ShaderCache

manage Shader Programs within a context

readyShaderProgram(vertexCode, fragmentCode, geometryCode)

make sure the specified shaders are compiled, linked, and bound

readyShaderProgram(shaders)

make sure the specified shaders are compiled, linked, and bound
will increment the reference count on the shaders if it
needs to keep them around

readyShaderProgram(shaderprogram)

make sure the specified shaders are compiled, linked, and bound

releaseCurrentShader()

Release the current shader. Basically go back to
having no shaders loaded. This is useful for old
legacy code that relies on no shaders being loaded.

releaseGraphicsResources(window)

Free up any resources being used by the provided shader

clearLastShaderBound()

Clear the last Shader bound, called by shaders as they release
their graphics resources

Source

index.js
import md5 from 'blueimp-md5';

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

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

const SET_GET_FIELDS = ['lastShaderBound', 'context', 'openGLRenderWindow'];

// ----------------------------------------------------------------------------
// vtkShaderCache methods
// ----------------------------------------------------------------------------

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

publicAPI.replaceShaderValues = (VSSource, FSSource, GSSource) => {
// first handle renaming any Fragment shader inputs
// if we have a geometry shader. By deafult fragment shaders
// assume their inputs come from a Vertex Shader. When we
// have a Geometry shader we rename the frament shader inputs
// to come from the geometry shader

let nFSSource = FSSource;
if (GSSource.length > 0) {
nFSSource = vtkShaderProgram.substitute(nFSSource, 'VSOut', 'GSOut')
.result;
}

const gl2 = model.openGLRenderWindow.getWebgl2();

let fragDepthString = '\n';

let version = '#version 100\n';
if (gl2) {
version =
'#version 300 es\n' +
'#define attribute in\n' +
'#define textureCube texture\n' +
'#define texture2D texture\n' +
'#define textureCubeLod textureLod\n' +
'#define texture2DLod textureLod\n';
} else {
model.context.getExtension('OES_standard_derivatives');
if (model.context.getExtension('EXT_frag_depth')) {
fragDepthString = '#extension GL_EXT_frag_depth : enable\n';
}
if (model.context.getExtension('EXT_shader_texture_lod')) {
fragDepthString +=
'#extension GL_EXT_shader_texture_lod : enable\n' +
'#define textureCubeLod textureCubeLodEXT\n' +
'#define texture2DLod texture2DLodEXT';
}
}

nFSSource = vtkShaderProgram.substitute(nFSSource, '//VTK::System::Dec', [
`${version}\n`,
gl2 ? '' : '#extension GL_OES_standard_derivatives : enable\n',
fragDepthString,
'#ifdef GL_FRAGMENT_PRECISION_HIGH',
'precision highp float;',
'precision highp int;',
'#else',
'precision mediump float;',
'precision mediump int;',
'#endif',
]).result;

let nVSSource = vtkShaderProgram.substitute(
VSSource,
'//VTK::System::Dec',
[
`${version}\n`,
'#ifdef GL_FRAGMENT_PRECISION_HIGH',
'precision highp float;',
'precision highp int;',
'#else',
'precision mediump float;',
'precision mediump int;',
'#endif',
]
).result;

if (gl2) {
nVSSource = vtkShaderProgram.substitute(nVSSource, 'varying', 'out')
.result;
nFSSource = vtkShaderProgram.substitute(nFSSource, 'varying', 'in')
.result;
nFSSource = vtkShaderProgram.substitute(
nFSSource,
'gl_FragData\\[0\\]',
'fragOutput0'
).result;
nFSSource = vtkShaderProgram.substitute(
nFSSource,
'//VTK::Output::Dec',
'layout(location = 0) out vec4 fragOutput0;'
).result;
}

// nFSSource = ShaderProgram.substitute(nFSSource, 'gl_FragData\\[0\\]',
// 'gl_FragColor').result;

const nGSSource = vtkShaderProgram.substitute(
GSSource,
'//VTK::System::Dec',
version
).result;

return { VSSource: nVSSource, FSSource: nFSSource, GSSource: nGSSource };
};

// return NULL if there is an issue
publicAPI.readyShaderProgramArray = (
vertexCode,
fragmentCode,
geometryCode
) => {
const data = publicAPI.replaceShaderValues(
vertexCode,
fragmentCode,
geometryCode
);

const shader = publicAPI.getShaderProgram(
data.VSSource,
data.FSSource,
data.GSSource
);

return publicAPI.readyShaderProgram(shader);
};

publicAPI.readyShaderProgram = (shader) => {
if (!shader) {
return null;
}

// compile if needed
if (!shader.getCompiled() && !shader.compileShader()) {
return null;
}

// bind if needed
if (!publicAPI.bindShader(shader)) {
return null;
}

return shader;
};

publicAPI.getShaderProgram = (vertexCode, fragmentCode, geometryCode) => {
// compute the MD5 and the check the map
const hashInput = `${vertexCode}${fragmentCode}${geometryCode}`;
const result = md5(hashInput);

// does it already exist?
const loc = Object.keys(model.shaderPrograms).indexOf(result);

if (loc === -1) {
// create one
const sps = vtkShaderProgram.newInstance();
sps.setContext(model.context);
sps.getVertexShader().setSource(vertexCode);
sps.getFragmentShader().setSource(fragmentCode);
if (geometryCode) {
sps.getGeometryShader().setSource(geometryCode);
}
sps.setMd5Hash(result);
model.shaderPrograms[result] = sps;
return sps;
}

return model.shaderPrograms[result];
};

publicAPI.releaseGraphicsResources = (win) => {
// NOTE:
// In the current implementation as of October 26th, if a shader
// program is created by ShaderCache then it should make sure
// that it releases the graphics resouces used by these programs.
// It is not wisely for callers to do that since then they would
// have to loop over all the programs were in use and invoke
// release graphics resources individually.

publicAPI.releaseCurrentShader();

Object.keys(model.shaderPrograms)
.map((key) => model.shaderPrograms[key])
.forEach((sp) => sp.releaseGraphicsResources(win));
};

publicAPI.releaseGraphicsResources = () => {
// release prior shader
if (model.astShaderBound) {
model.lastShaderBound.release();
model.lastShaderBound = null;
}
};

publicAPI.bindShader = (shader) => {
if (model.lastShaderBound === shader) {
return 1;
}

// release prior shader
if (model.lastShaderBound) {
model.lastShaderBound.release();
}
shader.bind();
model.lastShaderBound = shader;
return 1;
};
}

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

const DEFAULT_VALUES = {
lastShaderBound: null,
shaderPrograms: null,
context: null,
openGLRenderWindow: null,
};

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

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

// Internal objects
model.shaderPrograms = {};

// Build VTK API
macro.obj(publicAPI, model);
macro.setGet(publicAPI, model, SET_GET_FIELDS);

// Object methods
vtkShaderCache(publicAPI, model);

return Object.freeze(publicAPI);
}

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

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

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

export default { newInstance, extend };