state.js

//
// The code that follows was originally sourced from:
// https://www.khronos.org/registry/webgl/sdk/debug/webgl-debug.js
//

module.exports = stateReset

/*
** Copyright (c) 2012 The Khronos Group Inc.
**
** Permission is hereby granted, free of charge, to any person obtaining a
** copy of this software and/or associated documentation files (the
** "Materials"), to deal in the Materials without restriction, including
** without limitation the rights to use, copy, modify, merge, publish,
** distribute, sublicense, and/or sell copies of the Materials, and to
** permit persons to whom the Materials are furnished to do so, subject to
** the following conditions:
**
** The above copyright notice and this permission notice shall be included
** in all copies or substantial portions of the Materials.
**
** THE MATERIALS ARE PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
** EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
** MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
** IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
** CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
** TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
** MATERIALS OR THE USE OR OTHER DEALINGS IN THE MATERIALS.
*/
function stateReset(gl) {
  var numAttribs = gl.getParameter(gl.MAX_VERTEX_ATTRIBS)
  var tmp = gl.createBuffer()
  gl.bindBuffer(gl.ARRAY_BUFFER, tmp)
  for (var ii = 0; ii < numAttribs; ++ii) {
    gl.disableVertexAttribArray(ii)
    gl.vertexAttribPointer(ii, 4, gl.FLOAT, false, 0, 0)
    gl.vertexAttrib1f(ii, 0)
  }
  gl.deleteBuffer(tmp)

  var numTextureUnits = gl.getParameter(gl.MAX_TEXTURE_IMAGE_UNITS)
  for (var ii = 0; ii < numTextureUnits; ++ii) {
    gl.activeTexture(gl.TEXTURE0 + ii)
    gl.bindTexture(gl.TEXTURE_CUBE_MAP, null)
    gl.bindTexture(gl.TEXTURE_2D, null)
  }

  gl.activeTexture(gl.TEXTURE0)
  gl.useProgram(null)
  gl.bindBuffer(gl.ARRAY_BUFFER, null)
  gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, null)
  gl.bindFramebuffer(gl.FRAMEBUFFER, null)
  gl.bindRenderbuffer(gl.RENDERBUFFER, null)
  gl.disable(gl.BLEND)
  gl.disable(gl.CULL_FACE)
  gl.disable(gl.DEPTH_TEST)
  gl.disable(gl.DITHER)
  gl.disable(gl.SCISSOR_TEST)
  gl.blendColor(0, 0, 0, 0)
  gl.blendEquation(gl.FUNC_ADD)
  gl.blendFunc(gl.ONE, gl.ZERO)
  gl.clearColor(0, 0, 0, 0)
  gl.clearDepth(1)
  gl.clearStencil(-1)
  gl.colorMask(true, true, true, true)
  gl.cullFace(gl.BACK)
  gl.depthFunc(gl.LESS)
  gl.depthMask(true)
  gl.depthRange(0, 1)
  gl.frontFace(gl.CCW)
  gl.hint(gl.GENERATE_MIPMAP_HINT, gl.DONT_CARE)
  gl.lineWidth(1)
  gl.pixelStorei(gl.PACK_ALIGNMENT, 4)
  gl.pixelStorei(gl.UNPACK_ALIGNMENT, 4)
  gl.pixelStorei(gl.UNPACK_FLIP_Y_WEBGL, false)
  gl.pixelStorei(gl.UNPACK_PREMULTIPLY_ALPHA_WEBGL, false)
  gl.polygonOffset(0, 0)
  gl.sampleCoverage(1, false)
  gl.scissor(0, 0, gl.canvas.width, gl.canvas.height)
  gl.stencilFunc(gl.ALWAYS, 0, 0xFFFFFFFF)
  gl.stencilMask(0xFFFFFFFF)
  gl.stencilOp(gl.KEEP, gl.KEEP, gl.KEEP)
  gl.viewport(0, 0, gl.canvas.width, gl.canvas.height)
  gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT | gl.STENCIL_BUFFER_BIT)

  return gl
}