cesium
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CesiumJS is a JavaScript library for creating 3D globes and 2D maps in a web browser without a plugin.
221 lines (191 loc) • 8 kB
JavaScript
import defined from '../Core/defined.js';
import DeveloperError from '../Core/DeveloperError.js';
/**
* A function to port GLSL shaders from GLSL ES 1.00 to GLSL ES 3.00
*
* This function is nowhere near comprehensive or complete. It just
* handles some common cases.
*
* Note that this function requires the presence of the
* "#define OUTPUT_DECLARATION" line that is appended
* by ShaderSource.
*
* @private
*/
function modernizeShader(source, isFragmentShader) {
var outputDeclarationRegex = /#define OUTPUT_DECLARATION/;
var splitSource = source.split('\n');
if (/#version 300 es/g.test(source)) {
return source;
}
var outputDeclarationLine = -1;
var i, line;
for (i = 0; i < splitSource.length; ++i) {
line = splitSource[i];
if (outputDeclarationRegex.test(line)) {
outputDeclarationLine = i;
break;
}
}
if (outputDeclarationLine === -1) {
throw new DeveloperError('Could not find a #define OUTPUT_DECLARATION!');
}
var outputVariables = [];
for (i = 0; i < 10; i++) {
var fragDataString = 'gl_FragData\\[' + i + '\\]';
var newOutput = 'czm_out' + i;
var regex = new RegExp(fragDataString, 'g');
if (regex.test(source)) {
setAdd(newOutput, outputVariables);
replaceInSourceString(fragDataString, newOutput, splitSource);
splitSource.splice(outputDeclarationLine, 0, 'layout(location = ' + i + ') out vec4 ' + newOutput + ';');
outputDeclarationLine += 1;
}
}
var czmFragColor = 'czm_fragColor';
if (findInSource('gl_FragColor', splitSource)) {
setAdd(czmFragColor, outputVariables);
replaceInSourceString('gl_FragColor', czmFragColor, splitSource);
splitSource.splice(outputDeclarationLine, 0, 'layout(location = 0) out vec4 czm_fragColor;');
outputDeclarationLine += 1;
}
var variableMap = getVariablePreprocessorBranch(outputVariables, splitSource);
var lineAdds = {};
for (i = 0; i < splitSource.length; i++) {
line = splitSource[i];
for (var variable in variableMap) {
if (variableMap.hasOwnProperty(variable)) {
var matchVar = new RegExp('(layout)[^]+(out)[^]+(' + variable + ')[^]+', 'g');
if (matchVar.test(line)) {
lineAdds[line] = variable;
}
}
}
}
for (var layoutDeclaration in lineAdds) {
if (lineAdds.hasOwnProperty(layoutDeclaration)) {
var variableName = lineAdds[layoutDeclaration];
var lineNumber = splitSource.indexOf(layoutDeclaration);
var entry = variableMap[variableName];
var depth = entry.length;
var d;
for (d = 0; d < depth; d++) {
splitSource.splice(lineNumber, 0, entry[d]);
}
lineNumber += depth + 1;
for (d = depth - 1; d >= 0; d--) {
splitSource.splice(lineNumber, 0, '#endif //' + entry[d]);
}
}
}
var versionThree = '#version 300 es';
var foundVersion = false;
for (i = 0; i < splitSource.length; i++) {
if (/#version/.test(splitSource[i])) {
splitSource[i] = versionThree;
foundVersion = true;
}
}
if (!foundVersion) {
splitSource.splice(0, 0, versionThree);
}
removeExtension('EXT_draw_buffers', splitSource);
removeExtension('EXT_frag_depth', splitSource);
replaceInSourceString('texture2D', 'texture', splitSource);
replaceInSourceString('texture3D', 'texture', splitSource);
replaceInSourceString('textureCube', 'texture', splitSource);
replaceInSourceString('gl_FragDepthEXT', 'gl_FragDepth', splitSource);
if (isFragmentShader) {
replaceInSourceString('varying', 'in', splitSource);
} else {
replaceInSourceString('attribute', 'in', splitSource);
replaceInSourceString('varying', 'out', splitSource);
}
return compileSource(splitSource);
}
// Note that this fails if your string looks like
// searchString[singleCharacter]searchString
function replaceInSourceString(str, replacement, splitSource) {
var regexStr = '(^|[^\\w])(' + str + ')($|[^\\w])';
var regex = new RegExp(regexStr, 'g');
var splitSourceLength = splitSource.length;
for (var i = 0; i < splitSourceLength; ++i) {
var line = splitSource[i];
splitSource[i] = line.replace(regex, '$1' + replacement + '$3');
}
}
function replaceInSourceRegex(regex, replacement, splitSource) {
var splitSourceLength = splitSource.length;
for (var i = 0; i < splitSourceLength; ++i) {
var line = splitSource[i];
splitSource[i] = line.replace(regex, replacement);
}
}
function findInSource(str, splitSource) {
var regexStr = '(^|[^\\w])(' + str + ')($|[^\\w])';
var regex = new RegExp(regexStr, 'g');
var splitSourceLength = splitSource.length;
for (var i = 0; i < splitSourceLength; ++i) {
var line = splitSource[i];
if (regex.test(line)) {
return true;
}
}
return false;
}
function compileSource(splitSource) {
var wholeSource = '';
var splitSourceLength = splitSource.length;
for (var i = 0; i < splitSourceLength; ++i) {
wholeSource += splitSource[i] + '\n';
}
return wholeSource;
}
function setAdd(variable, set) {
if (set.indexOf(variable) === -1) {
set.push(variable);
}
}
function getVariablePreprocessorBranch(layoutVariables, splitSource) {
var variableMap = {};
var numLayoutVariables = layoutVariables.length;
var stack = [];
for (var i = 0; i < splitSource.length; ++i) {
var line = splitSource[i];
var hasIF = /(#ifdef|#if)/g.test(line);
var hasELSE = /#else/g.test(line);
var hasENDIF = /#endif/g.test(line);
if (hasIF) {
stack.push(line);
} else if (hasELSE) {
var top = stack[stack.length - 1];
var op = top.replace('ifdef', 'ifndef');
if (/if/g.test(op)) {
op = op.replace(/(#if\s+)(\S*)([^]*)/, '$1!($2)$3');
}
stack.pop();
stack.push(op);
} else if (hasENDIF) {
stack.pop();
} else if (!/layout/g.test(line)) {
for (var varIndex = 0; varIndex < numLayoutVariables; ++varIndex) {
var varName = layoutVariables[varIndex];
if (line.indexOf(varName) !== -1) {
if (!defined(variableMap[varName])) {
variableMap[varName] = stack.slice();
} else {
variableMap[varName] = variableMap[varName].filter(function(x) {
return stack.indexOf(x) >= 0;
});
}
}
}
}
}
return variableMap;
}
function removeExtension(name, splitSource) {
var regex = '#extension\\s+GL_' + name + '\\s+:\\s+[a-zA-Z0-9]+\\s*$';
replaceInSourceRegex(new RegExp(regex, 'g'), '', splitSource);
}
export default modernizeShader;