shader-core.js

'use strict'

var createUniformWrapper = require('./lib/create-uniforms')
var createAttributeWrapper = require('./lib/create-attributes')
var makeReflect = require('./lib/reflect')

//Shader object
function Shader(gl, prog, vertShader, fragShader) {
  this.gl = gl
  this.handle = prog
  this.attributes = null
  this.uniforms = null
  this.types = null
  this.vertexShader = vertShader
  this.fragmentShader = fragShader
}

//Binds the shader
Shader.prototype.bind = function() {
  this.gl.useProgram(this.handle)
}

//Destroy shader, release resources
Shader.prototype.dispose = function() {
  var gl = this.gl
  gl.deleteShader(this.vertexShader)
  gl.deleteShader(this.fragmentShader)
  gl.deleteProgram(this.handle)
}

Shader.prototype.updateExports = function(uniforms, attributes) {
  var locations = new Array(uniforms.length)
  var program = this.handle
  var gl = this.gl

  var doLink = relinkUniforms.bind(void 0,
    gl,
    program,
    locations,
    uniforms
  )
  doLink()

  this.types = {
    uniforms: makeReflect(uniforms),
    attributes: makeReflect(attributes)
  }

  this.attributes = createAttributeWrapper(
    gl,
    program,
    attributes,
    doLink
  )

  Object.defineProperty(this, 'uniforms', createUniformWrapper(
    gl,
    program,
    uniforms,
    locations
  ))
}

//Relinks all uniforms
function relinkUniforms(gl, program, locations, uniforms) {
  for(var i=0; i<uniforms.length; ++i) {
    locations[i] = gl.getUniformLocation(program, uniforms[i].name)
  }
}

//Compiles and links a shader program with the given attribute and vertex list
function createShader(
    gl
  , vertSource
  , fragSource
  , uniforms
  , attributes) {
  
  //Compile vertex shader
  var vertShader = gl.createShader(gl.VERTEX_SHADER)
  gl.shaderSource(vertShader, vertSource)
  gl.compileShader(vertShader)
  if(!gl.getShaderParameter(vertShader, gl.COMPILE_STATUS)) {
    var errLog = gl.getShaderInfoLog(vertShader)
    console.error('gl-shader: Error compling vertex shader:', errLog)
    throw new Error('gl-shader: Error compiling vertex shader:' + errLog)
  }
  
  //Compile fragment shader
  var fragShader = gl.createShader(gl.FRAGMENT_SHADER)
  gl.shaderSource(fragShader, fragSource)
  gl.compileShader(fragShader)
  if(!gl.getShaderParameter(fragShader, gl.COMPILE_STATUS)) {
    var errLog = gl.getShaderInfoLog(fragShader)
    console.error('gl-shader: Error compiling fragment shader:', errLog)
    throw new Error('gl-shader: Error compiling fragment shader:' + errLog)
  }
  
  //Link program
  var program = gl.createProgram()
  gl.attachShader(program, fragShader)
  gl.attachShader(program, vertShader)

  //Optional default attriubte locations
  attributes.forEach(function(a) {
    if (typeof a.location === 'number') 
      gl.bindAttribLocation(program, a.location, a.name)
  })

  gl.linkProgram(program)
  if(!gl.getProgramParameter(program, gl.LINK_STATUS)) {
    var errLog = gl.getProgramInfoLog(program)
    console.error('gl-shader: Error linking shader program:', errLog)
    throw new Error('gl-shader: Error linking shader program:' + errLog)
  }
  
  //Return final linked shader object
  var shader = new Shader(
    gl,
    program,
    vertShader,
    fragShader
  )
  shader.updateExports(uniforms, attributes)

  return shader
}

module.exports = createShader