(function loadscene() {
var canvas, gl, prog, bufObj = {}, textureObj, maskTextureObj;
function render(deltaMS){
var maxDist = document.getElementById( "maxDist" ).value / 100;
var exponent = document.getElementById( "exponent" ).value / 100;
var lightup = document.getElementById( "lightup" ).value / 100;
gl.viewport( 0, 0, vp_size[0], vp_size[1] );
gl.enable( gl.DEPTH_TEST );
gl.clearColor( 0.0, 0.0, 0.0, 1.0 );
gl.clear( gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT );
var texUnit = 0;
gl.activeTexture( gl.TEXTURE0 + texUnit );
gl.bindTexture( gl.TEXTURE_2D, textureObj );
var maskTexUnit = 1;
gl.activeTexture( gl.TEXTURE0 + maskTexUnit );
gl.bindTexture( gl.TEXTURE_2D, maskTextureObj );
ShProg.Use( progDraw );
var pos = [ 2.0, 2.0 ];
if (mousePos[0] > 0 && mousePos[1] > 0 )
pos = [2.0 * mousePos[0] / vp_size[0] - 1.0, 1.0 - 2.0 * mousePos[1] / vp_size[1]];
ShProg.SetF2( progDraw, "u_vpsize", vp_size );
ShProg.SetF2( progDraw, "u_mouse", pos );
ShProg.SetF1( progDraw, "u_maxDistance", maxDist );
ShProg.SetF1( progDraw, "u_exponent", exponent );
ShProg.SetF1( progDraw, "u_lightup", lightup );
ShProg.SetI1( progDraw, "u_texture", texUnit );
ShProg.SetI1( progDraw, "u_maskTexture", maskTexUnit );
gl.enableVertexAttribArray( progDraw.inPos );
gl.bindBuffer( gl.ARRAY_BUFFER, bufObj.pos );
gl.vertexAttribPointer( progDraw.inPos, 2, gl.FLOAT, false, 0, 0 );
gl.bindBuffer( gl.ELEMENT_ARRAY_BUFFER, bufObj.inx );
gl.drawElements( gl.TRIANGLES, bufObj.inx.len, gl.UNSIGNED_SHORT, 0 );
gl.disableVertexAttribArray( progDraw.pos );
requestAnimationFrame(render);
}
function initScene() {
canvas = document.getElementById( "scene-canvas");
gl = canvas.getContext( "experimental-webgl" );
if ( !gl )
return;
textureObj = Texture.LoadTexture2D( "https://raw.githubusercontent.com/Rabbid76/graphics-snippets/master/resource/texture/supermario.jpg", true );
maskTextureObj = Texture.LoadTexture2D( "https://raw.githubusercontent.com/Rabbid76/graphics-snippets/master/resource/texture/bat.png", true );
progDraw = ShProg.Create(
[ { source : "draw-shader-vs", stage : gl.VERTEX_SHADER },
{ source : "draw-shader-fs", stage : gl.FRAGMENT_SHADER }
] );
progDraw.inPos = gl.getAttribLocation( progDraw.progObj, "inPos" );
if ( progDraw.progObj == 0 )
return;
var pos = [ -1, -1, 1, -1, 1, 1, -1, 1 ];
var inx = [ 0, 1, 2, 0, 2, 3 ];
bufObj.pos = gl.createBuffer();
gl.bindBuffer( gl.ARRAY_BUFFER, bufObj.pos );
gl.bufferData( gl.ARRAY_BUFFER, new Float32Array( pos ), gl.STATIC_DRAW );
bufObj.inx = gl.createBuffer();
bufObj.inx.len = inx.length;
gl.bindBuffer( gl.ELEMENT_ARRAY_BUFFER, bufObj.inx );
gl.bufferData( gl.ELEMENT_ARRAY_BUFFER, new Uint16Array( inx ), gl.STATIC_DRAW );
window.onresize = resize;
resize();
requestAnimationFrame(render);
}
function resize() {
vp_size = [window.innerWidth, window.innerHeight]
canvas.width = vp_size[0];
canvas.height = vp_size[1];
}
var mousePos = [-1, -1];
(function() {
document.onmousemove = handleMouseMove;
function handleMouseMove(event) {
var dot, eventDoc, doc, body, pageX, pageY;
event = event || window.event;
if (event.pageX == null && event.clientX != null) {
eventDoc = (event.target && event.target.ownerDocument) || document;
doc = eventDoc.documentElement;
body = eventDoc.body;
event.pageX = event.clientX +
(doc && doc.scrollLeft || body && body.scrollLeft || 0) -
(doc && doc.clientLeft || body && body.clientLeft || 0);
event.pageY = event.clientY +
(doc && doc.scrollTop || body && body.scrollTop || 0) -
(doc && doc.clientTop || body && body.clientTop || 0 );
}
var x = event.pageX - canvas.offsetLeft;
var y = event.pageY - canvas.offsetTop;
mousePos = [-1, -1];
if ( x >= 0 && x < canvas.width && y >= 0 && y < canvas.height ) {
mousePos = [x, y];
}
}
})();
var ShProg = {
Create: function (shaderList) {
var shaderObjs = [];
for (var i_sh = 0; i_sh < shaderList.length; ++i_sh) {
var shderObj = this.Compile(shaderList[i_sh].source, shaderList[i_sh].stage);
if (shderObj) shaderObjs.push(shderObj);
}
var prog = {}
prog.progObj = this.Link(shaderObjs)
if (prog.progObj) {
prog.attrInx = {};
var noOfAttributes = gl.getProgramParameter(prog.progObj, gl.ACTIVE_ATTRIBUTES);
for (var i_n = 0; i_n < noOfAttributes; ++i_n) {
var name = gl.getActiveAttrib(prog.progObj, i_n).name;
prog.attrInx[name] = gl.getAttribLocation(prog.progObj, name);
}
prog.uniLoc = {};
var noOfUniforms = gl.getProgramParameter(prog.progObj, gl.ACTIVE_UNIFORMS);
for (var i_n = 0; i_n < noOfUniforms; ++i_n) {
var name = gl.getActiveUniform(prog.progObj, i_n).name;
prog.uniLoc[name] = gl.getUniformLocation(prog.progObj, name);
}
}
return prog;
},
AttrI: function (prog, name) { return prog.attrInx[name]; },
UniformL: function (prog, name) { return prog.uniLoc[name]; },
Use: function (prog) { gl.useProgram(prog.progObj); },
SetI1: function (prog, name, val) { if (prog.uniLoc[name]) gl.uniform1i(prog.uniLoc[name], val); },
SetF1: function (prog, name, val) { if (prog.uniLoc[name]) gl.uniform1f(prog.uniLoc[name], val); },
SetF2: function (prog, name, arr) { if (prog.uniLoc[name]) gl.uniform2fv(prog.uniLoc[name], arr); },
SetF3: function (prog, name, arr) { if (prog.uniLoc[name]) gl.uniform3fv(prog.uniLoc[name], arr); },
SetF4: function (prog, name, arr) { if (prog.uniLoc[name]) gl.uniform4fv(prog.uniLoc[name], arr); },
SetM33: function (prog, name, mat) { if (prog.uniLoc[name]) gl.uniformMatrix3fv(prog.uniLoc[name], false, mat); },
SetM44: function (prog, name, mat) { if (prog.uniLoc[name]) gl.uniformMatrix4fv(prog.uniLoc[name], false, mat); },
Compile: function (source, shaderStage) {
var shaderScript = document.getElementById(source);
if (shaderScript)
source = shaderScript.text;
var shaderObj = gl.createShader(shaderStage);
gl.shaderSource(shaderObj, source);
gl.compileShader(shaderObj);
var status = gl.getShaderParameter(shaderObj, gl.COMPILE_STATUS);
if (!status) alert(gl.getShaderInfoLog(shaderObj));
return status ? shaderObj : null;
},
Link: function (shaderObjs) {
var prog = gl.createProgram();
for (var i_sh = 0; i_sh < shaderObjs.length; ++i_sh)
gl.attachShader(prog, shaderObjs[i_sh]);
gl.linkProgram(prog);
status = gl.getProgramParameter(prog, gl.LINK_STATUS);
if ( !status ) alert(gl.getProgramInfoLog(prog));
return status ? prog : null;
} };
var Texture = {};
Texture.HandleLoadedTexture2D = function( image, texture, flipY ) {
gl.activeTexture( gl.TEXTURE0 );
gl.bindTexture( gl.TEXTURE_2D, texture );
gl.pixelStorei( gl.UNPACK_FLIP_Y_WEBGL, flipY != undefined && flipY == true );
gl.texImage2D( gl.TEXTURE_2D, 0, gl.RGBA, gl.RGBA, gl.UNSIGNED_BYTE, image );
gl.texParameteri( gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR );
gl.texParameteri( gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR );
gl.texParameteri( gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.REPEAT );
gl.texParameteri( gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.REPEAT );
gl.bindTexture( gl.TEXTURE_2D, null );
return texture;
}
Texture.LoadTexture2D = function( name, flip ) {
var texture = gl.createTexture();
texture.image = new Image();
texture.image.setAttribute('crossorigin', 'anonymous');
texture.image.onload = function () {
Texture.HandleLoadedTexture2D( texture.image, texture, flip )
}
texture.image.src = name;
return texture;
}
initScene();
})();
#gui { position : absolute; top : 0; left : 0; }
<script id="draw-shader-vs" type="x-shader/x-vertex">
precision mediump float;
attribute vec2 inPos;
varying vec2 vertPos;
void main()
{
vertPos = inPos;
gl_Position = vec4( inPos, 0.0, 1.0 );
}
</script>
<script id="draw-shader-fs" type="x-shader/x-fragment">
precision mediump float;
varying vec2 vertPos;
uniform sampler2D u_texture;
uniform sampler2D u_maskTexture;
uniform vec2 u_vpsize;
uniform vec2 u_mouse;
uniform float u_maxDistance;
uniform float u_exponent;
uniform float u_lightup;
void main()
{
float aspect = u_vpsize[0]/u_vpsize[1];
vec2 distVec = (vertPos - u_mouse) * vec2(max(1.0,aspect), max(1.0,1.0/aspect));
float distance = length(distVec);
float mixK = pow( distance / u_maxDistance, u_exponent );
vec2 texCoord = vertPos * 0.5 + 0.5;
vec3 texColor = texture2D( u_texture, texCoord.st ).rgb;
vec3 grayColor = vec3( 0.2126 * texColor.r + 0.7152 * texColor.g + 0.0722 * texColor.b );
vec2 maskTexCoord = 0.5 + 0.5 * distVec / u_maxDistance;
float mask = texture2D( u_maskTexture, maskTexCoord ).a;
vec3 finalColor = mix( grayColor, texColor * u_lightup, ( 1.0 - clamp( mixK, 0.0, 1.0 ) ) * mask );
gl_FragColor = vec4( finalColor.rgb, 1.0 );
}
</script>
<form id="gui" name="inputs">
<table>
<tr> <td> <font color= #CCF>max. distance</font> </td>
<td> <input type="range" id="maxDist" min="1" max="100" value="33"/></td> </tr>
<tr> <td> <font color= #CCF>exponent</font> </td>
<td> <input type="range" id="exponent" min="1" max="300" value="100"/></td> </tr>
<tr> <td> <font color= #CCF>light up</font> </td>
<td> <input type="range" id="lightup" min="50" max="200" value="150"/></td> </tr>
</table>
</form>
<canvas id="scene-canvas" style="border: none"></canvas>