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OpenGL ES3阴影贴图问题

shadow-mapping opengl-es-3.0 glsles opengl-es c++

user8581488 · 技术社区 · 7 年前

Image describes the problem 首先,我创建包含深度贴图的帧缓冲区:

glGenFramebuffers(1, &depthMapFBO);
glBindFramebuffer(GL_FRAMEBUFFER, depthMapFBO);
glGenTextures(1, &depthMap);
glBindTexture(GL_TEXTURE_2D, depthMap);
glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT, SHADOW_WIDTH, SHADOW_HEIGHT, 0, GL_DEPTH_COMPONENT, GL_FLOAT, 0);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_TEXTURE_2D, depthMap, 0);
glDrawBuffers(1, GL_NONE);
glReadBuffer(GL_NONE);
glBindTexture(GL_TEXTURE_2D, 0);
glBindFramebuffer(GL_FRAMEBUFFER, 0);

然后,我创建了一个着色器程序,用于编译深度着色器,如下所示:

#version 300 es
precision mediump float;

layout (location = 0) in vec3 position;
layout (location = 4) in ivec4 BoneIDs;
layout (location = 5) in vec4 Weights;

const int MAX_BONES = 100;

uniform mat4 lightSpaceMatrix;
uniform mat4 model;
uniform bool skinned;
uniform mat4 gBones[MAX_BONES];

void main(){
vec4 nPos;
if(skinned){
    mat4 BoneTransform = gBones[BoneIDs[0]] * Weights[0];
    BoneTransform     += gBones[BoneIDs[1]] * Weights[1];
    BoneTransform     += gBones[BoneIDs[2]] * Weights[2];
    BoneTransform     += gBones[BoneIDs[3]] * Weights[3];
    nPos=BoneTransform * vec4(position, 1.0);
}
else 
    nPos = vec4(position, 1.0);

vec4 p=model * nPos;
gl_Position = lightSpaceMatrix * p;
}

glCullFace(GL_FRONT);
        double delta = GetCurrentTime() - firstFrame;
        glm::mat4 camInv = glm::inverse(camera->getViewMatrix());
        glm::mat4 lightSpaceProjection = glm::ortho(-40.0f, 40.0f, -40.0f, 40.0f, -1.0f, 100.0f);
        glm::mat4 lightSpaceView = glm::lookAt(sun->direction, glm::vec3(0, 0, 0), glm::vec3(0, 1, 0));
        lightSpaceMatrix = lightSpaceProjection * (lightSpaceView*camInv) ;
        glViewport(0, 0, SHADOW_WIDTH, SHADOW_HEIGHT);
        glBindFramebuffer(GL_FRAMEBUFFER, depthMapFBO);

        glClear(GL_DEPTH_BUFFER_BIT);
        directDepthShader.use();
        glUniformMatrix4fv(glGetUniformLocation(directDepthShader.getProgramID(), "lightSpaceMatrix"), 1, GL_FALSE, glm::value_ptr(lightSpaceMatrix));
        for (mesh_it it = castShadowMeshes.begin(); it != castShadowMeshes.end(); it++) {
            it->get()->renderDepth(directDepthShader, delta);
        }
        glCullFace(GL_BACK);
glBindFramebuffer(GL_FRAMEBUFFER, 0);

shadowMap 统一以下代码:

glViewport(0, 0, width, height);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
phongShader.use();
if (sun != nullptr)
    if (sun->castShadow)
        glUniformMatrix4fv(glGetUniformLocation(phongShader.getProgramID(), "lightSpaceMatrix"), 1, GL_FALSE, glm::value_ptr(lightSpaceMatrix));
this->setLightsUniforms(phongShader);
this->setViewUniforms(phongShader);
for (mesh_it it = phongMeshes.begin(); it != phongMeshes.end(); it++) {
    if (it->get()->hasNormalMap) {
        glUniform1i(glGetUniformLocation(phongShader.getProgramID(), "has_normal_map"), 1);
        if (directlights.size() > 0) {
            for (dlight_it it = this->directlights.begin(); it != this->directlights.end(); ++it) {
                GLuint directLightPosLoc = glGetUniformLocation(phongShader.getProgramID(), (const GLchar*) ("directLightPos[" + ToString((*it)->index) + "]").c_str());
                glUniform3f(directLightPosLoc, (*it)->direction.x, (*it)->direction.y, (*it)->direction.z);
            }
        }
        if (pointlights.size() > 0) {
            for (plight_it it = this->pointlights.begin(); it != this->pointlights.end(); ++it) {
                GLuint pointLightPosLoc = glGetUniformLocation(phongShader.getProgramID(), (const GLchar*) ("pointLightPos[" + ToString((*it)->index) + "]").c_str());
                glUniform3f(pointLightPosLoc, (*it)->position.x, (*it)->position.y, (*it)->position.z);
            }
        }
        if (spotlights.size() > 0) {
            for (slight_it it = this->spotlights.begin(); it != this->spotlights.end(); ++it) {
                GLuint spotLightPosLoc = glGetUniformLocation(phongShader.getProgramID(), (const GLchar*) ("spotLightPos[" + ToString((*it)->index) + "]").c_str());
                glUniform3f(spotLightPosLoc, (*it)->position.x, (*it)->position.y, (*it)->position.z);
            }
        }
    }
    double first = GetCurrentTime() - firstFrame;
    it->get()->textures = 0;
    if (sun != nullptr)
        if (sun->castShadow) {
            glUniform1i(glGetUniformLocation(phongShader.getProgramID(), "shadowMap"), it->get()->textures);
            glActiveTexture(GL_TEXTURE0 + it->get()->textures);
            glBindTexture(GL_TEXTURE_2D, depthMap);
            it->get()->textures++;
        }
    it->get()->Render(phongShader, first, deltaTime);
    glBindTexture(GL_TEXTURE_2D, 0);
}

最后,着色器顶点和片段如下所示:

顶点:

#version 300 es
precision mediump float;

#define NR_DIRECT_LIGHTS 0
#define NR_POINT_LIGHTS 0
#define NR_SPOT_LIGHTS 0

layout (location = 0) in vec3 position;
layout (location = 1) in vec3 normal;
layout (location = 2) in vec2 texCoord;
layout (location = 3) in vec3 tangent;
layout (location = 4) in ivec4 BoneIDs;
layout (location = 5) in vec4 Weights;

const int MAX_BONES = 100;

out vec2 TexCoords;
out vec3 Normal;
out vec3 tDirectLightPos[NR_DIRECT_LIGHTS];
out vec3 tPointLightPos[NR_POINT_LIGHTS];
out vec3 tSpotLightPos[NR_SPOT_LIGHTS];
out vec3 tViewPos;
out vec3 tFragPos;
out vec4 FragPosLightSpace;

// conditions //
uniform bool has_normal_map;    
uniform bool skinned;
//

uniform mat4 model;
uniform mat4 view;
uniform mat4 projection;
uniform vec3 viewPos;
uniform mat4 lightSpaceMatrix;  
uniform mat4 gBones[MAX_BONES];

uniform vec3 directLightPos[NR_DIRECT_LIGHTS];
uniform vec3 pointLightPos[NR_POINT_LIGHTS];
uniform vec3 spotLightPos[NR_SPOT_LIGHTS];

void main(){    
    TexCoords = texCoord;
    vec4 nPos;
    vec3 N=transpose(inverse(mat3(model))) * normal;
    if(skinned){
        mat4 BoneTransform = gBones[BoneIDs[0]] * Weights[0];
        BoneTransform     += gBones[BoneIDs[1]] * Weights[1];
        BoneTransform     += gBones[BoneIDs[2]] * Weights[2];
        BoneTransform     += gBones[BoneIDs[3]] * Weights[3];
        nPos=BoneTransform * vec4(position, 1.0);   
        Normal=(BoneTransform*vec4(N,0.0)).xyz; 
    }
    else{
        nPos = vec4(position, 1.0);
        Normal=N;   
    }
    gl_Position = projection*view * model * nPos;

    vec3 FragPos = vec3(model * nPos);  
    if(has_normal_map){
        mat3 normalMatrix = transpose(inverse(mat3(model)));        
        vec3 T = normalize(normalMatrix * tangent);
        vec3 N = normalize(N);
        T = normalize(T - dot(T, N) * N);
        vec3 B = cross(N,T);    
        if (dot(cross(N, T), B) < 0.0)
           T = T * -1.0;    
        mat3 TBN = transpose(mat3(T, B, N));

        tViewPos=TBN*viewPos;
        tFragPos=TBN*FragPos;
        for(int i = 0; i < NR_DIRECT_LIGHTS-2; i++)
            tDirectLightPos[i]=TBN*directLightPos[i];
        for(int i = 0; i < NR_POINT_LIGHTS-2; i++)
            tPointLightPos[i]=TBN*pointLightPos[i];
        for(int i = 0; i < NR_SPOT_LIGHTS-2; i++)
            tSpotLightPos[i]=TBN*spotLightPos[i];
    }
    else{
        tViewPos=viewPos;
        tFragPos=FragPos;
    }
    FragPosLightSpace = lightSpaceMatrix * vec4(FragPos,1.0);       
}

#version 300 es
precision mediump float;

#define NR_DIRECT_LIGHTS 0
#define NR_POINT_LIGHTS 0
#define NR_SPOT_LIGHTS 0

out vec4 glFragColor;

vec2 poissonDisk[4] = vec2[](
vec2( -0.94201624, -0.39906216 ),
vec2( 0.94558609, -0.76890725 ),
vec2( -0.094184101, -0.92938870 ),
vec2( 0.34495938, 0.29387760 )
);
struct SpotLight{
    vec3 position;
    vec3 direction;
    vec3 color;

    float constant;
    float linear;
    float quadratic;
    float cutoff;
    float outerCutOff;
    float intensity;
    int castShadow;
};

struct PointLight{
    vec3 position;
    vec3 color;

    float constant;
    float linear;
    float quadratic;
    float intensity;
};

struct DirectLight {
    vec3 direction;
    vec3 color;
    float intensity;
    int castShadow;
};

in vec2 TexCoords;
in vec3 Normal;
in vec4 FragPosLightSpace;
in vec3 tDirectLightPos[NR_DIRECT_LIGHTS];
in vec3 tPointLightPos[NR_POINT_LIGHTS];
in vec3 tSpotLightPos[NR_SPOT_LIGHTS];
in vec3 tViewPos;
in vec3 tFragPos;

uniform bool Has_normal_map;

uniform sampler2D mat_diffuse;
uniform sampler2D mat_specular;
uniform sampler2D mat_normal;
uniform sampler2D shadowMap;

uniform vec3 matDiffuse;
uniform vec3 matSpecular;
uniform float shininess;

uniform float far_plane;

uniform DirectLight directLights[NR_DIRECT_LIGHTS];
uniform PointLight pointLights[NR_POINT_LIGHTS];
uniform SpotLight spotLights[NR_SPOT_LIGHTS];

vec3 calcDirectLight(DirectLight,vec3,vec3,vec3,vec3);
vec3 calcPointLight(PointLight,vec3,vec3,vec3,vec3);
vec3 calcSpotLight(SpotLight,vec3,vec3,vec3,vec3);
float directShadowCalculation();

void main(){
    vec3 normal;
    if(Has_normal_map){
        normal=texture(mat_normal, TexCoords).rgb;
        normal = normalize(normal * 2.0 - 1.0);  // this normal is in tangent space
    }
    else
        normal=normalize(Normal);

    vec3 diffColor= matDiffuse+vec3(texture(mat_diffuse, TexCoords));   
    vec3 specColor= matSpecular+vec3(texture(mat_specular,TexCoords));

    vec3 result;
    result=vec3(0.0);
    for(int i = 0; i < NR_DIRECT_LIGHTS-2; i++)
        result += calcDirectLight(directLights[i],normal,tDirectLightPos[i],diffColor,specColor);
    for(int i = 0; i < NR_POINT_LIGHTS-2; i++)
        result += calcPointLight(pointLights[i],normal,tPointLightPos[i],vec3(0.0,0.2,0.4),specColor);
    for(int i = 0; i < NR_SPOT_LIGHTS-2; i++)
        result += calcSpotLight(spotLights[i],normal,tSpotLightPos[i],diffColor,specColor);
    vec4 color =vec4(result,1.0);   
    float gamma = 2.2;
    color.rgb = pow(color.rgb, vec3(1.0/gamma));
    vec4 ambient=vec4(0.2,0.2,0.2,1.0)*vec4(diffColor,1.0);
    glFragColor=ambient+color;
}

vec3 calcDirectLight(DirectLight light,vec3 norm,vec3 tLightPos,vec3 diffColor,vec3 specColor){ 
    vec3 lightDir ;
    if(Has_normal_map)
        lightDir= normalize(tLightPos);
    else
        lightDir = normalize(light.direction);

    float diff = max(dot(lightDir,norm), 0.0);
    vec3 diffuse = light.color * diff *diffColor;

    vec3 viewDir = normalize(tViewPos- tFragPos);       
    vec3 halfwayDir = normalize(lightDir + viewDir);
    float spec = pow(max(dot(norm, halfwayDir), 0.0), 32.0);
    vec3 specular = shininess* spec *specColor* light.color;
    vec3 result;
    if(light.castShadow==1){
        float shadow = directShadowCalculation();
        result =light.intensity* ( shadow* (diffuse + specular));
    }
    else
        result =light.intensity* (diffuse + specular);
    return result;
}

vec3 calcPointLight(PointLight light,vec3 norm,vec3 tLightPos,vec3 diffColor,vec3 specColor){
    vec3 lightDir ;
    if(Has_normal_map)
        lightDir= normalize(tLightPos-tFragPos);
    else
        lightDir = normalize(light.position - tFragPos);
    float diff = max(dot(lightDir,norm), 0.0);
    vec3 diffuse = light.color * diff * diffColor;

    vec3 viewDir = normalize(tViewPos- tFragPos);
    vec3 halfwayDir = normalize(lightDir + viewDir);
    float spec = pow(max(dot(norm, halfwayDir), 0.0), 16.0);        
    vec3 specular =shininess* specColor * spec * light.color;

    vec3 result;
    float distance = length(light.position - tFragPos);
    float attenuation = 1.0f / (light.constant + light.linear * distance +light.quadratic * (distance * distance));
    diffuse *= attenuation;
    specular *= attenuation;
    result=light.intensity*(diffuse+specular);
    return result;
}

vec3 calcSpotLight(SpotLight light,vec3 norm,vec3 tLightPos,vec3 diffColor,vec3 specColor){                   
    vec3 lightDir ;
    if(Has_normal_map)
        lightDir= normalize(tLightPos-tFragPos);
    else
        lightDir = normalize(light.position - tFragPos);
    float diff = max(dot(lightDir,norm), 0.0);
    vec3 diffuse = light.color * diff * diffColor;

    vec3 viewDir = normalize(tViewPos- tFragPos);

    float spec =0.0;
    vec3 halfwayDir = normalize(lightDir + viewDir);
    spec = pow(max(dot(norm, halfwayDir), 0.0), 16.0);    
    vec3 specular = shininess* light.color * spec * specColor;

    // Spotlight (soft edges)
    float theta = dot(lightDir, normalize(-light.direction)); 
    float epsilon = (light.cutoff - light.outerCutOff);
    float intensity = clamp((theta - light.outerCutOff) / epsilon, 0.0, 1.0);
    diffuse  *= intensity;
    specular *= intensity;

    // Attenuation
    float distance    = length(light.position - tFragPos);
    float attenuation = 1.0f / (light.constant + light.linear * distance + light.quadratic * (distance * distance));    
    diffuse  *= attenuation;
    specular *= attenuation;   

    vec3 result = intensity*(diffuse+specular);
    return result;
}

float directShadowCalculation(){
    vec3 projCoords = FragPosLightSpace.xyz / FragPosLightSpace.w;
    projCoords = projCoords * 0.5 + 0.5;
    float shadow = 1.0; 
    for (int i=0;i<4;i++){
        if ( texture( shadowMap, -projCoords.xy + poissonDisk[i]/700.0 ).z  <  -projCoords.z ){
           shadow-=0.2;
        }
    } 
    if(projCoords.z > 1.0)
        shadow = 0.0; 
    return shadow;
}

很抱歉,所有的代码,但我不知道哪里是问题,它需要一个星期的搜索和调试没有进展。

编辑 2-我更改了 directShadowCalculation() 收件人:

    float directShadowCalculation(){
    vec3 projCoords = FragPosLightSpace.xyz / FragPosLightSpace.w;
    projCoords = projCoords * 0.5 + 0.5;
    float shadow = 1.0; 
    for (int i=0;i<4;i++){
        if ( texture( shadowMap, projCoords.xy + poissonDisk[i]/700.0 ).z  <  projCoords.z ){
           shadow-=0.2;
        }
    } 
    if(projCoords.z > 1.0)
        shadow = 0.0; 
    return shadow;
}

这就是结果

1 回复 | 直到 7 年前

Rabbid76 5 年前

如果必须将视图空间坐标转换为光源的局部空间,则 lightSpaceMatrix

lightSpaceMatrix = lightSpaceProjection * (lightSpaceView*camInv)

camInv . 然后你必须转换世界空间坐标,从光源看( lightSpaceView ). 最后,你必须把它投射出来 lightSpaceProjection .

但您可以在顶点着色器中直接从世界坐标转换到光源的局部空间:

FragPosLightSpace = lightSpaceMatrix * vec4(FragPos,1.0);

这样地:

lightSpaceMatrix = lightSpaceProjection * lightSpaceView

w 片段坐标的分量。NDC在范围(-1,-1,-1)到(1,1,1)之间。这与正交投影或透视投影无关。

将投影碎片位置(光空间)除以其 projCoords 在(-1,-1,-1)到(1,1,1)的范围内。 projCoords = projCoords * 0.5 + 0.5; 将XY坐标变换为纹理坐标,并将Z坐标变换为范围[0,1]内的深度值。

vec3 projCoords = FragPosLightSpace.xyz / FragPosLightSpace.w;
projCoords = projCoords * 0.5 + 0.5;

if ( texture( shadowMap, projCoords.xy ).z < projCoords.z )
{
    ....
}

如果 sun->direction

glm::mat4 lightSpaceView = glm::lookAt(sun->direction, glm::vec3(0, 0, 0), glm::vec3(0, 1, 0));

但是,如果 太阳->方向 是太阳照射的方向 lightSpaceView

glm::mat4 lightSpaceView = glm::lookAt(-sun->direction, glm::vec3(0, 0, 0), glm::vec3(0, 1, 0));

由于对灯光使用正交投影,并且灯光空间矩阵的原点靠近世界空间的原点,因此灯光投影的近平面应远离灯光空间的背面。否则近的

glm::mat4 lightSpaceProjection = glm::ortho(-40.0f, 40.0f, -40.0f, 40.0f, -100.0f, 100.0f);

由于灯光计算是在视图空间中完成的,因此必须将灯光位置从世界空间转换为视图空间:

GLuint directLightPosLoc = glGetUniformLocation(phongShader.getProgramID(), (const GLchar*) ("directLightPos[" + ToString((*it)->index) + "]").c_str());
glm::vec3 dir = glm::mat3(camera->getViewMatrix()) * (*it)->direction;
glUniform3fv( directLightPosLoc, 1, &dir[0] );


GLuint pointLightPosLoc = glGetUniformLocation(phongShader.getProgramID(), (const GLchar*) ("pointLightPos[" + ToString((*it)->index) + "]").c_str());
glm::vec4 pos = camera->getViewMatrix( * glm::vec4((*it)->position.x, (*it)->position.y, (*it)->position.z, 1.0);
glUniform3fv( directLightPosLoc, 1, &pos[0] );


GLuint spotLightPosLoc = glGetUniformLocation(phongShader.getProgramID(), (const GLchar*) ("spotLightPos[" + ToString((*it)->index) + "]").c_str());
glm::vec4 pos = camera->getViewMatrix( * glm::vec4((*it)->position.x, (*it)->position.y, (*it)->position.z, 1.0);
glUniform3fv( spotLightPosLoc, 1, &pos[0] );

(function loadscene() {

var sliderScale = 100.0
var gl;
var progShadow;
var progDraw;
var shadowFB;
var bufTorus;
var bufGround;
var canvas;
var vp_size;
var fb_size;

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 = document.getElementById( "shininess" ).value;

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

var lightPos = [-3.0, 0.0, 2.0];
var lightAnimationMat = RotateAxis( IdentityMat44(), CalcAng( deltaMS, 20.0 ), 2 );
lightPos = Transform( lightPos, lightAnimationMat );
var lightDir = [ -lightPos[0], -lightPos[1], -lightPos[2] ];
var light  = Camera.Create( lightPos, [0, 0, 0], [0, 0, 1], 110, [ 5.0, 5.0 ], -20.0, 20.0 );
var camera = Camera.Create( [0, 2.5, 2], [0, 0, 0], [0, 0, 1], 110, [vp_size[0], vp_size[1]], 0.5, 100.0 );

var lightPrjMat = Camera.Ortho( light );
var lightViewMat = Camera.LookAt( light );
var prjMat = Camera.Perspective( camera );
var viewMat = Camera.LookAt( camera );
var modelMat = IdentityMat44();
modelMat = RotateAxis( modelMat, CalcAng( deltaMS, 13.0 ), 0 );
modelMat = RotateAxis( modelMat, CalcAng( deltaMS, 17.0 ), 1 );
groundModelMat = IdentityMat44();
var viewLightDir = TransformVec( lightDir, viewMat );
    
gl.viewport( 0, 0, fb_size[0], fb_size[1] );
gl.enable( gl.DEPTH_TEST );

shadowFB.Bind( true );
ShaderProgram.Use( progShadow );
ShaderProgram.SetUniformM44( progShadow, "u_projectionMat44", lightPrjMat );
ShaderProgram.SetUniformM44( progShadow, "u_viewMat44", lightViewMat );
ShaderProgram.SetUniformM44( progShadow, "u_modelMat44", modelMat );
ShaderProgram.SetUniformF2( progShadow, "u_depthRange", [light.near, light.far] );

VertexBuffer.Draw( bufTorus );

gl.viewport( 0, 0, vp_size[0], vp_size[1] );
shadowFB.Release( true );
shadowFB.BindTexture( 1 );
ShaderProgram.Use( progDraw );
ShaderProgram.SetUniformM44( progDraw, "u_projectionMat44", prjMat );
ShaderProgram.SetUniformM44( progDraw, "u_viewMat44", viewMat );
ShaderProgram.SetUniformM44( progDraw, "u_lightProjectionMat44", lightPrjMat );
ShaderProgram.SetUniformM44( progDraw, "u_lightViewMat44", lightViewMat );
ShaderProgram.SetUniformM44( progDraw, "u_modelMat44", modelMat );
ShaderProgram.SetUniformI1( progDraw, "u_depthSampler", 1 );
ShaderProgram.SetUniformF3( progDraw, "u_lightDir", viewLightDir )
ShaderProgram.SetUniformF1( progDraw, "u_ambient", ambient )
ShaderProgram.SetUniformF1( progDraw, "u_diffuse", diffuse )
ShaderProgram.SetUniformF1( progDraw, "u_specular", specular )
ShaderProgram.SetUniformF1( progDraw, "u_shininess", shininess )

VertexBuffer.Draw( bufTorus );
ShaderProgram.SetUniformM44( progDraw, "u_modelMat44", groundModelMat );
VertexBuffer.Draw( bufGround );

requestAnimationFrame(render);
}

function nearestPow2( aSize ){
  return Math.pow( 2, Math.round( Math.log( aSize ) / Math.log( 2 ) ) ); 
}

function resize() {
    //vp_size = [gl.drawingBufferWidth, gl.drawingBufferHeight];
    vp_size = [window.innerWidth, window.innerHeight]
    canvas.width = vp_size[0];
    canvas.height = vp_size[1];

    var size = Math.max(256, Math.max(vp_size[0], vp_size[1]));
    size = nearestPow2(size/2);
    fb_size = [size, size]
    shadowFB = FrameBuffer.Create( fb_size ); 
}

function initScene() {

document.getElementById( "ambient" ).value = 0.2 * sliderScale;
document.getElementById( "diffuse" ).value = 0.7 * sliderScale;
document.getElementById( "specular" ).value = 0.5 * sliderScale;
document.getElementById( "shininess" ).value = 8.0;

canvas = document.getElementById( "scene-canvas");
vp_size = [canvas.width, canvas.height];
gl = canvas.getContext( "experimental-webgl" );
if ( !gl )
  return;

progShadow = ShaderProgram.Create( 
[ { source : "shadow-shader-vs", stage : gl.VERTEX_SHADER },
{ source : "shadow-shader-fs", stage : gl.FRAGMENT_SHADER }
] );
if (!progShadow.progObj)
    return null;
progShadow.inPos = ShaderProgram.AttributeIndex( progShadow, "inPos" );
progShadow.inNV  = ShaderProgram.AttributeIndex( progShadow, "inNV" );
progShadow.inCol = ShaderProgram.AttributeIndex( progShadow, "inCol" );

progDraw = ShaderProgram.Create( 
  [ { source : "draw-shader-vs", stage : gl.VERTEX_SHADER },
    { source : "draw-shader-fs", stage : gl.FRAGMENT_SHADER }
  ] );
if (!progDraw.progObj)
    return null;
progDraw.inPos = ShaderProgram.AttributeIndex( progDraw, "inPos" );
progDraw.inNV  = ShaderProgram.AttributeIndex( progDraw, "inNV" );
progDraw.inCol = ShaderProgram.AttributeIndex( progDraw, "inCol" );

// 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
);

var g_l = 8.0;
var g_h = -2.5;
var g_c = [ 0.8, 0.6, 0.8 ];
bufGround = VertexBuffer.Create( 
    [ { data : [ -g_l, -g_l, g_h, g_l, -g_l, g_h, g_l, g_l, g_h, -g_l, g_l, g_h ], attrSize : 3, attrLoc : progDraw.inPos },
      { data : [ 0.0, 0.0, 1.0, 0.0, 0.0, 1.0, 0.0, 0.0, 1.0, 0.0, 0.0, 1.0 ], attrSize : 3, attrLoc : progDraw.inNV },
      { data : [ g_c[0], g_c[1], g_c[2], g_c[0], g_c[1], g_c[2], g_c[0], g_c[1], g_c[2], g_c[0], g_c[1], g_c[2] ], attrSize : 3, attrLoc : progDraw.inCol } ],
    [ 0, 1, 2, 0, 2, 3 ]
);

window.onresize = resize;
resize();
requestAnimationFrame(render);
}

var startTime;
function Fract( val ) { 
    return val - Math.trunc( val );
}
function CalcAng( deltaTime, intervall ) {
    return Fract( deltaTime / (1000*intervall) ) * 2.0 * Math.PI;
}

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 = IdentityMat44();
    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 ];
}

Transform = function(vec, mat) {
    return [
        vec[0] * mat[0*4+0] + vec[1] * mat[1*4+0] + vec[2] * mat[2*4+0] + mat[3*4+0],
        vec[0] * mat[0*4+1] + vec[1] * mat[1*4+1] + vec[2] * mat[2*4+1] + mat[3*4+1],
        vec[0] * mat[0*4+2] + vec[1] * mat[1*4+2] + vec[2] * mat[2*4+2] + mat[3*4+2],
        vec[0] * mat[0*4+3] + vec[1] * mat[1*4+3] + vec[2] * mat[2*4+3] + mat[3*4+3] ]
    if ( h[3] == 0.0 )
        return [0, 0, 0]
    return [ h[0]/h[3], h[1]/h[3], h[2]/h[3] ];
}

TransformVec = function(vec, mat) {
   return [
        vec[0] * mat[0*4+0] + vec[1] * mat[1*4+0] + vec[2] * mat[2*4+0],
        vec[0] * mat[0*4+1] + vec[1] * mat[1*4+1] + vec[2] * mat[2*4+1],
        vec[0] * mat[0*4+2] + vec[1] * mat[1*4+2] + vec[2] * mat[2*4+2] ]
}

var Camera = {};
Camera.Create = function( pos, target, up, fov_y, vp, near, far ) {
    var camera = {};
    camera.pos    = pos;
    camera.target = target;
    camera.up     = up;
    camera.fov_y  = fov_y;
    camera.vp     = vp;
    camera.near   = near;
    camera.far    = far;
    return camera;
}
Camera.Ortho = function( camera ) {
    var fn = camera.far + camera.near;
    var f_n = camera.far - camera.near;
    var w = camera.vp[0];
    var h = camera.vp[1];
    var m = IdentityMat44();
    m[0]  = 2 / w; m[1]  = 0;     m[2]  =  0;        m[3]  = 0;
    m[4]  = 0;     m[5]  = 2 / h; m[6]  =  0;        m[7]  = 0;
    m[8]  = 0;     m[9]  = 0;     m[10] = -2 / f_n;  m[11] = 0;
    m[12] = 0;     m[13] = 0;     m[14] = -fn / f_n; m[15] = 1;
    return m;
}
Camera.Perspective = function( camera ) {
    var fn = camera.far + camera.near;
    var f_n = camera.far - camera.near;
    var r = camera.vp[0] / camera.vp[1];
    var t = 1 / Math.tan( Math.PI * camera.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 * camera.far * camera.near / f_n; m[15] =  0;
    return m;
}
Camera.LookAt = function( camera ) {
    var mz = Normalize( [ camera.pos[0]-camera.target[0], camera.pos[1]-camera.target[1], camera.pos[2]-camera.target[2] ] );
    var mx = Normalize( Cross( camera.up, mz ) );
    var my = Normalize( Cross( mz, mx ) );
    var tx = Dot( mx, camera.pos );
    var ty = Dot( my, camera.pos );
    var tz = Dot( [-mz[0], -mz[1], -mz[2]], camera.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 prog = {}
    prog.progObj = this.LinkProgram(shaderObjs)
    if (prog.progObj) {
        prog.attribIndex = {};
        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.attribIndex[name] = gl.getAttribLocation(prog.progObj, name);
        }
        prog.unifomLocation = {};
        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.unifomLocation[name] = gl.getUniformLocation(prog.progObj, name);
        }
    }
    return prog;
}
ShaderProgram.AttributeIndex = function (prog, name) { return prog.attribIndex[name]; }
ShaderProgram.UniformLocation = function (prog, name) { return prog.unifomLocation[name]; }
ShaderProgram.Use = function (prog) { gl.useProgram(prog.progObj); }
ShaderProgram.SetUniformI1 = function (prog, name, val) { if (prog.unifomLocation[name]) gl.uniform1i(prog.unifomLocation[name], val); }
ShaderProgram.SetUniformF1 = function (prog, name, val) { if (prog.unifomLocation[name]) gl.uniform1f(prog.unifomLocation[name], val); }
ShaderProgram.SetUniformF2 = function (prog, name, arr) { if (prog.unifomLocation[name]) gl.uniform2fv(prog.unifomLocation[name], arr); }
ShaderProgram.SetUniformF3 = function (prog, name, arr) { if (prog.unifomLocation[name]) gl.uniform3fv(prog.unifomLocation[name], arr); }
ShaderProgram.SetUniformF4 = function (prog, name, arr) { if (prog.unifomLocation[name]) gl.uniform4fv(prog.unifomLocation[name], arr); }
ShaderProgram.SetUniformM33 = function (prog, name, mat) { if (prog.unifomLocation[name]) gl.uniformMatrix3fv(prog.unifomLocation[name], false, mat); }
ShaderProgram.SetUniformM44 = function (prog, name, mat) { if (prog.unifomLocation[name]) gl.uniformMatrix4fv(prog.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 );
}

var FrameBuffer = {};
FrameBuffer.Create = function( vp, texturePlan ) {
    var texPlan = texturePlan ? new Uint8Array( texturePlan ) : null;
    var fb = gl.createFramebuffer();
    var fbsize = Math.max(vp[0], vp[1]);
    fbsize = 1 << 31 - Math.clz32(fbsize); // nearest power of 2
    fb.width = fbsize;
    fb.height = fbsize;
    gl.bindFramebuffer( gl.FRAMEBUFFER, fb );
    fb.color0_texture = gl.createTexture();
    gl.bindTexture( gl.TEXTURE_2D, fb.color0_texture );
    gl.texImage2D( gl.TEXTURE_2D, 0, gl.RGBA, fb.width, fb.height, 0, gl.RGBA, gl.UNSIGNED_BYTE, texPlan );
    gl.texParameteri( gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST );
    gl.texParameteri( gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST );
    gl.texParameteri( gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE );
    gl.texParameteri( gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE );
    fb.renderbuffer = gl.createRenderbuffer();
    gl.bindRenderbuffer( gl.RENDERBUFFER, fb.renderbuffer );
    gl.renderbufferStorage( gl.RENDERBUFFER, gl.DEPTH_COMPONENT16, fb.width, fb.height );
    gl.framebufferTexture2D( gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, fb.color0_texture, 0 );
    gl.framebufferRenderbuffer( gl.FRAMEBUFFER, gl.DEPTH_ATTACHMENT, gl.RENDERBUFFER, fb.renderbuffer );
    gl.bindTexture( gl.TEXTURE_2D, null );
    gl.bindRenderbuffer( gl.RENDERBUFFER, null );
    gl.bindFramebuffer( gl.FRAMEBUFFER, null );

    fb.Bind = function( clear ) {
        gl.bindFramebuffer( gl.FRAMEBUFFER, this );
        if ( clear ) {
            gl.clearColor( 0.0, 0.0, 0.0, 1.0 );
            gl.clear( gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT );
        }
    };

    fb.Release = function( clear ) {
        gl.bindFramebuffer( gl.FRAMEBUFFER, null );
        if ( clear ) {
            gl.clearColor( 0.0, 0.0, 0.0, 1.0 );
            gl.clear( gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT );
        }
    };

    fb.BindTexture = function( textureUnit ) {
        gl.activeTexture( gl.TEXTURE0 + textureUnit );
        gl.bindTexture( gl.TEXTURE_2D, this.color0_texture );
    };

    return fb;
}

initScene();
  
})();

html,body {
    height: 100%;
    width: 100%;
    margin: 0;
    overflow: hidden;
}

#gui {
    position : absolute;
    top : 0;
    left : 0;
}

<script id="shadow-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;
  varying vec4 vPosPrj;
  
  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;
      vPosPrj       = u_projectionMat44 * viewPos;
      gl_Position   = vPosPrj;
  }
</script>

<script id="shadow-shader-fs" type="x-shader/x-fragment">
    precision mediump float;
    
    varying vec3 vertPos;
    varying vec3 vertNV;
    varying vec3 vertCol;
    varying vec4 vPosPrj;

    uniform vec2 u_depthRange;

    vec3 PackDepth( in float depth )
    {
        float depthVal = depth * (256.0*256.0*256.0 - 1.0) / (256.0*256.0*256.0);
        vec4 encode = fract( depthVal * vec4(1.0, 256.0, 256.0*256.0, 256.0*256.0*256.0) );
        return encode.xyz - encode.yzw / 256.0 + 1.0/512.0;
    }
    
    void main()
    {
        float ndc_depth = vPosPrj.z / vPosPrj.w;
        float nearZ     = u_depthRange.x;
        float farZ      = u_depthRange.y;
        float depth     = ndc_depth * 0.5 + 0.5;
        gl_FragColor    = vec4( PackDepth( depth ).xyz, 1.0 );
    }
</script>

<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;
varying vec4 lightPrj;
varying vec4 vPosPrj;

uniform mat4 u_projectionMat44;
uniform mat4 u_viewMat44;
uniform mat4 u_modelMat44;
uniform mat4 u_lightProjectionMat44;
uniform mat4 u_lightViewMat44;

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 lightPos = u_lightViewMat44 * modelPos;
    vec4 viewPos  = u_viewMat44 * modelPos;
    lightPrj      = u_lightProjectionMat44 * lightPos;
    vertPos       = viewPos.xyz / viewPos.w;
    vPosPrj       = u_projectionMat44 * viewPos;
    gl_Position   = vPosPrj;
}
</script>
  
<script id="draw-shader-fs" type="x-shader/x-fragment">
precision mediump float;

varying vec3 vertPos;
varying vec3 vertNV;
varying vec3 vertCol;
varying vec4 lightPrj;
varying vec4 vPosPrj;

uniform sampler2D u_depthSampler;
uniform vec3      u_lightDir;
uniform float     u_ambient;
uniform float     u_diffuse;
uniform float     u_specular;
uniform float     u_shininess;

float UnpackDepth( in vec3 pack )
{
  float depth = dot( pack, 1.0 / vec3(1.0, 256.0, 256.0*256.0) );
  return depth * (256.0*256.0*256.0) / (256.0*256.0*256.0 - 1.0);
}

float Depth( in sampler2D depthSampler, in vec2 texC )
{
  vec3 depthVal = texture2D( depthSampler, texC.st ).xyz;  
  return UnpackDepth( depthVal.rgb );
}

void main()
{
    vec3  ndc_light  = lightPrj.xyz / lightPrj.w;
    vec2  lightTexC  = ndc_light.xy * 0.5 + 0.5;
    float lightDepth = ndc_light.z * 0.5 + 0.5;
    float testDepth  = Depth( u_depthSampler, lightTexC );
    float shadow     = step( lightDepth-0.01, testDepth ) + step( testDepth, 0.0 );
    vec3  color      = vertCol;
    vec3  lightCol   = u_ambient * color;
    vec3  normalV    = normalize( vertNV );
    vec3  lightV     = normalize( -u_lightDir );
    float NdotL      = max( 0.0, dot( normalV, lightV ) );
    lightCol        += shadow * NdotL * u_diffuse * color;
    vec3  eyeV       = normalize( -vertPos );
    vec3  halfV      = normalize( eyeV + lightV );
    float NdotH      = max( 0.0, dot( normalV, halfV ) );
    float kSpecular  = ( u_shininess + 2.0 ) * pow( NdotH, u_shininess ) / ( 2.0 * 3.14159265 );
    lightCol        += shadow * kSpecular * u_specular * color;
    gl_FragColor     = vec4( lightCol.rgb, 1.0 );
}
</script>

<div><form id="gui" name="inputs"><table>
    <tr> <td> <font color= #CCF>ambient</font> </td> 
            <td> <input type="range" id="ambient" min="0" max="100" value="0"/></td> </tr>
    <tr> <td> <font color= #CCF>diffuse</font> </td> 
            <td> <input type="range" id="diffuse" min="0" max="100" value="0"/></td> </tr>
    <tr> <td> <font color= #CCF>specular</font> </td> 
            <td> <input type="range" id="specular" min="0" max="100" value="0"/></td> </tr>
    <tr> <td> <font color= #CCF>shininess</font> </td> 
            <td> <input type="range" id="shininess" min="0" max="100" value="0"/></td> </tr>
</table></form></div>

<canvas id="scene-canvas" style="border: none;" width="512" height="512"></canvas>