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12-shading.html
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<!DOCTYPE html>
<html>
<head>
<title>hwshen WebGL — Gouraud Shading </title>
<meta http-equiv="content-type" content="text/html; charset=ISO-8859-1">
<script type="text/javascript" src="glMatrix-0.9.5.min.js"></script>
<!-- ************** Fragment Shader ************* -->
<script id="shader-fs" type="x-shader/x-fragment">
precision mediump float;
uniform mat4 uMMatrix;
uniform mat4 uVMatrix;
uniform mat4 uPMatrix;
uniform mat4 uNMatrix;
uniform vec4 light_pos;
uniform vec4 ambient_coef;
uniform vec4 diffuse_coef;
uniform vec4 specular_coef;
uniform float mat_shininess;
uniform vec4 light_ambient;
uniform vec4 light_diffuse;
uniform vec4 light_specular;
varying vec4 eye_pos;
varying vec3 v_normal;
varying vec4 vColor;
void main(void) {
gl_FragColor =vColor;
}
</script>
<!-- ************** Vertex Shader ************* -->
<script id="shader-vs" type="x-shader/x-vertex">
precision mediump float;
attribute vec3 aVertexPosition;
attribute vec3 aVertexNormal;
attribute vec3 aVertexColor;
uniform mat4 uMMatrix;
uniform mat4 uVMatrix;
uniform mat4 uPMatrix;
uniform mat4 uNMatrix;
uniform vec4 light_pos;
uniform vec4 ambient_coef;
uniform vec4 diffuse_coef;
uniform vec4 specular_coef;
uniform float mat_shininess;
uniform vec4 light_ambient;
uniform vec4 light_diffuse;
uniform vec4 light_specular;
varying vec4 eye_pos; //vertex position in eye space
varying vec3 v_normal; // vertex normal
varying vec4 vColor;
void main(void) {
// transform light pos from world to eye space
// vec4 light_pos_in_eye = uVMatrix * light_pos;
vec4 light_pos_in_eye = light_pos;
// transform normal from local to eye space: normal matrix is the inverse transpose of the modelview matrix
v_normal =normalize(vec3(uNMatrix*vec4(aVertexNormal,0.0)));
// transform the vertex position to eye space
eye_pos = uVMatrix*uMMatrix*vec4(aVertexPosition, 1.0);
// light vector L = l-p
vec3 light_vector = normalize(vec3(light_pos_in_eye - eye_pos));
// eye vector V = e-p, where e is (0,0,0)
vec3 eye_vector = normalize(-vec3(eye_pos));
// halfway vector (L+V)
vec3 halfv = normalize(light_vector+eye_vector);
vec4 ambient = ambient_coef * light_ambient;
float ndotl = max(dot(v_normal, light_vector), 0.0);
vec4 diffuse = diffuse_coef * light_diffuse* vec4(ndotl, ndotl, ndotl, 1.0);
// both lines below are okay. One is to use the reflect function the other is to compute by yourself
// vec3 R= normalize(vec3(reflect(-light_vector, v_normal)));
vec3 R = normalize(2.0 * ndotl *v_normal-light_vector);
float rdotv = max(dot(R, eye_vector), 0.0);
vec4 specular;
float rdotv_val = pow(rdotv, mat_shininess);
if (ndotl>0.0)
specular = specular_coef* light_specular* vec4(rdotv_val, rdotv_val, rdotv_val, 1.0);
else
specular = vec4(0,0,0,1);
gl_Position = uPMatrix*uVMatrix*uMMatrix*vec4(aVertexPosition, 1.0);
vColor = ambient+diffuse+specular;
//vColor = diffuse;
// vColor = specular;
// vColor = vec4(eye_vector, 1.0);
// vColor = vec4(aVertexColor, 1.0);
// vColor = vec4(aVertexNormal, 1.0);
// vColor = vec4(v_normal, 1.0);
}
</script>
<script type="text/javascript" src="shaders_setup.js"></script>
<script type="text/javascript" src="12-shading.js"></script>
</head>
<body onload="webGLStart();">
<canvas id="code03-canvas"style="border:none;"width="700"height="700"></canvas>
<h4> Geometry: </h4>
<button onclick="geometry(0)"> POINTS</button>
<button onclick="geometry(1)"> LINEs</button>
<button onclick="geometry(2)"> FACES</button>
<h4> Background: </h4>
<button onclick="BG(1,0,0)"> Red</button>
<button onclick="BG(0,1,0)"> Green</button>
<button onclick="BG(0,0,1)"> Blue</button>
<button onclick="BG(0.5,0.5,0.5)"> Grey</button>
<button onclick="BG(0,0,0)"> Black</button>
<button onclick="BG(1,1,1)"> White</button>
<div>
<h4>
Click on the left mouse button and move the coursor to rotate
</h4>
<button onclick="redraw()"> Go Back! </button>
</div>
<div>
<h3>
<div id="title"> code09.html COMMENTS</div>
</h3>
<h5>
A simple 3D rendering of cube using gl elemenntary array
</h5>
</div>
</body>
</html>