Files
matrix/js/std140.js

78 lines
2.9 KiB
JavaScript

const supportedLayoutTypes = {
["i32"]: { alignAtByte: 1, sizeInBytes: 1, baseType: "i32" },
["u32"]: { alignAtByte: 1, sizeInBytes: 1, baseType: "u32" },
["f32"]: { alignAtByte: 1, sizeInBytes: 1, baseType: "f32" },
["atomic<i32>"]: { alignAtByte: 1, sizeInBytes: 1, baseType: "i32" },
["vec2<i32>"]: { alignAtByte: 2, sizeInBytes: 2, baseType: "i32" },
["vec3<i32>"]: { alignAtByte: 4, sizeInBytes: 3, baseType: "i32" },
["vec4<i32>"]: { alignAtByte: 4, sizeInBytes: 4, baseType: "i32" },
["atomic<u32>"]: { alignAtByte: 1, sizeInBytes: 1, baseType: "u32" },
["vec2<u32>"]: { alignAtByte: 2, sizeInBytes: 2, baseType: "u32" },
["vec3<u32>"]: { alignAtByte: 4, sizeInBytes: 3, baseType: "u32" },
["vec4<u32>"]: { alignAtByte: 4, sizeInBytes: 4, baseType: "u32" },
["atomic<f32>"]: { alignAtByte: 1, sizeInBytes: 1, baseType: "f32" },
["vec2<f32>"]: { alignAtByte: 2, sizeInBytes: 2, baseType: "f32" },
["vec3<f32>"]: { alignAtByte: 4, sizeInBytes: 3, baseType: "f32" },
["vec4<f32>"]: { alignAtByte: 4, sizeInBytes: 4, baseType: "f32" },
["mat2x2<f32>"]: { alignAtByte: 2, sizeInBytes: 4, baseType: "f32" },
["mat3x2<f32>"]: { alignAtByte: 2, sizeInBytes: 6, baseType: "f32" },
["mat4x2<f32>"]: { alignAtByte: 2, sizeInBytes: 8, baseType: "f32" },
["mat2x3<f32>"]: { alignAtByte: 4, sizeInBytes: 8, baseType: "f32" },
["mat3x3<f32>"]: { alignAtByte: 4, sizeInBytes: 12, baseType: "f32" },
["mat4x3<f32>"]: { alignAtByte: 4, sizeInBytes: 16, baseType: "f32" },
["mat2x4<f32>"]: { alignAtByte: 4, sizeInBytes: 8, baseType: "f32" },
["mat3x4<f32>"]: { alignAtByte: 4, sizeInBytes: 12, baseType: "f32" },
["mat4x4<f32>"]: { alignAtByte: 4, sizeInBytes: 16, baseType: "f32" },
};
const computeStructLayout = (types) => {
const entries = [];
let byteOffset = 0;
for (const type of types) {
if (supportedLayoutTypes[type] == null) {
throw new Error(`Unsupported type: ${type}`);
}
const { alignAtByte, sizeInBytes, baseType } = supportedLayoutTypes[type];
byteOffset = Math.ceil(byteOffset / alignAtByte) * alignAtByte;
entries.push({ baseType, byteOffset });
byteOffset += sizeInBytes;
}
// console.log(types);
// console.log(entries);
const size = byteOffset * Float32Array.BYTES_PER_ELEMENT;
return {
entries,
size,
build: (values, buffer = null) => buildStruct(entries, values, buffer ?? new ArrayBuffer(size)),
};
};
const buildStruct = (entries, values, buffer) => {
if (values.length !== entries.length) {
throw new Error(`This struct contains ${entries.length} values, and you supplied ${values.length}.`);
}
const views = {
i32: new Int32Array(buffer),
u32: new Uint32Array(buffer),
f32: new Float32Array(buffer),
};
for (let i = 0; i < values.length; i++) {
const view = views[entries[i].baseType];
const value = values[i];
const array = value[Symbol.iterator] == null ? [value] : value;
view.set(array, entries[i].byteOffset);
}
return buffer;
};
export default computeStructLayout;