Add files

src/graphics/graphics-library/frame-buffer/intermediate-frame-buffer.ts

@@ -0,0 +1,97 @@
+import { enableExtension } from '../helper/enable-extension';
+import { FrameBuffer } from './frame-buffer';
+
+export class IntermediateFrameBuffer extends FrameBuffer {
+  private frameTexture: WebGLTexture;
+  private floatLinearEnabled = false;
+
+  constructor(gl: WebGL2RenderingContext) {
+    super(gl);
+
+    enableExtension(gl, 'EXT_color_buffer_float');
+
+    try {
+      enableExtension(gl, 'OES_texture_float_linear');
+      this.floatLinearEnabled = true;
+    } catch {
+      // it's okay
+    }
+
+    const texture = this.gl.createTexture();
+    if (!texture) {
+      throw new Error('Could not create texture');
+    }
+    this.frameTexture = texture;
+    this.configureTexture();
+
+    const frameBuffer = this.gl.createFramebuffer();
+    if (!frameBuffer) {
+      throw new Error('Could not create frame buffer');
+    }
+    this.frameBuffer = frameBuffer;
+    this.configureFrameBuffer();
+
+    this.setSize();
+  }
+
+  public get colorTexture(): WebGLTexture {
+    return this.frameTexture;
+  }
+
+  public setSize(): boolean {
+    const hasChanged = super.setSize();
+    if (hasChanged) {
+      this.gl.bindTexture(this.gl.TEXTURE_2D, this.frameTexture);
+
+      this.gl.texImage2D(
+        this.gl.TEXTURE_2D,
+        0,
+        this.gl.RG16F,
+        this.size.x,
+        this.size.y,
+        0,
+        this.gl.RG,
+        this.gl.FLOAT,
+        null
+      );
+    }
+
+    return hasChanged;
+  }
+
+  private configureTexture() {
+    this.gl.bindTexture(this.gl.TEXTURE_2D, this.frameTexture);
+    this.gl.texParameteri(
+      this.gl.TEXTURE_2D,
+      this.gl.TEXTURE_MAG_FILTER,
+      this.floatLinearEnabled ? this.gl.LINEAR : this.gl.NEAREST
+    );
+    this.gl.texParameteri(
+      this.gl.TEXTURE_2D,
+      this.gl.TEXTURE_MIN_FILTER,
+      this.floatLinearEnabled ? this.gl.LINEAR : this.gl.NEAREST
+    );
+    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
+    );
+  }
+}