Basic shader generation refactoring (#6250)

* Basic shader generation refactoring

* feedback

---------

Co-authored-by: Martin Valigursky <mvaligursky@snapchat.com>

src/core/preprocessor.js

@@ -44,12 +44,17 @@ class Preprocessor {
      * Run c-like preprocessor on the source code, and resolves the code based on the defines and ifdefs
      *
      * @param {string} source - The source code to work on.
-     * @param {Map<string, string>} [includes] - An object containing key-value pairs of include names and their
-     * content.
+     * @param {Map<string, string>} [defines] - A map containing key-value pairs of define names
+     * and their values. These are used for resolving #ifdef style of directives in the source.
+     * @param {Map<string, string>} [includes] - A map containing key-value pairs of include names
+     * and their content. These are used for resolving #include directives in the source.
      * @param {boolean} [stripUnusedColorAttachments] - If true, strips unused color attachments.
      * @returns {string|null} Returns preprocessed source code, or null in case of error.
      */
-    static run(source, includes = new Map(), stripUnusedColorAttachments = false) {
+    static run(source, defines, includes = new Map(), stripUnusedColorAttachments = false) {
+
+        // shallow clone as we will modify the map
+        defines = defines ? new Map(defines) : new Map();
 
         // strips comments, handles // and many cases of /*
         source = source.replace(/\/\*[\s\S]*?\*\/|([^\\:]|^)\/\/.*$/gm, '$1');
@@ -60,7 +65,6 @@ class Preprocessor {
             .join('\n');
 
         // generate defines to remove unused color attachments
-        const defines = new Map();
         if (stripUnusedColorAttachments) {
 
             // find out how many times pcFragColorX is used (see gles3.js)

src/platform/graphics/shader-utils.js

@@ -50,7 +50,20 @@ class ShaderUtils {
      * @param {string} [options.fragmentDefines] - The fragment shader defines.
      * @param {string} [options.fragmentExtensions] - The fragment shader extensions code.
      * @param {string} [options.fragmentPreamble] - The preamble string for the fragment shader.
-     * @param {boolean} [options.useTransformFeedback] - Whether to use transform feedback. Defaults to false.
+     * @param {boolean} [options.useTransformFeedback] - Whether to use transform feedback. Defaults
+     * to false.
+     * @param {Map<string, string>} [options.vertexIncludesMap] - A map containing key-value pairs of
+     * include names and their content. These are used for resolving #include directives in the
+     * vertex shader source.
+     * @param {Map<string, string>} [options.vertexDefinesMap] - A map containing key-value pairs of
+     * define names and their values. These are used for resolving #ifdef style of directives in the
+     * vertex code.
+     * @param {Map<string, string>} [options.fragmentIncludesMap] - A map containing key-value pairs
+     * of include names and their content. These are used for resolving #include directives in the
+     * fragment shader source.
+     * @param {Map<string, string>} [options.fragmentDefinesMap] - A map containing key-value pairs of
+     * define names and their values. These are used for resolving #ifdef style of directives in the
+     * fragment code.
      * @param {string | string[]} [options.fragmentOutputTypes] - Fragment shader output types,
      * which default to vec4. Passing a string will set the output type for all color attachments.
      * Passing an array will set the output type for each color attachment.
@@ -112,6 +125,10 @@ class ShaderUtils {
             name: name,
             attributes: attribs,
             vshader: vertCode,
+            vdefines: options.vertexDefinesMap,
+            vincludes: options.vertexIncludesMap,
+            fdefines: options.fragmentDefinesMap,
+            fincludes: options.fragmentIncludesMap,
             fshader: fragCode,
             useTransformFeedback: options.useTransformFeedback
         };

src/platform/graphics/shader.js

@@ -53,6 +53,18 @@ class Shader {
      * useTransformFeedback or compute shader is specified.
      * @param {string} [definition.cshader] - Compute shader source (WGSL code). Only supported on
      * WebGPU platform.
+     * @param {Map<string, string>} [definition.vincludes] - A map containing key-value pairs of
+     * include names and their content. These are used for resolving #include directives in the
+     * vertex shader source.
+     * @param {Map<string, string>} [definition.vdefines] - A map containing key-value pairs of
+     * define names and their values. These are used for resolving #ifdef style of directives in the
+     * vertex code.
+     * @param {Map<string, string>} [definition.fincludes] - A map containing key-value pairs
+     * of include names and their content. These are used for resolving #include directives in the
+     * fragment shader source.
+     * @param {Map<string, string>} [definition.fdefines] - A map containing key-value pairs of
+     * define names and their values. These are used for resolving #ifdef style of directives in the
+     * fragment code.
      * @param {boolean} [definition.useTransformFeedback] - Specifies that this shader outputs
      * post-VS data to a buffer.
      * @param {string | string[]} [definition.fragmentOutputTypes] - Fragment shader output types,
@@ -106,13 +118,13 @@ class Shader {
             Debug.assert(definition.fshader, 'No fragment shader has been specified when creating a shader.');
 
             // pre-process shader sources
-            definition.vshader = Preprocessor.run(definition.vshader);
+            definition.vshader = Preprocessor.run(definition.vshader, definition.vdefines, definition.vincludes);
 
             // Strip unused color attachments from fragment shader.
             // Note: this is only needed for iOS 15 on WebGL2 where there seems to be a bug where color attachments that are not
             // written to generate metal linking errors. This is fixed on iOS 16, and iOS 14 does not support WebGL2.
             const stripUnusedColorAttachments = graphicsDevice.isWebGL2 && (platform.name === 'osx' || platform.name === 'ios');
-            definition.fshader = Preprocessor.run(definition.fshader, undefined, stripUnusedColorAttachments);
+            definition.fshader = Preprocessor.run(definition.fshader, definition.fdefines, definition.fincludes, stripUnusedColorAttachments);
         }
 
         this.impl = graphicsDevice.createShaderImpl(this);

src/scene/shader-lib/program-library.js

@@ -172,6 +172,10 @@ class ProgramLibrary {
                 name: `${generatedShaderDef.name}${passName}-proc`,
                 attributes: generatedShaderDef.attributes,
                 vshader: generatedShaderDef.vshader,
+                vdefines: generatedShaderDef.vdefines,
+                vincludes: generatedShaderDef.vincludes,
+                fdefines: generatedShaderDef.fdefines,
+                fincludes: generatedShaderDef.fincludes,
                 fshader: generatedShaderDef.fshader,
                 processingOptions: processingOptions,
                 shaderLanguage: generatedShaderDef.shaderLanguage