使用Triangle_Strips和高度图，我创建了一个山区，并使用3D平面投影进行纹理处理。对于3D平面投影，我遵循以下链接的1.5节。 https://developer.nvidia.com/gpugems/GPUGems3/gpugems3_ch01.html
这是在Phong Lighting之前的样子。 Unitl纹理化，没关系。
这是Phong Lighting的外观。请注意，我假设是定向光，所以我假设光方向面向-y轴方向。我将其设置为shader.setVec3("light.direction", 0.0f, -0.1f, 0.0f);
地形的某些部分突然变亮，好像光线仅在那些部分变强。
我检查了正常向量是否正确。因此，我通过几何着色器将它们可视化。这是结果。
如您所见，法线向量实际上是正确的。因此，在我的着色器程序中一定有问题。这是代码。首先是顶点着色器。
#version 330 core
layout (location = 0) in vec3 aPos;
layout (location = 1) in vec3 aNormal;
uniform mat4 model;
uniform mat4 view;
uniform mat4 projection;
float scale = 0.5;
out vec2 TexX;
out vec2 TexY;
out vec2 TexZ;
out vec3 blend_weights;
out vec3 FragPos;
out vec3 wNormal;
void main()
{
FragPos = vec3(model * vec4(aPos, 1.0));
blend_weights = abs(aNormal.xyz);
blend_weights = (blend_weights - 0.2) * 0.7;
blend_weights = max(blend_weights, 0);
blend_weights /= (blend_weights.x + blend_weights.y + blend_weights.z);
TexX = aPos.yz * scale;
TexY = aPos.zx * scale;
TexZ = aPos.xy * scale;
wNormal = mat3(transpose(inverse(model))) * aNormal;
gl_Position = projection * view * vec4(FragPos, 1.0);
}
这是我的片段着色器。
#version 330 core
out vec4 FragColor;
struct Material{
//aka terrainTexture;
sampler2D diffuse;
sampler2D specular;
float shininess;
};
struct Light {
// Direction has to be in world coordinates.
vec3 direction;
vec3 ambient;
vec3 diffuse;
vec3 specular;
};
uniform Light light;
uniform Material material;
uniform vec3 viewPos;
in vec3 FragPos; //world Coordinate!
in vec2 TexX;
in vec2 TexY;
in vec2 TexZ;
in vec3 wNormal;
in vec3 blend_weights;
void main()
{
vec4 ColorNoLighting = texture(material.diffuse, TexX)*blend_weights.x + texture(material.diffuse, TexY)*blend_weights.y + texture(material.diffuse, TexZ)*blend_weights.z;
vec3 ambient = light.ambient * ColorNoLighting.xyz;
vec3 norm = normalize(wNormal);
vec3 lightDir = normalize(-light.direction);
float diff = max(dot(norm, lightDir), 0.0);
vec3 diffuse = light.diffuse * diff * ColorNoLighting.xyz;
vec3 viewDir = normalize(viewPos - FragPos);
vec3 reflectDir = reflect(-lightDir, norm);
float spec = pow(max(dot(viewDir, reflectDir), 0.0), material.shininess);
vec3 specular = light.specular * spec * ColorNoLighting.xyz;
vec3 result = ambient + diffuse + specular;
FragColor = vec4(result, 1.0);
}
最后，这就是我设置所有制服的方式。
shader.use();
shader.setInt("material.diffuse", 0);
shader.setInt("material.specular", 1);
shader.setVec3("light.direction", 0.0f, -0.1f, 0.0f);
shader.setVec3("viewPos", camera.Position);
shader.setVec3("light.ambient", 0.2f, 0.2f, 0.2f);
shader.setVec3("light.diffuse", 0.5f, 0.5f, 0.5f);
shader.setVec3("light.specular", 1.0f, 1.0f, 1.0f);
shader.setFloat("material.shininess", 32.0f);
shader.setMat4("model", model);
shader.setMat4("view", view);
shader.setMat4("projection", projection);
我不明白为什么在次顶灯照亮后我的地形的某些部分突然变得如此明亮。任何帮助，将不胜感激。预先感谢！
答案 0 :(得分：1)
与Phong镜面反射高光相比，光的Lambertian散射分量微弱。
在着色器代码中，漫反射组件的强度由参数light.diffuse设置：
float diff = max(dot(norm, lightDir), 0.0);
vec3 diffuse = light.diffuse * diff * ColorNoLighting.xyz;
镜面反射分量的强度及其大小分别由light.specular material.shininess设置：
float spec = pow(max(dot(viewDir, reflectDir), 0.0), material.shininess);
vec3 specular = light.specular * spec * ColorNoLighting.xyz;
请注意，如果减小光泽参数，则镜面高光的大小会增加，但会变得更平滑。
更改参数以解决您的问题。
例如
shader.setVec3("light.diffuse", 1.0f, 1.0f, 1.0f);
shader.setVec3("light.specular", 0.5f, 0.5f, 0.5f);
shader.setFloat("material.shininess", 10.0f);
请参见示例，该示例演示了参数的作用：
(function loadscene() {
var sliderScale = 100.0
var gl;
var canvas;
var vp_size;
var progDraw;
var bufTorus = {};
function render(deltaMS){
var ambient = document.getElementById( "ambient" ).value / sliderScale;
var diffuse = document.getElementById( "diffuse" ).value / sliderScale;
var specular = document.getElementById( "specular" ).value / sliderScale;
var shininess = Math.max(1, document.getElementById( "shininess" ).value / 2);
document.getElementById( "ambient_val" ).innerHTML = ambient;
document.getElementById( "diffuse_val" ).innerHTML = diffuse;
document.getElementById( "specular_val" ).innerHTML = specular;
document.getElementById( "shininess_val" ).innerHTML = shininess;
Camera.create();
Camera.vp = [canvas.width, canvas.height];
gl.viewport( 0, 0, canvas.width, canvas.height );
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 );
// set up draw shader
ShaderProgram.Use( progDraw );
ShaderProgram.SetUniformMat44( progDraw, "u_projectionMat44", Camera.Perspective() );
ShaderProgram.SetUniformMat44( progDraw, "u_viewMat44", Camera.LookAt() );
ShaderProgram.SetUniform3f( progDraw, "u_lightDir", [-1.0, -0.5, -2.0] )
ShaderProgram.SetUniformFloat( progDraw, "u_ambient", ambient )
ShaderProgram.SetUniformFloat( progDraw, "u_diffuse", diffuse )
ShaderProgram.SetUniformFloat( progDraw, "u_specular", specular )
ShaderProgram.SetUniformFloat( progDraw, "u_shininess", shininess )
var modelMat = IdentityMat44()
modelMat = RotateAxis( modelMat, CalcAng( deltaMS, 13.0 ), 0 );
modelMat = RotateAxis( modelMat, CalcAng( deltaMS, 17.0 ), 1 );
ShaderProgram.SetUniformMat44( progDraw, "u_modelMat44", modelMat );
// draw scene
VertexBuffer.Draw( bufTorus );
requestAnimationFrame(render);
}
function initScene() {
document.getElementById( "ambient" ).value = 0.2 * sliderScale;
document.getElementById( "diffuse" ).value = 0.75 * sliderScale;
document.getElementById( "specular" ).value = 0.75 * sliderScale;
document.getElementById( "shininess" ).value = 20.0;
canvas = document.getElementById( "phong-canvas");
vp_size = [canvas.width, canvas.height];
gl = canvas.getContext( "experimental-webgl" );
if ( !gl )
return;
progDraw = ShaderProgram.Create(
[ { source : "draw-shader-vs", stage : gl.VERTEX_SHADER },
{ source : "draw-shader-fs", stage : gl.FRAGMENT_SHADER }
],
[ "u_projectionMat44", "u_viewMat44", "u_modelMat44",
"u_lightDir", "u_ambient", "u_diffuse", "u_specular", "u_shininess", ] );
progDraw.inPos = gl.getAttribLocation( progDraw, "inPos" );
progDraw.inNV = gl.getAttribLocation( progDraw, "inNV" );
progDraw.inCol = gl.getAttribLocation( progDraw, "inCol" );
if ( progDraw == 0 )
return;
// create torus
var circum_size = 32, tube_size = 32;
var rad_circum = 1.0;
var rad_tube = 0.5;
var torus_pts = [];
var torus_nv = [];
var torus_col = [];
var torus_inx = [];
var col = [1, 0.5, 0.0];
for ( var i_c = 0; i_c < circum_size; ++ i_c ) {
var center = [
Math.cos(2 * Math.PI * i_c / circum_size),
Math.sin(2 * Math.PI * i_c / circum_size) ]
for ( var i_t = 0; i_t < tube_size; ++ i_t ) {
var tubeX = Math.cos(2 * Math.PI * i_t / tube_size)
var tubeY = Math.sin(2 * Math.PI * i_t / tube_size)
var pt = [
center[0] * ( rad_circum + tubeX * rad_tube ),
center[1] * ( rad_circum + tubeX * rad_tube ),
tubeY * rad_tube ]
var nv = [ pt[0] - center[0] * rad_tube, pt[1] - center[1] * rad_tube, tubeY * rad_tube ]
torus_pts.push( pt[0], pt[1], pt[2] );
torus_nv.push( nv[0], nv[1], nv[2] );
torus_col.push( col[0], col[1], col[2] );
var i_cn = (i_c+1) % circum_size
var i_tn = (i_t+1) % tube_size
var i_c0 = i_c * tube_size;
var i_c1 = i_cn * tube_size;
torus_inx.push( i_c0+i_t, i_c0+i_tn, i_c1+i_t, i_c0+i_tn, i_c1+i_t, i_c1+i_tn )
}
}
bufTorus = VertexBuffer.Create(
[ { data : torus_pts, attrSize : 3, attrLoc : progDraw.inPos },
{ data : torus_nv, attrSize : 3, attrLoc : progDraw.inNV },
{ data : torus_col, attrSize : 3, attrLoc : progDraw.inCol } ],
torus_inx
);
window.onresize = resize;
resize();
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];
}
function Fract( val ) {
return val - Math.trunc( val );
}
function CalcAng( deltaMS, intervall ) {
return Fract( deltaMS / (1000*intervall) ) * 2.0 * Math.PI;
}
function CalcMove( deltaMS, intervall, range ) {
var pos = self.Fract( deltaMS / (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 ];
}
function IdentityMat44() { return [1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1]; }
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 = matA.slice(0);
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, 3, 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;
}
// shader program object
var ShaderProgram = {};
ShaderProgram.Create = function( shaderList, uniformNames ) {
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.unifomLocation = {};
for ( var i_n = 0; i_n < uniformNames.length; ++ i_n ) {
var name = uniformNames[i_n];
progObj.unifomLocation[name] = gl.getUniformLocation( progObj, name );
}
}
return progObj;
}
ShaderProgram.Use = function( progObj ) { gl.useProgram( progObj ); }
ShaderProgram.SetUniformInt = function( progObj, name, val ) { gl.uniform1i( progObj.unifomLocation[name], val ); }
ShaderProgram.SetUniformFloat = function( progObj, name, val ) { gl.uniform1f( progObj.unifomLocation[name], val ); }
ShaderProgram.SetUniform2f = function( progObj, name, arr ) { gl.uniform2fv( progObj.unifomLocation[name], arr ); }
ShaderProgram.SetUniform3f = function( progObj, name, arr ) { gl.uniform3fv( progObj.unifomLocation[name], arr ); }
ShaderProgram.SetUniformMat44 = function( progObj, name, mat ) { gl.uniformMatrix4fv( progObj.unifomLocation[name], false, mat ); }
ShaderProgram.CompileShader = function( source, shaderStage ) {
var shaderScript = document.getElementById(source);
if (shaderScript) {
source = "";
var node = shaderScript.firstChild;
while (node) {
if (node.nodeType == 3) source += node.textContent;
node = node.nextSibling;
}
}
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 : 0;
}
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 : 0;
}
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 { margin: 0; overflow: hidden; }
#gui { position : absolute; top : 0; left : 0; }<script id="draw-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="draw-shader-fs" type="x-shader/x-fragment">
precision mediump float;
varying vec3 vertPos;
varying vec3 vertNV;
varying vec3 vertCol;
uniform vec3 u_lightDir;
uniform float u_ambient;
uniform float u_diffuse;
uniform float u_specular;
uniform float u_shininess;
void main()
{
vec3 color = vertCol;
vec3 lightCol = u_ambient * color;
vec3 normalV = normalize( vertNV );
vec3 lightV = normalize( -u_lightDir );
vec3 eyeV = normalize( -vertPos );
// Lambertian
float NdotL = max( 0.0, dot( normalV, lightV ) );
lightCol += NdotL * u_diffuse * color;
// Phong
vec3 reflectV = reflect(-lightV, normalV);
float VdotR = max( 0.0, dot( eyeV, reflectV ) );
float kSpecular = ( u_shininess + 2.0 ) * pow( VdotR, u_shininess ) / ( 2.0 * 3.14159265 );
lightCol += kSpecular * u_specular * color;
gl_FragColor = vec4( lightCol.rgb, 1.0 );
}
</script>
<form id="gui" name="inputs">
<table>
<tr> <td> <font color=#40f040>ambient</font> </td>
<td> <input type="range" id="ambient" min="0" max="100" value="0"/></td> <td> <font color= #CCF><span id="ambient_val">0</span></font> </td> </tr>
<tr> <td> <font color=#40f040>diffuse</font> </td>
<td> <input type="range" id="diffuse" min="0" max="100" value="0"/></td> <td> <font color= #CCF><span id="diffuse_val">0</span></font> </td></tr>
<tr> <td> <font color=#40f040>specular</font> </td>
<td> <input type="range" id="specular" min="0" max="100" value="0"/></td> <td> <font color= #CCF><span id="specular_val">0</span></font> </td></tr>
<tr> <td> <font color=#40f040>shininess</font> </td>
<td> <input type="range" id="shininess" min="0" max="100" value="0"/></td> <td> <font color= #CCF><span id="shininess_val">0</span></font> </td></tr>
</table>
</form>
<canvas id="phong-canvas" style="border: none;"></canvas>