text: /*
   * Copyright (C) 2009 Apple Inc. All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   *
   * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
   * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
   * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
   * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
   * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
   * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
   * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
   * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
   * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  
  #include "config.h"
  
  #include "core/html/canvas/WebGLProgram.h"
  
  #include "core/html/canvas/WebGLContextGroup.h"
  #include "core/html/canvas/WebGLRenderingContextBase.h"
  
  namespace blink {
  
  PassRefPtr<WebGLProgram> WebGLProgram::create(WebGLRenderingContextBase* ctx)
  {
      return adoptRef(new WebGLProgram(ctx));
  }
  
  WebGLProgram::WebGLProgram(WebGLRenderingContextBase* ctx)
      : WebGLSharedObject(ctx)
      , m_linkStatus(false)
      , m_linkCount(0)
      , m_infoValid(true)
  {
      setObject(ctx->webContext()->createProgram());
  }
  
  WebGLProgram::~WebGLProgram()
  {
  #if ENABLE(OILPAN)
      // These heap objects handle detachment on their own. Clear out
      // the references to prevent deleteObjectImpl() from trying to do
      // same, as we cannot safely access other heap objects from this
      // destructor.
      m_vertexShader = nullptr;
      m_fragmentShader = nullptr;
  #endif
      // Always call detach here to ensure that platform object deletion
      // happens with Oilpan enabled. It keeps the code regular to do it
      // with or without Oilpan enabled.
      //
      // See comment in WebGLBuffer's destructor for additional
      // information on why this is done for WebGLSharedObject-derived
      // objects.
      detachAndDeleteObject();
  }
  
  void WebGLProgram::deleteObjectImpl(blink::WebGraphicsContext3D* context3d, Platform3DObject obj)
  {
      context3d->deleteProgram(obj);
      if (m_vertexShader) {
          m_vertexShader->onDetached(context3d);
          m_vertexShader = nullptr;
      }
      if (m_fragmentShader) {
          m_fragmentShader->onDetached(context3d);
          m_fragmentShader = nullptr;
      }
  }
  
  unsigned WebGLProgram::numActiveAttribLocations()
  {
      cacheInfoIfNeeded();
      return m_activeAttribLocations.size();
  }
  
  GLint WebGLProgram::getActiveAttribLocation(GLuint index)
  {
      cacheInfoIfNeeded();
      if (index >= numActiveAttribLocations())
          return -1;
      return m_activeAttribLocations[index];
  }
  
  bool WebGLProgram::isUsingVertexAttrib0()
  {
      cacheInfoIfNeeded();
      for (unsigned ii = 0; ii < numActiveAttribLocations(); ++ii) {
          if (!getActiveAttribLocation(ii))
              return true;
      }
      return false;
  }
  
  bool WebGLProgram::linkStatus()
  {
      cacheInfoIfNeeded();
      return m_linkStatus;
  }
  
  void WebGLProgram::increaseLinkCount()
  {
      ++m_linkCount;
      m_infoValid = false;
  }
  
  WebGLShader* WebGLProgram::getAttachedShader(GLenum type)
  {
      switch (type) {
      case GL_VERTEX_SHADER:
          return m_vertexShader.get();
      case GL_FRAGMENT_SHADER:
          return m_fragmentShader.get();
      default:
          return 0;
      }
  }
  
  bool WebGLProgram::attachShader(WebGLShader* shader)
  {
      if (!shader || !shader->object())
          return false;
      switch (shader->type()) {
      case GL_VERTEX_SHADER:
          if (m_vertexShader)
              return false;
          m_vertexShader = shader;
          return true;
      case GL_FRAGMENT_SHADER:
          if (m_fragmentShader)
              return false;
          m_fragmentShader = shader;
          return true;
      default:
          return false;
      }
  }
  
  bool WebGLProgram::detachShader(WebGLShader* shader)
  {
      if (!shader || !shader->object())
          return false;
      switch (shader->type()) {
      case GL_VERTEX_SHADER:
          if (m_vertexShader != shader)
              return false;
          m_vertexShader = nullptr;
          return true;
      case GL_FRAGMENT_SHADER:
          if (m_fragmentShader != shader)
              return false;
          m_fragmentShader = nullptr;
          return true;
      default:
          return false;
      }
  }
  
  void WebGLProgram::cacheActiveAttribLocations(blink::WebGraphicsContext3D* context3d)
  {
      m_activeAttribLocations.clear();
  
      GLint numAttribs = 0;
      context3d->getProgramiv(object(), GL_ACTIVE_ATTRIBUTES, &numAttribs);
      m_activeAttribLocations.resize(static_cast<size_t>(numAttribs));
      for (int i = 0; i < numAttribs; ++i) {
          blink::WebGraphicsContext3D::ActiveInfo info;
          context3d->getActiveAttrib(object(), i, info);
          m_activeAttribLocations[i] = context3d->getAttribLocation(object(), info.name.utf8().data());
      }
  }
  
  void WebGLProgram::cacheInfoIfNeeded()
  {
      if (m_infoValid)
          return;
  
      if (!object())
          return;
  
      if (!contextGroup())
          return;
      blink::WebGraphicsContext3D* context = contextGroup()->getAWebGraphicsContext3D();
      if (!context)
          return;
      GLint linkStatus = 0;
      context->getProgramiv(object(), GL_LINK_STATUS, &linkStatus);
      m_linkStatus = linkStatus;
      if (m_linkStatus)
          cacheActiveAttribLocations(context);
      m_infoValid = true;
  }
  
  }
  