c – 纹理平面上的OpenGL Lighting无法正常工作
作者：互联网
我想点亮纹理平面,但这不起作用.实心球上的光很好,但纹理平面不轻.
实心球上的照明效果很好.
但是,纹理平面上的照明不起作用. (GL_DECAL,GL_REPLACE;我也试过GL_MODULATE)
这是我的渲染代码的片段. (Whole code on GitHub)
加载纹理.
sf::Image image;
if (!image.loadFromFile(path))
return false;
glGenTextures(1, &id);
glBindTexture(GL_TEXTURE_2D, id);
glTexImage2D(
GL_TEXTURE_2D, 0, GL_RGBA,
image.getSize().x, image.getSize().y, 0,
GL_RGBA, GL_UNSIGNED_BYTE,
image.getPixelsPtr()
);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
初始化
glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
glClearDepth(1.0f);
glEnable(GL_DEPTH_TEST);
glDepthFunc(GL_LEQUAL);
glShadeModel(GL_SMOOTH);
//glEnable(GL_CULL_FACE);
glFrontFace(GL_CCW);
glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);
glutSetCursor(GLUT_CURSOR_NONE);
light.Init();
camera.SetPin((GLfloat)width / 2, (GLfloat)height/2);
显示回调
adjustPerspective();
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glEnable(GL_LIGHTING);
glPushMatrix();
camera.SetLookAt();
light.On();
// TODO: dsiplay processing
for (auto& obj : display_objs)
{
glPushMatrix();
obj->Draw();
glPopMatrix();
}
glPopMatrix();
// print fps and swap buffers
光初始化功能
glEnable(GL_LIGHTING);
glEnable(GL_LIGHT0);
glColorMaterial(GL_FRONT, GL_AMBIENT_AND_DIFFUSE);
glEnable(GL_COLOR_MATERIAL);
// Set lighting intensity and color
glLightfv(GL_LIGHT0, GL_AMBIENT, qaAmbientLight);
glLightfv(GL_LIGHT0, GL_DIFFUSE, qaDiffuseLight);
glLightfv(GL_LIGHT0, GL_POSITION, qaLightPosition);
glLightfv(GL_LIGHT0, GL_SPECULAR, qaSpecularLight);
////////////////////////////////////////////////
glLightf(GL_LIGHT0, GL_SPOT_CUTOFF, 80.0);// set cutoff angle
glLightfv(GL_LIGHT0, GL_SPOT_DIRECTION, dirVector0);
glLightf(GL_LIGHT0, GL_SPOT_EXPONENT, 10.0); // set focusing strength
Light.On()函数
glPushMatrix();
glTranslatef(2.0, 10.0, 2.0);
//glRotatef(90, 1, 0, 0);
glLightfv(GL_LIGHT0, GL_POSITION, qaLightPosition);
glLightfv(GL_LIGHT0, GL_SPOT_DIRECTION, dirVector0);
glPopMatrix();
glPushMatrix();
glDisable(GL_LIGHTING);
glTranslatef(2.0, 0.0, 2.0);
glRotatef(-90.0, 1.0, 0.0, 0.0);
glutWireCone(tan(80.0 / 180.0 * 3.14159265),10.0,20,20);
glEnable(GL_LIGHTING);
glPopMatrix();
这是纹理平面绘制功能.
float tile_x = 0.125;
glTranslatef(x, y, z);
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glEnable(GL_TEXTURE_2D);
glBindTexture(GL_TEXTURE_2D, tex.GetId());
glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
glBegin(GL_QUADS);
// Both of the following cases not work.
glNormal3f(0, -1, 0);
glNormal3f(0, 1, 0);
glTexCoord2f(0.0, 0.0); glVertex3f(0, 0, 0);
glTexCoord2f(height*tile_x, 0.0); glVertex3f(0, 0, width);
glTexCoord2f(height*tile_x, width*tile_x); glVertex3f(height, 0, width);
glTexCoord2f(0.0, width*tile_x); glVertex3f(height, 0, 0);
glEnd();
glDisable(GL_TEXTURE_2D);
glDisable(GL_BLEND);
我更改了向量方向,更改了glTexEnvf属性,更改了代码的顺序,但没有修复错误.我认为我的代码存在根本性错误,但我找不到它.为什么会发生这种情况,我该如何解决？
解决方法:
I want to light to the texture plane but this is not work. Light on solid sphere is very well, but texture plane is not light.
这是由OpenGL标准灯模型的Gouraud Shading模型引起的问题.虽然Phong shading的共同意思是在Gouraud Shading处进行每个片段的光计算的技术,但是每个顶点进行光计算.根据图元上片段的Barycentric coordinate对计算出的光进行插值.
这意味着在您的情况下,计算地面四边形角的光.对如此计算的光进行插值以对其间的所有片段进行插值.在光矢量的角落处的法向矢量的角度倾向于90°.因此,整个地面四边形看起来几乎没有光.
由于每个顶点计算光,因此计算的光比四边形的4个角更多的位置,并且质量增加.请注意,球体上的光看起来几乎是完美的,因为球体围绕其形状包含许多顶点.
尝试以下代码,将四元组拆分为tile：
int tiles = 5;
float u_max = height*tile_x;
float v_max = width*tile_x
glBegin(GL_QUADS);
glNormal3f(0, 1, 0);
for (int x=0; x < tiles; ++x)
{
for (int y=0; y < tiles; ++y)
{
x0 = (float)x/(float)tiles;
x1 = (float)(x+1)/(float)tiles;
y0 = (float)y/(float)tiles;
y1 = (float)(y+1)/(float)tiles;
glTexCoord2f(u_max*x0, v_max*y0); glVertex3f(height*x0, 0, widht*y0);
glTexCoord2f(u_max*x1, v_max*y0); glVertex3f(height*x0, 0, widht*y1);
glTexCoord2f(u_max*x1, v_max*y1); glVertex3f(height*x1, 0, widht*y1);
glTexCoord2f(u_max*x0, v_max*y1); glVertex3f(height*x1, 0, widht*y0);
}
}
glEnd();
当然,您也可以编写自己的着色器并实现每个片段照明.但是不推荐使用的固定功能管道OpenGL标准光模型不支持每个片段照明.
查看WebGL示例中的差异：
(function loadscene() {
var resize, gl, gouraudDraw, phongDraw, vp_size;
var bufSphere = {};
function render(delteMS){
var shading = document.getElementById( "shading" ).value;
var shininess = document.getElementById( "shininess" ).value;
var ambientCol = [0.2, 0.2, 0.2];
var diffuseCol = [0.6, 0.6, 0.6];
var specularCol = [0.8, 0.8, 0.8];
Camera.create();
Camera.vp = vp_size;
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 );
gl.disable(gl.CULL_FACE);
var progDraw = shading == 0 ? gouraudDraw : phongDraw;;
// set up draw shader
ShaderProgram.Use( progDraw.prog );
ShaderProgram.SetUniformM44( progDraw.prog, "u_projectionMat44", Camera.Perspective() );
ShaderProgram.SetUniformM44( progDraw.prog, "u_viewMat44", Camera.LookAt() );
ShaderProgram.SetUniformF3( progDraw.prog, "u_lightSource.lightPos", [0.0, 0.0, 0.25] )
ShaderProgram.SetUniformF3( progDraw.prog, "u_lightSource.ambient", ambientCol )
ShaderProgram.SetUniformF3( progDraw.prog, "u_lightSource.diffuse", diffuseCol )
ShaderProgram.SetUniformF3( progDraw.prog, "u_lightSource.specular", specularCol )
ShaderProgram.SetUniformF1( progDraw.prog, "u_lightSource.shininess", shininess )
var modelMat = IdentityMat44()
modelMat = RotateAxis( modelMat, -1.5, 0 );
modelMat = RotateAxis( modelMat, CalcAng( delteMS, 17.0 ), 1 );
ShaderProgram.SetUniformM44( progDraw.prog, "u_modelMat44", modelMat );
// draw scene
VertexBuffer.Draw( bufSphere );
requestAnimationFrame(render);
}
function resize() {
//vp_size = [gl.drawingBufferWidth, gl.drawingBufferHeight];
vp_size = [window.innerWidth, window.innerHeight]
canvas.width = vp_size[0];
canvas.height = vp_size[1];
gl.viewport( 0, 0, vp_size[0], vp_size[1] );
}
function initScene() {
canvas = document.getElementById( "canvas");
gl = canvas.getContext( "experimental-webgl" );
if ( !gl )
return null;
gouraudDraw = {}
gouraudDraw.prog = ShaderProgram.Create(
[ { source : "gouraud-shader-vs", stage : gl.VERTEX_SHADER },
{ source : "gouraud-shader-fs", stage : gl.FRAGMENT_SHADER }
],
[ "u_projectionMat44", "u_viewMat44", "u_modelMat44",
"u_lightSource.lightDir", "u_lightSource.ambient", "u_lightSource.diffuse", "u_lightSource.specular", "u_lightSource.shininess", ] );
if ( gouraudDraw.prog == 0 )
return;
gouraudDraw.inPos = gl.getAttribLocation( gouraudDraw.prog, "inPos" );
gouraudDraw.inNV = gl.getAttribLocation( gouraudDraw.prog, "inNV" );
gouraudDraw.inCol = gl.getAttribLocation( gouraudDraw.prog, "inCol" );
phongDraw = {}
phongDraw.prog = ShaderProgram.Create(
[ { source : "phong-shader-vs", stage : gl.VERTEX_SHADER },
{ source : "phong-shader-fs", stage : gl.FRAGMENT_SHADER }
],
[ "u_projectionMat44", "u_viewMat44", "u_modelMat44",
"u_lightSource.lightDir", "u_lightSource.ambient", "u_lightSource.diffuse", "u_lightSource.specular", "u_lightSource.shininess", ] );
if ( phongDraw.prog == 0 )
return;
phongDraw.inPos = gl.getAttribLocation( phongDraw.prog, "inPos" );
phongDraw.inNV = gl.getAttribLocation( phongDraw.prog, "inNV" );
phongDraw.inCol = gl.getAttribLocation( phongDraw.prog, "inCol" );
// create cube
var layer_size = 16, circum_size = 32;
var rad_circum = 1.0;
var rad_tube = 0.5;
var sphere_pts = [-1.0, -1.0, 0.0, 1.0, -1.0, 0.0, 1.0, 1.0, 0.0, -1.0, 1.0, 0.0];
var sphere_nv = [0.0, 0.0, 1.0, 0.0, 0.0, 1.0, 0.0, 0.0, 1.0, 0.0, 0.0, 1.0];
var sphere_col = [0.8, 0.6, 0.3, 0.8, 0.6, 0.3, 0.8, 0.6, 0.3, 0.8, 0.6, 0.3];
var sphere_inx = [0, 1, 2, 0, 2, 3];
bufSphere = VertexBuffer.Create(
[ { data : sphere_pts, attrSize : 3, attrLoc : gouraudDraw.inPos },
{ data : sphere_nv, attrSize : 3, attrLoc : gouraudDraw.inNV },
{ data : sphere_col, attrSize : 3, attrLoc : gouraudDraw.inCol } ],
sphere_inx );
window.onresize = resize;
resize();
requestAnimationFrame(render);
}
function Fract( val ) {
return val - Math.trunc( val );
}
function CalcAng( deltaTime, intervall ) {
return Fract( deltaTime / (1000*intervall) ) * 2.0 * Math.PI;
}
function CalcMove( deltaTime, intervall, range ) {
var pos = self.Fract( deltaTime / (1000*intervall) ) * 2.0
var pos = pos < 1.0 ? pos : (2.0-pos)
return range[0] + (range[1] - range[0]) * pos;
}
function EllipticalPosition( a, b, angRag ) {
var a_b = a * a - b * b
var ea = (a_b <= 0) ? 0 : Math.sqrt( a_b );
var eb = (a_b >= 0) ? 0 : Math.sqrt( -a_b );
return [ a * Math.sin( angRag ) - ea, b * Math.cos( angRag ) - eb, 0 ];
}
glArrayType = typeof Float32Array !="undefined" ? Float32Array : ( typeof WebGLFloatArray != "undefined" ? WebGLFloatArray : Array );
function IdentityMat44() {
var m = new glArrayType(16);
m[0] = 1; m[1] = 0; m[2] = 0; m[3] = 0;
m[4] = 0; m[5] = 1; m[6] = 0; m[7] = 0;
m[8] = 0; m[9] = 0; m[10] = 1; m[11] = 0;
m[12] = 0; m[13] = 0; m[14] = 0; m[15] = 1;
return m;
};
function RotateAxis(matA, angRad, axis) {
var aMap = [ [1, 2], [2, 0], [0, 1] ];
var a0 = aMap[axis][0], a1 = aMap[axis][1];
var sinAng = Math.sin(angRad), cosAng = Math.cos(angRad);
var matB = new glArrayType(16);
for ( var i = 0; i < 16; ++ i ) matB[i] = matA[i];
for ( var i = 0; i < 3; ++ i ) {
matB[a0*4+i] = matA[a0*4+i] * cosAng + matA[a1*4+i] * sinAng;
matB[a1*4+i] = matA[a0*4+i] * -sinAng + matA[a1*4+i] * cosAng;
}
return matB;
}
function Cross( a, b ) { return [ a[1] * b[2] - a[2] * b[1], a[2] * b[0] - a[0] * b[2], a[0] * b[1] - a[1] * b[0], 0.0 ]; }
function Dot( a, b ) { return a[0]*b[0] + a[1]*b[1] + a[2]*b[2]; }
function Normalize( v ) {
var len = Math.sqrt( v[0] * v[0] + v[1] * v[1] + v[2] * v[2] );
return [ v[0] / len, v[1] / len, v[2] / len ];
}
var Camera = {};
Camera.create = function() {
this.pos = [0, 2, 0.0];
this.target = [0, 0, 0];
this.up = [0, 0, 1];
this.fov_y = 90;
this.vp = [800, 600];
this.near = 0.5;
this.far = 100.0;
}
Camera.Perspective = function() {
var fn = this.far + this.near;
var f_n = this.far - this.near;
var r = this.vp[0] / this.vp[1];
var t = 1 / Math.tan( Math.PI * this.fov_y / 360 );
var m = IdentityMat44();
m[0] = t/r; m[1] = 0; m[2] = 0; m[3] = 0;
m[4] = 0; m[5] = t; m[6] = 0; m[7] = 0;
m[8] = 0; m[9] = 0; m[10] = -fn / f_n; m[11] = -1;
m[12] = 0; m[13] = 0; m[14] = -2 * this.far * this.near / f_n; m[15] = 0;
return m;
}
Camera.LookAt = function() {
var mz = Normalize( [ this.pos[0]-this.target[0], this.pos[1]-this.target[1], this.pos[2]-this.target[2] ] );
var mx = Normalize( Cross( this.up, mz ) );
var my = Normalize( Cross( mz, mx ) );
var tx = Dot( mx, this.pos );
var ty = Dot( my, this.pos );
var tz = Dot( [-mz[0], -mz[1], -mz[2]], this.pos );
var m = IdentityMat44();
m[0] = mx[0]; m[1] = my[0]; m[2] = mz[0]; m[3] = 0;
m[4] = mx[1]; m[5] = my[1]; m[6] = mz[1]; m[7] = 0;
m[8] = mx[2]; m[9] = my[2]; m[10] = mz[2]; m[11] = 0;
m[12] = tx; m[13] = ty; m[14] = tz; m[15] = 1;
return m;
}
var ShaderProgram = {};
ShaderProgram.Create = function( shaderList ) {
var shaderObjs = [];
for ( var i_sh = 0; i_sh < shaderList.length; ++ i_sh ) {
var shderObj = this.CompileShader( shaderList[i_sh].source, shaderList[i_sh].stage );
if ( shderObj == 0 )
return 0;
shaderObjs.push( shderObj );
}
var progObj = this.LinkProgram( shaderObjs )
if ( progObj != 0 ) {
progObj.attribIndex = {};
var noOfAttributes = gl.getProgramParameter( progObj, gl.ACTIVE_ATTRIBUTES );
for ( var i_n = 0; i_n < noOfAttributes; ++ i_n ) {
var name = gl.getActiveAttrib( progObj, i_n ).name;
progObj.attribIndex[name] = gl.getAttribLocation( progObj, name );
}
progObj.unifomLocation = {};
var noOfUniforms = gl.getProgramParameter( progObj, gl.ACTIVE_UNIFORMS );
for ( var i_n = 0; i_n < noOfUniforms; ++ i_n ) {
var name = gl.getActiveUniform( progObj, i_n ).name;
progObj.unifomLocation[name] = gl.getUniformLocation( progObj, name );
}
}
return progObj;
}
ShaderProgram.AttributeIndex = function( progObj, name ) { return progObj.attribIndex[name]; }
ShaderProgram.UniformLocation = function( progObj, name ) { return progObj.unifomLocation[name]; }
ShaderProgram.Use = function( progObj ) { gl.useProgram( progObj ); }
ShaderProgram.SetUniformI1 = function( progObj, name, val ) { if(progObj.unifomLocation[name]) gl.uniform1i( progObj.unifomLocation[name], val ); }
ShaderProgram.SetUniformF1 = function( progObj, name, val ) { if(progObj.unifomLocation[name]) gl.uniform1f( progObj.unifomLocation[name], val ); }
ShaderProgram.SetUniformF2 = function( progObj, name, arr ) { if(progObj.unifomLocation[name]) gl.uniform2fv( progObj.unifomLocation[name], arr ); }
ShaderProgram.SetUniformF3 = function( progObj, name, arr ) { if(progObj.unifomLocation[name]) gl.uniform3fv( progObj.unifomLocation[name], arr ); }
ShaderProgram.SetUniformF4 = function( progObj, name, arr ) { if(progObj.unifomLocation[name]) gl.uniform4fv( progObj.unifomLocation[name], arr ); }
ShaderProgram.SetUniformM33 = function( progObj, name, mat ) { if(progObj.unifomLocation[name]) gl.uniformMatrix3fv( progObj.unifomLocation[name], false, mat ); }
ShaderProgram.SetUniformM44 = function( progObj, name, mat ) { if(progObj.unifomLocation[name]) gl.uniformMatrix4fv( progObj.unifomLocation[name], false, mat ); }
ShaderProgram.CompileShader = 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;
}
ShaderProgram.LinkProgram = 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("Could not initialise shaders");
gl.useProgram( null );
return status ? prog : null;
}
var VertexBuffer = {};
VertexBuffer.Create = function( attributes, indices ) {
var buffer = {};
buffer.buf = [];
buffer.attr = []
for ( var i = 0; i < attributes.length; ++ i ) {
buffer.buf.push( gl.createBuffer() );
buffer.attr.push( { size : attributes[i].attrSize, loc : attributes[i].attrLoc } );
gl.bindBuffer( gl.ARRAY_BUFFER, buffer.buf[i] );
gl.bufferData( gl.ARRAY_BUFFER, new Float32Array( attributes[i].data ), gl.STATIC_DRAW );
}
buffer.inx = gl.createBuffer();
gl.bindBuffer( gl.ELEMENT_ARRAY_BUFFER, buffer.inx );
gl.bufferData( gl.ELEMENT_ARRAY_BUFFER, new Uint16Array( indices ), gl.STATIC_DRAW );
buffer.inxLen = indices.length;
gl.bindBuffer( gl.ARRAY_BUFFER, null );
gl.bindBuffer( gl.ELEMENT_ARRAY_BUFFER, null );
return buffer;
}
VertexBuffer.Draw = function( bufObj ) {
for ( var i = 0; i < bufObj.buf.length; ++ i ) {
gl.bindBuffer( gl.ARRAY_BUFFER, bufObj.buf[i] );
gl.vertexAttribPointer( bufObj.attr[i].loc, bufObj.attr[i].size, gl.FLOAT, false, 0, 0 );
gl.enableVertexAttribArray( bufObj.attr[i].loc );
}
gl.bindBuffer( gl.ELEMENT_ARRAY_BUFFER, bufObj.inx );
gl.drawElements( gl.TRIANGLES, bufObj.inxLen, gl.UNSIGNED_SHORT, 0 );
for ( var i = 0; i < bufObj.buf.length; ++ i )
gl.disableVertexAttribArray( bufObj.attr[i].loc );
gl.bindBuffer( gl.ARRAY_BUFFER, null );
gl.bindBuffer( gl.ELEMENT_ARRAY_BUFFER, null );
}
initScene();
})();html,body {
height: 100%;
width: 100%;
margin: 0;
overflow: hidden;
}
#gui {
position : absolute;
top : 0;
left : 0;
}<script id="gouraud-shader-vs" type="x-shader/x-vertex">
precision mediump float;
attribute vec3 inPos;
attribute vec3 inNV;
attribute vec3 inCol;
varying vec3 vertPos;
varying vec3 vertNV;
varying vec3 vertCol;
uniform mat4 u_projectionMat44;
uniform mat4 u_viewMat44;
uniform mat4 u_modelMat44;
struct TLightSource
{
vec3 lightPos;
vec3 ambient;
vec3 diffuse;
vec3 specular;
float shininess;
};
uniform TLightSource u_lightSource;
vec3 Light( vec3 eyeV, vec3 N, vec3 P )
{
vec3 lightCol = u_lightSource.ambient;
vec3 L = normalize( u_lightSource.lightPos-P );
float NdotL = max( 0.0, dot( N, L ) );
lightCol += NdotL * u_lightSource.diffuse;
vec3 H = normalize( eyeV + L );
float NdotH = max( 0.0, dot( N, H ) );
float kSpecular = ( u_lightSource.shininess + 2.0 ) * pow( NdotH, u_lightSource.shininess ) / ( 2.0 * 3.14159265 );
lightCol += kSpecular * u_lightSource.specular;
return lightCol;
}
void main()
{
vec3 modelNV = mat3( u_modelMat44 ) * normalize( inNV );
vertNV = mat3( u_viewMat44 ) * modelNV;
vec4 modelPos = u_modelMat44 * vec4( inPos, 1.0 );
vec4 viewPos = u_viewMat44 * modelPos;
vertPos = viewPos.xyz / viewPos.w;
vec3 eyeV = normalize( -vertPos );
vec3 normalV = normalize( vertNV ) * sign(vertNV.z);
vertCol = inCol * Light( eyeV, normalV, vertPos );
gl_Position = u_projectionMat44 * viewPos;
}
</script>
<script id="gouraud-shader-fs" type="x-shader/x-fragment">
precision mediump float;
varying vec3 vertPos;
varying vec3 vertNV;
varying vec3 vertCol;
void main()
{
gl_FragColor = vec4( vertCol, 1.0 );
}
</script>
<script id="phong-shader-vs" type="x-shader/x-vertex">
precision mediump float;
attribute vec3 inPos;
attribute vec3 inNV;
attribute vec3 inCol;
varying vec3 vertPos;
varying vec3 vertNV;
varying vec3 vertCol;
uniform mat4 u_projectionMat44;
uniform mat4 u_viewMat44;
uniform mat4 u_modelMat44;
void main()
{
vec3 modelNV = mat3( u_modelMat44 ) * normalize( inNV );
vertNV = mat3( u_viewMat44 ) * modelNV;
vertCol = inCol;
vec4 modelPos = u_modelMat44 * vec4( inPos, 1.0 );
vec4 viewPos = u_viewMat44 * modelPos;
vertPos = viewPos.xyz / viewPos.w;
gl_Position = u_projectionMat44 * viewPos;
}
</script>
<script id="phong-shader-fs" type="x-shader/x-fragment">
precision mediump float;
varying vec3 vertPos;
varying vec3 vertNV;
varying vec3 vertCol;
struct TLightSource
{
vec3 lightPos;
vec3 ambient;
vec3 diffuse;
vec3 specular;
float shininess;
};
uniform TLightSource u_lightSource;
vec3 Light( vec3 eyeV, vec3 N, vec3 P )
{
vec3 lightCol = u_lightSource.ambient;
vec3 L = normalize( u_lightSource.lightPos - P );
float NdotL = max( 0.0, dot( N, L ) );
lightCol += NdotL * u_lightSource.diffuse;
vec3 H = normalize( eyeV + L );
float NdotH = max( 0.0, dot( N, H ) );
float kSpecular = ( u_lightSource.shininess + 2.0 ) * pow( NdotH, u_lightSource.shininess ) / ( 2.0 * 3.14159265 );
lightCol += kSpecular * u_lightSource.specular;
return lightCol;
}
void main()
{
vec3 eyeV = normalize( -vertPos );
vec3 normalV = normalize( vertNV ) * sign(vertNV.z);
vec3 color = vertCol * Light( eyeV, normalV, vertPos );
gl_FragColor = vec4( color, 1.0 );
}
</script>
<form id="gui" name="inputs"><table><tr>
<td><font color= #CCF>Shading:</font></td>
<td><select id="shading">>
<option value="0">Gouraud</option>
<option value="1">Phong</option>
</select></td>
</tr><tr>
<td><font color= #CCF>Shininess:</font></td>
<td><input type="range" id="shininess" min="0" max="100" value="10"/></td>
</tr></table></form>
<canvas id="canvas" style="border: none;" width="100%" height="100%"></canvas>标签：c,opengl,textures,lighting,opengl-compat 来源： https://codeday.me/bug/20190929/1832897.html