feat: Allow shader generators to report different language keys

Author: iwoplaza

packages/typegpu-gl/src/glslGenerator.ts

@@ -84,6 +84,10 @@ export class GlslGenerator extends WgslGenerator {
   #functionType: TgpuShaderStage | 'normal' | undefined;
   #entryFnState: EntryFnState | undefined;
 
+  static {
+    GlslGenerator.prototype.languageKey = 'glsl';
+  }
+
   override typeAnnotation(data: d.BaseData): string {
     // For WGSL identity types (scalars, vectors, common matrices), map to GLSL directly.
     if (!d.isLooseData(data)) {

packages/typegpu-gl/tests/glslGenerator.test.ts

@@ -1,5 +1,5 @@
 import { describe, expect, it } from 'vitest';
-import { tgpu, d } from 'typegpu';
+import { tgpu, d, std } from 'typegpu';
 import { glOptions } from '@typegpu/gl';
 import { translateWgslTypeToGlsl } from '../src/glslGenerator.ts';
 
@@ -47,6 +47,21 @@ describe('translateWgslTypeToGlsl', () => {
   });
 });
 
+describe('GlslGenerator', () => {
+  it('reports "glsl" as the language', () => {
+    function foo() {
+      'use gpu';
+      return std.getTargetShaderLanguage() === 'glsl';
+    }
+
+    expect(tgpu.resolve([foo], glOptions())).toMatchInlineSnapshot(`
+      "bool foo() {
+        return true;
+      }"
+    `);
+  });
+});
+
 describe('GlslGenerator - variable declarations', () => {
   it('generates GLSL-style variable declarations for JS function', () => {
     const main = () => {

packages/typegpu/src/std/environment.ts

@@ -50,12 +50,12 @@ export const isBeingTranspiled = impl;
  * @note
  * Inside `lazy`, it always returns `wgsl`.
  * Inside `simulate`, it always returns `undefined`.
- * Inside `comptime`, it returns `wgsl` if called during the resolution process; otherwise, `undefined`.
+ * Inside `comptime`, it returns the shader language that is ultimately being generated (usually `wgsl`) if called during the resolution process; otherwise, `undefined`.
  */
 export const getTargetShaderLanguage = comptime((() => {
   const ctx = getResolutionCtx();
   if (!ctx) {
     return undefined;
   }
-  return getExecMode().type !== 'simulate' ? 'wgsl' : undefined;
+  return getExecMode().type !== 'simulate' ? ctx.gen.languageKey : undefined;
 }) as () => string | undefined);

packages/typegpu/src/tgsl/shaderGenerator.ts

@@ -37,6 +37,8 @@ export interface VariableDefinitionOptions {
  * shader code in the target language (WGSL, GLSL, etc.).
  */
 export interface ShaderGenerator {
+  readonly languageKey: string;
+
   initGenerator(ctx: GenerationCtx): void;
 
   declareGlobalConst(options: ConstantDefinitionOptions): ResolvedSnippet;

packages/typegpu/src/tgsl/wgslGenerator.ts

@@ -213,6 +213,13 @@ export class WgslGenerator implements ShaderGenerator {
   // used to detect `continue` and `break` nodes in loop body
   #unrolling = false;
 
+  // prototype properties
+  declare languageKey: string;
+
+  static {
+    WgslGenerator.prototype.languageKey = 'wgsl';
+  }
+
   public initGenerator(ctx: GenerationCtx) {
     this.#ctx = ctx;
   }