maxTextures use gl.MAX_COMBINED_TEXTURE_IMAGE_UNITS

[06wj]

The maxTextures should use gl.MAX_COMBINED_TEXTURE_IMAGE_UNITS instead of gl.MAX_TEXTURE_IMAGE_UNITS.

See https://developer.mozilla.org/en-US/docs/Web/API/WebGLRenderingContext/activeTexture#Parameters

[Mugen87]

From WebGL stats:

MAX_TEXTURE_IMAGE_UNITS: The maximum number of texture units that can be used in a fragment shader (see http://webglstats.com/webgl/parameter/MAX_TEXTURE_IMAGE_UNITS)

MAX_COMBINED_TEXTURE_IMAGE_UNITS: The maximum number of texture units that can be used. If a unit is used by both vertex and fragment shader, this counts as two units against this limit. (http://webglstats.com/webgl/parameter/MAX_COMBINED_TEXTURE_IMAGE_UNITS)

[mrdoob]

Thanks!