playcanvas
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Open-source WebGL/WebGPU 3D engine for the web
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JavaScript
var gsplatWorkBufferGeometry_default = (
/* glsl */
`
// world-space transform data previously written to the work buffer (see gsplatWriteVS)
uniform highp usampler2D uWorkBufferTransformA;
uniform highp usampler2D uWorkBufferTransformB;
// inverse of matrix_model, to convert stored world-space data back to local space
uniform mat4 matrix_model_inverse;
// world-space camera position
uniform vec3 uCameraPosition;
ivec2 wbCoord;
uvec4 wbTransformA;
// cache transformA at the destination pixel; must be called before any getters
void initWorkBufferGeometry(ivec2 coord) {
wbCoord = coord;
wbTransformA = texelFetch(uWorkBufferTransformA, coord, 0);
}
vec3 workBufferWorldCenter() {
return vec3(uintBitsToFloat(wbTransformA.x), uintBitsToFloat(wbTransformA.y), uintBitsToFloat(wbTransformA.z));
}
// world-space rotation (x,y,z,w), decoded to match the work buffer write encoding
vec4 workBufferWorldRotation() {
// half-angle projected quaternion, 11+11+10 bits (see containerCompactWrite)
uint data = texelFetch(uWorkBufferTransformB, wbCoord, 0).x;
vec3 p = vec3(
float(data & 0x7FFu) / 2047.0 * 2.0 - 1.0,
float((data >> 11u) & 0x7FFu) / 2047.0 * 2.0 - 1.0,
float((data >> 22u) & 0x3FFu) / 1023.0 * 2.0 - 1.0
);
float d = dot(p, p);
return vec4(sqrt(max(0.0, 2.0 - d)) * p, 1.0 - d);
// rotation.xy in transformA.w, rotation.z in transformB.x (see containerPackedWrite)
vec2 rotXY = unpackHalf2x16(wbTransformA.w);
vec3 r = vec3(rotXY, unpackHalf2x16(texelFetch(uWorkBufferTransformB, wbCoord, 0).x).x);
return vec4(r, sqrt(max(0.0, 1.0 - dot(r, r))));
}
vec3 workBufferWorldScale() {
// log-encoded scale, 3x8 bits: 0 = true zero, 1-255 maps to e^-12..e^9 (see containerCompactWrite)
uint data = wbTransformA.w;
float sx = float(data & 0xFFu);
float sy = float((data >> 8u) & 0xFFu);
float sz = float((data >> 16u) & 0xFFu);
const float logRange = 21.0 / 255.0;
const float logMin = -12.0;
return vec3(
sx == 0.0 ? 0.0 : exp(sx * logRange + logMin),
sy == 0.0 ? 0.0 : exp(sy * logRange + logMin),
sz == 0.0 ? 0.0 : exp(sz * logRange + logMin)
);
uvec2 b = texelFetch(uWorkBufferTransformB, wbCoord, 0).xy;
return vec3(unpackHalf2x16(b.x).y, unpackHalf2x16(b.y));
}
// rotate vector by the inverse of unit quaternion q (x,y,z,w)
vec3 quatRotateInv(vec4 q, vec3 v) {
vec3 t = -q.xyz;
return v + 2.0 * cross(t, cross(t, v) + q.w * v);
}
// Source-format-compatible getters for user modifier code: local-space values reconstructed
// from the stored world-space data (quantized by the work buffer format, so rotation and
// scale are approximate).
vec3 getCenter() {
return (matrix_model_inverse * vec4(workBufferWorldCenter(), 1.0)).xyz;
}
// returns (w,x,y,z) to match the source format getRotation convention
vec4 getRotation() {
vec4 worldRotation = workBufferWorldRotation();
vec4 localRotation = quatMul(vec4(-model_rotation.xyz, model_rotation.w), worldRotation);
return localRotation.wxyz;
}
vec3 getScale() {
return workBufferWorldScale() / model_scale;
}
`
);
export {
gsplatWorkBufferGeometry_default as default
};