65 lines
2.0 KiB
JavaScript
65 lines
2.0 KiB
JavaScript
// Copyright (c) 2026 Dominic Masters
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//
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// This software is released under the MIT License.
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// https://opensource.org/licenses/MIT
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"use strict";
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// DMF - Dusk Mesh Format
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//
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// Header (12 bytes):
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// [0-3] "DMF\0" magic
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// [4-7] uint32 version (little-endian)
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// [8-11] uint32 vertCount (little-endian)
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//
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// Followed by vertCount vertices, each 20 bytes:
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// [0-7] float32[2] uv (little-endian)
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// [8-19] float32[3] pos (little-endian)
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const DMF = (() => {
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const MAGIC = [0x44, 0x4d, 0x46, 0x00]; // "DMF\0"
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const VERSION = 1;
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const HEADER_SIZE = 12;
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const VERTEX_FLOATS = 5; // uv[2] + pos[3]
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const VERTEX_SIZE = VERTEX_FLOATS * 4;
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// Decode a DMF ArrayBuffer into { version, vertexCount, floats }, where
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// floats is a Float32Array of tightly interleaved [u, v, x, y, z] per
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// vertex - ready to hand straight to gl.bufferData().
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function decode(buffer) {
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const bytes = new Uint8Array(buffer);
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const view = new DataView(buffer);
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if(bytes.length < HEADER_SIZE) throw new Error("File too small to be a valid DMF");
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if(
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bytes[0] !== MAGIC[0] || bytes[1] !== MAGIC[1] ||
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bytes[2] !== MAGIC[2] || bytes[3] !== MAGIC[3]
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) {
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throw new Error("Invalid DMF magic bytes - not a DMF file");
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}
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const version = view.getUint32(4, true);
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if(version !== VERSION) {
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throw new Error(`Unsupported DMF version: ${version}`);
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}
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const vertexCount = view.getUint32(8, true);
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const expected = HEADER_SIZE + vertexCount * VERTEX_SIZE;
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if(bytes.length < expected) {
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throw new Error(`DMF vertex data truncated (expected ${expected} bytes, got ${bytes.length})`);
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}
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const floats = new Float32Array(vertexCount * VERTEX_FLOATS);
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for(let i = 0; i < floats.length; i++) {
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floats[i] = view.getFloat32(HEADER_SIZE + i * 4, true);
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}
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return { version, vertexCount, floats };
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}
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return Object.freeze({
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decode,
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VERSION, HEADER_SIZE, VERTEX_FLOATS, VERTEX_SIZE,
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});
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})();
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