// Type definitions for WebGL Extensions
// Project: http://webgl.org/
// Definitions by: Arthur Langereis <https://github.com/zenmumbler>
// Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped/webgl-ext
// TypeScript Version: 2.7

// render-gl1/declarations - WebGL 1 extension definitions (beyond TS lib)
// Extracted from Stardazed - https://github.com/stardazed/stardazed

interface HTMLCanvasElement {
	getContext(contextId: "webgl" | "experimental-webgl", contextAttributes?: WebGLContextAttributes): (WebGLRenderingContext & WebGL1Extensions) | null;
}

interface WebGL1Extensions {
	getExtension(name: "EXT_color_buffer_half_float"): EXT_color_buffer_half_float;

	getExtension(name: "WEBGL_compressed_texture_atc"): WEBGL_compressed_texture_atc;
	getExtension(name: "WEBGL_compressed_texture_etc1"): WEBGL_compressed_texture_etc1;
	getExtension(name: "WEBGL_compressed_texture_pvrtc"): WEBKIT_WEBGL_compressed_texture_pvrtc;

	// Prefixed versions appearing in the wild as per February 2018
	getExtension(name: "WEBKIT_EXT_texture_filter_anisotropic"): EXT_texture_filter_anisotropic; // Chrome
	getExtension(name: "WEBKIT_WEBGL_compressed_texture_atc"): WEBGL_compressed_texture_atc; // Android
	getExtension(name: "WEBKIT_WEBGL_compressed_texture_pvrtc"): WEBKIT_WEBGL_compressed_texture_pvrtc; // Safari iOS
	getExtension(name: "WEBKIT_WEBGL_compressed_texture_s3tc"): WEBGL_compressed_texture_s3tc; // Chrome
	getExtension(name: "WEBKIT_WEBGL_depth_texture"): WEBGL_depth_texture; // Chrome
	getExtension(name: "WEBKIT_WEBGL_lose_context"): WEBGL_lose_context; // Chrome
}


// WebGL 1 Type Branding
interface WebGLObject { readonly __WebGLObject: void; }
interface WebGLBuffer { readonly __WebGLBuffer: void; }
interface WebGLFramebuffer { readonly __WebGLFramebuffer: void; }
interface WebGLProgram { readonly __WebGLProgram: void; }
interface WebGLRenderbuffer { readonly __WebGLRenderbuffer: void; }
interface WebGLShader { readonly __WebGLShader: void; }
interface WebGLTexture { readonly __WebGLTexture: void; }
interface WebGLUniformLocation { readonly __WebGLUniformLocation: void; }
interface WebGLVertexArrayObjectOES extends WebGLObject { readonly __WebGLVertexArrayObjectOES: void; }

interface EXT_frag_depth { readonly __EXT_frag_depth: void; }
interface EXT_shader_texture_lod { readonly __EXT_shader_texture_lod: void; }

interface OES_element_index_uint { readonly __OESElementIndexUint: void; }
interface OES_texture_float { readonly __OES_texture_float: void; }
interface OES_texture_float_linear { readonly __OES_texture_float_linear: void; }
interface OES_texture_half_float_linear { readonly __OES_texture_half_float_linear: void; }


// WebGL 1 Extensions
interface EXT_color_buffer_half_float {
	readonly RGBA16F_EXT: number;
	readonly RGB16F_EXT: number;
	readonly FRAMEBUFFER_ATTACHMENT_COMPONENT_TYPE_EXT: number;
	readonly UNSIGNED_NORMALIZED_EXT: number;
}

interface OES_vertex_array_object {
	// TS's lib.dom (as of v3.1.3) does not specify the nulls
	createVertexArrayOES(): WebGLVertexArrayObjectOES | null;
	deleteVertexArrayOES(arrayObject: WebGLVertexArrayObjectOES | null): void;
	isVertexArrayOES(arrayObject: WebGLVertexArrayObjectOES | null): boolean;
	bindVertexArrayOES(arrayObject: WebGLVertexArrayObjectOES | null): void;
}

interface WEBGL_compressed_texture_atc {
	readonly COMPRESSED_RGB_ATC_WEBGL: number;
	readonly COMPRESSED_RGBA_ATC_EXPLICIT_ALPHA_WEBGL: number;
	readonly COMPRESSED_RGBA_ATC_INTERPOLATED_ALPHA_WEBGL: number;
}

interface WEBGL_compressed_texture_etc1 {
	readonly COMPRESSED_RGB_ETC1_WEBGL: number;
}

interface WEBKIT_WEBGL_compressed_texture_pvrtc {
	readonly COMPRESSED_RGB_PVRTC_4BPPV1_IMG: number;
	readonly COMPRESSED_RGB_PVRTC_2BPPV1_IMG: number;
	readonly COMPRESSED_RGBA_PVRTC_4BPPV1_IMG: number;
	readonly COMPRESSED_RGBA_PVRTC_2BPPV1_IMG: number;
}