Source: Renderer/ContextLimits.js

/*global define*/
define([
        '../Core/defineProperties'
    ], function(
        defineProperties) {
    'use strict';

    /**
     * @private
     */
    var ContextLimits = {
        _maximumCombinedTextureImageUnits : 0,
        _maximumCubeMapSize : 0,
        _maximumFragmentUniformVectors : 0,
        _maximumTextureImageUnits : 0,
        _maximumRenderbufferSize : 0,
        _maximumTextureSize : 0,
        _maximumVaryingVectors : 0,
        _maximumVertexAttributes : 0,
        _maximumVertexTextureImageUnits : 0,
        _maximumVertexUniformVectors : 0,
        _minimumAliasedLineWidth : 0,
        _maximumAliasedLineWidth : 0,
        _minimumAliasedPointSize : 0,
        _maximumAliasedPointSize : 0,
        _maximumViewportWidth : 0,
        _maximumViewportHeight : 0,
        _maximumTextureFilterAnisotropy : 0,
        _maximumDrawBuffers : 0,
        _maximumColorAttachments : 0,
        _highpFloatSupported: false,
        _highpIntSupported: false
    };

    defineProperties(ContextLimits, {

        /**
         * The maximum number of texture units that can be used from the vertex and fragment
         * shader with this WebGL implementation.  The minimum is eight.  If both shaders access the
         * same texture unit, this counts as two texture units.
         * @memberof ContextLimits
         * @type {Number}
         * @see {@link https://www.khronos.org/opengles/sdk/docs/man/xhtml/glGet.xml|glGet} with <code>MAX_COMBINED_TEXTURE_IMAGE_UNITS</code>.
         */
        maximumCombinedTextureImageUnits : {
            get: function () {
                return ContextLimits._maximumCombinedTextureImageUnits;
            }
        },

        /**
         * The approximate maximum cube mape width and height supported by this WebGL implementation.
         * The minimum is 16, but most desktop and laptop implementations will support much larger sizes like 8,192.
         * @memberof ContextLimits
         * @type {Number}
         * @see {@link https://www.khronos.org/opengles/sdk/docs/man/xhtml/glGet.xml|glGet} with <code>MAX_CUBE_MAP_TEXTURE_SIZE</code>.
         */
        maximumCubeMapSize : {
            get: function () {
                return ContextLimits._maximumCubeMapSize;
            }
        },

        /**
         * The maximum number of <code>vec4</code>, <code>ivec4</code>, and <code>bvec4</code>
         * uniforms that can be used by a fragment shader with this WebGL implementation.  The minimum is 16.
         * @memberof ContextLimits
         * @type {Number}
         * @see {@link https://www.khronos.org/opengles/sdk/docs/man/xhtml/glGet.xml|glGet} with <code>MAX_FRAGMENT_UNIFORM_VECTORS</code>.
         */
        maximumFragmentUniformVectors : {
            get: function () {
                return ContextLimits._maximumFragmentUniformVectors;
            }
        },

        /**
         * The maximum number of texture units that can be used from the fragment shader with this WebGL implementation.  The minimum is eight.
         * @memberof ContextLimits
         * @type {Number}
         * @see {@link https://www.khronos.org/opengles/sdk/docs/man/xhtml/glGet.xml|glGet} with <code>MAX_TEXTURE_IMAGE_UNITS</code>.
         */
        maximumTextureImageUnits : {
            get: function () {
                return ContextLimits._maximumTextureImageUnits;
            }
        },

        /**
         * The maximum renderbuffer width and height supported by this WebGL implementation.
         * The minimum is 16, but most desktop and laptop implementations will support much larger sizes like 8,192.
         * @memberof ContextLimits
         * @type {Number}
         * @see {@link https://www.khronos.org/opengles/sdk/docs/man/xhtml/glGet.xml|glGet} with <code>MAX_RENDERBUFFER_SIZE</code>.
         */
        maximumRenderbufferSize : {
            get: function () {
                return ContextLimits._maximumRenderbufferSize;
            }
        },

        /**
         * The approximate maximum texture width and height supported by this WebGL implementation.
         * The minimum is 64, but most desktop and laptop implementations will support much larger sizes like 8,192.
         * @memberof ContextLimits
         * @type {Number}
         * @see {@link https://www.khronos.org/opengles/sdk/docs/man/xhtml/glGet.xml|glGet} with <code>MAX_TEXTURE_SIZE</code>.
         */
        maximumTextureSize : {
            get: function () {
                return ContextLimits._maximumTextureSize;
            }
        },

        /**
         * The maximum number of <code>vec4</code> varying variables supported by this WebGL implementation.
         * The minimum is eight.  Matrices and arrays count as multiple <code>vec4</code>s.
         * @memberof ContextLimits
         * @type {Number}
         * @see {@link https://www.khronos.org/opengles/sdk/docs/man/xhtml/glGet.xml|glGet} with <code>MAX_VARYING_VECTORS</code>.
         */
        maximumVaryingVectors : {
            get: function () {
                return ContextLimits._maximumVaryingVectors;
            }
        },

        /**
         * The maximum number of <code>vec4</code> vertex attributes supported by this WebGL implementation.  The minimum is eight.
         * @memberof ContextLimits
         * @type {Number}
         * @see {@link https://www.khronos.org/opengles/sdk/docs/man/xhtml/glGet.xml|glGet} with <code>MAX_VERTEX_ATTRIBS</code>.
         */
        maximumVertexAttributes : {
            get: function () {
                return ContextLimits._maximumVertexAttributes;
            }
        },

        /**
         * The maximum number of texture units that can be used from the vertex shader with this WebGL implementation.
         * The minimum is zero, which means the GL does not support vertex texture fetch.
         * @memberof ContextLimits
         * @type {Number}
         * @see {@link https://www.khronos.org/opengles/sdk/docs/man/xhtml/glGet.xml|glGet} with <code>MAX_VERTEX_TEXTURE_IMAGE_UNITS</code>.
         */
        maximumVertexTextureImageUnits : {
            get: function () {
                return ContextLimits._maximumVertexTextureImageUnits;
            }
        },

        /**
         * The maximum number of <code>vec4</code>, <code>ivec4</code>, and <code>bvec4</code>
         * uniforms that can be used by a vertex shader with this WebGL implementation.  The minimum is 16.
         * @memberof ContextLimits
         * @type {Number}
         * @see {@link https://www.khronos.org/opengles/sdk/docs/man/xhtml/glGet.xml|glGet} with <code>MAX_VERTEX_UNIFORM_VECTORS</code>.
         */
        maximumVertexUniformVectors : {
            get: function () {
                return ContextLimits._maximumVertexUniformVectors;
            }
        },

        /**
         * The minimum aliased line width, in pixels, supported by this WebGL implementation.  It will be at most one.
         * @memberof ContextLimits
         * @type {Number}
         * @see {@link https://www.khronos.org/opengles/sdk/docs/man/xhtml/glGet.xml|glGet} with <code>ALIASED_LINE_WIDTH_RANGE</code>.
         */
        minimumAliasedLineWidth : {
            get: function () {
                return ContextLimits._minimumAliasedLineWidth;
            }
        },

        /**
         * The maximum aliased line width, in pixels, supported by this WebGL implementation.  It will be at least one.
         * @memberof ContextLimits
         * @type {Number}
         * @see {@link https://www.khronos.org/opengles/sdk/docs/man/xhtml/glGet.xml|glGet} with <code>ALIASED_LINE_WIDTH_RANGE</code>.
         */
        maximumAliasedLineWidth : {
            get: function () {
                return ContextLimits._maximumAliasedLineWidth;
            }
        },

        /**
         * The minimum aliased point size, in pixels, supported by this WebGL implementation.  It will be at most one.
         * @memberof ContextLimits
         * @type {Number}
         * @see {@link https://www.khronos.org/opengles/sdk/docs/man/xhtml/glGet.xml|glGet} with <code>ALIASED_POINT_SIZE_RANGE</code>.
         */
        minimumAliasedPointSize : {
            get: function () {
                return ContextLimits._minimumAliasedPointSize;
            }
        },

        /**
         * The maximum aliased point size, in pixels, supported by this WebGL implementation.  It will be at least one.
         * @memberof ContextLimits
         * @type {Number}
         * @see {@link https://www.khronos.org/opengles/sdk/docs/man/xhtml/glGet.xml|glGet} with <code>ALIASED_POINT_SIZE_RANGE</code>.
         */
        maximumAliasedPointSize : {
            get: function () {
                return ContextLimits._maximumAliasedPointSize;
            }
        },

        /**
         * The maximum supported width of the viewport.  It will be at least as large as the visible width of the associated canvas.
         * @memberof ContextLimits
         * @type {Number}
         * @see {@link https://www.khronos.org/opengles/sdk/docs/man/xhtml/glGet.xml|glGet} with <code>MAX_VIEWPORT_DIMS</code>.
         */
        maximumViewportWidth : {
            get: function () {
                return ContextLimits._maximumViewportWidth;
            }
        },

        /**
         * The maximum supported height of the viewport.  It will be at least as large as the visible height of the associated canvas.
         * @memberof ContextLimits
         * @type {Number}
         * @see {@link https://www.khronos.org/opengles/sdk/docs/man/xhtml/glGet.xml|glGet} with <code>MAX_VIEWPORT_DIMS</code>.
         */
        maximumViewportHeight : {
            get: function () {
                return ContextLimits._maximumViewportHeight;
            }
        },

        /**
         * The maximum degree of anisotropy for texture filtering
         * @memberof ContextLimits
         * @type {Number}
         */
        maximumTextureFilterAnisotropy : {
            get: function () {
                return ContextLimits._maximumTextureFilterAnisotropy;
            }
        },

        /**
         * The maximum number of simultaneous outputs that may be written in a fragment shader.
         * @memberof ContextLimits
         * @type {Number}
         */
        maximumDrawBuffers : {
            get: function () {
                return ContextLimits._maximumDrawBuffers;
            }
        },

        /**
         * The maximum number of color attachments supported.
         * @memberof ContextLimits
         * @type {Number}
         */
        maximumColorAttachments : {
            get: function () {
                return ContextLimits._maximumColorAttachments;
            }
        },

        /**
         * High precision float supported (<code>highp</code>) in fragment shaders.
         * @memberof ContextLimits
         * @type {Boolean}
         */
        highpFloatSupported : {
            get: function () {
                return ContextLimits._highpFloatSupported;
            }
        },

        /**
         * High precision int supported (<code>highp</code>) in fragment shaders.
         * @memberof ContextLimits
         * @type {Boolean}
         */
        highpIntSupported : {
            get: function () {
                return ContextLimits._highpIntSupported;
            }
        }

    });

    return ContextLimits;
});