//--------------------------------------------------------------------------------
//NOTE(martin): global app state
//--------------------------------------------------------------------------------
var	APP =
{
	canvas: document.getElementById('wa_canvas'),
	instance: null,
	memory: null,
};

var HEAP32, HEAPU8, HEAPU16, HEAPU32, HEAPF32;
var WASM_MEMORY, WASM_HEAP;
var WASM_HEAP_MAX = 256*1024*1024; //max 256MB

//--------------------------------------------------------------------------------
//NOTE(martin): log and abort functions
//--------------------------------------------------------------------------------
function log_error(code, msg)
{
	console.log('ERROR (' + code + '): ' + msg + '\n');
}

var ABORT = false;
function abort(code, msg)
{
	ABORT = true;
	log_error(code, msg);
	throw 'abort';
}

const utf8Decoder = new TextDecoder('utf-8');

function console_log(ptr, len)
{
	console.log(utf8Decoder.decode(new Uint8Array(APP.memory.buffer, ptr, len)));
}

//--------------------------------------------------------------------------------
//NOTE(martin): Memory interaction
//--------------------------------------------------------------------------------
function MemorySetBufferViews()
{
	var buf = APP.memory.buffer;
	HEAP32 = new Int32Array(buf);
	HEAPU8 = new Uint8Array(buf);
	HEAPU16 = new Uint16Array(buf);
	HEAPU32 = new Uint32Array(buf);
	HEAPF32 = new Float32Array(buf);
}

function WriteHeapString(str, ptr, max_length)
{
	// Put a string from javascript onto the wasm memory heap (encoded as UTF8)
	if(!(0<max_length))return 0;
	for(var e=str,r=HEAPU8,f=ptr,i=max_length,a=f,t=f+i-1,b=0;b<e.length;++b)
	{
		var k=e.charCodeAt(b);
		if(55296<=k&&k<=57343&&(k=65536+((1023&k)<<10)|1023&e.charCodeAt(++b)),k<=127){if(t<=f)break;r[f++]=k;}
		else if(k<=2047){if(t<=f+1)break;r[f++]=192|k>>6,r[f++]=128|63&k;}
		else if(k<=65535){if(t<=f+2)break;r[f++]=224|k>>12,r[f++]=128|k>>6&63,r[f++]=128|63&k;}
		else if(k<=2097151){if(t<=f+3)break;r[f++]=240|k>>18,r[f++]=128|k>>12&63,r[f++]=128|k>>6&63,r[f++]=128|63&k;}
		else if(k<=67108863){if(t<=f+4)break;r[f++]=248|k>>24,r[f++]=128|k>>18&63,r[f++]=128|k>>12&63,r[f++]=128|k>>6&63,r[f++]=128|63&k;}
		else{if(t<=f+5)break;r[f++]=252|k>>30,r[f++]=128|k>>24&63,r[f++]=128|k>>18&63,r[f++]=128|k>>12&63,r[f++]=128|k>>6&63,r[f++]=128|63&k;}
	}
	return r[f]=0,f-a;
}

function ReadHeapString(ptr, length)
{
	// Read a string from the wasm memory heap to javascript (decoded as UTF8)
	if (length === 0 || !ptr) return '';
	for (var hasUtf = 0, t, i = 0; !length || i != length; i++)
	{
		t = HEAPU8[((ptr)+(i))>>0];
		if (t == 0 && !length) break;
		hasUtf |= t;
	}
	if (!length) length = i;
	if (hasUtf & 128)
	{
		for(var r=HEAPU8,o=ptr,p=ptr+length,F=String.fromCharCode,e,f,i,n,C,t,a,g='';;)
		{
			if(o==p||(e=r[o++],!e)) return g;
			128&e?(f=63&r[o++],192!=(224&e)?(i=63&r[o++],224==(240&e)?e=(15&e)<<12|f<<6|i:(n=63&r[o++],240==(248&e)?e=(7&e)<<18|f<<12|i<<6|n:(C=63&r[o++],248==(252&e)?e=(3&e)<<24|f<<18|i<<12|n<<6|C:(t=63&r[o++],e=(1&e)<<30|f<<24|i<<18|n<<12|C<<6|t))),65536>e?g+=F(e):(a=e-65536,g+=F(55296|a>>10,56320|1023&a))):g+=F((31&e)<<6|f)):g+=F(e);
		}
	}
	// split up into chunks, because .apply on a huge string can overflow the stack
	for (var ret = '', curr; length > 0; ptr += 1024, length -= 1024)
		ret += String.fromCharCode.apply(String, HEAPU8.subarray(ptr, ptr + Math.min(length, 1024)));
	return ret;
}

//------------------------------------------------------------------------------------------------
//NOTE(martin): WebGL bindings
//------------------------------------------------------------------------------------------------
var GLctx =  null;
var GLcounter =  1;
var GLbuffers =  [];
var GLprograms =  [];
var GLframebuffers =  [];
var GLtextures =  [];
var GLuniforms =  [];
var GLshaders =  [];
var GLprogramInfos =  {};
var GLpackAlignment =  4;
var GLunpackAlignment =  4;
var GLMINI_TEMP_BUFFER_SIZE =  256;
var GLminiTempBuffer =  null;
var GLminiTempBufferViews =  [0];

function GLsetupContext(canvas, attr)
{
	var attr = { majorVersion: 2, minorVersion: 0, antialias: false, alpha: false };
	var errorInfo = '';
	try
	{
		let onContextCreationError = function(event) { errorInfo = event.statusMessage || errorInfo; };
		canvas.addEventListener('webglcontextcreationerror', onContextCreationError, false);
		try { GLctx = canvas.getContext('webgl2', attr); }
		finally { canvas.removeEventListener('webglcontextcreationerror', onContextCreationError, false); }
		if (!GLctx) throw 'Could not create context';
	}
	catch (e) { abort('WEBGL', e + (errorInfo ? ' (' + errorInfo + ')' : '')); }


	var exts = GLctx.getSupportedExtensions();
	if (exts && exts.length > 0)
	{
		// These are the 'safe' feature-enabling extensions that don't add any performance impact related to e.g. debugging, and
		// should be enabled by default so that client GLES2/GL code will not need to go through extra hoops to get its stuff working.
		// As new extensions are ratified at http://www.khronos.org/registry/webgl/extensions/ , feel free to add your new extensions
		// here, as long as they don't produce a performance impact for users that might not be using those extensions.
		// E.g. debugging-related extensions should probably be off by default.
		var W = 'WEBGL_', O = 'OES_', E = 'EXT_', T = 'texture_', C = 'compressed_'+T;
		var automaticallyEnabledExtensions = [ // Khronos ratified WebGL extensions ordered by number (no debug extensions):
			O+T+'float', O+T+'half_float', O+'standard_derivatives',
			O+'vertex_array_object', W+C+'s3tc', W+'depth_texture',
			O+'element_index_uint', E+T+'filter_anisotropic', E+'frag_depth',
			W+'draw_buffers', 'ANGLE_instanced_arrays', O+T+'float_linear',
			O+T+'half_float_linear', E+'blend_minmax', E+'shader_texture_lod',
			// Community approved WebGL extensions ordered by number:
			W+C+'pvrtc', E+'color_buffer_half_float', W+'color_buffer_float',
			E+'sRGB', W+C+'etc1', E+'disjoint_timer_query',
			W+C+'etc', W+C+'astc', E+'color_buffer_float',
			W+C+'s3tc_srgb', E+'disjoint_timer_query_webgl2'];
		exts.forEach(function(ext)
		{
			if (automaticallyEnabledExtensions.indexOf(ext) != -1)
			{
				// Calling .getExtension enables that extension permanently, no need to store the return value to be enabled.
				GLctx.getExtension(ext);
			}
		});
	}

	return true;
};

var GLlastError;

function GLBindImports(env)
{
	GLminiTempBuffer = new Float32Array(GLMINI_TEMP_BUFFER_SIZE);
	for (var i = 0; i < GLMINI_TEMP_BUFFER_SIZE; i++) GLminiTempBufferViews[i] = GLminiTempBuffer.subarray(0, i+1);

	function getNewId(table)
	{
		var ret = GLcounter++;
		for (var i = table.length; i < ret; i++) table[i] = null;
		return ret;
	}
	function getSource(shader, count, string, length)
	{
		var source = '';
		for (var i = 0; i < count; ++i)
		{
			var frag;
			if (length)
			{
				var len = HEAP32[(((length)+(i*4))>>2)];
				if (len < 0) frag = ReadHeapString(HEAP32[(((string)+(i*4))>>2)]);
				else frag = ReadHeapString(HEAP32[(((string)+(i*4))>>2)], len);
			}
			else frag = ReadHeapString(HEAP32[(((string)+(i*4))>>2)]);
			source += frag;
		}
		return source;
	}
	function populateUniformTable(program)
	{
		var p = GLprograms[program];
		GLprogramInfos[program] =
		{
			uniforms: {},
			maxUniformLength: 0, // This is eagerly computed below, since we already enumerate all uniforms anyway.
			maxAttributeLength: -1, // This is lazily computed and cached, computed when/if first asked, '-1' meaning not computed yet.
			maxUniformBlockNameLength: -1 // Lazily computed as well
		};

		var ptable = GLprogramInfos[program];
		var utable = ptable.uniforms;

		// A program's uniform table maps the string name of an uniform to an integer location of that uniform.
		// The global GLuniforms map maps integer locations to WebGLUniformLocations.
		var numUniforms = GLctx.getProgramParameter(p, GLctx.ACTIVE_UNIFORMS);
		for (var i = 0; i < numUniforms; ++i)
		{
			var u = GLctx.getActiveUniform(p, i);

			var name = u.name;
			ptable.maxUniformLength = Math.max(ptable.maxUniformLength, name.length+1);

			// Strip off any trailing array specifier we might have got, e.g. '[0]'.
			if (name.indexOf(']', name.length-1) !== -1)
			{
				var ls = name.lastIndexOf('[');
				name = name.slice(0, ls);
			}

			// Optimize memory usage slightly: If we have an array of uniforms, e.g. 'vec3 colors[3];', then
			// only store the string 'colors' in utable, and 'colors[0]', 'colors[1]' and 'colors[2]' will be parsed as 'colors'+i.
			// Note that for the GLuniforms table, we still need to fetch the all WebGLUniformLocations for all the indices.
			var loc = GLctx.getUniformLocation(p, name);

			if (loc != null)
			{
				var id = getNewId(GLuniforms);
				utable[name] = [u.size, id];
				GLuniforms[id] = loc;

				for (var j = 1; j < u.size; ++j)
				{
					var n = name + '['+j+']';
					loc = GLctx.getUniformLocation(p, n);
					id = getNewId(GLuniforms);

					GLuniforms[id] = loc;
				}
			}
		}
	}
	function GLrecordError(err)
	{
		if (!GLlastError) GLlastError = err;
	}

	env.glActiveTexture = function(x0) { GLctx.activeTexture(x0); };
	env.glAttachShader = function(program, shader) { GLctx.attachShader(GLprograms[program], GLshaders[shader]); };
	env.glBindAttribLocation = function(program, index, name) { GLctx.bindAttribLocation(GLprograms[program], index, ReadHeapString(name)); };
	env.glBindBuffer = function(target, buffer) { GLctx.bindBuffer(target, buffer ? GLbuffers[buffer] : null); };
	env.glBindFramebuffer = function(target, framebuffer) { GLctx.bindFramebuffer(target, framebuffer ? GLframebuffers[framebuffer] : null); };
	env.glBindTexture = function(target, texture) { GLctx.bindTexture(target, texture ? GLtextures[texture] : null); };
	env.glBlendFunc = function(x0, x1) { GLctx.blendFunc(x0, x1); };
	env.glBlendFuncSeparate = function(x0, x1, x2, x3) { GLctx.blendFuncSeparate(x0, x1, x2, x3); }
	env.glBlendColor = function(x0, x1, x2, x3) { GLctx.blendColor(x0, x1, x2, x3); }
	env.glBlendEquation = function(x0) { GLctx.blendEquation(x0); }
	env.glBlendEquationSeparate = function(x0, x1) { GLctx.blendEquationSeparate(x0, x1); }

	env.glBufferData = function(target, size, data, usage)
	{
		if (!data) GLctx.bufferData(target, size, usage);
		else GLctx.bufferData(target, HEAPU8.subarray(data, data+size), usage);
	};

	env.glBufferSubData = function(target, offset, size, data) { GLctx.bufferSubData(target, offset, HEAPU8.subarray(data, data+size)); };
	env.glCheckFramebufferStatus = function(target) { return(GLctx.checkFramebufferStatus(target));};
	env.glClear = function(x0) { GLctx.clear(x0); };
	env.glClearColor = function(x0, x1, x2, x3) { GLctx.clearColor(x0, x1, x2, x3); };
	env.glColorMask = function(red, green, blue, alpha) { GLctx.colorMask(!!red, !!green, !!blue, !!alpha); };
	env.glCompileShader = function(shader) {
		GLctx.compileShader(GLshaders[shader]);
		var message = GLctx.getShaderInfoLog(GLshaders[shader]);
		if(message.length > 0)
		{
			throw message;
		}
	};

	env.glCreateProgram = function()
	{
		var id = getNewId(GLprograms);
		var program = GLctx.createProgram();
		program.name = id;
		GLprograms[id] = program;
		return id;
	};

	env.glCreateShader = function(shaderType)
	{
		var id = getNewId(GLshaders);
		GLshaders[id] = GLctx.createShader(shaderType);
		return id;
	};

	env.glDeleteBuffers = function(n, buffers)
	{
		for (var i = 0; i < n; i++)
		{
			var id = HEAP32[(((buffers)+(i*4))>>2)];
			var buffer = GLbuffers[id];

			// From spec: "glDeleteBuffers silently ignores 0's and names that do not correspond to existing buffer objects."
			if (!buffer) continue;

			GLctx.deleteBuffer(buffer);
			buffer.name = 0;
			GLbuffers[id] = null;
		}
	};

	env.glDeleteFramebuffers = function(n, framebuffers)
	{
		for (var i = 0; i < n; ++i)
		{
			var id = HEAP32[(((framebuffers)+(i*4))>>2)];
			var framebuffer = GLframebuffers[id];
			if (!framebuffer) continue; // GL spec: "glDeleteFramebuffers silently ignores 0s and names that do not correspond to existing framebuffer objects".
			GLctx.deleteFramebuffer(framebuffer);
			framebuffer.name = 0;
			GLframebuffers[id] = null;
		}
	};

	env.glDeleteProgram = function(id)
	{
		if (!id) return;
		var program = GLprograms[id];
		if (!program)
		{
			// glDeleteProgram actually signals an error when deleting a nonexisting object, unlike some other GL delete functions.
			GLrecordError(0x0501); // GL_INVALID_VALUE
			return;
		}
		GLctx.deleteProgram(program);
		program.name = 0;
		GLprograms[id] = null;
		GLprogramInfos[id] = null;
	};

	env.glDeleteShader = function(id)
	{
		if (!id) return;
		var shader = GLshaders[id];
		if (!shader)
		{
			// glDeleteShader actually signals an error when deleting a nonexisting object, unlike some other GL delete functions.
			GLrecordError(0x0501); // GL_INVALID_VALUE
			return;
		}
		GLctx.deleteShader(shader);
		GLshaders[id] = null;
	};

	env.glDeleteTextures = function(n, textures)
	{
		for (var i = 0; i < n; i++)
		{
			var id = HEAP32[(((textures)+(i*4))>>2)];
			var texture = GLtextures[id];
			if (!texture) continue; // GL spec: "glDeleteTextures silently ignores 0s and names that do not correspond to existing textures".
			GLctx.deleteTexture(texture);
			texture.name = 0;
			GLtextures[id] = null;
		}
	};

	env.glDepthFunc = function(x0) { GLctx.depthFunc(x0); };
	env.glDepthMask = function(flag) { GLctx.depthMask(!!flag); };
	env.glDetachShader = function(program, shader) { GLctx.detachShader(GLprograms[program], GLshaders[shader]); };

	env.glDisable = function(x0) { GLctx.disable(x0); };
	env.glDisableVertexAttribArray = function(index) { GLctx.disableVertexAttribArray(index); };
	env.glDrawArrays = function(mode, first, count) { GLctx.drawArrays(mode, first, count); };
	env.glDrawElements = function(mode, count, type, indices) { GLctx.drawElements(mode, count, type, indices); };
	env.glEnable = function(x0) { GLctx.enable(x0); };
	env.glEnableVertexAttribArray = function(index) { GLctx.enableVertexAttribArray(index); };
	env.glFramebufferTexture2D = function(target, attachment, textarget, texture, level) { GLctx.framebufferTexture2D(target, attachment, textarget, GLtextures[texture], level); };

	env.glGenBuffers = function(n, buffers)
	{
		for (var i = 0; i < n; i++)
		{
			var buffer = GLctx.createBuffer();
			if (!buffer)
			{
				GLrecordError(0x0502); // GL_INVALID_OPERATION
				while(i < n) HEAP32[(((buffers)+(i++*4))>>2)]=0;
				return;
			}
			var id = getNewId(GLbuffers);
			buffer.name = id;
			GLbuffers[id] = buffer;
			HEAP32[(((buffers)+(i*4))>>2)]=id;
		}
	};

	env.glGenFramebuffers = function(n, ids)
	{
		for (var i = 0; i < n; ++i)
		{
			var framebuffer = GLctx.createFramebuffer();
			if (!framebuffer)
			{
				GLrecordError(0x0502); // GL_INVALID_OPERATION
				while(i < n) HEAP32[(((ids)+(i++*4))>>2)]=0;
				return;
			}
			var id = getNewId(GLframebuffers);
			framebuffer.name = id;
			GLframebuffers[id] = framebuffer;
			HEAP32[(((ids)+(i*4))>>2)] = id;
		}
	};

	env.glGenTextures = function(n, textures)
	{
		for (var i = 0; i < n; i++)
		{
			var texture = GLctx.createTexture();
			if (!texture)
			{
				// GLES + EGL specs don't specify what should happen here, so best to issue an error and create IDs with 0.
				GLrecordError(0x0502); // GL_INVALID_OPERATION
				while(i < n) HEAP32[(((textures)+(i++*4))>>2)]=0;
				return;
			}
			var id = getNewId(GLtextures);
			texture.name = id;
			GLtextures[id] = texture;
			HEAP32[(((textures)+(i*4))>>2)]=id;
		}
	};

	env.glGetActiveUniform = function(program, index, bufSize, length, size, type, name)
	{
		program = GLprograms[program];
		var info = GLctx.getActiveUniform(program, index);
		if (!info) return; // If an error occurs, nothing will be written to length, size, type and name.

		if (bufSize > 0 && name)
		{
			var numBytesWrittenExclNull = WriteHeapString(info.name, name, bufSize);
			if (length) HEAP32[((length)>>2)]=numBytesWrittenExclNull;
		} else {
			if (length) HEAP32[((length)>>2)]=0;
		}

		if (size) HEAP32[((size)>>2)]=info.size;
		if (type) HEAP32[((type)>>2)]=info.type;
	};

	env.glGetAttribLocation = function(program, name)
	{
		program = GLprograms[program];
		name = ReadHeapString(name);
		return GLctx.getAttribLocation(program, name);
	};

	function webGLGet(name_, p, type)
	{
		// Guard against user passing a null pointer.
		// Note that GLES2 spec does not say anything about how passing a null pointer should be treated.
		// Testing on desktop core GL 3, the application crashes on glGetIntegerv to a null pointer, but
		// better to report an error instead of doing anything random.
		if (!p) { GLrecordError(0x0501); return; } // GL_INVALID_VALUE

		var ret = undefined;
		switch(name_)
		{
			// Handle a few trivial GLES values
			case 0x8DFA: ret = 1; break; // GL_SHADER_COMPILER
			case 0x8DF8: // GL_SHADER_BINARY_FORMATS
				if (type !== 'Integer' && type !== 'Integer64') GLrecordError(0x0500); // GL_INVALID_ENUM
				return; // Do not write anything to the out pointer, since no binary formats are supported.
			case 0x8DF9: ret = 0; break; // GL_NUM_SHADER_BINARY_FORMATS
			case 0x86A2: // GL_NUM_COMPRESSED_TEXTURE_FORMATS
				// WebGL doesn't have GL_NUM_COMPRESSED_TEXTURE_FORMATS (it's obsolete since GL_COMPRESSED_TEXTURE_FORMATS returns a JS array that can be queried for length),
				// so implement it ourselves to allow C++ GLES2 code get the length.
				var formats = GLctx.getParameter(0x86A3); // GL_COMPRESSED_TEXTURE_FORMATS
				ret = formats.length;
				break;
		}

		if (ret === undefined)
		{
			var result = GLctx.getParameter(name_);
			switch (typeof(result))
			{
				case 'number':
					ret = result;
					break;
				case 'boolean':
					ret = result ? 1 : 0;
					break;
				case 'string':
					GLrecordError(0x0500); // GL_INVALID_ENUM
					return;
				case 'object':
					if (result === null)
					{
						// null is a valid result for some (e.g., which buffer is bound - perhaps nothing is bound), but otherwise
						// can mean an invalid name_, which we need to report as an error
						switch(name_)
						{
							case 0x8894: // ARRAY_BUFFER_BINDING
							case 0x8B8D: // CURRENT_PROGRAM
							case 0x8895: // ELEMENT_ARRAY_BUFFER_BINDING
							case 0x8CA6: // FRAMEBUFFER_BINDING
							case 0x8CA7: // RENDERBUFFER_BINDING
							case 0x8069: // TEXTURE_BINDING_2D
							case 0x8514: // TEXTURE_BINDING_CUBE_MAP
								ret = 0;
								break;
							default:
								GLrecordError(0x0500); // GL_INVALID_ENUM
								return;
						}
					}
					else if (result instanceof Float32Array || result instanceof Uint32Array || result instanceof Int32Array || result instanceof Array)
					{
						for (var i = 0; i < result.length; ++i) {
							switch (type)
							{
								case 'Integer': HEAP32[(((p)+(i*4))>>2)]=result[i]; break;
								case 'Float':   HEAPF32[(((p)+(i*4))>>2)]=result[i]; break;
								case 'Boolean': HEAPU8[(((p)+(i))>>0)]=result[i] ? 1 : 0; break;
								default: abort('WEBGL', 'internal glGet error, bad type: ' + type);
							}
						}
						return;
					}
					else if (result instanceof WebGLBuffer || result instanceof WebGLProgram || result instanceof WebGLFramebuffer || result instanceof WebGLRenderbuffer || result instanceof WebGLTexture)
					{
						ret = result.name | 0;
					}
					else
					{
						GLrecordError(0x0500); // GL_INVALID_ENUM
						return;
					}
					break;
				default:
					GLrecordError(0x0500); // GL_INVALID_ENUM
					return;
			}
		}

		switch (type)
		{
			case 'Integer64': (tempI64 = [ret>>>0,(tempDouble=ret,(+(Math.abs(tempDouble))) >= 1.0 ? (tempDouble > 0.0 ? ((Math.min((+(Math.floor((tempDouble)/4294967296.0))), 4294967295.0))|0)>>>0 : (~~((+(Math.ceil((tempDouble - +(((~~(tempDouble)))>>>0))/4294967296.0)))))>>>0) : 0)],HEAP32[((p)>>2)]=tempI64[0],HEAP32[(((p)+(4))>>2)]=tempI64[1]); break;
			case 'Integer': HEAP32[((p)>>2)] = ret; break;
			case 'Float':   HEAPF32[((p)>>2)] = ret; break;
			case 'Boolean': HEAPU8[((p)>>0)] = ret ? 1 : 0; break;
			default: abort('WEBGL', 'internal glGet error, bad type: ' + type);
		}
	}

	env.glGetError = function()
	{
		if (GLlastError)
		{
			var e = GLlastError;
			GLlastError = 0;
			return e;
		}
		return GLctx.getError();
	};

	env.glGetIntegerv = function(name_, p)
	{
		webGLGet(name_, p, 'Integer');
	};

	env.glGetProgramInfoLog = function(program, maxLength, length, infoLog)
	{
		var log = GLctx.getProgramInfoLog(GLprograms[program]);
		if (log === null) log = '(unknown error)';
		if (maxLength > 0 && infoLog)
		{
			var numBytesWrittenExclNull = WriteHeapString(log, infoLog, maxLength);
			if (length) HEAP32[((length)>>2)]=numBytesWrittenExclNull;
		}
		else if (length) HEAP32[((length)>>2)]=0;
	};

	env.glGetProgramiv = function(program, pname, p)
	{
		if (!p)
		{
			// GLES2 specification does not specify how to behave if p is a null pointer. Since calling this function does not make sense
			// if p == null, issue a GL error to notify user about it.
			GLrecordError(0x0501); // GL_INVALID_VALUE
			return;
		}

		if (program >= GLcounter)
		{
			GLrecordError(0x0501); // GL_INVALID_VALUE
			return;
		}

		var ptable = GLprogramInfos[program];
		if (!ptable)
		{
			GLrecordError(0x0502); //GL_INVALID_OPERATION
			return;
		}

		if (pname == 0x8B84) // GL_INFO_LOG_LENGTH
		{
			var log = GLctx.getProgramInfoLog(GLprograms[program]);
			if (log === null) log = '(unknown error)';
			HEAP32[((p)>>2)] = log.length + 1;
		}
		else if (pname == 0x8B87) //GL_ACTIVE_UNIFORM_MAX_LENGTH
		{
			HEAP32[((p)>>2)] = ptable.maxUniformLength;
		}
		else if (pname == 0x8B8A) //GL_ACTIVE_ATTRIBUTE_MAX_LENGTH
		{
			if (ptable.maxAttributeLength == -1)
			{
				program = GLprograms[program];
				var numAttribs = GLctx.getProgramParameter(program, GLctx.ACTIVE_ATTRIBUTES);
				ptable.maxAttributeLength = 0; // Spec says if there are no active attribs, 0 must be returned.
				for (var i = 0; i < numAttribs; ++i)
				{
					var activeAttrib = GLctx.getActiveAttrib(program, i);
					ptable.maxAttributeLength = Math.max(ptable.maxAttributeLength, activeAttrib.name.length+1);
				}
			}
			HEAP32[((p)>>2)] = ptable.maxAttributeLength;
		}
		else if (pname == 0x8A35) //GL_ACTIVE_UNIFORM_BLOCK_MAX_NAME_LENGTH
		{
			if (ptable.maxUniformBlockNameLength == -1)
			{
				program = GLprograms[program];
				var numBlocks = GLctx.getProgramParameter(program, GLctx.ACTIVE_UNIFORM_BLOCKS);
				ptable.maxUniformBlockNameLength = 0;
				for (var i = 0; i < numBlocks; ++i)
				{
					var activeBlockName = GLctx.getActiveUniformBlockName(program, i);
					ptable.maxUniformBlockNameLength = Math.max(ptable.maxUniformBlockNameLength, activeBlockName.length+1);
				}
			}
			HEAP32[((p)>>2)] = ptable.maxUniformBlockNameLength;
		}
		else
		{
			HEAP32[((p)>>2)] = GLctx.getProgramParameter(GLprograms[program], pname);
		}
	};

	env.glGetShaderInfoLog = function(shader, maxLength, length, infoLog)
	{
		var log = GLctx.getShaderInfoLog(GLshaders[shader]);
		if (log === null) log = '(unknown error)';
		if (maxLength > 0 && infoLog)
		{
			var numBytesWrittenExclNull = WriteHeapString(log, infoLog, maxLength);
			if (length) HEAP32[((length)>>2)] = numBytesWrittenExclNull;
		}
		else if (length) HEAP32[((length)>>2)] = 0;
	};

	env.glGetShaderiv = function(shader, pname, p)
	{
		if (!p)
		{
			// GLES2 specification does not specify how to behave if p is a null pointer. Since calling this function does not make sense
			// if p == null, issue a GL error to notify user about it.
			GLrecordError(0x0501); // GL_INVALID_VALUE
			return;
		}
		if (pname == 0x8B84) // GL_INFO_LOG_LENGTH
		{
			var log = GLctx.getShaderInfoLog(GLshaders[shader]);
			if (log === null) log = '(unknown error)';
			HEAP32[((p)>>2)] = log.length + 1;
		}
		else if (pname == 0x8B88) // GL_SHADER_SOURCE_LENGTH
		{
			var source = GLctx.getShaderSource(GLshaders[shader]);
			var sourceLength = (source === null || source.length == 0) ? 0 : source.length + 1;
			HEAP32[((p)>>2)] = sourceLength;
		}
		else HEAP32[((p)>>2)] = GLctx.getShaderParameter(GLshaders[shader], pname);
	};

	env.glGetUniformLocation = function(program, name)
	{
		name = ReadHeapString(name);

		var arrayOffset = 0;
		if (name.indexOf(']', name.length-1) !== -1)
		{
			// If user passed an array accessor "[index]", parse the array index off the accessor.
			var ls = name.lastIndexOf('[');
			var arrayIndex = name.slice(ls+1, -1);
			if (arrayIndex.length > 0)
			{
				arrayOffset = parseInt(arrayIndex);
				if (arrayOffset < 0) return -1;
			}
			name = name.slice(0, ls);
		}

		var ptable = GLprogramInfos[program];
		if (!ptable){ console.log("ptable == null"); return -1};
		var utable = ptable.uniforms;
		var uniformInfo = utable[name]; // returns pair [ dimension_of_uniform_array, uniform_location ]
		if (uniformInfo && arrayOffset < uniformInfo[0])
		{
			// Check if user asked for an out-of-bounds element, i.e. for 'vec4 colors[3];' user could ask for 'colors[10]' which should return -1.
			return uniformInfo[1] + arrayOffset;
		}
		return -1;
	};

	env.glLineWidth = function(x0) { GLctx.lineWidth(x0); };

	env.glLinkProgram = function(program)
	{
		GLctx.linkProgram(GLprograms[program]);
		GLprogramInfos[program] = null; // uniforms no longer keep the same names after linking
		populateUniformTable(program);
	};

	env.glPixelStorei = function(pname, param)
	{
		if (pname == 0x0D05) GLpackAlignment = param; //GL_PACK_ALIGNMENT
		else if (pname == 0x0cf5) GLunpackAlignment = param; //GL_UNPACK_ALIGNMENT
		GLctx.pixelStorei(pname, param);
	};

	function webGLGetTexPixelData(type, format, width, height, pixels, internalFormat)
	{
		var sizePerPixel;
		var numChannels;
		switch(format)
		{
			case 0x1906: case 0x1909: case 0x1902: numChannels = 1; break; //GL_ALPHA, GL_LUMINANCE, GL_DEPTH_COMPONENT
			case 0x190A: numChannels = 2; break; //GL_LUMINANCE_ALPHA
			case 0x1907: case 0x8C40: numChannels = 3; break; //GL_RGB, GL_SRGB_EXT
			case 0x1908: case 0x8C42: numChannels = 4; break; //GL_RGBA, GL_SRGB_ALPHA_EXT
			default: GLrecordError(0x0500); return null; //GL_INVALID_ENUM
		}
		switch (type)
		{
			case 0x1401: sizePerPixel = numChannels*1; break; //GL_UNSIGNED_BYTE
			case 0x1403: case 0x8D61: sizePerPixel = numChannels*2; break; //GL_UNSIGNED_SHORT, GL_HALF_FLOAT_OES
			case 0x1405: case 0x1406: sizePerPixel = numChannels*4; break; //GL_UNSIGNED_INT, GL_FLOAT
			case 0x84FA: sizePerPixel = 4; break; //GL_UNSIGNED_INT_24_8_WEBGL/GL_UNSIGNED_INT_24_8
			case 0x8363: case 0x8033: case 0x8034: sizePerPixel = 2; break; //GL_UNSIGNED_SHORT_5_6_5, GL_UNSIGNED_SHORT_4_4_4_4, GL_UNSIGNED_SHORT_5_5_5_1
			default: GLrecordError(0x0500); return null; //GL_INVALID_ENUM
		}

		function roundedToNextMultipleOf(x, y) { return Math.floor((x + y - 1) / y) * y; }
		var plainRowSize = width * sizePerPixel;
		var alignedRowSize = roundedToNextMultipleOf(plainRowSize, GLunpackAlignment);
		var bytes = (height <= 0 ? 0 : ((height - 1) * alignedRowSize + plainRowSize));

		switch(type)
		{
			case 0x1401: return HEAPU8.subarray((pixels),(pixels+bytes)); //GL_UNSIGNED_BYTE
			case 0x1406: return HEAPF32.subarray((pixels)>>2,(pixels+bytes)>>2); //GL_FLOAT
			case 0x1405: case 0x84FA: return HEAPU32.subarray((pixels)>>2,(pixels+bytes)>>2); //GL_UNSIGNED_INT, GL_UNSIGNED_INT_24_8_WEBGL/GL_UNSIGNED_INT_24_8
			case 0x1403: case 0x8363: case 0x8033: case 0x8034: case 0x8D61: return HEAPU16.subarray((pixels)>>1,(pixels+bytes)>>1); //GL_UNSIGNED_SHORT, GL_UNSIGNED_SHORT_5_6_5, GL_UNSIGNED_SHORT_4_4_4_4, GL_UNSIGNED_SHORT_5_5_5_1, GL_HALF_FLOAT_OES
			default: GLrecordError(0x0500); return null; //GL_INVALID_ENUM
		}
	}

	env.glReadPixels = function(x, y, width, height, format, type, pixels)
	{
		var pixelData = webGLGetTexPixelData(type, format, width, height, pixels, format);
		if (!pixelData) return GLrecordError(0x0500); // GL_INVALID_ENUM
		GLctx.readPixels(x, y, width, height, format, type, pixelData);
	};

	env.glScissor = function(x0, x1, x2, x3) { GLctx.scissor(x0, x1, x2, x3) };

	env.glShaderSource = function(shader, count, string, length)
	{
		var source = getSource(shader, count, string, length);
		GLctx.shaderSource(GLshaders[shader], source);
	};

	env.glTexImage2D = function(target, level, internalFormat, width, height, border, format, type, pixels)
	{
		var pixelData = null;
		if (pixels) pixelData = webGLGetTexPixelData(type, format, width, height, pixels, internalFormat);
		GLctx.texImage2D(target, level, internalFormat, width, height, border, format, type, pixelData);
	};

	env.glTexParameteri = function(x0, x1, x2)
	{
		GLctx.texParameteri(x0, x1, x2);
	};

	env.glTexSubImage2D = function(target, level, xoffset, yoffset, width, height, format, type, pixels)
	{
		var pixelData = null;
		if (pixels) pixelData = webGLGetTexPixelData(type, format, width, height, pixels, 0);
		GLctx.texSubImage2D(target, level, xoffset, yoffset, width, height, format, type, pixelData);
	};

	env.glUniform1f = function(loc, v0) { GLctx.uniform1f(GLuniforms[loc], v0); };
	env.glUniform1i = function(loc, v0) { GLctx.uniform1i(GLuniforms[loc], v0); };
	env.glUniform2i = function(loc, v0, v1) { GLctx.uniform2i(GLuniforms[loc], v0, v1); };
	env.glUniform2f = function(loc, v0, v1) { GLctx.uniform2f(GLuniforms[loc], v0, v1); };
	env.glUniform3f = function(loc, v0, v1, v2) { GLctx.uniform3f(GLuniforms[loc], v0, v1, v2); };

	env.glUniform3fv = function(loc, count, value)
	{
		var view;
		if (3*count <= GLMINI_TEMP_BUFFER_SIZE)
		{
			// avoid allocation when uploading few enough uniforms
			view = GLminiTempBufferViews[3*count-1];
			for (var ptr = value>>2, i = 0; i != 3*count; i++)
			{
				view[i] = HEAPF32[ptr+i];
			}
		}
		else view = HEAPF32.subarray((value)>>2,(value+count*12)>>2);
		GLctx.uniform3fv(GLuniforms[loc], view);
	};

	env.glUniform4f = function(loc, v0, v1, v2, v3) { GLctx.uniform4f(GLuniforms[loc], v0, v1, v2, v3); };

	env.glUniformMatrix4fv = function(loc, count, transpose, value)
	{
		count<<=4;
		var view;
		if (count <= GLMINI_TEMP_BUFFER_SIZE)
		{
			// avoid allocation when uploading few enough uniforms
			view = GLminiTempBufferViews[count-1];
			for (var ptr = value>>2, i = 0; i != count; i += 4)
			{
				view[i  ] = HEAPF32[ptr+i  ];
				view[i+1] = HEAPF32[ptr+i+1];
				view[i+2] = HEAPF32[ptr+i+2];
				view[i+3] = HEAPF32[ptr+i+3];
			}
		}
		else view = HEAPF32.subarray((value)>>2,(value+count*4)>>2);
		GLctx.uniformMatrix4fv(GLuniforms[loc], !!transpose, view);
	};

	env.glUseProgram = function(program) { GLctx.useProgram(program ? GLprograms[program] : null); };
	env.glVertexAttrib4f = function(x0, x1, x2, x3, x4) { GLctx.vertexAttrib4f(x0, x1, x2, x3, x4); };
	env.glVertexAttrib4fv = function(index, v) { GLctx.vertexAttrib4f(index, HEAPF32[v>>2], HEAPF32[v+4>>2], HEAPF32[v+8>>2], HEAPF32[v+12>>2]); };
	env.glVertexAttribPointer = function(index, size, type, normalized, stride, ptr) { GLctx.vertexAttribPointer(index, size, type, !!normalized, stride, ptr); };

	env.glViewport = function(x0, x1, x2, x3) { GLctx.viewport(x0, x1, x2, x3); };

	var initTime;

	env.WAJS_SetupCanvas = function(width, height)
	{
		var cnvs = APP.canvas;
		cnvs.width = width;
		cnvs.height = height;
		cnvs.height = cnvs.clientHeight;
		cnvs.width = cnvs.clientWidth;

		if (!GLsetupContext(cnvs)) return;

		initTime = Date.now();

		var draw_func_ex = function() { if (ABORT) return; window.requestAnimationFrame(draw_func_ex); APP.instance.exports.WAFNDraw(); };
		window.requestAnimationFrame(draw_func_ex);
	};

	env.WAJS_GetTime = function(type) { return Date.now() - initTime; };
}

//------------------------------------------------------------------------------------------------
//NOTE(martin): Fill environments with functions
//------------------------------------------------------------------------------------------------

const env = {};

env.console_log = console_log;
env.cosf = Math.cos;
env.sinf = Math.sin;
env.tanf = Math.tan;
env.sqrtf = Math.sqrt;
env.floorf = Math.floor;

env.canvas_width = function(){return(APP.canvas.width);};
env.canvas_height = function(){return(APP.canvas.height);};
env.window_width = function(){return(window.innerWidth);};
env.window_height = function(){return(window.innerHeight);};

GLBindImports(env);

//------------------------------------------------------------------------------------------------
//NOTE(martin): wasm instantiation
//------------------------------------------------------------------------------------------------
async function runWasm(canvasSize)
{
	try
	{
		if(WebAssembly.instantiateStreaming)
		{
			const response = fetch('./main.wasm');
			({ instance: APP.instance } = await WebAssembly.instantiateStreaming(response, { env }));
		}
		else
		{
			const response = await fetch('./main.wasm');
			const bytes = await response.arrayBuffer();
			({ instance: APP.instance } = await WebAssembly.instantiate(bytes, { env }));
		}
	}
	catch(e)
	{
		console.log(`error instancing wasm: ${e}`);
		return;
	}

	APP.memory = APP.instance.exports.memory;
	MemorySetBufferViews();

	APP.canvas.addEventListener('dblclick', APP.instance.exports.reset);
	APP.canvas.addEventListener('mouseup', (ev) => APP.instance.exports.mouse_up());
	APP.canvas.addEventListener('mousedown', (ev) => APP.instance.exports.mouse_down(ev.offsetX, ev.offsetY));
	APP.canvas.addEventListener('mousemove', (ev) => APP.instance.exports.mouse_move(ev.offsetX, ev.offsetY, ev.movementX, ev.movementY));

	if(APP.instance.exports.init)
	{
		var result = APP.instance.exports.init(canvasSize)
	}
	else
	{
		console.log('no exported init function');
	}
}

console.log("Hello world, from js");
runWasm(800);