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    <title>Origami Simulator</title>

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    <script id="vertexShader" type="x-shader/x-vertex">
        attribute vec2 a_position;
        void main() {
           gl_Position = vec4(a_position, 0, 1);
        }
    </script>

    <script id="packToBytesShader" type="x-shader/x-fragment">
        precision mediump float;
        uniform vec2 u_floatTextureDim;
        uniform sampler2D u_floatTexture;
        uniform float u_vectorLength;
        float shift_right (float v, float amt) {
            v = floor(v) + 0.5;
            return floor(v / exp2(amt));
        }
        float shift_left (float v, float amt) {
            return floor(v * exp2(amt) + 0.5);
        }
        float mask_last (float v, float bits) {
            return mod(v, shift_left(1.0, bits));
        }
        float extract_bits (float num, float from, float to) {
            from = floor(from + 0.5); to = floor(to + 0.5);
            return mask_last(shift_right(num, from), to - from);
        }
        vec4 encode_float (float val) {
            if (val == 0.0) return vec4(0, 0, 0, 0);
            float sign = val > 0.0 ? 0.0 : 1.0;
            val = abs(val);
            float exponent = floor(log2(val));
            float biased_exponent = exponent + 127.0;
            float fraction = ((val / exp2(exponent)) - 1.0) * 8388608.0;
            float t = biased_exponent / 2.0;
            float last_bit_of_biased_exponent = fract(t) * 2.0;
            float remaining_bits_of_biased_exponent = floor(t);
            float byte4 = extract_bits(fraction, 0.0, 8.0) / 255.0;
            float byte3 = extract_bits(fraction, 8.0, 16.0) / 255.0;
            float byte2 = (last_bit_of_biased_exponent * 128.0 + extract_bits(fraction, 16.0, 23.0)) / 255.0;
            float byte1 = (sign * 128.0 + remaining_bits_of_biased_exponent) / 255.0;
            return vec4(byte4, byte3, byte2, byte1);
        }
        void main(){
            vec2 fragCoord = gl_FragCoord.xy;
            float textureXcoord = floor((fragCoord.x - 0.5)/u_vectorLength+0.0001) + 0.5;
            vec4 data = texture2D(u_floatTexture, vec2(textureXcoord, fragCoord.y)/u_floatTextureDim);
            int textureIndex = int(floor(mod(fragCoord.x-0.5+0.0001, u_vectorLength)));
            if (textureIndex == 0) gl_FragColor = encode_float(data[0]);
            else if (textureIndex == 1) gl_FragColor = encode_float(data[1]);
            else if (textureIndex == 2) gl_FragColor = encode_float(data[2]);
            else if (textureIndex == 3) gl_FragColor = encode_float(data[3]);
        }
    </script>

    <script id="zeroTexture" type="x-shader/x-fragment">
        void main(){
            gl_FragColor = vec4(0.0);
        }
    </script>
    <script id="centerTexture" type="x-shader/x-fragment">
        precision mediump float;
        uniform sampler2D u_lastPosition;
        uniform vec2 u_textureDim;
        uniform vec3 u_center;
        void main(){
            vec2 fragCoord = gl_FragCoord.xy;
            vec2 scaledFragCoord = fragCoord/u_textureDim;
            vec3 position = texture2D(u_lastPosition, scaledFragCoord).xyz;
            gl_FragColor = vec4(position-u_center, 0.0);
        }
    </script>

    <script id="positionCalcShader" type="x-shader/x-fragment">
        precision mediump float;
        uniform vec2 u_textureDim;
        uniform float u_dt;
        uniform sampler2D u_lastPosition;
        uniform sampler2D u_velocity;
        uniform sampler2D u_mass;

        void main(){
            vec2 fragCoord = gl_FragCoord.xy;
            vec2 scaledFragCoord = fragCoord/u_textureDim;

            vec3 lastPosition = texture2D(u_lastPosition, scaledFragCoord).xyz;

            float isFixed = texture2D(u_mass, scaledFragCoord).y;
            if (isFixed == 1.0){
                gl_FragColor = vec4(lastPosition, 0.0);
                return;
            }

            vec4 velocityData = texture2D(u_velocity, scaledFragCoord);
            vec3 position = velocityData.xyz*u_dt + lastPosition;
            gl_FragColor = vec4(position, velocityData.a);//velocity.a has error info
        }
    </script>

    <script id="velocityCalcShader" type="x-shader/x-fragment">
        precision mediump float;
        uniform vec2 u_textureDim;
        uniform vec2 u_textureDimEdges;
        uniform vec2 u_textureDimFaces;
        uniform vec2 u_textureDimCreases;
        uniform vec2 u_textureDimNodeCreases;
        uniform float u_creasePercent;
        uniform float u_dt;
        uniform sampler2D u_lastPosition;
        uniform sampler2D u_lastVelocity;
        uniform sampler2D u_originalPosition;
        uniform sampler2D u_externalForces;
        uniform sampler2D u_mass;
        uniform sampler2D u_meta;//[beamsIndex, numBeam, creaseMeta2Index, numCreases]
        uniform sampler2D u_beamMeta;//[k, d, length, otherNodeIndex]
        uniform sampler2D u_creaseMeta;//[k, d, targetTheta]
        uniform sampler2D u_creaseMeta2;//[creaseIndex, momentArmLength, nodeIndex]
        uniform sampler2D u_normals;
        uniform sampler2D u_theta;//[theta, z, normal1Index, normal2Index]

        void main(){
            vec2 fragCoord = gl_FragCoord.xy;
            vec2 scaledFragCoord = fragCoord/u_textureDim;

            vec2 mass = texture2D(u_mass, scaledFragCoord).xy;
            if (mass[1] == 1.0){//fixed
                gl_FragColor = vec4(0.0);
                return;
            }
            vec3 force = texture2D(u_externalForces, scaledFragCoord).xyz;
            vec3 lastPosition = texture2D(u_lastPosition, scaledFragCoord).xyz;
            vec3 lastVelocity = texture2D(u_lastVelocity, scaledFragCoord).xyz;
            vec3 originalPosition = texture2D(u_originalPosition, scaledFragCoord).xyz;

            vec4 neighborIndices = texture2D(u_meta, scaledFragCoord);
            vec4 meta = texture2D(u_meta, scaledFragCoord);

            float nodeError = 0.0;

            for (int j=0;j<100;j++){//for all beams (up to 100, had to put a const int in here)
                if (j >= int(meta[1])) break;

                float beamIndex1D = meta[0]+float(j);
                vec2 beamIndex = vec2(mod(beamIndex1D, u_textureDimEdges.x)+0.5, floor(beamIndex1D/u_textureDimEdges.x)+0.5);
                vec2 scaledBeamIndex = beamIndex/u_textureDimEdges;
                vec4 beamMeta = texture2D(u_beamMeta, scaledBeamIndex);

                float neighborIndex1D = beamMeta[3];
                vec2 neighborIndex = vec2(mod(neighborIndex1D, u_textureDim.x)+0.5, floor(neighborIndex1D/u_textureDim.x)+0.5);
                vec2 scaledNeighborIndex = neighborIndex/u_textureDim;
                vec3 neighborLastPosition = texture2D(u_lastPosition, scaledNeighborIndex).xyz;
                vec3 neighborLastVelocity = texture2D(u_lastVelocity, scaledNeighborIndex).xyz;
                vec3 neighborOriginalPosition = texture2D(u_originalPosition, scaledNeighborIndex).xyz;

                vec3 nominalDist = neighborOriginalPosition-originalPosition;
                vec3 deltaP = neighborLastPosition-lastPosition+nominalDist;
                float deltaPLength = length(deltaP);
                deltaP -= deltaP*(beamMeta[2]/deltaPLength);
                nodeError += abs(deltaPLength/length(nominalDist) - 1.0);
                vec3 deltaV = neighborLastVelocity-lastVelocity;

                vec3 _force = deltaP*beamMeta[0] + deltaV*beamMeta[1];
                force += _force;
            }
            nodeError /= meta[1];

            for (int j=0;j<100;j++){//for all creases (up to 100, had to put a const int in here)
                if (j >= int(meta[3])) break;

                float nodeCreaseIndex1D = meta[2]+float(j);
                vec2 nodeCreaseIndex = vec2(mod(nodeCreaseIndex1D, u_textureDimNodeCreases.x)+0.5, floor(nodeCreaseIndex1D/u_textureDimNodeCreases.x)+0.5);
                vec2 scaledNodeCreaseIndex = nodeCreaseIndex/u_textureDimNodeCreases;
                vec4 creaseMeta2 = texture2D(u_creaseMeta2, scaledNodeCreaseIndex);//[creaseIndex, length to node, nodeType (1 or 2), isReaction]

                float creaseIndex1D = creaseMeta2[0];
                vec2 creaseIndex = vec2(mod(creaseIndex1D, u_textureDimCreases.x)+0.5, floor(creaseIndex1D/u_textureDimCreases.x)+0.5);
                vec2 scaledCreaseIndex = creaseIndex/u_textureDimCreases;

                vec4 thetas = texture2D(u_theta, scaledCreaseIndex);
                vec3 creaseMeta = texture2D(u_creaseMeta, scaledCreaseIndex).xyz;//[k, d, targetTheta]

                float targetTheta = creaseMeta[2] * u_creasePercent;
                float angForce = creaseMeta[0]*(targetTheta-thetas[0]);// + creaseMeta[1]*thetas[1];

                if (creaseMeta2[3] < 0.0){//crease reaction
                    float nodeNum = creaseMeta2[2];

                    //node #1
                    float normalIndex1D = thetas[2];
                    vec2 normalsIndex = vec2(mod(normalIndex1D, u_textureDimFaces.x)+0.5, floor(normalIndex1D/u_textureDimFaces.x)+0.5);
                    vec2 scaledNormalsIndex = normalsIndex/u_textureDimFaces;
                    vec3 normal1 = texture2D(u_normals, scaledNormalsIndex).xyz;

                    //node #2
                    normalIndex1D = thetas[3];
                    normalsIndex = vec2(mod(normalIndex1D, u_textureDimFaces.x)+0.5, floor(normalIndex1D/u_textureDimFaces.x)+0.5);
                    scaledNormalsIndex = normalsIndex/u_textureDimFaces;
                    vec3 normal2 = texture2D(u_normals, scaledNormalsIndex).xyz;

                    float momentArm1 = creaseMeta2[1];
                    float momentArm2 = creaseMeta2[2];

                    vec3 _force = -0.5*(angForce/momentArm1*normal1 + angForce/momentArm2*normal2);
                    force += _force;
                } else {
                    float nodeNum = creaseMeta2[2];
                    float normalIndex1D = thetas[2];//node #1
                    if (nodeNum > 1.1) {
                        normalIndex1D = thetas[3];//node #2
                    }
                    vec2 normalsIndex = vec2(mod(normalIndex1D, u_textureDimFaces.x)+0.5, floor(normalIndex1D/u_textureDimFaces.x)+0.5);
                    vec2 scaledNormalsIndex = normalsIndex/u_textureDimFaces;
                    vec3 normal = texture2D(u_normals, scaledNormalsIndex).xyz;

                    float momentArm = creaseMeta2[1];

                    vec3 _force = angForce/momentArm*normal;
                    force += _force;
                }

            }

            vec3 velocity = force*u_dt/mass[0] + lastVelocity;
            gl_FragColor = vec4(velocity,nodeError);
        }
    </script>

    <script id="thetaCalcShader" type="x-shader/x-fragment">
        #define TWO_PI 6.283185307179586476925286766559
        precision mediump float;
        uniform vec2 u_textureDim;
        uniform vec2 u_textureDimFaces;
        uniform vec2 u_textureDimCreases;
        uniform sampler2D u_normals;
        uniform sampler2D u_lastTheta;
        uniform sampler2D u_creaseVectors;
        uniform sampler2D u_lastPosition;
        uniform sampler2D u_originalPosition;
        uniform float u_dt;

        void main(){

            vec2 fragCoord = gl_FragCoord.xy;
            vec2 scaledFragCoord = fragCoord/u_textureDimCreases;

            vec4 lastTheta = texture2D(u_lastTheta, scaledFragCoord);

            if (lastTheta[2]<0.0){
                gl_FragColor = vec4(lastTheta[0], 0.0, -1.0, -1.0);
                return;
            }

            vec2 normal1Index = vec2(mod(lastTheta[2], u_textureDimFaces.x)+0.5, floor(lastTheta[2]/u_textureDimFaces.x)+0.5);
            normal1Index /= u_textureDimFaces;
            vec2 normal2Index = vec2(mod(lastTheta[3], u_textureDimFaces.x)+0.5, floor(lastTheta[3]/u_textureDimFaces.x)+0.5);
            normal2Index /= u_textureDimFaces;

            vec3 normal1 = texture2D(u_normals, normal1Index).xyz;
            vec3 normal2 = texture2D(u_normals, normal2Index).xyz;

            float dotNormals = dot(normal1, normal2);//normals are already normalized, no need to divide by length
            if (dotNormals < -1.0) dotNormals = -1.0;
            else if (dotNormals > 1.0) dotNormals = 1.0;

            vec2 creaseVectorIndices = texture2D(u_creaseVectors, scaledFragCoord).xy;
            vec2 creaseNodeIndex = vec2(mod(creaseVectorIndices[0], u_textureDim.x)+0.5, floor(creaseVectorIndices[0]/u_textureDim.x)+0.5);
            vec2 scaledNodeIndex = creaseNodeIndex/u_textureDim;
            vec3 node0 = texture2D(u_lastPosition, scaledNodeIndex).xyz + texture2D(u_originalPosition, scaledNodeIndex).xyz;
            creaseNodeIndex = vec2(mod(creaseVectorIndices[1], u_textureDim.x)+0.5, floor(creaseVectorIndices[1]/u_textureDim.x)+0.5);
            scaledNodeIndex = creaseNodeIndex/u_textureDim;
            vec3 node1 = texture2D(u_lastPosition, scaledNodeIndex).xyz + texture2D(u_originalPosition, scaledNodeIndex).xyz;

            //https://math.stackexchange.com/questions/47059/how-do-i-calculate-a-dihedral-angle-given-cartesian-coordinates
            vec3 creaseVector = normalize(node1-node0);
            float x = dotNormals;
            float y = dot(cross(normal1, creaseVector), normal2);

            float theta = atan(y, x);

            float diff = theta-lastTheta[0];
            float origDiff = diff;
            if (diff < -5.0) {
                diff += TWO_PI;
            } else if (diff > 5.0) {
                diff  -= TWO_PI;
            }
            //if (abs(diff)>0.01) diff = 0.0;
            theta = lastTheta[0] + diff;
            gl_FragColor = vec4(theta, origDiff, lastTheta[2], lastTheta[3]);//[theta, w, normal1Index, normal2Index]
        }
    </script>

    <script id="normalCalc" type="x-shader/x-fragment">
        precision mediump float;
        uniform vec2 u_textureDim;
        uniform vec2 u_textureDimFaces;
        uniform sampler2D u_faceVertexIndices;
        uniform sampler2D u_lastPosition;
        uniform sampler2D u_originalPosition;

        void main(){
            vec2 fragCoord = gl_FragCoord.xy;
            vec2 scaledFragCoord = fragCoord/u_textureDimFaces;

            vec3 indices = texture2D(u_faceVertexIndices, scaledFragCoord).xyz;

            float nodeIndex1D = indices[0];
            vec2 nodeIndex = vec2(mod(nodeIndex1D, u_textureDim.x)+0.5, floor(nodeIndex1D/u_textureDim.x)+0.5);
            vec2 scaledNodeIndex = nodeIndex/u_textureDim;
            vec3 a = texture2D(u_lastPosition, scaledNodeIndex).xyz + texture2D(u_originalPosition, scaledNodeIndex).xyz;

            nodeIndex1D = indices[1];
            nodeIndex = vec2(mod(nodeIndex1D, u_textureDim.x)+0.5, floor(nodeIndex1D/u_textureDim.x)+0.5);
            scaledNodeIndex = nodeIndex/u_textureDim;
            vec3 b = texture2D(u_lastPosition, scaledNodeIndex).xyz + texture2D(u_originalPosition, scaledNodeIndex).xyz;

            nodeIndex1D = indices[2];
            nodeIndex = vec2(mod(nodeIndex1D, u_textureDim.x)+0.5, floor(nodeIndex1D/u_textureDim.x)+0.5);
            scaledNodeIndex = nodeIndex/u_textureDim;
            vec3 c = texture2D(u_lastPosition, scaledNodeIndex).xyz + texture2D(u_originalPosition, scaledNodeIndex).xyz;

            vec3 normal = normalize(cross(b-a, c-a));

            gl_FragColor = vec4(normal, 0.0);
        }
    </script>

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<div id="controls">
    <div>
        <a href="#" id="reset" class="btn floatRight btn-lg btn-default">Reset</a>
        <a href="#" id="start" class="btn floatRight btn-lg btn-success">Start Simulation</a>
        <a href="#" id="pause" class="btn floatRight btn-lg btn-warning">Pause Simulation</a>
        <br/><br/>
        <div id="stepForwardOptions" class="floatRight">
            Num Steps: &nbsp;&nbsp;<input id="numSteps" value="100" placeholder="" class="form-control" type="text">
            <a href="#" id="stepForward" class="btn btn-lg btn-default">Step Forward</a>
            <br/><br/>
        </div><br/>
    </div>
    <b>Simulation Type:</b><br/>
    <div class="indent">
        <label class="radio">
            <input name="simType" value="dynamic" data-toggle="radio" class="custom-radio" type="radio"><span class="icons"><span class="icon-unchecked"></span><span class="icon-checked"></span></span>
            Compliant Dynamic Simulation <a class="about floatRight" href="#" id="aboutDynamicSim"><span class="fui-question-circle"></span></a>
        </label>
        <label class="radio">
            <input name="simType" value="static" data-toggle="radio" class="custom-radio" type="radio"><span class="icons"><span class="icon-unchecked"></span><span class="icon-checked"></span></span>
            Compliant Static Simulation (not finished yet) <a class="about floatRight" href="#" id="aboutStaticSim"><span class="fui-question-circle"></span></a>
        </label>
    </div><br/>
    <label class="checkbox" for="userInteractionEnabled">
        <input id="userInteractionEnabled" data-toggle="checkbox" class="custom-checkbox layersSelector" type="checkbox"><span class="icons"><span class="icon-unchecked"></span><span class="icon-checked"></span></span>
        Allow User Interaction
    </label><br/>
    <b>Stiffness Settings:</b><a class="floatRight about" href="#" id="aboutStiffness"><span class="fui-question-circle"></span></a><br/><br/>
    <div class="sliderInput" id="axialStiffness">
        <span class="label-slider">Axial Stiffness : </span><div class="flat-slider ui-slider ui-corner-all ui-slider-horizontal ui-widget ui-widget-content"></div>
        <input value="" placeholder="" class="form-control" type="text">
    </div>
    <div class="sliderInput" id="creaseStiffness">
        <span class="label-slider">Fold Stiffness : </span><div class="flat-slider ui-slider ui-corner-all ui-slider-horizontal ui-widget ui-widget-content"></div>
        <input value="" placeholder="" class="form-control" type="text">
    </div>
    <div class="sliderInput" id="panelStiffness">
        <span class="label-slider">Facet Stiffness : </span><div class="flat-slider ui-slider ui-corner-all ui-slider-horizontal ui-widget ui-widget-content"></div>
        <input value="" placeholder="" class="form-control" type="text">
    </div>
    <div class="sliderInput" id="percentDamping">
        <span class="label-slider">Damping (0-1): </span><div class="flat-slider ui-slider ui-corner-all ui-slider-horizontal ui-widget ui-widget-content"></div>
        <input value="" placeholder="" class="form-control" type="text">
    </div>
    <br/><br/>
    <b>Error:</b><br/>
    <div class="indent">
        <label>Average node error: <span id="globalError"></span></label>
        <a class="about floatRight" href="#" id="aboutError"><span class="fui-question-circle"></span></a>
    </div><br/>
    <b>Animation Settings:</b><br/>
        <div class="indent">
            <span class="smallTxt">&Delta; t = <span id="deltaT"></span> seconds</span><br/><br/>
            <a href="#" id="shouldCenterGeo" class="floatRight btn btn-lg btn-default">Re-center geometry</a>
        </div>
    <div class="extraSpace"></div>
</div>
<div id="svgViewer"></div>

<div id="controlsLeft" class="flipped">
    <div>
        <b>View Settings:</b><br/><br/>
        <div class="indent">
            Mesh Material:
            <div class="indent">
                <label class="checkbox" for="meshVisible">
                    <input id="meshVisible" data-toggle="checkbox" class="custom-checkbox layersSelector" type="checkbox"><span class="icons"><span class="icon-unchecked"></span><span class="icon-checked"></span></span>
                    Mesh Visible
                </label>
                <div id="meshMaterialOptions">
                    <label class="radio">
                        <input name="colorMode" value="color" data-toggle="radio" class="custom-radio" type="radio"><span class="icons"><span class="icon-unchecked"></span><span class="icon-checked"></span></span>
                        Colored Material
                    </label>
                    <div id="coloredMaterialOptions" class="indent">
                        <label>Color 1 (rgb hex): &nbsp;&nbsp;</label><input id="color1" value="" placeholder="" class="hexVal form-control" type="text"><br/>
                        <label>Color 2 (rgb hex): &nbsp;&nbsp;</label><input id="color2" value="" placeholder="" class="hexVal form-control" type="text"><br/>
                    </div>
                    <label class="radio">
                        <input name="colorMode" value="normal" data-toggle="radio" class="custom-radio" type="radio"><span class="icons"><span class="icon-unchecked"></span><span class="icon-checked"></span></span>
                        Face Normals Material
                    </label>
                    <label class="radio">
                        <input name="colorMode" value="axialStrain" data-toggle="radio" class="custom-radio" type="radio"><span class="icons"><span class="icon-unchecked"></span><span class="icon-checked"></span></span>
                        Axial Strain Visualization<a class="about floatRight" href="#" id="aboutAxialStrain"><span class="fui-question-circle"></span></a>
                    </label>
                    <div id="axialStrainMaterialOptions" class="indent">
                        <label>Max Strain: &nbsp;&nbsp;</label>
                        <input id="strainClip" value="" placeholder="" class="float form-control" type="text"> %<br/>
                    </div>
                </div>
            </div><br/>
            Edges:
            <div class="indent">
                <label class="checkbox" for="edgesVisible">
                    <input id="edgesVisible" data-toggle="checkbox" class="custom-checkbox layersSelector" type="checkbox"><span class="icons"><span class="icon-unchecked"></span><span class="icon-checked"></span></span>
                    Edges Visible
                </label>
                <div id="edgeVisOptions" class="indent">
                    <label class="checkbox" for="mtnsVisible">
                        <input id="mtnsVisible" data-toggle="checkbox" class="custom-checkbox layersSelector" type="checkbox"><span class="icons"><span class="icon-unchecked"></span><span class="icon-checked"></span></span>
                        Mountains
                    </label>
                    <label class="checkbox" for="valleysVisible">
                        <input id="valleysVisible" data-toggle="checkbox" class="custom-checkbox layersSelector" type="checkbox"><span class="icons"><span class="icon-unchecked"></span><span class="icon-checked"></span></span>
                        Valleys
                    </label>
                    <label class="checkbox" for="panelsVisible">
                        <input id="panelsVisible" data-toggle="checkbox" class="custom-checkbox layersSelector" type="checkbox"><span class="icons"><span class="icon-unchecked"></span><span class="icon-checked"></span></span>
                        Facet Creases
                    </label>
                    <label class="checkbox" for="passiveEdgesVisible">
                        <input id="passiveEdgesVisible" data-toggle="checkbox" class="custom-checkbox layersSelector" type="checkbox"><span class="icons"><span class="icon-unchecked"></span><span class="icon-checked"></span></span>
                        Undriven Edges
                    </label>
                </div>
            </div><br/>
            <!--Rendering:-->
            <!--<div class="indent">-->
                <!--<label class="checkbox" for="ambientOcclusion">-->
                    <!--<input id="ambientOcclusion" data-toggle="checkbox" class="custom-checkbox layersSelector" type="checkbox"><span class="icons"><span class="icon-unchecked"></span><span class="icon-checked"></span></span>-->
                    <!--Ambient Occlusion-->
                <!--</label>-->
            <!--</div>-->
            VR:
            <div class="indent smallTxt">
                Status: &nbsp;<span id="VRstatus"></span>
                <a class="about floatRight" href="#" id="aboutVR"><span class="fui-question-circle"></span></a><br/>
                <div id="VRoptions">
                    <label class="checkbox" for="vrEnabled">
                        <input id="vrEnabled" data-toggle="checkbox" class="custom-checkbox layersSelector" type="checkbox"><span class="icons"><span class="icon-unchecked"></span><span class="icon-checked"></span></span>
                        Connect
                    </label>
                </div>
            </div>
        </div>
    </div>
</div>
<div class="modal fade" id="aboutModal" tabindex="-1" role="dialog">
    <div class="modal-dialog modal-lg">
        <div class="modal-content">
            <div class="modal-body">
                <p><b>Origami Simulator</b><br/><br/>
                    <a target="_blank" href="http://www2.eng.cam.ac.uk/~sdg/preprint/5OSME.pdf">Origami Folding; A Structural Engineering Approach</a><br/>
                    <a target="_blank" href="http://origami.c.u-tokyo.ac.jp/~tachi/cg/SimulationOfRigidOrigami_tachi_4OSME.pdf">Rigid Origami Simulator</a><br/>
                    <br/>
                    This app uses <a target="_blank" href="https://threejs.org/">three.js</a> to visualize and interact with the 3D geometry of the folding.<br/>
                    Triangulation of quad faces in origami patterns is achieved by adding the shortest edge across the quad (this helps to preserve symmetry, which
                    makes the simulation work better). Arbitrary polygonal faces are triangulated using the <a target="_blank" href="https://github.com/mapbox/earcut">Earcut Library</a>.<br/>
                    Additionally, I used <a target="_blank" href="https://jquery.com/">jQuery</a>, <a target="_blank" href="http://getbootstrap.com/">Bootstrap</a> and the
                    <a target="_blank" href="http://designmodo.github.io/Flat-UI/">Flat UI theme</a> to build the GUI.<br/>
                    <br/>
                    Built by <a href="http://www.amandaghassaei.com/" target="_blank">Amanda Ghassaei</a> as a final project for <a href="http://courses.csail.mit.edu/6.849/spring17/" target="_blank">Geometric Folding Algorithms</a>.
                    Code available on <a href="https://github.com/amandaghassaei/OrigamiSimulator" target="_blank">Github</a>.  If you have interesting crease patterns that would
                    make good demo files, please send them to me (Amanda) so I can add them to the <b>Examples</b> menu.  My email address is on my website.  Thanks!
                </p>
            </div>
        </div><!-- /.modal-content -->
    </div><!-- /.modal-dialog -->
</div><!-- /.modal -->
<div class="modal fade" id="tipsModal" tabindex="-1" role="dialog">
    <div class="modal-dialog modal-lg">
        <div class="modal-content">
            <div class="modal-body">
                <p><b>File Import Tips</b><br/><br/>
                    Bad design files will throw errors and create models that explode or cannot be solved, here are some tips for
                    importing FOLD or svg files that work.<br/><br/>
                    <b>Importing FOLD:</b><br/><br/>
                    The FOLD file format is specified in <a target="_blank" href="https://github.com/edemaine/fold">these docs</a>.
                    This tool imports FOLD v1.0 files with <b>all</b> of the following fields populated:
                    <ul>
                        <li>vertices_coords</li>
                        <li>edges_vertices</li>
                        <li>edges_assignment</li>
                        <li>faces_vertices</li>
                    </ul>
                    If you are unsure whether your FOLD file is valid, you can inspect it using the
                    <a target="_blank" href="https://edemaine.github.io/fold/examples/foldviewer.html">FOLD Viewer</a>.<br/>
                    <br/>
                    <b>Importing SVG:</b><br/><br/>
                    <ul>
                        <li>The SVG importer supports path objects and line objects (coming).  Please convert polygons to paths before importing.</li>
                        <li>Valley folds are <span style="color:red">red</span> - rgb(255, 0, 0), hex #ff0000</li>
                        <li>Mountain folds are <span style="color:blue">blue</span> - rgb(0, 0, 255), hex #0000ff</li>
                        <li>Outline edges are <span style="color:black">black</span> - rgb(0, 0, 0), hex #000000</li>
                        <img src="assets/examplepattern.jpg"/>
                        <li>This tool will automatically triangulate regions in the pattern that form polygons with more than three sides.
                        To control the triangulations draw lines in <span style="color:#cccc00">yellow</span> - rgb(255, 255, 0), hex #ffff00<br/>
                        In general, patterns move better when their triangulation is symmetric and minimizes long, skinny triangles.</li>
                        <img src="assets/patternwithtriangulations.jpg"/>
                        <li>Stroke and line style do not matter.</li>
                        <li>The final fold angle of a mountain or valley fold is set by its opacity. For example, 1.0 = 180&deg;
                        (fully folded), 0.5 = 90&deg;, 0 = 0&deg; (flat).  Any fold angle between  0&deg; and 180&deg; may be used.</li>
                        <li>This tool should be able to automatically clean files of slightly misaligned vertices, stray vertices,
                        duplicate lines (coming), and extra vertices falling in the middle of an edge (coming),
                        but it is recommended to remove these errors yourself in order to avoid problems.</li>
                        <li>If your simulation is not working, check that the pattern looks correct by clicking on the "Pattern" view in the top nav bar.</li>
                    </ul><br/>

                <b>For Adobe Illustrator users:</b><br/><br/>
                I use Illustrator to create SVGs (though any vector editing program should be fine), here are some tips I've found for making svgs to import into this tool.<br/><br/>
                    <ul>
                        <li>If you are starting with a pre-made vector file, first ungroup any groups, release all compound paths
                        (<b>Select all + Object>Compound Path>Release</b>), and release all clipping masks (<b>Select all + Object>Clipping Mask>Release</b>).</li>
                        <li>Create geometry using the <b>Line Segment Tool</b>.</li>
                        <li>Illustrator can help you select all lines of a particular type so that you can edit their color or opacity together.  Click the line,
                        then go to <b>Select>Same>Appearance</b> to select all similar lines in the pattern.
                        <li>To turn lines and polygons into path objects, select the geometry then right click and select <b>Make Compound Path</b>.</li>
                        <li>Finally hit <b>Save As</b> and select <b>.svg</b> extension. I'm using the default SVG 1.1 settings, but version 1.0 will work as well.</li>
                    </ul>
                </p>
            </div>
        </div><!-- /.modal-content -->
    </div><!-- /.modal-dialog -->
</div><!-- /.modal -->
<div class="modal fade" id="aboutVRmodal" tabindex="-1" role="dialog">
    <div class="modal-dialog modal-med">
        <div class="modal-content">
            <div class="modal-body">
                <button type="button" class="close" data-dismiss="modal" aria-label="Close">
                  <span aria-hidden="true">&times;</span>
                </button>
                <b>VR</b><br/><br/>
                Working on VR support for Vive....
            </div>
        </div><!-- /.modal-content -->
    </div><!-- /.modal-dialog -->
</div><!-- /.modal -->
<div class="modal fade" id="exportSTLModal" tabindex="-1" role="dialog">
    <div class="modal-dialog modal-med">
        <div class="modal-content">
            <div class="modal-body">
                <button type="button" class="close" data-dismiss="modal" aria-label="Close">
                  <span aria-hidden="true">&times;</span>
                </button>
                <b>Export STL</b><br/><br/>
                Filename: &nbsp;&nbsp;<input id="stlFilename" value="" placeholder="" class="bigInput text form-control" type="text"> .stl<br/><br/>
                Scale: &nbsp;&nbsp;<input value="" placeholder="" class="exportScale form-control" type="text"><br/><br/>
                Dimensions: &nbsp;&nbsp;<b><span class="exportDimensions"></span></b><br/>
                <span class="smallTxt">(the STL file format is unitless, but typically assumed to be either in inches or mm)</span><br/>
                <label class="bigLabel checkbox" for="doublesidedSTL">
                    <input id="doublesidedSTL" data-toggle="checkbox" class="custom-checkbox layersSelector" type="checkbox"><span class="icons"><span class="icon-unchecked"></span><span class="icon-checked"></span></span>
                    Double Sided
                </label>
            </div>
            <div class="modal-footer">
                <button id="doSTLsave" type="button" class="actionButton btn btn-success" data-dismiss="modal">Save</button>
            </div>
        </div><!-- /.modal-content -->
    </div><!-- /.modal-dialog -->
</div><!-- /.modal -->
<div class="modal fade" id="exportFOLDModal" tabindex="-1" role="dialog">
    <div class="modal-dialog modal-med">
        <div class="modal-content">
            <div class="modal-body">
                <button type="button" class="close" data-dismiss="modal" aria-label="Close">
                  <span aria-hidden="true">&times;</span>
                </button>
                <b>Export FOLD</b><br/><br/>
                Filename: &nbsp;&nbsp;<input id="foldFilename" value="" placeholder="" class="bigInput text form-control" type="text"> .fold<br/><br/>
                Author: &nbsp;&nbsp;<input id="foldAuthor" value="Amanda Ghassaei" placeholder="" class="bigInput text form-control" type="text"><br/><br/>
                Scale: &nbsp;&nbsp;<input value="" placeholder="" class="exportScale form-control" type="text">&nbsp;&nbsp;&nbsp;&nbsp;
                Units: &nbsp;&nbsp;
                <div class="btn-group">
                    <button data-toggle="dropdown" class="btn btn-default dropdown-toggle" type="button"><span class="unitsDisplay"></span> <span class="caret"></span></button>
                    <ul id="unitsDropdown" role="menu" class="dropdown-menu">
                        <li><a class="units" data-id="unit" href="#">unitless</a></li>
                        <li><a class="units" data-id="in" href="#">in</a></li>
                        <li><a class="units" data-id="pt" href="#">pt</a></li>
                        <li><a class="units" data-id="m" href="#">m</a></li>
                        <li><a class="units" data-id="cm" href="#">cm</a></li>
                        <li><a class="units" data-id="mm" href="#">mm</a></li>
                        <li><a class="units" data-id="um" href="#">um</a></li>
                        <li><a class="units" data-id="nm" href="#">nm</a></li>
                    </ul>
                </div>
                <br/><br/>
                Dimensions: &nbsp;&nbsp;<b><span class="exportDimensions"></span> <span class="unitsDisplay"></span></b><br/>
                <label class="bigLabel checkbox" for="triangulateFOLDexport">
                    <input id="triangulateFOLDexport" data-toggle="checkbox" class="custom-checkbox layersSelector" type="checkbox"><span class="icons"><span class="icon-unchecked"></span><span class="icon-checked"></span></span>
                    Save with triangulated faces
                </label>
                <label class="bigLabel checkbox" for="exportFoldAngle">
                    <input id="exportFoldAngle" data-toggle="checkbox" disabled class="custom-checkbox layersSelector" type="checkbox"><span class="icons"><span class="icon-unchecked"></span><span class="icon-checked"></span></span>
                    Save with vertices_foldAngles (coming soon)
                </label>
                <span class="smallTxt">For more information about the FOLD file format, see the <a target="_blank" href="https://github.com/edemaine/fold">offical docs</a></span>.
            </div>
            <div class="modal-footer">
                <button id="doFOLDsave" type="button" class="actionButton btn btn-success" data-dismiss="modal">Save</button>
            </div>
        </div><!-- /.modal-content -->
    </div><!-- /.modal-dialog -->
</div><!-- /.modal -->
<div class="modal fade" id="importFoldModal" tabindex="-1" role="dialog">
    <div class="modal-dialog modal-med">
        <div class="modal-content">
            <div class="modal-body">
                <button type="button" class="close" data-dismiss="modal" aria-label="Close">
                  <span aria-hidden="true">&times;</span>
                </button>
                <b>Import FOLD</b><br/><br/>
                <label class="bigLabel checkbox" for="foldUseAngles">
                    <input id="foldUseAngles" data-toggle="checkbox" class="custom-checkbox layersSelector" type="checkbox"><span class="icons"><span class="icon-unchecked"></span><span class="icon-checked"></span></span>
                    Use current angles as target fold angles
                </label>
            </div>
            <div class="modal-footer">
                <button data-dismiss="modal" type="button" class="btn btn-success">OK</button>
            </div>
        </div><!-- /.modal-content -->
    </div><!-- /.modal-dialog -->
</div><!-- /.modal -->
<div class="modal fade" id="warningModal" tabindex="-1" role="dialog">
    <div class="modal-dialog sm">
        <div class="modal-content">
            <div class="modal-body">
                <p id="warningMessage">
                </p>
            </div>
        </div><!-- /.modal-content -->
    </div><!-- /.modal-dialog -->
</div><!-- /.modal -->
<div class="modal fade" id="aboutErrorModal" tabindex="-1" role="dialog">
    <div class="modal-dialog modal-med">
        <div class="modal-content">
            <div class="modal-body">
                <button type="button" class="close" data-dismiss="modal" aria-label="Close">
                  <span aria-hidden="true">&times;</span>
                </button>
                <p><b>Simulation Error</b><br/><br/>
                    "Average node error" gives a sense of how much the distance constraints in the
                    origami pattern are being violated.  The error at each node is evaluated by averaging the
                    percent deviation of all its distance constraints with adjacent nodes.  This error is
                    reported as a percent of the total length of the distance constraint to remove scaling effects.
                    <br/><br/>
                    This measurement is equivalent to <a href="https://en.wikipedia.org/wiki/Deformation_(mechanics)#Engineering_strain" target="_blank">
                        Cauchy strain or engineering strain</a> of the axial constraints on this system.
                    Increasing the "Axial Stiffness" will tighten these constraints and
                    lower the error in the simulation.<br/>
                    <br/>
                    To visualize the error of each node graphically, select "Axial Strain Visualization" under "Mesh Material"
                     in the left menu.
                </p>
            </div>
        </div><!-- /.modal-content -->
    </div><!-- /.modal-dialog -->
</div><!-- /.modal -->
<div class="modal fade" id="aboutStiffnessModal" tabindex="-1" role="dialog">
    <div class="modal-dialog modal-med">
        <div class="modal-content">
            <div class="modal-body">
                <button type="button" class="close" data-dismiss="modal" aria-label="Close">
                  <span aria-hidden="true">&times;</span>
                </button>
                <p><b>Stiffness Settings</b><br/><br/>
                    ....
                </p>
            </div>
        </div><!-- /.modal-content -->
    </div><!-- /.modal-dialog -->
</div><!-- /.modal -->
<div class="modal fade" id="aboutDynamicSimModal" tabindex="-1" role="dialog">
    <div class="modal-dialog modal-med">
        <div class="modal-content">
            <div class="modal-body">
                <button type="button" class="close" data-dismiss="modal" aria-label="Close">
                  <span aria-hidden="true">&times;</span>
                </button>
                <p><b>Compliant Dynamic Simulation</b><br/><br/>
                    ....
                </p>
            </div>
        </div><!-- /.modal-content -->
    </div><!-- /.modal-dialog -->
</div><!-- /.modal -->
<div class="modal fade" id="aboutStaticSimModal" tabindex="-1" role="dialog">
    <div class="modal-dialog modal-med">
        <div class="modal-content">
            <div class="modal-body">
                <button type="button" class="close" data-dismiss="modal" aria-label="Close">
                  <span aria-hidden="true">&times;</span>
                </button>
                <p><b>Compliant Static Simulation</b><br/><br/>
                    ....
                </p>
            </div>
        </div><!-- /.modal-content -->
    </div><!-- /.modal-dialog -->
</div><!-- /.modal -->
<div class="modal fade" id="aboutAxialStrainModal" tabindex="-1" role="dialog">
    <div class="modal-dialog modal-med">
        <div class="modal-content">
            <div class="modal-body">
                <button type="button" class="close" data-dismiss="modal" aria-label="Close">
                  <span aria-hidden="true">&times;</span>
                </button>
                <p><b>Axial Strain</b><br/><br/>
                    ....
                </p>
            </div>
        </div><!-- /.modal-content -->
    </div><!-- /.modal-dialog -->
</div><!-- /.modal -->
</body>
</html>