Question

我需要解决webGl问题的任务，我必须在旋转动画多维数据集上应用着色。当我尝试这样做时，问题是阴影被应用但是它是固定的。当立方体旋转时，当我需要看到它们以动态方式变化时，我看到相同的面部变暗，而其他面部变得更亮。

这是我的代码：

HTML

<!DOCTYPE html>
<html>

<button id = "ButtonX">Rotate X</button>
<button id = "ButtonY">Rotate Y</button>
<button id = "ButtonZ">Rotate Z</button>
<button id = "ButtonT">Toggle Rotation</button>
<button id="Direction">Change Direction</button>
<button id="OrthoPersp">Change Ortho/Persp</button>


<div>Traslation on X  <input id="slideX" type="range"
    min="-1" max="1" step="0.1" value="0" />
    </div>

<div>Traslation on Y  <input id="slideY" type="range"
    min="-1" max="1" step="0.1" value="0" />
     </div>

<div>Traslation on Z  <input id="slideZ" type="range"
    min="-1" max="1" step="0.1" value="0" />
     </div>

<div>Scaling on X  <input id="ScalingX" type="range"
    min="0" max="1" step="0.1" value="0" />
     </div>
<div>Scaling on Y <input id="ScalingY" type="range"
    min="0" max="1" step="0.1" value="0" />
     </div>
<div>Scaling on Z  <input id="ScalingZ" type="range"
    min="0" max="1" step="0.1" value="0" />
     </div>

<div>
    zNear Min<input id="zNearSlider" type="range" min="0.00" max="2.8" step="0.1" value="0.3">
        Max
</div>

<div>
    zFar Min<input id="zFarSlider" type="range" min="3" max="10" step="3.0" value="3">
        Max
</div>







<script id="vertex-shader" type="x-shader/x-vertex">

attribute  vec4 vPosition;
attribute  vec4 vColor;

varying vec4 fColor;

//uniform vec3 theta;

// Point 2 -> Move the matrices
// Per spostare le matrici le abbiamo dovuto dichiarare nel file GLSL come uniform
// le matrici rx ry e rz sono rispettivamente le matrici di rotazione sugli assi
uniform mat4 rx;
uniform mat4 ry;
uniform mat4 rz;

// Points 3 -> Traslation Matrix
uniform mat4 traslation;
// Points 3 -> Scaling Matrix
uniform mat4 scaling;

//Point 4 -> MV and P matrices
uniform mat4 modelView;
uniform mat4 projection;

//Poinit 6 -> Light Source

attribute vec3 vNormal;
uniform vec4 ambientProduct, diffuseProduct, specularProduct;
uniform vec4 lightPosition;
uniform float shininess;

void main()
{
    // Compute the sines and cosines of theta for each of
    //   the three axes in one computation.
    //vec3 angles = radians( theta );
    //vec3 c = cos( angles );
    //vec3 s = sin( angles );

    // Remember: the matrices are column-major
    /*
    mat4 rx = mat4( 1.0,  0.0,  0.0, 0.0,
            0.0,  c.x,  s.x, 0.0,
            0.0, -s.x,  c.x, 0.0,
            0.0,  0.0,  0.0, 1.0 );

    mat4 ry = mat4( c.y, 0.0, -s.y, 0.0,
            0.0, 1.0,  0.0, 0.0,
            s.y, 0.0,  c.y, 0.0,
            0.0, 0.0,  0.0, 1.0 );


    mat4 rz = mat4( c.z, s.z, 0.0, 0.0,
            -s.z,  c.z, 0.0, 0.0,
            0.0,  0.0, 1.0, 0.0,
            0.0,  0.0, 0.0, 1.0 );
     */

    //fColor = vColor;
    // ORDINE : scaling -> rotazione -> traslation

    //gl_Position = projection*modelView*scaling *rz * ry * rx * traslation *vPosition ;
    //gl_Position.z = -gl_Position.z;

    //Point 6
    vec3 pos = -(modelView * vPosition).xyz;
    vec3 light = lightPosition.xyz;
    vec3 L = normalize( light - pos );
    vec3 E = normalize( -pos );
    vec3 H = normalize( L + E );
    vec4 NN = vec4(vNormal,0);
    vec3 N = normalize( (modelView*NN).xyz);

    vec4 ambient = ambientProduct;

    float Kd = max( dot(L, N), 0.0 );
    vec4 diffuse = Kd*diffuseProduct;

    float Ks = pow( max(dot(N, H), 0.0), shininess );
    vec4 specular = Ks * specularProduct;

    if( dot(L, N) < 0.0 ) {
        specular = vec4(0.0, 0.0, 0.0, 1.0);
    }

    gl_Position = projection*modelView*scaling *rz * ry * rx * traslation *vPosition ;
    //fColor = vColor;
    //fColor = ambient + diffuse + specular;
    fColor = (ambient + diffuse + specular);
    fColor.a = 1.0;


    // *******************

}
</script>

<script id="fragment-shader" type="x-shader/x-fragment">

precision mediump float;

varying vec4 fColor;

void
main()
{
    gl_FragColor = fColor;

}
</script>

<script type="text/javascript" src="../Common/webgl-utils.js"></script>
<script type="text/javascript" src="../Common/initShaders.js"></script>
<script type="text/javascript" src="../Common/MV.js"></script>
<script type="text/javascript" src="Homework1.js"></script>



<body>
<canvas id="gl-canvas" width="1024" height="1024">
Oops ... your browser doesn't support the HTML5 canvas element
</canvas>
</body>
</html>

的JavaScript

"use strict";

var canvas;
var gl;

var numVertices  = 36;

var numChecks = 8;

var program;

var c;

var flag = true;

var direction = true;

var rx;
var ry;
var rz;
var traslation_loc;
var tx = 0 ;
var ty = 0;
var tz = 0;
var scaling_loc;
var sx = 1.0;
var sy = 1.0;
var sz = 1.0;

var pointsArray = [];
var colorsArray = [];





//Point 4

var near = 0.3;
var far = 3.0;

//var radius = 1.0;
var theta  = 0.0;
//var phi    = 0.0;
//var dr = 5.0 * Math.PI/180.0;

var left = -1.0;
var right = 1.0;
var ytop = 1.0;
var bottom = -1.0;

var mvMatrix, pMatrix;
var modelView, projection;
var eye;

const at = vec3(0.0, 0.0, 0.0);
const up = vec3(0.0, 1.0, 0.0);

var eye = vec3(1, 1, 1);
//var eye = vec3(0.02, 0.02, 0.02);
//

//Point 5
var fovy = 45.0;
var aspect;
var orthoBool = true;
var aspect = 1.0;
//


//Poinit 6
var lightAmbient = vec4(0.2, 0.2, 0.2, 1.0);
var lightDiffuse = vec4(1.0, 1.0, 1.0, 1.0);
var lightSpecular = vec4(1.0, 1.0, 1.0, 1.0);
var lightPosition = vec4(1.0, 2.0, 3.0,1.0);



var materialAmbient = vec4(1.0, 0.0, 1.0, 1.0);
var materialDiffuse = vec4(1.0, 0.8, 0.0, 1.0);
var materialSpecular = vec4(1.0, 0.8, 0.0, 1.0);
var materialShininess = 100.0;

var ambientColor, diffuseColor, specularColor;
var normalsArray = [];




//


var vertices = [
    vec4( -0.5, -0.5,  0.5, 1.0 ),
    vec4( -0.5,  0.5,  0.5, 1.0 ),
    vec4( 0.5,  0.5,  0.5, 1.0 ),
    vec4( 0.5, -0.5,  0.5, 1.0 ),
    vec4( -0.5, -0.5, -0.5, 1.0 ),
    vec4( -0.5,  0.5, -0.5, 1.0 ),
    vec4( 0.5,  0.5, -0.5, 1.0 ),
    vec4( 0.5, -0.5, -0.5, 1.0 )
];
/*
var vertexColors = [
    vec4( 0.0, 0.0, 0.0, 1.0 ),  // black
    vec4( 1.0, 0.0, 0.0, 1.0 ),  // red
    vec4( 1.0, 1.0, 0.0, 1.0 ),  // yellow
    vec4( 0.0, 1.0, 0.0, 1.0 ),  // green
    vec4( 0.0, 0.0, 1.0, 1.0 ),  // blue
    vec4( 1.0, 0.0, 1.0, 1.0 ),  // magenta
    vec4( 0.0, 1.0, 1.0, 1.0 ),  // white
    vec4( 0.0, 1.0, 1.0, 1.0 )   // cyan
];
*/
var xAxis = 0;
var yAxis = 1;
var zAxis = 2;
var axis = xAxis;

var theta = [45.0, 45.0, 45.0];


//var thetaLoc;






function quad(a, b, c, d) {

    // Point 6
    var t1 = subtract(vertices[b], vertices[a]);
    var t2 = subtract(vertices[c], vertices[b]);
    var normal = cross(t1, t2);
    var normal = vec3(normal);
    // *****

    //*** Abbiamo rimpizzato i colori on queli del materiale per svolgere il punto 6

     pointsArray.push(vertices[a]);
     //colorsArray.push(vertexColors[a]);
     normalsArray.push(normal);

     pointsArray.push(vertices[b]);
     //colorsArray.push(vertexColors[a]);
     normalsArray.push(normal);

     pointsArray.push(vertices[c]);
     //colorsArray.push(vertexColors[a]);
     normalsArray.push(normal);

     pointsArray.push(vertices[a]);
     //colorsArray.push(vertexColors[a]);
     normalsArray.push(normal);

     pointsArray.push(vertices[c]);
     //colorsArray.push(vertexColors[a]);
     normalsArray.push(normal);

     pointsArray.push(vertices[d]);
     //colorsArray.push(vertexColors[a]);
     normalsArray.push(normal);
}

function colorCube()
{
    quad( 1, 0, 3, 2 );
    quad( 2, 3, 7, 6 );
    quad( 3, 0, 4, 7 );
    quad( 6, 5, 1, 2 );
    quad( 4, 5, 6, 7 );
    quad( 5, 4, 0, 1 );
}


window.onload = function init() {

    canvas = document.getElementById( "gl-canvas" );

    gl = WebGLUtils.setupWebGL( canvas );
    if ( !gl ) { alert( "WebGL isn't available" ); }

    gl.viewport( 0, 0, canvas.width, canvas.height );

    // Point 5 -> define aspect
    aspect = canvas.width/canvas.height;

    gl.clearColor( 1.0, 1.0, 1.0, 1.0 );

    gl.enable(gl.DEPTH_TEST);

    //
    //  Load shaders and initialize attribute buffers
    //
    program = initShaders( gl, "vertex-shader", "fragment-shader" );


    gl.useProgram( program );

    colorCube();


    //Point 6

    var nBuffer = gl.createBuffer();
    gl.bindBuffer( gl.ARRAY_BUFFER, nBuffer );
    gl.bufferData( gl.ARRAY_BUFFER, flatten(normalsArray), gl.STATIC_DRAW );

    var vNormal = gl.getAttribLocation( program, "vNormal" );
    gl.vertexAttribPointer( vNormal, 3, gl.FLOAT, false, 0, 0 );
    gl.enableVertexAttribArray( vNormal );


    //*************
    // RIMPIAZZATI I COLORI PER IL PUNTO 6
    //var cBuffer = gl.createBuffer();
    //gl.bindBuffer( gl.ARRAY_BUFFER, cBuffer );
    //gl.bufferData( gl.ARRAY_BUFFER, flatten(colorsArray), gl.STATIC_DRAW );

    //var vColor = gl.getAttribLocation( program, "vColor" );
    //gl.vertexAttribPointer( vColor, 4, gl.FLOAT, false, 0, 0 );
    //gl.enableVertexAttribArray( vColor );

    var vBuffer = gl.createBuffer();
    gl.bindBuffer( gl.ARRAY_BUFFER, vBuffer);
    gl.bufferData( gl.ARRAY_BUFFER, flatten(pointsArray), gl.STATIC_DRAW );

    var vPosition = gl.getAttribLocation( program, "vPosition" );
    gl.vertexAttribPointer( vPosition, 4, gl.FLOAT, false, 0, 0 );
    gl.enableVertexAttribArray( vPosition );

    // Possiamo commentare quello che riguarda il theta per il punto 2
    //thetaLoc = gl.getUniformLocation(program, "theta");

    // Point 2 - Rotation

    //X AXIS

    rx = gl.getUniformLocation(program, "rx");


    //Y AXIS

    ry = gl.getUniformLocation(program, "ry");



    //Z AXIS

     rz = gl.getUniformLocation(program, "rz");


    // Traslation Matrix

    traslation_loc = gl.getUniformLocation(program , "traslation");

    // Scaling Matrix

    scaling_loc = gl.getUniformLocation(program , "scaling");

    // Projection and Model matrix
    modelView = gl.getUniformLocation( program, "modelView" );
    projection = gl.getUniformLocation( program, "projection" );


    //**************


 document.getElementById("ButtonX").onclick = function(){axis = xAxis;};
 document.getElementById("ButtonY").onclick = function(){axis = yAxis;};
 document.getElementById("ButtonZ").onclick = function(){axis = zAxis;};
 document.getElementById("ButtonT").onclick = function(){flag = !flag;};
 document.getElementById("Direction").onclick = function() { direction = !direction;};
 document.getElementById( "slideX" ).oninput = function(){ tx = parseFloat(event.target.value,10); };
 document.getElementById( "slideY" ).oninput = function(){ ty = parseFloat(event.target.value,10); };
 document.getElementById( "slideZ" ).oninput = function(){ tz = parseFloat(event.target.value,10); };
 document.getElementById( "ScalingX" ).oninput = function(){ sx = parseFloat(event.target.value,10); };
 document.getElementById( "ScalingY" ).oninput = function(){ sy = parseFloat(event.target.value,10); };
 document.getElementById( "ScalingZ" ).oninput = function(){ sz = parseFloat(event.target.value,10); };

 // Point 5
 document.getElementById("OrthoPersp").onclick = function(){orthoBool = !orthoBool;};

 // Point 4

    // per documentazine leggi la parte sotto il codice a pag 244 con spiegazione sul clip out
    // cambiato inserito due sliders // perspective -> ortho -> + lontano


    document.getElementById("zFarSlider").onchange = function() {
        far = event.srcElement.value;
    };

    document.getElementById("zNearSlider").onchange = function() {
        near = event.srcElement.value;
    };

    //Point 6

    var ambientProduct = mult(lightAmbient, materialAmbient);
    var diffuseProduct = mult(lightDiffuse, materialDiffuse);
    var specularProduct = mult(lightSpecular, materialSpecular);

    gl.uniform4fv(gl.getUniformLocation(program, "ambientProduct"),
                  flatten(ambientProduct));
    gl.uniform4fv(gl.getUniformLocation(program, "diffuseProduct"),
                  flatten(diffuseProduct) );
    gl.uniform4fv(gl.getUniformLocation(program, "specularProduct"),
                  flatten(specularProduct) );
    gl.uniform4fv(gl.getUniformLocation(program, "lightPosition"),
                  flatten(lightPosition) );
    gl.uniform1f(gl.getUniformLocation(program, "shininess"),materialShininess);

    //*************************************



    render();
}








var render = function() {
    gl.clear( gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);


    // Point 4
    //*************************************
    //eye = vec3(radius*Math.sin(phi), radius*Math.sin(theta),
              // radius*Math.cos(phi)); RIMANE COMMENTATO

    //mvMatrix = lookAt(eye, at , up);
    //pMatrix = ortho(left, right, bottom, ytop, near, far);

    //gl.uniformMatrix4fv( modelView, false, flatten(mvMatrix) );
    //gl.uniformMatrix4fv( projection, false, flatten(pMatrix) );


    //*************************************




    //Point 5
    //*************************************
    mvMatrix = lookAt(eye, at , up);

    if (orthoBool) {
        pMatrix = ortho(left, right, bottom, ytop, near, far); }
    else {
        pMatrix=perspective(fovy , aspect , near , far); }

    gl.uniformMatrix4fv( modelView, false, flatten(mvMatrix) );
    gl.uniformMatrix4fv( projection, false, flatten(pMatrix) );


    //*************************************


    // Point 3 -> Scaling

    var scaling = [sx , 0.0 , 0.0 , 0.0,
                   0.0  , sy, 0.0 , 0.0,
                   0.0 , 0.0 , sz , 0.0,
                   0.0 , 0.0 , 0.0 , 1];
    gl.uniformMatrix4fv(scaling_loc,false,scaling);


    // ****************************************
    //X AXIS - Point 2
    var theta_x_degree  = theta[0];
    var theta_x_radians = theta_x_degree * Math.PI / 180;
    var s_x = Math.sin(theta_x_radians);
    var c_x = Math.cos(theta_x_radians);
    var rx_loc = [ 1.0,  0.0,  0.0, 0.0,
                  0.0,  c_x,  s_x, 0.0,
                  0.0, -s_x,  c_x, 0.0,
                  0.0,  0.0,  0.0, 1.0 ];
    gl.uniformMatrix4fv(rx, false, rx_loc);

    //Y AXIS - Point 2
    var theta_y_degree  = theta[1];
    var theta_y_radians = theta_y_degree * Math.PI / 180;
    var s_y = Math.sin(theta_y_radians);
    var c_y = Math.cos(theta_y_radians);
    var ry_loc = [ c_y, 0.0, -s_y, 0.0,
                  0.0, 1.0,  0.0, 0.0,
                  s_y, 0.0,  c_y, 0.0,
                  0.0, 0.0,  0.0, 1.0 ];
    gl.uniformMatrix4fv(ry, false, ry_loc);


    //Z AXIS - Point 2
    var theta_z_degree  = theta[2];
    var theta_z_radians = theta_z_degree * Math.PI / 180;
    var s_z = Math.sin(theta_z_radians);
    var c_z = Math.cos(theta_z_radians);
    var rz_loc = [ c_z, s_z, 0.0, 0.0,
                  -s_z,  c_z, 0.0, 0.0,
                  0.0,  0.0, 1.0, 0.0,
                  0.0,  0.0, 0.0, 1.0  ];
    gl.uniformMatrix4fv(rz, false, rz_loc);

    // ****************************************

    // Point 3 -> Traslation

    var traslation = [1.0 , 0.0 , 0.0 , 0.0,
                      0.0 , 1.0 , 0.0 , 0.0,
                      0.0 , 0.0 , 1.0 , 0.0,
                       tx , ty , tz , 1.0];

    gl.uniformMatrix4fv(traslation_loc,false,traslation);


    // ****************************************




    // ****************************************

    // Point 1 --> Change and Toggle Rotation
    if((direction)&&(!flag)) theta[axis] += -2.0;
    if((!direction)&&(!flag)) theta[axis] += +2.0;

    if(!direction) {theta[axis] += -2.0; }
    if(direction) {theta[axis] += 2.0 ; }

    // ****************************************

    //gl.uniform3fv(thetaLoc, theta);
    gl.drawArrays( gl.TRIANGLES, 0, numVertices );
    requestAnimFrame(render);
}

Answer 1

您的问题似乎源于您在顶点着色器中计算最终颜色然后将其传递给片段着色器这一事实，这种方法称为gourad着色。您想要做的是传递用于光照计算的方向矢量，并在片段着色器中执行它们，即每像素照明/ phong着色。

着色WebGL，修复着色和动态着色

1 个答案: