Add frame buffers

frontend/src/scripts/drawing/graphics-library/intermediate-frame-buffer.ts

@@ -0,0 +1,75 @@
+import { FragmentShaderOnlyProgram } from './fragment-shader-only-program';
+import { FrameBuffer } from './frame-buffer';
+
+export class IntermediateFrameBuffer extends FrameBuffer {
+  private frameTexture: WebGLTexture;
+
+  constructor(
+    gl: WebGL2RenderingContext,
+    programs: Array<FragmentShaderOnlyProgram>
+  ) {
+    super(gl, programs);
+
+    this.frameTexture = this.gl.createTexture();
+    this.configureTexture();
+
+    this.frameBuffer = this.gl.createFramebuffer();
+    this.configureFrameBuffer();
+
+    this.setSize();
+  }
+
+  public get texture(): WebGLTexture {
+    return this.frameTexture;
+  }
+
+  public setSize() {
+    super.setSize();
+
+    this.gl.bindTexture(this.gl.TEXTURE_2D, this.frameTexture);
+
+    this.gl.texImage2D(
+      this.gl.TEXTURE_2D,
+      0,
+      this.gl.RGBA,
+      this.size.x,
+      this.size.y,
+      0,
+      this.gl.RGBA,
+      this.gl.UNSIGNED_BYTE,
+      null
+    );
+  }
+
+  private configureTexture() {
+    this.gl.bindTexture(this.gl.TEXTURE_2D, this.frameTexture);
+
+    this.gl.texParameteri(
+      this.gl.TEXTURE_2D,
+      this.gl.TEXTURE_MIN_FILTER,
+      this.gl.LINEAR
+    );
+    this.gl.texParameteri(
+      this.gl.TEXTURE_2D,
+      this.gl.TEXTURE_WRAP_S,
+      this.gl.CLAMP_TO_EDGE
+    );
+    this.gl.texParameteri(
+      this.gl.TEXTURE_2D,
+      this.gl.TEXTURE_WRAP_T,
+      this.gl.CLAMP_TO_EDGE
+    );
+  }
+
+  private configureFrameBuffer() {
+    this.gl.bindFramebuffer(this.gl.FRAMEBUFFER, this.frameBuffer);
+    const attachmentPoint = this.gl.COLOR_ATTACHMENT0;
+    this.gl.framebufferTexture2D(
+      this.gl.FRAMEBUFFER,
+      attachmentPoint,
+      this.gl.TEXTURE_2D,
+      this.frameTexture,
+      0
+    );
+  }
+}