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raymarching-shader.html
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raymarching-shader.html
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<!DOCTYPE html>
<html>
<head>
<title>A-Frame - custom shaders</title>
<meta name="description" content="A-Frame - custom shaders">
<script src="js/aframe-master-v1.3.0.min.js"></script>
<script src="js/aframe-environment-component.js"></script>
<script src="js/controller-listener.js"></script>
<script src="js/player-move.js"></script>
<script src="js/raycaster-extras.js"></script>
</head>
<body>
<script>
AFRAME.registerShader('raymarching', {
schema:
{
timeMsec: {type: 'time', is: 'uniform'},
tex: {type: 'map', is: 'uniform'},
rayOrigin: {type: 'vec3', is: 'uniform', default: {x:0, y:0, z:-1}},
},
vertexShader: `
varying vec2 vUv;
void main()
{
vUv = uv;
gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );
}
`,
fragmentShader: `
varying vec2 vUv;
uniform sampler2D tex;
uniform float timeMsec;
#define MAX_STEPS 50
#define MAX_DIST 30.0
#define SURF_DIST 0.001
// shapes ----------------------------------------------------------------
float sdSphere(vec3 p, vec3 center, float radius)
{
return length(p - center) - radius;
}
float sdPlane(vec3 p, vec3 normal, float height) // always normalize the normal
{
return dot(p, normal) + height;
}
float sdPlaneLow(vec3 p, float height) // horizonal plane
{
return p.y + height;
}
float sdBox(vec3 p, vec3 b)
{
vec3 q = abs(p) - b;
return length(max(q, 0.0)) + min(max(q.x, max(q.y, q.z)), 0.0);
}
float sdRoundBox(vec3 p, vec3 b, float r)
{
vec3 q = abs(p) - b;
return length(max(q, 0.0)) + min(max(q.x, max(q.y, q.z)), 0.0) - r;
}
// operations ------------------------------------------------------------
vec4 opUnion(vec4 obj1, vec4 obj2)
{
return obj1.w < obj2.w ? obj1 : obj2;
}
vec3 mod3(vec3 x, vec3 y)
{
return x - y * floor(x / y);
}
// smoothed square wave
float ssw(float x)
{
float s = sin(3.1416 * x);
return 0.5 + 0.5 * s / sqrt(0.01 + s * s);
}
// TODO: specify colors
vec3 checkerboard2(vec2 uv, vec2 size)
{
uv /= size;
float isLight = ssw(ssw(uv.x) + ssw(uv.y) - 0.5);
return mix(vec3(0.2, 0.2, 0.2), vec3(0.8, 0.8, 0.8), isLight);
}
mat3 rotateY(float theta)
{
float c = cos(theta);
float s = sin(theta);
return mat3( c, 0, s,
0, 1, 0,
-s, 0, c );
}
mat3 rotateX(float theta)
{
float c = cos(theta);
float s = sin(theta);
return mat3( 1, 0, 0,
0, c, -s,
0, s, c );
}
// main ------------------------------------------------------------------
// combine all scene elements
vec4 GetScene(vec3 p)
{
const vec3 red = vec3(1.00, 0.25, 0.25);
const vec3 orange = vec3(1.00, 0.50, 0.00);
const vec3 yellow = vec3(1.00, 1.00, 0.00);
const vec3 green = vec3(0.00, 1.00, 0.00);
const vec3 blue = vec3(0.25, 0.25, 1.00);
const vec3 violet = vec3(0.50, 0.00, 1.00);
vec4 checkerPlane = vec4(checkerboard2(p.xz, vec2(0.5,0.5)), sdPlaneLow(p, 0.5));
float time = timeMsec / 1000.0;
vec4 box1 = vec4(red, sdRoundBox( rotateY(0.73 * time) * rotateX(time) * (p + vec3( 0.4, 0.0, -0.8)), vec3(0.2, 0.2, 0.2), 0.05) );
vec4 box2 = vec4(blue, sdRoundBox( rotateY(0.73 * time) * rotateX(time) * (p + vec3(-0.4, 0.0, -0.8)), vec3(0.2, 0.2, 0.2), 0.05) );
vec4 scene = vec4(0,0,0,0);
scene = checkerPlane;
scene = opUnion(scene, box1);
scene = opUnion(scene, box2);
return scene;
}
float Raymarch(vec3 rayOrigin, vec3 rayDirection)
{
float dO = 0.0;
vec4 dS;
for (int i = 0; i < MAX_STEPS; i++)
{
vec3 p = rayOrigin + dO * rayDirection;
dS = GetScene(p);
dO += dS.w;
if (dS.w < SURF_DIST || dO > MAX_DIST)
break;
}
return dO;
}
vec3 GetNormal(vec3 p)
{
vec2 epsilon = vec2(0.01, 0);
vec3 n = GetScene(p).w - vec3(
GetScene(p - epsilon.xyy).w,
GetScene(p - epsilon.yxy).w,
GetScene(p - epsilon.yyx).w
);
return normalize(n);
}
// to simulate point light: vec3 lightDirection = normalize(lightPosition - p);
vec3 GetLightD(vec3 p, vec3 lightDirection)
{
lightDirection = normalize(lightDirection);
vec3 normal = GetNormal(p);
float diffuse = clamp(dot(normal, lightDirection), 0.2, 1.0);
vec4 scene = GetScene(p);
vec3 color = scene.rgb;
return diffuse * color;
}
uniform vec3 rayOrigin;
void main()
{
vec2 uv = vUv - 0.5;
vec3 rayDirection = normalize(vec3(uv.x, uv.y, 1));
vec4 col = vec4(0,0,0,1);
float ray_distance = Raymarch(rayOrigin, rayDirection);
if (ray_distance < MAX_DIST)
{
vec3 p = rayOrigin + rayDirection * ray_distance;
vec3 lightDirection = vec3(0, 4, -1);
vec3 diffuseColor = GetLightD(p, lightDirection);
float dist = smoothstep(10.0, 0.0, 4.0 * length(p));
float fogStart = 5.0;
float fogEnd = 10.0;
float fogPercent = clamp((length(p) - fogStart) / (fogEnd - fogStart), 0.0, 1.0);
vec3 fogColor = vec3(0, 0, 0);
col.rgb = mix(diffuseColor, fogColor, fogPercent);
}
else
{
col.rgb = vec3(0,0,0);
}
gl_FragColor = col;
}
`,
});
</script>
<a-scene environment>
<a-assets>
<img id="gradientRainbow" src="images/gradient-rainbow.png"/>
<img id="gradient" src="images/gradient-fade.png" />
</a-assets>
<a-sky color = "#000337"></a-sky>
<a-entity
id="player"
position="0 0 0"
player-move="controllerListenerId: #controller-data;
navigationMeshClass: environmentGround;">
<a-camera></a-camera>
<a-entity
id="controller-data"
controller-listener="leftControllerId: #left-controller;
rightControllerId: #right-controller;">
</a-entity>
<a-entity
id="left-controller"
oculus-touch-controls="hand: left">
</a-entity>
<a-entity
id="right-controller"
oculus-touch-controls="hand: right"
raycaster="objects: .raycaster-target, .environmentGround;"
raycaster-extras="controllerListenerId: #controller-data;
beamImageSrc: #gradient; beamLength: 0.5;">
</a-entity>
</a-entity>
<a-plane
id="raymarch-plane"
position = "0 1 -2"
width="2" height="2"
material = "shader: raymarching; transparent: true;">
</a-plane>
</a-scene>
</body>
</html>