src/viewer/scene/mesh/shadow/ShadowShaderSource.js

/**
 * @private
 */
class ShadowShaderSource {
    constructor(mesh) {
        this.vertex = buildVertex(mesh);
        this.fragment = buildFragment(mesh);
    }
}

function buildVertex(mesh) {
    const scene = mesh.scene;
    const clipping = scene._sectionPlanesState.sectionPlanes.length > 0;
    const quantizedGeometry = !!mesh._geometry._state.compressGeometry;
    const src = [];
    src.push("// Mesh shadow vertex shader");
    src.push("in vec3 position;");
    src.push("uniform mat4 modelMatrix;");
    src.push("uniform mat4 shadowViewMatrix;");
    src.push("uniform mat4 shadowProjMatrix;");
    src.push("uniform vec3 offset;");
    if (quantizedGeometry) {
        src.push("uniform mat4 positionsDecodeMatrix;");
    }
    if (clipping) {
        src.push("out vec4 vWorldPosition;");
    }
    src.push("void main(void) {");
    src.push("vec4 localPosition = vec4(position, 1.0); ");
    src.push("vec4 worldPosition;");
    if (quantizedGeometry) {
        src.push("localPosition = positionsDecodeMatrix * localPosition;");
    }
    src.push("worldPosition = modelMatrix * localPosition;");
    src.push("worldPosition.xyz = worldPosition.xyz + offset;");
    src.push("vec4 viewPosition  = shadowViewMatrix * worldPosition; ");
    if (clipping) {
        src.push("vWorldPosition = worldPosition;");
    }
    src.push("   gl_Position = shadowProjMatrix * viewPosition;");
    src.push("}");
    return src;
}

function buildFragment(mesh) {
    const scene = mesh.scene;
    const gl = scene.canvas.gl;
    const sectionPlanesState = scene._sectionPlanesState;
    const clipping = sectionPlanesState.getNumAllocatedSectionPlanes() > 0;
    const src = [];
    src.push("// Mesh shadow fragment shader");

    src.push("#ifdef GL_FRAGMENT_PRECISION_HIGH");
    src.push("precision highp float;");
    src.push("precision highp int;");
    src.push("#else");
    src.push("precision mediump float;");
    src.push("precision mediump int;");
    src.push("#endif");

    if (clipping) {
        src.push("uniform bool clippable;");
        src.push("in vec4 vWorldPosition;");
        for (var i = 0; i < sectionPlanesState.getNumAllocatedSectionPlanes(); i++) {
            src.push("uniform bool sectionPlaneActive" + i + ";");
            src.push("uniform vec3 sectionPlanePos" + i + ";");
            src.push("uniform vec3 sectionPlaneDir" + i + ";");
        }
    }

    src.push("vec4 encodeFloat( const in float depth ) {");
    src.push("  const vec4 bitShift = vec4(256 * 256 * 256, 256 * 256, 256, 1.0);");
    src.push("  const vec4 bitMask = vec4(0, 1.0 / 256.0, 1.0 / 256.0, 1.0 / 256.0);");
    src.push("  vec4 comp = fract(depth * bitShift);");
    src.push("  comp -= comp.xxyz * bitMask;");
    src.push("  return comp;");
    src.push("}");

    src.push("out vec4 outColor;");

    src.push("void main(void) {");
    if (clipping) {
        src.push("if (clippable) {");
        src.push("  float dist = 0.0;");
        for (var i = 0; i < sectionPlanesState.getNumAllocatedSectionPlanes(); i++) {
            src.push("if (sectionPlaneActive" + i + ") {");
            src.push("   dist += clamp(dot(-sectionPlaneDir" + i + ".xyz, vWorldPosition.xyz - sectionPlanePos" + i + ".xyz), 0.0, 1000.0);");
            src.push("}");
        }
        src.push("  if (dist > 0.0) { discard; }");
        src.push("}");
    }
    src.push("outColor = encodeFloat(gl_FragCoord.z);");
    src.push("}");
    return src;
}

export {ShadowShaderSource};