SphereMapper

OpenGL sphere mapper

vtkOpenGLSphereMapper is designed to view/render a vtkSphereMapper.

buildBufferObjects

Set 3 points to form an equilateral triangle.

Source

index.js
import { mat4 } from 'gl-matrix';
import { ObjectType } from 'vtk.js/Sources/Rendering/OpenGL/BufferObject/Constants';

import macro from 'vtk.js/Sources/macro';

import vtkBufferObject from 'vtk.js/Sources/Rendering/OpenGL/BufferObject';
import * as vtkMath from 'vtk.js/Sources/Common/Core/Math';

import vtkShaderProgram from 'vtk.js/Sources/Rendering/OpenGL/ShaderProgram';
import vtkOpenGLPolyDataMapper from 'vtk.js/Sources/Rendering/OpenGL/PolyDataMapper';

import vtkSphereMapperVS from 'vtk.js/Sources/Rendering/OpenGL/glsl/vtkSphereMapperVS.glsl';
import vtkPolyDataFS from 'vtk.js/Sources/Rendering/OpenGL/glsl/vtkPolyDataFS.glsl';

const { vtkErrorMacro } = macro;

// ----------------------------------------------------------------------------
// vtkOpenGLSphereMapper methods
// ----------------------------------------------------------------------------

function vtkOpenGLSphereMapper(publicAPI, model) {
// Set our className
model.classHierarchy.push('vtkOpenGLSphereMapper');

// Capture 'parentClass' api for internal use
const superClass = Object.assign({}, publicAPI);

publicAPI.getShaderTemplate = (shaders, ren, actor) => {
shaders.Vertex = vtkSphereMapperVS;
shaders.Fragment = vtkPolyDataFS;
shaders.Geometry = '';
};

publicAPI.replaceShaderValues = (shaders, ren, actor) => {
let VSSource = shaders.Vertex;
let FSSource = shaders.Fragment;

VSSource = vtkShaderProgram.substitute(VSSource, '//VTK::Camera::Dec', [
'uniform mat4 VCDCMatrix;\n',
'uniform mat4 MCVCMatrix;',
]).result;

FSSource = vtkShaderProgram.substitute(FSSource, '//VTK::PositionVC::Dec', [
'varying vec4 vertexVCVSOutput;',
]).result;

// we create vertexVC below, so turn off the default
// implementation
FSSource = vtkShaderProgram.substitute(
FSSource,
'//VTK::PositionVC::Impl',
['vec4 vertexVC = vertexVCVSOutput;\n']
).result;

// for lights kit and positional the VCDC matrix is already defined
// so don't redefine it
const replacement = [
'uniform float invertedDepth;\n',
'uniform int cameraParallel;\n',
'varying float radiusVCVSOutput;\n',
'varying vec3 centerVCVSOutput;\n',
'uniform mat4 VCDCMatrix;\n',
];
FSSource = vtkShaderProgram.substitute(
FSSource,
'//VTK::Normal::Dec',
replacement
).result;

let fragString = '';
if (model.context.getExtension('EXT_frag_depth')) {
fragString = 'gl_FragDepthEXT = (pos.z / pos.w + 1.0) / 2.0;\n';
}
if (model.openGLRenderWindow.getWebgl2()) {
fragString = 'gl_FragDepth = (pos.z / pos.w + 1.0) / 2.0;\n';
}
FSSource = vtkShaderProgram.substitute(FSSource, '//VTK::Depth::Impl', [
// compute the eye position and unit direction
' vec3 EyePos;\n',
' vec3 EyeDir;\n',
' if (cameraParallel != 0) {\n',
' EyePos = vec3(vertexVC.x, vertexVC.y, vertexVC.z + 3.0*radiusVCVSOutput);\n',
' EyeDir = vec3(0.0,0.0,-1.0); }\n',
' else {\n',
' EyeDir = vertexVC.xyz;\n',
' EyePos = vec3(0.0,0.0,0.0);\n',
' float lengthED = length(EyeDir);\n',
' EyeDir = normalize(EyeDir);\n',
// we adjust the EyePos to be closer if it is too far away
// to prevent floating point precision noise
' if (lengthED > radiusVCVSOutput*3.0) {\n',
' EyePos = vertexVC.xyz - EyeDir*3.0*radiusVCVSOutput; }\n',
' }\n',

// translate to Sphere center
' EyePos = EyePos - centerVCVSOutput;\n',
// scale to radius 1.0
' EyePos = EyePos/radiusVCVSOutput;\n',
// find the intersection
' float b = 2.0*dot(EyePos,EyeDir);\n',
' float c = dot(EyePos,EyePos) - 1.0;\n',
' float d = b*b - 4.0*c;\n',
' vec3 normalVCVSOutput = vec3(0.0,0.0,1.0);\n',
' if (d < 0.0) { discard; }\n',
' else {\n',
' float t = (-b - invertedDepth*sqrt(d))*0.5;\n',

// compute the normal, for unit sphere this is just
// the intersection point
' normalVCVSOutput = invertedDepth*normalize(EyePos + t*EyeDir);\n',
// compute the intersection point in VC
' vertexVC.xyz = normalVCVSOutput*radiusVCVSOutput + centerVCVSOutput;\n',
' }\n',
// compute the pixel's depth
// ' normalVCVSOutput = vec3(0,0,1);\n'
' vec4 pos = VCDCMatrix * vertexVC;\n',
fragString,
]).result;

// Strip out the normal line -- the normal is computed as part of the depth
FSSource = vtkShaderProgram.substitute(FSSource, '//VTK::Normal::Impl', '')
.result;

if (model.haveSeenDepthRequest) {
// special depth impl
FSSource = vtkShaderProgram.substitute(FSSource, '//VTK::ZBuffer::Impl', [
'if (depthRequest == 1) {',
'float computedZ = (pos.z / pos.w + 1.0) / 2.0;',
'float iz = floor(computedZ * 65535.0 + 0.1);',
'float rf = floor(iz/256.0)/255.0;',
'float gf = mod(iz,256.0)/255.0;',
'gl_FragData[0] = vec4(rf, gf, 0.0, 1.0); }',
]).result;
}

shaders.Vertex = VSSource;
shaders.Fragment = FSSource;

superClass.replaceShaderValues(shaders, ren, actor);
};

publicAPI.setMapperShaderParameters = (cellBO, ren, actor) => {
if (
cellBO.getCABO().getElementCount() &&
(model.VBOBuildTime > cellBO.getAttributeUpdateTime().getMTime() ||
cellBO.getShaderSourceTime().getMTime() >
cellBO.getAttributeUpdateTime().getMTime()) &&
cellBO.getProgram().isAttributeUsed('offsetMC')
) {
if (
!cellBO.getVAO().addAttributeArray(
cellBO.getProgram(),
cellBO.getCABO(),
'offsetMC',
12, // 12:this->VBO->ColorOffset+sizeof(float)
cellBO.getCABO().getStride(),
model.context.FLOAT,
2,
false
)
) {
vtkErrorMacro("Error setting 'offsetMC' in shader VAO.");
}
}

if (cellBO.getProgram().isUniformUsed('invertedDepth')) {
cellBO
.getProgram()
.setUniformf('invertedDepth', model.invert ? -1.0 : 1.0);
}

superClass.setMapperShaderParameters(cellBO, ren, actor);
};

publicAPI.setCameraShaderParameters = (cellBO, ren, actor) => {
const program = cellBO.getProgram();

const cam = ren.getActiveCamera();
const keyMats = model.openGLCamera.getKeyMatrices(ren);

if (program.isUniformUsed('VCDCMatrix')) {
program.setUniformMatrix('VCDCMatrix', keyMats.vcdc);
}

if (program.isUniformUsed('MCVCMatrix')) {
if (!actor.getIsIdentity()) {
const actMats = model.openGLActor.getKeyMatrices();
const tmp4 = mat4.create();
mat4.multiply(tmp4, keyMats.wcvc, actMats.mcwc);
program.setUniformMatrix('MCVCMatrix', tmp4);
} else {
program.setUniformMatrix('MCVCMatrix', keyMats.wcvc);
}
}

if (program.isUniformUsed('cameraParallel')) {
cellBO
.getProgram()
.setUniformi('cameraParallel', cam.getParallelProjection());
}
};

publicAPI.getOpenGLMode = (rep, type) => model.context.TRIANGLES;

publicAPI.buildBufferObjects = (ren, actor) => {
const poly = model.currentInput;

if (poly === null) {
return;
}

model.renderable.mapScalars(poly, 1.0);
const c = model.renderable.getColorMapColors();

const vbo = model.primitives[model.primTypes.Tris].getCABO();

const pointData = poly.getPointData();
const points = poly.getPoints();
const numPoints = points.getNumberOfPoints();
const pointArray = points.getData();

const pointSize = 5; // x,y,z,orientation1,orientation2
let scales = null;

if (
model.renderable.getScaleArray() != null &&
pointData.hasArray(model.renderable.getScaleArray())
) {
scales = pointData.getArray(model.renderable.getScaleArray()).getData();
}

let colorData = null;
let colorComponents = 0;
let packedUCVBO = null;
if (c) {
colorComponents = c.getNumberOfComponents();
vbo.setColorOffset(0);
vbo.setColorBOStride(4);
colorData = c.getData();
packedUCVBO = new Uint8Array(3 * numPoints * 4);
if (!vbo.getColorBO()) {
vbo.setColorBO(vtkBufferObject.newInstance());
}
vbo.getColorBO().setOpenGLRenderWindow(model.openGLRenderWindow);
} else if (vbo.getColorBO()) {
vbo.setColorBO(null);
}
vbo.setColorComponents(colorComponents);

const packedVBO = new Float32Array(pointSize * numPoints * 3);

vbo.setStride(pointSize * 4);

const cos30 = Math.cos(vtkMath.radiansFromDegrees(30.0));
let pointIdx = 0;
let colorIdx = 0;

//
// Generate points and point data for sides
//
let vboIdx = 0;
let ucIdx = 0;
for (let i = 0; i < numPoints; ++i) {
let radius = model.renderable.getRadius();
if (scales) {
radius = scales[i];
}

pointIdx = i * 3;
packedVBO[vboIdx++] = pointArray[pointIdx++];
packedVBO[vboIdx++] = pointArray[pointIdx++];
packedVBO[vboIdx++] = pointArray[pointIdx++];
packedVBO[vboIdx++] = -2.0 * radius * cos30;
packedVBO[vboIdx++] = -radius;
if (colorData) {
colorIdx = i * colorComponents;
packedUCVBO[ucIdx++] = colorData[colorIdx];
packedUCVBO[ucIdx++] = colorData[colorIdx + 1];
packedUCVBO[ucIdx++] = colorData[colorIdx + 2];
packedUCVBO[ucIdx++] = colorData[colorIdx + 3];
}

pointIdx = i * 3;
packedVBO[vboIdx++] = pointArray[pointIdx++];
packedVBO[vboIdx++] = pointArray[pointIdx++];
packedVBO[vboIdx++] = pointArray[pointIdx++];
packedVBO[vboIdx++] = 2.0 * radius * cos30;
packedVBO[vboIdx++] = -radius;
if (colorData) {
packedUCVBO[ucIdx++] = colorData[colorIdx];
packedUCVBO[ucIdx++] = colorData[colorIdx + 1];
packedUCVBO[ucIdx++] = colorData[colorIdx + 2];
packedUCVBO[ucIdx++] = colorData[colorIdx + 3];
}

pointIdx = i * 3;
packedVBO[vboIdx++] = pointArray[pointIdx++];
packedVBO[vboIdx++] = pointArray[pointIdx++];
packedVBO[vboIdx++] = pointArray[pointIdx++];
packedVBO[vboIdx++] = 0.0;
packedVBO[vboIdx++] = 2.0 * radius;
if (colorData) {
packedUCVBO[ucIdx++] = colorData[colorIdx];
packedUCVBO[ucIdx++] = colorData[colorIdx + 1];
packedUCVBO[ucIdx++] = colorData[colorIdx + 2];
packedUCVBO[ucIdx++] = colorData[colorIdx + 3];
}
}

vbo.setElementCount(vboIdx / pointSize);
vbo.upload(packedVBO, ObjectType.ARRAY_BUFFER);
if (c) {
vbo.getColorBO().upload(packedUCVBO, ObjectType.ARRAY_BUFFER);
}

model.VBOBuildTime.modified();
};
}

// ----------------------------------------------------------------------------
// Object factory
// ----------------------------------------------------------------------------

const DEFAULT_VALUES = {};

// ----------------------------------------------------------------------------

export function extend(publicAPI, model, initialValues = {}) {
Object.assign(model, DEFAULT_VALUES, initialValues);

// Inheritance
vtkOpenGLPolyDataMapper.extend(publicAPI, model, initialValues);

// Object methods
vtkOpenGLSphereMapper(publicAPI, model);
}

// ----------------------------------------------------------------------------

export const newInstance = macro.newInstance(extend, 'vtkOpenGLSphereMapper');

// ----------------------------------------------------------------------------

export default { newInstance, extend };