Support paletted rendering in WebGL

2021-12-20 18:25:49 -07:00
parent 0c11a7514d
commit 59186f2afd
6 changed files with 221 additions and 10 deletions
@@ -0,0 +1,50 @@
+/**
+ * @module ol/webgl/PaletteTexture
+ */
+
+class PaletteTexture {
+  /**
+   * @param {string} name The name of the texture.
+   * @param {Uint8Array} data The texture data.
+   */
+  constructor(name, data) {
+    this.name = name;
+    this.data = data;
+
+    /**
+     * @type {WebGLTexture}
+     * @private
+     */
+    this.texture_ = null;
+  }
+
+  /**
+   * @param {WebGLRenderingContext} gl Rendering context.
+   * @return {WebGLTexture} The texture.
+   */
+  getTexture(gl) {
+    if (!this.texture_) {
+      const texture = gl.createTexture();
+      gl.bindTexture(gl.TEXTURE_2D, texture);
+      gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE);
+      gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE);
+      gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST);
+      gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST);
+      gl.texImage2D(
+        gl.TEXTURE_2D,
+        0,
+        gl.RGBA,
+        this.data.length / 4,
+        1,
+        0,
+        gl.RGBA,
+        gl.UNSIGNED_BYTE,
+        this.data
+      );
+      this.texture_ = texture;
+    }
+    return this.texture_;
+  }
+}
+
+export default PaletteTexture;