x);
uv.x = r * cos(phi) + 0.5;
uv.y = r * sin(phi) + 0.5;
} else {
uv = _st.xy;
}
return uv;
}
vec4 sphereTexture(in sampler2D _tex, in vec2 _uv, float _time) {
vec2 st = sphereCoords(_uv, 1.0);
float aspect = u_tex0Resolution.y/u_tex0Resolution.x;
st.x = fract(st.x * aspect + _time);
return texture2D(_tex, st);
}
void main() {
vec2 uv = gl_FragCoord.xy / u_resolution.xy;
vec3 diff = vec3( vec2(1.0) / u_resolution.xy, 0.0);
vec2 mouse_uv = u_mouse.xy / u_resolution.xy;
float mouse_pointer = smoothstep(1.5, 0.5, length((mouse_uv - uv) * u_resolution) );
#if defined( BUFFER_0 )
// Ping
vec4 center = texture2D(u_buffer1, uv);
float top = texture2D(u_buffer1, uv - diff.zy).r;
float left = texture2D(u_buffer1, uv - diff.xz).r;
float right = texture2D(u_buffer1, uv + diff.xz).r;
float bottom = texture2D(u_buffer1, uv + diff.zy).r;
float red = -(center.g - 0.5) * 2.0 + (top + left + right + bottom - 2.0);
red += mouse_pointer; // mouse
red *= 0.98; // damping
red *= step(0.1, u_time); // hacky way of clearing the buffer
red = 0.5 + red * 0.5;
red = clamp(red, 0., 1.);
gl_FragColor = vec4(red, center.r, 0.0, 0.0);
#elif defined( BUFFER_1 )
// Pong
// Note: in this example you can get away with only one buffer...
// still is good to show off how easy is to make another buffer
vec4 ping = texture2D(u_buffer0, uv, 0.0);
if (u_time < 1.) {
ping = vec4(vec3(0.5), 1.);
}
gl_FragColor = ping;
#else
// Main Buffer
vec4 ripples = texture2D(u_buffer1, uv);
float offset = ripples.r - 0.5;
vec2 st = gl_FragCoord.xy/u_resolution.xy;
st = scale(st, 2.0);
st = ratio(st, u_resolution);
st += offset;
vec4 color = sphereTexture(u_tex0, st, u_time * 0.01);
float radius = 1.0 - circleSDF(st);
color.rgb *= smoothstep(0.001, 0.02, radius);
color.rgb += (ripples.r - .5) * 2.;
gl_FragColor = color;
#endif
}
" width="800" height="600"></canvas>
</body>
<script>
var canvas = document.getElementById("glslCanvas");
var sandbox = new GlslCanvas(canvas);
var texCounter = 0;
var sandbox_content = "";
var sandbox_title = "";
var sandbox_author = "";
var sandbox_thumbnail = "";
canvas.style.width = '100%';
canvas.style.height = '100%';
</script>
</html>