message: dpoit, fix webgl1 support
  in webgl1 drawbuffers must be in the same format for some reason
diff: @@ -21,6 +21,7 @@ import { blendBackDpoit_frag } from '../../mol-gl/shader/blend-back-dpoit.frag';
  import { Framebuffer } from '../../mol-gl/webgl/framebuffer';
  import { Vec2 } from '../../mol-math/linear-algebra';
  import { isDebugMode, isTimingMode } from '../../mol-util/debug';
  +import { isWebGL2 } from '../../mol-gl/webgl/compat';
  const BlendBackDpoitSchema = {
  ...QuadSchema,
  @@ -187,15 +188,22 @@ export class DpoitPass {
  for (let i = 0; i < 2; i++) {
  // depth
  this.depthFramebuffers[i].bind();
  - drawBuffers!.drawBuffers([drawBuffers!.COLOR_ATTACHMENT0, drawBuffers!.COLOR_ATTACHMENT1, drawBuffers!.COLOR_ATTACHMENT2]);
  + drawBuffers!.drawBuffers([
  + drawBuffers!.COLOR_ATTACHMENT0,
  + drawBuffers!.COLOR_ATTACHMENT1,
  + drawBuffers!.COLOR_ATTACHMENT2
  + ]);
  - this.depthTextures[i].attachFramebuffer(this.depthFramebuffers[i], 'color2');
  this.colorFrontTextures[i].attachFramebuffer(this.depthFramebuffers[i], 'color0');
  this.colorBackTextures[i].attachFramebuffer(this.depthFramebuffers[i], 'color1');
  + this.depthTextures[i].attachFramebuffer(this.depthFramebuffers[i], 'color2');
  // color
  this.colorFramebuffers[i].bind();
  - drawBuffers!.drawBuffers([drawBuffers!.COLOR_ATTACHMENT0, drawBuffers!.COLOR_ATTACHMENT1]);
  + drawBuffers!.drawBuffers([
  + drawBuffers!.COLOR_ATTACHMENT0,
  + drawBuffers!.COLOR_ATTACHMENT1
  + ]);
  this.colorFrontTextures[i].attachFramebuffer(this.colorFramebuffers[i], 'color0');
  this.colorBackTextures[i].attachFramebuffer(this.colorFramebuffers[i], 'color1');
  @@ -232,6 +240,7 @@ export class DpoitPass {
  this.depthTextures[0].define(width, height);
  this.depthTextures[1].define(width, height);
  + if (isWebGL2(webgl.gl)) {
  this.colorFrontTextures = colorBufferHalfFloat && textureHalfFloat ? [
  resources.texture('image-float16', 'rgba', 'fp16', 'nearest'),
  resources.texture('image-float16', 'rgba', 'fp16', 'nearest')
  @@ -239,8 +248,6 @@ export class DpoitPass {
  resources.texture('image-float32', 'rgba', 'float', 'nearest'),
  resources.texture('image-float32', 'rgba', 'float', 'nearest')
  ];
  - this.colorFrontTextures[0].define(width, height);
  - this.colorFrontTextures[1].define(width, height);
  this.colorBackTextures = colorBufferHalfFloat && textureHalfFloat ? [
  resources.texture('image-float16', 'rgba', 'fp16', 'nearest'),
  @@ -249,6 +256,23 @@ export class DpoitPass {
  resources.texture('image-float32', 'rgba', 'float', 'nearest'),
  resources.texture('image-float32', 'rgba', 'float', 'nearest')
  ];
  + } else {
  + // in webgl1 drawbuffers must be in the same format for some reason
  +
  + this.colorFrontTextures = [
  + resources.texture('image-float32', 'rgba', 'float', 'nearest'),
  + resources.texture('image-float32', 'rgba', 'float', 'nearest')
  + ];
  +
  + this.colorBackTextures = [
  + resources.texture('image-float32', 'rgba', 'float', 'nearest'),
  + resources.texture('image-float32', 'rgba', 'float', 'nearest')
  + ];
  + }
  +
  + this.colorFrontTextures[0].define(width, height);
  + this.colorFrontTextures[1].define(width, height);
  +
  this.colorBackTextures[0].define(width, height);
  this.colorBackTextures[1].define(width, height);
  