From 5d16c727f86203316a96bd5a3f6040060ec06494 Mon Sep 17 00:00:00 2001
From: Alexander Artemev <al.artemev@2gis.ru>
Date: Tue, 24 Jan 2023 00:36:36 +0700
Subject: [PATCH] TILES-4933: Support depth texture

---
 index.d.ts          |  2 ++
 src/RenderTarget.js | 55 +++++++++++++++++++++++++++++++++++++++------
 src/Texture.js      |  4 ++++
 3 files changed, 54 insertions(+), 7 deletions(-)

diff --git a/index.d.ts b/index.d.ts
index f40b381..b68d8ea 100644
--- a/index.d.ts
+++ b/index.d.ts
@@ -140,6 +140,7 @@ declare module '2gl' {
 
     export interface RenderTargetOptions extends TextureOptions {
         size: Vec2;
+        depthTexture: boolean;
     }
 
     export class Object3D {
@@ -186,6 +187,7 @@ declare module '2gl' {
         public remove(gl: WebGLRenderingContext): this;
         public setSize(size: Vec2): this;
         public getTexture(): Texture;
+        public getDepthBuffer(): Texture | WebGLRenderbuffer | null;
     }
 
     export interface RendererState {
diff --git a/src/RenderTarget.js b/src/RenderTarget.js
index 0eca1d2..dfdbf5e 100644
--- a/src/RenderTarget.js
+++ b/src/RenderTarget.js
@@ -21,6 +21,13 @@ class RenderTarget {
          */
         this._texture = new Texture(null, this.options);
 
+
+        /**
+         * @type {Texture | WebGLRenderbuffer | null}
+         * @ignore
+         */
+        this._depthBuffer = null;
+
         /**
          * Контекст WebGL, в котором был инициализирован фреймбуфер.
          * Используется только для удаления, подумать хорошо, прежде чем использовать для чего-то ещё.
@@ -79,6 +86,14 @@ class RenderTarget {
         return this._texture;
     }
 
+    /**
+     * Возвращает текущие буфер или текстуру глубины фреймбуфера
+     * @return {Texture | WebGLRenderbuffer | null}
+     */
+    getDepthBuffer() {
+        return this._depthBuffer;
+    }
+
     /**
      * Инициализирует фреймбуфер, текстуры и рендербуфер
      * @param {WebGLRenderingContext} gl
@@ -96,12 +111,32 @@ class RenderTarget {
         this._frameBuffer = gl.createFramebuffer();
         gl.bindFramebuffer(gl.FRAMEBUFFER, this._frameBuffer);
 
-        this._renderBuffer = gl.createRenderbuffer();
-        gl.bindRenderbuffer(gl.RENDERBUFFER, this._renderBuffer);
-        gl.renderbufferStorage(gl.RENDERBUFFER, gl.DEPTH_COMPONENT16, this.options.size[0], this.options.size[1]);
-
         gl.framebufferTexture2D(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, this._texture.getTexture(), 0);
-        gl.framebufferRenderbuffer(gl.FRAMEBUFFER, gl.DEPTH_ATTACHMENT, gl.RENDERBUFFER, this._renderBuffer);
+
+        if (this.options.depthTexture) {
+            this._depthBuffer = new Texture(null, {
+                magFilter: Texture.NearestFilter,
+                minFilter: Texture.NearestFilter,
+                format: Texture.DepthComponentFormat,
+                size: this.options.size,
+                premultiplyAlpha: false,
+                generateMipmaps: false,
+                type: Texture.UnsignedInt,
+            });
+            this._depthBuffer.prepare(gl);
+            gl.framebufferTexture2D(
+                gl.FRAMEBUFFER,
+                gl.DEPTH_ATTACHMENT,
+                gl.TEXTURE_2D,
+                this._depthBuffer.getTexture(),
+                0
+            );
+        } else {
+            this._depthBuffer = gl.createRenderbuffer();
+            gl.bindRenderbuffer(gl.RENDERBUFFER, this._depthBuffer);
+            gl.renderbufferStorage(gl.RENDERBUFFER, gl.DEPTH_COMPONENT16, this.options.size[0], this.options.size[1]);
+            gl.framebufferRenderbuffer(gl.FRAMEBUFFER, gl.DEPTH_ATTACHMENT, gl.RENDERBUFFER, this._depthBuffer);
+        }
 
         this._checkComplete(gl);
 
@@ -119,11 +154,15 @@ class RenderTarget {
             this._texture = null;
         }
 
+        if (this._depthBuffer) {
+            this._depthBuffer instanceof Texture ?
+                this._depthBuffer.remove(this._glContext) : this._glContext.deleteRenderbuffer(this._depthBuffer);
+            this._depthBuffer = null;
+        }
+
         if (this._frameBuffer) {
             this._glContext.deleteFramebuffer(this._frameBuffer);
-            this._glContext.deleteRenderbuffer(this._renderBuffer);
             this._frameBuffer = null;
-            this._renderBuffer = null;
         }
     }
 
@@ -154,6 +193,7 @@ class RenderTarget {
 RenderTarget.defaultOptions = Object.assign({}, Texture.defaultOptions, {
     size: [0, 0],
     generateMipmaps: false,
+    depthTexture: false,
 });
 
 export default RenderTarget;
@@ -163,4 +203,5 @@ export default RenderTarget;
  *
  * @typedef {Object} RenderTargetOptions
  * @property {Number[]} size
+ * @property {Boolean} depthTexture
  */
diff --git a/src/Texture.js b/src/Texture.js
index 2ccffd0..39fa710 100644
--- a/src/Texture.js
+++ b/src/Texture.js
@@ -165,9 +165,11 @@ class Texture {
         if (param === Texture.RgbaFormat) { return gl.RGBA; }
         if (param === Texture.AlphaFormat) { return gl.ALPHA; }
         if (param === Texture.RgbFormat) { return gl.RGB; }
+        if (param === Texture.DepthComponentFormat) { return gl.DEPTH_COMPONENT; }
 
         if (param === Texture.UnsignedByte) { return gl.UNSIGNED_BYTE; }
         if (param === Texture.Float) { return gl.FLOAT; }
+        if (param === Texture.UnsignedInt) { return gl.UNSIGNED_INT; }
 
         return null;
     }
@@ -184,12 +186,14 @@ Texture.LinearFilter = 4;
 Texture.LinearMipMapNearestFilter = 5;
 Texture.LinearMipMapLinearFilter = 6;
 
+Texture.DepthComponentFormat = 7;
 Texture.RgbaFormat = 11;
 Texture.AlphaFormat = 12;
 Texture.RgbFormat = 13;
 
 Texture.UnsignedByte = 14;
 Texture.Float = 15;
+Texture.UnsignedInt = 16;
 
 Texture.defaultOptions = {
     magFilter: Texture.LinearFilter,