@animech-public/playcanvas
Version:
PlayCanvas WebGL game engine
221 lines (219 loc) • 6.78 kB
JavaScript
const KEYWORD = /[ \t]*#(ifn?def|if|endif|else|elif|define|undef|extension|include)/g;
const DEFINE = /define[ \t]+([^\n]+)\r?(?:\n|$)/g;
const EXTENSION = /extension[ \t]+([\w-]+)[ \t]*:[ \t]*(enable|require)/g;
const UNDEF = /undef[ \t]+([^\n]+)\r?(?:\n|$)/g;
const IF = /(ifdef|ifndef|if)[ \t]*([^\r\n]+)\r?\n/g;
const ENDIF = /(endif|else|elif)([ \t][^\r\n]+)?\r?(?:\n|$)/g;
const IDENTIFIER = /([\w-]+)/;
const DEFINED = /(!|\s)?defined\(([\w-]+)\)/;
const INVALID = /[><=|&+-]/g;
const INCLUDE = /include[ \t]+"([\w-]+)"\r?(?:\n|$)/g;
class Preprocessor {
static run(source, includes = new Map(), stripUnusedColorAttachments = false) {
source = source.replace(/\/\*[\s\S]*?\*\/|([^\\:]|^)\/\/.*$/gm, '$1');
source = source.split(/\r?\n/).map(line => line.trimEnd()).join('\n');
const defines = new Map();
if (stripUnusedColorAttachments) {
const counts = new Map();
const regex = /(pcFragColor[1-8])\b/g;
const matches = source.match(regex);
matches == null || matches.forEach(match => {
var _counts$get;
const index = parseInt(match.charAt(match.length - 1), 10);
counts.set(index, ((_counts$get = counts.get(index)) != null ? _counts$get : 0) + 1);
});
counts.forEach((count, index) => {
if (count === 1) {
defines.set(`REMOVE_COLOR_ATTACHMENT_${index}`, '');
}
});
}
source = this._preprocess(source, defines, includes);
const intDefines = new Map();
defines.forEach((value, key) => {
if (Number.isInteger(parseFloat(value)) && !value.includes('.')) {
intDefines.set(key, value);
}
});
source = this.RemoveEmptyLines(source);
source = this.processArraySize(source, intDefines);
return source;
}
static processArraySize(source, intDefines) {
if (source !== null) {
intDefines.forEach((value, key) => {
source = source.replace(new RegExp(`\\[${key}\\]`, 'g'), `[${value}]`);
});
}
return source;
}
static RemoveEmptyLines(source) {
if (source !== null) {
source = source.split(/\r?\n/).map(line => line.trim() === '' ? '' : line).join('\n');
source = source.replace(/(\n\n){3,}/g, '\n\n');
}
return source;
}
static _preprocess(source, defines = new Map(), includes) {
const originalSource = source;
const stack = [];
let error = false;
let match;
while ((match = KEYWORD.exec(source)) !== null) {
const keyword = match[1];
switch (keyword) {
case 'define':
{
DEFINE.lastIndex = match.index;
const define = DEFINE.exec(source);
error || (error = define === null);
const expression = define[1];
IDENTIFIER.lastIndex = define.index;
const identifierValue = IDENTIFIER.exec(expression);
const identifier = identifierValue[1];
let value = expression.substring(identifier.length).trim();
if (value === '') value = 'true';
const keep = Preprocessor._keep(stack);
if (keep) {
defines.set(identifier, value);
}
KEYWORD.lastIndex = define.index + define[0].length;
break;
}
case 'undef':
{
UNDEF.lastIndex = match.index;
const undef = UNDEF.exec(source);
const identifier = undef[1].trim();
const keep = Preprocessor._keep(stack);
if (keep) {
defines.delete(identifier);
}
KEYWORD.lastIndex = undef.index + undef[0].length;
break;
}
case 'extension':
{
EXTENSION.lastIndex = match.index;
const extension = EXTENSION.exec(source);
error || (error = extension === null);
if (extension) {
const identifier = extension[1];
const keep = Preprocessor._keep(stack);
if (keep) {
defines.set(identifier, 'true');
}
}
KEYWORD.lastIndex = extension.index + extension[0].length;
break;
}
case 'ifdef':
case 'ifndef':
case 'if':
{
IF.lastIndex = match.index;
const iff = IF.exec(source);
const expression = iff[2];
const evaluated = Preprocessor.evaluate(expression, defines);
error || (error = evaluated.error);
let result = evaluated.result;
if (keyword === 'ifndef') {
result = !result;
}
stack.push({
anyKeep: result,
keep: result,
start: match.index,
end: IF.lastIndex
});
KEYWORD.lastIndex = iff.index + iff[0].length;
break;
}
case 'endif':
case 'else':
case 'elif':
{
ENDIF.lastIndex = match.index;
const endif = ENDIF.exec(source);
const blockInfo = stack.pop();
const blockCode = blockInfo.keep ? source.substring(blockInfo.end, match.index) : '';
source = source.substring(0, blockInfo.start) + blockCode + source.substring(ENDIF.lastIndex);
KEYWORD.lastIndex = blockInfo.start + blockCode.length;
const endifCommand = endif[1];
if (endifCommand === 'else' || endifCommand === 'elif') {
let result = false;
if (!blockInfo.anyKeep) {
if (endifCommand === 'else') {
result = !blockInfo.keep;
} else {
const evaluated = Preprocessor.evaluate(endif[2], defines);
result = evaluated.result;
error || (error = evaluated.error);
}
}
stack.push({
anyKeep: blockInfo.anyKeep || result,
keep: result,
start: KEYWORD.lastIndex,
end: KEYWORD.lastIndex
});
}
break;
}
case 'include':
{
INCLUDE.lastIndex = match.index;
const include = INCLUDE.exec(source);
error || (error = include === null);
const identifier = include[1].trim();
const keep = Preprocessor._keep(stack);
if (keep) {
const includeSource = includes == null ? void 0 : includes.get(identifier);
if (includeSource) {
source = source.substring(0, include.index - 1) + includeSource + source.substring(INCLUDE.lastIndex);
KEYWORD.lastIndex = include.index;
} else {
console.error(`Include not found: ${identifier}`);
error = true;
}
}
break;
}
}
}
if (error) {
console.warn('Failed to preprocess shader: ', {
source: originalSource
});
return originalSource;
}
return source;
}
static _keep(stack) {
for (let i = 0; i < stack.length; i++) {
if (!stack[i].keep) {
return false;
}
}
return true;
}
static evaluate(expression, defines) {
const correct = INVALID.exec(expression) === null;
let invert = false;
const defined = DEFINED.exec(expression);
if (defined) {
invert = defined[1] === '!';
expression = defined[2];
}
expression = expression.trim();
let exists = defines.has(expression);
if (invert) {
exists = !exists;
}
return {
result: exists,
error: !correct
};
}
}
export { Preprocessor };