add #pragma branching

src/002-webgpu-instead/main.ts

@@ -2,9 +2,10 @@ import { WebGPUApp } from "../renderer/webgpu";
 import { MeshRenderer } from "../renderer/mesh-renderer";
 import plane from "../meshes/plane";
 import rainbowPlane from "./rainbow-plane.wgsl";
+import { Shader } from "../renderer/shader";
 
 const app = new WebGPUApp({ fov: 20 });
 
 const renderer = new MeshRenderer(app, plane);
-console.log({ rainbowPlane });
+const shader = new Shader(rainbowPlane);
 app.start();

src/renderer/shader.ts

@@ -1,19 +1,38 @@
 import { WebGPUApp } from "./webgpu";
 import oopsWsgl from "./oops.wgsl";
 
+const pragmaRegexp = new RegExp("#pragma ([a-z]+) ([a-zA-Z_0-9]+)", "g");
+
 export class Shader {
   private _module: GPUShaderModule | null = null;
-  constructor(private code: string[]) {}
+  public vertexMain: string = "main";
+  public fragmentMain: string = "main";
+  public code: string;
+
+  constructor(...code: string[]) {
+    this.code = code.join("\n");
+
+    // pragma preprocessing
+    const matches = this.code.matchAll(pragmaRegexp);
+    for (const match of matches || []) {
+      switch (match[1]) {
+        case "fragment":
+          this.fragmentMain = match[2];
+          break;
+        case "vertex":
+          this.vertexMain = match[2];
+          break;
+      }
+    }
+  }
 
   module(app: WebGPUApp) {
-    this._module =
+    return (this._module =
       this._module ||
       (this._module = app.device.createShaderModule({
-        code: this.code.join("\n"),
-      }));
-
-    return this._module;
+        code: this.code,
+      })));
   }
 }
 
-export const Oops = new Shader([oopsWsgl]);
+export const Oops = new Shader(oopsWsgl);