import * as three from "three";
export default function createPickingMaterial(
nodePositionsTexture: three.DataTexture,
initialCameraDistance: number
) {
const pickingMaterial = new three.ShaderMaterial({
depthTest: true,
depthWrite: true,
transparent: false,
blending: three.NoBlending,
uniforms: {
nodePosTex: { value: nodePositionsTexture },
textureSize: { value: nodePositionsTexture.image.width },
camDist: { value: initialCameraDistance },
},
vertexShader: `
precision highp float;
uniform sampler2D nodePosTex;
uniform float textureSize;
uniform float camDist;
varying vec3 vColor;
vec3 getNodePos(float idx) {
float size = textureSize;
float fx = mod(idx, size);
float fy = floor(idx / size);
vec2 uv = (vec2(fx, fy) + 0.5) / size;
return texture2D(nodePosTex, uv).xyz;
}
void main() {
float id = float(gl_InstanceID);
vec3 nodePos = getNodePos(id);
vColor = vec3(
mod(id, 256.0) / 255.0,
mod(floor(id / 256.0), 256.0) / 255.0,
floor(id / 65536.0) / 255.0
);
// vColor = vec3(fract(sin(id * 12.9898) * 43758.5453));
float baseNodeSize = 4.0;
// Normalize camera distance into [0,1]
float t = clamp((camDist - 500.0) / (2000.0 - 500.0), 0.0, 1.0);
float nodeSize = baseNodeSize * mix(1.0, 2.0, t);
vec3 transformed = nodePos + position * nodeSize;
gl_Position = projectionMatrix * modelViewMatrix * vec4(transformed, 1.0);
}
`,
fragmentShader: `
precision highp float;
varying vec3 vColor;
void main() {
gl_FragColor = vec4(vColor, 1.0);
}
`,
});
return pickingMaterial;
}
