feat: add gradient mesh line

app/src/lib/graph-interface/edges/MeshGradientLine/MeshGradientLineMaterial.svelte

@@ -0,0 +1,111 @@
+<script lang="ts">
+  import { T, useThrelte } from '@threlte/core';
+  import { Color, ShaderMaterial, Vector2 } from 'three';
+  import fragmentShader from './fragment.frag';
+  import type { MeshLineMaterialProps } from './types';
+  import vertexShader from './vertex.vert';
+
+  let {
+    opacity = 1,
+    colorStart = '#ffffff',
+    colorEnd = '#ffffff',
+    dashOffset = 0,
+    dashArray = 0,
+    dashRatio = 0,
+    attenuate = true,
+    width = 1,
+    scaleDown = 0,
+    alphaMap,
+    ref = $bindable(),
+    children,
+    ...props
+  }: MeshLineMaterialProps = $props();
+
+  let { invalidate, size } = useThrelte();
+
+  const uniforms = {
+    lineWidth: { value: width },
+    colorStart: { value: new Color(colorStart) },
+    colorEnd: { value: new Color(colorEnd) },
+    opacity: { value: opacity },
+    resolution: { value: new Vector2(1, 1) },
+    sizeAttenuation: { value: attenuate ? 1 : 0 },
+    dashArray: { value: dashArray },
+    useDash: { value: dashArray > 0 ? 1 : 0 },
+    dashOffset: { value: dashOffset },
+    dashRatio: { value: dashRatio },
+    scaleDown: { value: scaleDown / 10 },
+    alphaTest: { value: 0 },
+    alphaMap: { value: alphaMap },
+    useAlphaMap: { value: alphaMap ? 1 : 0 }
+  };
+
+  const material = new ShaderMaterial({ uniforms });
+
+  $effect.pre(() => {
+    uniforms.lineWidth.value = width;
+    invalidate();
+  });
+
+  $effect.pre(() => {
+    uniforms.opacity.value = opacity;
+    invalidate();
+  });
+
+  $effect.pre(() => {
+    uniforms.resolution.value.set($size.width, $size.height);
+    invalidate();
+  });
+
+  $effect.pre(() => {
+    uniforms.sizeAttenuation.value = attenuate ? 1 : 0;
+    invalidate();
+  });
+
+  $effect.pre(() => {
+    uniforms.dashArray.value = dashArray;
+    uniforms.useDash.value = dashArray > 0 ? 1 : 0;
+    invalidate();
+  });
+
+  $effect.pre(() => {
+    uniforms.dashOffset.value = dashOffset;
+    invalidate();
+  });
+
+  $effect.pre(() => {
+    uniforms.dashRatio.value = dashRatio;
+    invalidate();
+  });
+
+  $effect.pre(() => {
+    uniforms.scaleDown.value = scaleDown / 10;
+    invalidate();
+  });
+
+  $effect.pre(() => {
+    uniforms.alphaMap.value = alphaMap;
+    uniforms.useAlphaMap.value = alphaMap ? 1 : 0;
+    invalidate();
+  });
+
+  $effect.pre(() => {
+    uniforms.colorStart.value.set(colorStart);
+    invalidate();
+  });
+
+  $effect.pre(() => {
+    uniforms.colorEnd.value.set(colorEnd);
+    invalidate();
+  });
+</script>
+
+<T
+  is={material}
+  bind:ref
+  {fragmentShader}
+  {vertexShader}
+  {...props}
+>
+  {@render children?.({ ref: material })}
+</T>

app/src/lib/graph-interface/edges/MeshGradientLine/fragment.frag

@@ -0,0 +1,30 @@
+uniform vec3 colorStart;
+uniform vec3 colorEnd;
+
+uniform float useDash;
+uniform float dashArray;
+uniform float dashOffset;
+uniform float dashRatio;
+uniform sampler2D alphaMap;
+uniform float useAlphaMap;
+
+varying vec2 vUV;
+varying vec4 vColor;
+varying float vCounters;
+
+vec4 CustomLinearTosRGB( in vec4 value ) {
+	return vec4( mix( pow( value.rgb, vec3( 0.41666 ) ) * 1.055 - vec3( 0.055 ), value.rgb * 12.92, vec3( lessThanEqual( value.rgb, vec3( 0.0031308 ) ) ) ), value.a );
+}
+
+void main()	{
+
+  vec4 c = mix(vec4(colorStart,1.0),vec4(colorEnd, 1.0), vCounters);
+
+	if( useAlphaMap == 1. ) c.a *= texture2D( alphaMap, vUV ).r;
+
+	if( useDash == 1. ){
+		c.a *= ceil(mod(vCounters + dashOffset, dashArray) - (dashArray * dashRatio));
+	}
+
+	gl_FragColor = CustomLinearTosRGB(c);
+}

app/src/lib/graph-interface/edges/MeshGradientLine/types.ts

@@ -0,0 +1,68 @@
+import type { Props } from '@threlte/core';
+import type { BufferGeometry, Vector3 } from 'three';
+import type { ColorRepresentation, ShaderMaterial, Texture } from 'three';
+
+export type MeshLineGeometryProps = Props<BufferGeometry> & {
+  /**
+   * @default []
+   */
+  points: Vector3[];
+
+  /**
+   * @default 'none'
+   */
+  shape?: 'none' | 'taper' | 'custom';
+
+  /**
+   * @default () => 1
+   */
+  shapeFunction?: (p: number) => number;
+};
+
+export type MeshLineMaterialProps =
+  & Omit<
+    Props<ShaderMaterial>,
+    'uniforms' | 'fragmentShader' | 'vertexShader'
+  >
+  & {
+    /**
+     * @default 1
+     */
+    opacity?: number;
+
+    /**
+     * @default '#ffffff'
+     */
+    color?: ColorRepresentation;
+
+    /**
+     * @default 0
+     */
+    dashOffset?: number;
+
+    /**
+     * @default 0
+     */
+    dashArray?: number;
+
+    /**
+     * @default 0
+     */
+    dashRatio?: number;
+
+    /**
+     * @default true
+     */
+    attenuate?: boolean;
+
+    /**
+     * @default 1
+     */
+    width?: number;
+
+    /**
+     * @default 0
+     */
+    scaleDown?: number;
+    alphaMap?: Texture | undefined;
+  };

app/src/lib/graph-interface/edges/MeshGradientLine/vertex.vert

@@ -0,0 +1,83 @@
+attribute vec3 previous;
+attribute vec3 next;
+attribute float side;
+attribute float width;
+attribute float counters;
+
+uniform vec2 resolution;
+uniform float lineWidth;
+uniform vec3 color;
+uniform float opacity;
+uniform float sizeAttenuation;
+uniform float scaleDown;
+
+varying vec2 vUV;
+varying vec4 vColor;
+varying float vCounters;
+
+vec2 intoScreen(vec4 i) {
+    return resolution * (0.5 * i.xy / i.w + 0.5);
+}
+
+void main() {
+    float aspect = resolution.y / resolution.x;
+
+    mat4 m = projectionMatrix * modelViewMatrix;
+
+    vec4 currentClip = m * vec4( position, 1.0 );
+    vec4 prevClip = m * vec4( previous, 1.0 );
+    vec4 nextClip = m * vec4( next, 1.0 );
+
+    vec4 currentNormed = currentClip / currentClip.w;
+    vec4 prevNormed = prevClip / prevClip.w;
+    vec4 nextNormed = nextClip / nextClip.w;
+
+    vec2 currentScreen = intoScreen(currentNormed);
+    vec2 prevScreen = intoScreen(prevNormed);
+    vec2 nextScreen = intoScreen(nextNormed);
+
+    float actualWidth = lineWidth * width;
+
+    vec2 dir;
+    if(nextScreen == currentScreen) {
+        dir = normalize( currentScreen - prevScreen );
+    } else if(prevScreen == currentScreen) {
+        dir = normalize( nextScreen - currentScreen );
+    } else {
+        vec2 inDir = currentScreen - prevScreen;
+        vec2 outDir = nextScreen - currentScreen;
+        vec2 fullDir = nextScreen - prevScreen;
+
+        if(length(fullDir) > 0.0) {
+            dir = normalize(fullDir);
+        } else if(length(inDir) > 0.0){
+            dir = normalize(inDir);
+        } else {
+            dir = normalize(outDir);
+        }
+    }
+
+    vec2 normal = vec2(-dir.y, dir.x);
+
+    if(sizeAttenuation != 0.0) {
+        normal /= currentClip.w;
+        normal *= min(resolution.x, resolution.y);
+    }
+
+    if (scaleDown > 0.0) {
+        float dist = length(nextNormed - prevNormed);
+        normal *= smoothstep(0.0, scaleDown, dist);
+    }
+
+    vec2 offsetInScreen = actualWidth * normal * side * 0.5;
+
+    vec2 withOffsetScreen = currentScreen + offsetInScreen;
+    vec3 withOffsetNormed = vec3((2.0 * withOffsetScreen/resolution - 1.0), currentNormed.z);
+
+    vCounters = counters;
+    vColor = vec4( color, opacity );
+    vUV = uv;
+
+    gl_Position = currentClip.w * vec4(withOffsetNormed, 1.0);
+
+}