Method _getFramebufferColorFormat

src/webgl/p5.RendererGL.js:1549–1593

* To create a WebGL texture, one needs to supply three pieces of information: * the type (the data type each channel will be stored as, e.g. int or float), * the format (the color channels that will each be stored in the previously * specified type, e.g. rgb or rgba), and the internal forma

(framebuffer)

   * @private
   */
  _getFramebufferColorFormat(framebuffer) {
    let type, format, internalFormat;
    const gl = this.GL;

    if (framebuffer.format === constants.FLOAT) {
      type = gl.FLOAT;
    } else if (framebuffer.format === constants.HALF_FLOAT) {
      type = this.webglVersion === constants.WEBGL2
        ? gl.HALF_FLOAT
        : gl.getExtension('OES_texture_half_float').HALF_FLOAT_OES;
    } else {
      type = gl.UNSIGNED_BYTE;
    }

    if (framebuffer.channels === RGBA) {
      format = gl.RGBA;
    } else {
      format = gl.RGB;
    }

    if (this.webglVersion === constants.WEBGL2) {
      // https://webgl2fundamentals.org/webgl/lessons/webgl-data-textures.html
      const table = {
        [gl.FLOAT]: {
          [gl.RGBA]: gl.RGBA32F
          // gl.RGB32F is not available in Firefox without an alpha channel
        },
        [gl.HALF_FLOAT]: {
          [gl.RGBA]: gl.RGBA16F
          // gl.RGB16F is not available in Firefox without an alpha channel
        },
        [gl.UNSIGNED_BYTE]: {
          [gl.RGBA]: gl.RGBA8, // gl.RGBA4
          [gl.RGB]: gl.RGB8 // gl.RGB565
        }
      };
      internalFormat = table[type][format];
    } else if (framebuffer.format === constants.HALF_FLOAT) {
      internalFormat = gl.RGBA;
    } else {
      internalFormat = format;
    }

    return { internalFormat, format, type };
  }

  /**
   * To create a WebGL texture, one needs to supply three pieces of information: