TmMolStar/src/mol-gl/shader/cylinders.frag.ts

/**
 * Copyright (c) 2020-2022 mol* contributors, licensed under MIT, See LICENSE file for more info.
 *
 * @author Alexander Rose <alexander.rose@weirdbyte.de>
 */

export const cylinders_frag = `
precision highp float;
precision highp int;

#define bumpEnabled
#define multiColor

uniform mat4 uView;

varying mat4 vTransform;
varying vec3 vStart;
varying vec3 vEnd;
varying float vSize;
varying float vCap;
varying float vColorMode;

uniform vec3 uCameraDir;
uniform vec3 uCameraPosition;
uniform mat4 uInvView;

#include common
#include common_frag_params
#include color_frag_params
#include light_frag_params
#include common_clip

#ifdef dSolidInterior
    const bool solidInterior = true;
#else
    const bool solidInterior = false;
#endif

// adapted from https://www.shadertoy.com/view/4lcSRn
// The MIT License, Copyright 2016 Inigo Quilez
bool CylinderImpostor(
    in vec3 rayOrigin, in vec3 rayDir,
    in vec3 start, in vec3 end, in float radius,
    out vec3 cameraNormal, out bool interior,
    out vec3 modelPosition, out vec3 viewPosition, out float fragmentDepth
){
    vec3 ba = end - start;
    vec3 oc = rayOrigin - start;

    float baba = dot(ba, ba);
    float bard = dot(ba, rayDir);
    float baoc = dot(ba, oc);

    float k2 = baba - bard * bard;
    float k1 = baba * dot(oc, rayDir) - baoc * bard;
    float k0 = baba * dot(oc, oc) - baoc * baoc - radius * radius * baba;

    float h = k1 * k1 - k2 * k0;
    if (h < 0.0) return false;

    bool topCap = (vCap > 0.9 && vCap < 1.1) || vCap >= 2.9;
    bool bottomCap = (vCap > 1.9 && vCap < 2.1) || vCap >= 2.9;

    #ifdef dSolidInterior
        bool topInterior = !topCap;
        bool bottomInterior = !bottomCap;
        topCap = true;
        bottomCap = true;
    #else
        bool topInterior = false;
        bool bottomInterior = false;
    #endif

    bool clipped = false;
    bool objectClipped = false;

    // body outside
    h = sqrt(h);
    float t = (-k1 - h) / k2;
    float y = baoc + t * bard;
    if (y > 0.0 && y < baba) {
        interior = false;
        cameraNormal = (oc + t * rayDir - ba * y / baba) / radius;
        modelPosition = rayOrigin + t * rayDir;
        viewPosition = (uView * vec4(modelPosition, 1.0)).xyz;
        fragmentDepth = calcDepth(viewPosition);
        #if defined(dClipVariant_pixel) && dClipObjectCount != 0
            if (clipTest(vec4(modelPosition, 0.0))) {
                objectClipped = true;
                fragmentDepth = -1.0;
                #ifdef dSolidInterior
                    topCap = !topInterior;
                    bottomCap = !bottomInterior;
                #endif
            }
        #endif
        if (fragmentDepth > 0.0) return true;
        clipped = true;
    }

    if (!clipped) {
        if (topCap && y < 0.0) {
            // top cap
            t = -baoc / bard;
            if (abs(k1 + k2 * t) < h) {
                interior = topInterior;
                cameraNormal = -ba / baba;
                modelPosition = rayOrigin + t * rayDir;
                viewPosition = (uView * vec4(modelPosition, 1.0)).xyz;
                fragmentDepth = calcDepth(viewPosition);
                #if defined(dClipVariant_pixel) && dClipObjectCount != 0
                    if (clipTest(vec4(modelPosition, 0.0))) {
                        objectClipped = true;
                        fragmentDepth = -1.0;
                        #ifdef dSolidInterior
                            topCap = !topInterior;
                            bottomCap = !bottomInterior;
                        #endif
                    }
                #endif
                if (fragmentDepth > 0.0) {
                    #ifdef dSolidInterior
                        if (interior) cameraNormal = -rayDir;
                    #endif
                    return true;
                }
            }
        } else if (bottomCap && y >= 0.0) {
            // bottom cap
            t = (baba - baoc) / bard;
            if (abs(k1 + k2 * t) < h) {
                interior = bottomInterior;
                cameraNormal = ba / baba;
                modelPosition = rayOrigin + t * rayDir;
                viewPosition = (uView * vec4(modelPosition, 1.0)).xyz;
                fragmentDepth = calcDepth(viewPosition);
                #if defined(dClipVariant_pixel) && dClipObjectCount != 0
                    if (clipTest(vec4(modelPosition, 0.0))) {
                        objectClipped = true;
                        fragmentDepth = -1.0;
                        #ifdef dSolidInterior
                            topCap = !topInterior;
                            bottomCap = !bottomInterior;
                        #endif
                    }
                #endif
                if (fragmentDepth > 0.0) {
                    #ifdef dSolidInterior
                        if (interior) cameraNormal = -rayDir;
                    #endif
                    return true;
                }
            }
        }
    }

    if (uDoubleSided || solidInterior) {
        // body inside
        h = -h;
        t = (-k1 - h) / k2;
        y = baoc + t * bard;
        if (y > 0.0 && y < baba) {
            interior = true;
            cameraNormal = -(oc + t * rayDir - ba * y / baba) / radius;
            modelPosition = rayOrigin + t * rayDir;
            viewPosition = (uView * vec4(modelPosition, 1.0)).xyz;
            fragmentDepth = calcDepth(viewPosition);
            if (fragmentDepth > 0.0) {
                #ifdef dSolidInterior
                    if (!objectClipped) {
                        fragmentDepth = 0.0 + (0.0000002 / vSize);
                        cameraNormal = -rayDir;
                    }
                #endif
                return true;
            }
        }

        if (topCap && y < 0.0) {
            // top cap
            t = -baoc / bard;
            if (abs(k1 + k2 * t) < -h) {
                interior = true;
                cameraNormal = ba / baba;
                modelPosition = rayOrigin + t * rayDir;
                viewPosition = (uView * vec4(modelPosition, 1.0)).xyz;
                fragmentDepth = calcDepth(viewPosition);
                if (fragmentDepth > 0.0) {
                    #ifdef dSolidInterior
                        if (!objectClipped) {
                            fragmentDepth = 0.0 + (0.0000002 / vSize);
                            cameraNormal = -rayDir;
                        }
                    #endif
                    return true;
                }
            }
        } else if (bottomCap && y >= 0.0) {
            // bottom cap
            t = (baba - baoc) / bard;
            if (abs(k1 + k2 * t) < -h) {
                interior = true;
                cameraNormal = -ba / baba;
                modelPosition = rayOrigin + t * rayDir;
                viewPosition = (uView * vec4(modelPosition, 1.0)).xyz;
                fragmentDepth = calcDepth(viewPosition);
                if (fragmentDepth > 0.0) {
                    #ifdef dSolidInterior
                        if (!objectClipped) {
                            fragmentDepth = 0.0 + (0.0000002 / vSize);
                            cameraNormal = -rayDir;
                        }
                    #endif
                    return true;
                }
            }
        }
    }

    return false;
}

void main() {
    vec3 rayOrigin = vModelPosition;
    vec3 rayDir = mix(normalize(vModelPosition - uCameraPosition), uCameraDir, uIsOrtho);

    vec3 cameraNormal;
    vec3 modelPosition;
    vec3 viewPosition;
    float fragmentDepth;
    bool hit = CylinderImpostor(rayOrigin, rayDir, vStart, vEnd, vSize, cameraNormal, interior, modelPosition, viewPosition, fragmentDepth);
    if (!hit) discard;

    if (fragmentDepth < 0.0) discard;
    if (fragmentDepth > 1.0) discard;

    gl_FragDepthEXT = fragmentDepth;

    vec3 vViewPosition = viewPosition;
    vec3 vModelPosition = modelPosition;

    #include clip_pixel
    #include assign_material_color

    #if defined(dRenderVariant_pick)
        #include check_picking_alpha
        #ifdef requiredDrawBuffers
            gl_FragColor = vObject;
            gl_FragData[1] = vInstance;
            gl_FragData[2] = vGroup;
            gl_FragData[3] = packDepthToRGBA(fragmentDepth);
        #else
            gl_FragColor = vColor;
        #endif
    #elif defined(dRenderVariant_depth)
        gl_FragColor = material;
    #elif defined(dRenderVariant_marking)
        gl_FragColor = material;
    #elif defined(dRenderVariant_color)
        mat3 normalMatrix = transpose3(inverse3(mat3(uView)));
        vec3 normal = normalize(normalMatrix * -normalize(cameraNormal));
        #include apply_light_color

        #include apply_interior_color
        #include apply_marker_color
        #include apply_fog
        #include wboit_write
        #include dpoit_write
    #endif
}
`;