glbuffers.cpp Example File

  /****************************************************************************
  **
  ** Copyright (C) 2016 The Qt Company Ltd.
  ** Contact: https://www.qt.io/licensing/
  **
  ** This file is part of the demonstration applications of the Qt Toolkit.
  **
  ** $QT_BEGIN_LICENSE:BSD$
  ** Commercial License Usage
  ** Licensees holding valid commercial Qt licenses may use this file in
  ** accordance with the commercial license agreement provided with the
  ** Software or, alternatively, in accordance with the terms contained in
  ** a written agreement between you and The Qt Company. For licensing terms
  ** and conditions see https://www.qt.io/terms-conditions. For further
  ** information use the contact form at https://www.qt.io/contact-us.
  **
  ** BSD License Usage
  ** Alternatively, you may use this file under the terms of the BSD license
  ** as follows:
  **
  ** "Redistribution and use in source and binary forms, with or without
  ** modification, are permitted provided that the following conditions are
  ** met:
  **   * Redistributions of source code must retain the above copyright
  **     notice, this list of conditions and the following disclaimer.
  **   * 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.
  **   * Neither the name of The Qt Company Ltd nor the names of its
  **     contributors may be used to endorse or promote products derived
  **     from this software without specific prior written permission.
  **
  **
  ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  ** "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 THE COPYRIGHT
  ** OWNER 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."
  **
  ** $QT_END_LICENSE$
  **
  ****************************************************************************/

  #include "glbuffers.h"
  #include <QtGui/qmatrix4x4.h>

  void qgluPerspective(GLdouble fovy, GLdouble aspect, GLdouble zNear, GLdouble zFar)
  {
      const GLdouble ymax = zNear * tan(fovy * M_PI / 360.0);
      const GLdouble ymin = -ymax;
      const GLdouble xmin = ymin * aspect;
      const GLdouble xmax = ymax * aspect;
      glFrustum(xmin, xmax, ymin, ymax, zNear, zFar);
  }

  //============================================================================//
  //                                  GLTexture                                 //
  //============================================================================//

  GLTexture::GLTexture() : m_texture(0), m_failed(false)
  {
      glGenTextures(1, &m_texture);
  }

  GLTexture::~GLTexture()
  {
      glDeleteTextures(1, &m_texture);
  }

  //============================================================================//
  //                                 GLTexture2D                                //
  //============================================================================//

  GLTexture2D::GLTexture2D(int width, int height)
  {
      glBindTexture(GL_TEXTURE_2D, m_texture);
      glTexImage2D(GL_TEXTURE_2D, 0, 4, width, height, 0,
          GL_BGRA, GL_UNSIGNED_BYTE, 0);

      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
      //glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
      //glTexParameteri(GL_TEXTURE_2D, GL_GENERATE_MIPMAP, GL_TRUE);
      glBindTexture(GL_TEXTURE_2D, 0);
  }

  GLTexture2D::GLTexture2D(const QString& fileName, int width, int height)
  {
      // TODO: Add error handling.
      QImage image(fileName);

      if (image.isNull()) {
          m_failed = true;
          return;
      }

      image = image.convertToFormat(QImage::Format_ARGB32);

      //qDebug() << "Image size:" << image.width() << "x" << image.height();
      if (width <= 0)
          width = image.width();
      if (height <= 0)
          height = image.height();
      if (width != image.width() || height != image.height())
          image = image.scaled(width, height, Qt::IgnoreAspectRatio, Qt::SmoothTransformation);

      glBindTexture(GL_TEXTURE_2D, m_texture);

      // Works on x86, so probably works on all little-endian systems.
      // Does it work on big-endian systems?
      glTexImage2D(GL_TEXTURE_2D, 0, 4, image.width(), image.height(), 0,
          GL_BGRA, GL_UNSIGNED_BYTE, image.bits());

      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
      //glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
      //glTexParameteri(GL_TEXTURE_2D, GL_GENERATE_MIPMAP, GL_TRUE);
      glBindTexture(GL_TEXTURE_2D, 0);
  }

  void GLTexture2D::load(int width, int height, QRgb *data)
  {
      glBindTexture(GL_TEXTURE_2D, m_texture);
      glTexImage2D(GL_TEXTURE_2D, 0, 4, width, height, 0,
          GL_BGRA, GL_UNSIGNED_BYTE, data);
      glBindTexture(GL_TEXTURE_2D, 0);
  }

  void GLTexture2D::bind()
  {
      glBindTexture(GL_TEXTURE_2D, m_texture);
      glEnable(GL_TEXTURE_2D);
  }

  void GLTexture2D::unbind()
  {
      glBindTexture(GL_TEXTURE_2D, 0);
      glDisable(GL_TEXTURE_2D);
  }

  //============================================================================//
  //                                 GLTexture3D                                //
  //============================================================================//

  GLTexture3D::GLTexture3D(int width, int height, int depth)
  {
      GLBUFFERS_ASSERT_OPENGL("GLTexture3D::GLTexture3D", glTexImage3D, return)

      glBindTexture(GL_TEXTURE_3D, m_texture);
      glTexImage3D(GL_TEXTURE_3D, 0, 4, width, height, depth, 0,
          GL_BGRA, GL_UNSIGNED_BYTE, 0);

      glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_WRAP_S, GL_REPEAT);
      glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_WRAP_T, GL_REPEAT);
      glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_WRAP_R, GL_REPEAT);
      glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
      glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
      //glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
      //glTexParameteri(GL_TEXTURE_3D, GL_GENERATE_MIPMAP, GL_TRUE);
      glBindTexture(GL_TEXTURE_3D, 0);
  }

  void GLTexture3D::load(int width, int height, int depth, QRgb *data)
  {
      GLBUFFERS_ASSERT_OPENGL("GLTexture3D::load", glTexImage3D, return)

      glBindTexture(GL_TEXTURE_3D, m_texture);
      glTexImage3D(GL_TEXTURE_3D, 0, 4, width, height, depth, 0,
          GL_BGRA, GL_UNSIGNED_BYTE, data);
      glBindTexture(GL_TEXTURE_3D, 0);
  }

  void GLTexture3D::bind()
  {
      glBindTexture(GL_TEXTURE_3D, m_texture);
      glEnable(GL_TEXTURE_3D);
  }

  void GLTexture3D::unbind()
  {
      glBindTexture(GL_TEXTURE_3D, 0);
      glDisable(GL_TEXTURE_3D);
  }

  //============================================================================//
  //                                GLTextureCube                               //
  //============================================================================//

  GLTextureCube::GLTextureCube(int size)
  {
      glBindTexture(GL_TEXTURE_CUBE_MAP, m_texture);

      for (int i = 0; i < 6; ++i)
          glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X + i, 0, 4, size, size, 0,
              GL_BGRA, GL_UNSIGNED_BYTE, 0);

      glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
      glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
      glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_R, GL_CLAMP_TO_EDGE);
      glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
      glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
      //glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
      //glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_GENERATE_MIPMAP, GL_TRUE);
      glBindTexture(GL_TEXTURE_CUBE_MAP, 0);
  }

  GLTextureCube::GLTextureCube(const QStringList& fileNames, int size)
  {
      // TODO: Add error handling.

      glBindTexture(GL_TEXTURE_CUBE_MAP, m_texture);

      int index = 0;
      foreach (QString file, fileNames) {
          QImage image(file);
          if (image.isNull()) {
              m_failed = true;
              break;
          }

          image = image.convertToFormat(QImage::Format_ARGB32);

          //qDebug() << "Image size:" << image.width() << "x" << image.height();
          if (size <= 0)
              size = image.width();
          if (size != image.width() || size != image.height())
              image = image.scaled(size, size, Qt::IgnoreAspectRatio, Qt::SmoothTransformation);

          // Works on x86, so probably works on all little-endian systems.
          // Does it work on big-endian systems?
          glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X + index, 0, 4, image.width(), image.height(), 0,
              GL_BGRA, GL_UNSIGNED_BYTE, image.bits());

          if (++index == 6)
              break;
      }

      // Clear remaining faces.
      while (index < 6) {
          glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X + index, 0, 4, size, size, 0,
              GL_BGRA, GL_UNSIGNED_BYTE, 0);
          ++index;
      }

      glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
      glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
      glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_R, GL_CLAMP_TO_EDGE);
      glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
      glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
      //glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
      //glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_GENERATE_MIPMAP, GL_TRUE);
      glBindTexture(GL_TEXTURE_CUBE_MAP, 0);
  }

  void GLTextureCube::load(int size, int face, QRgb *data)
  {
      glBindTexture(GL_TEXTURE_CUBE_MAP, m_texture);
          glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X + face, 0, 4, size, size, 0,
              GL_BGRA, GL_UNSIGNED_BYTE, data);
      glBindTexture(GL_TEXTURE_CUBE_MAP, 0);
  }

  void GLTextureCube::bind()
  {
      glBindTexture(GL_TEXTURE_CUBE_MAP, m_texture);
      glEnable(GL_TEXTURE_CUBE_MAP);
  }

  void GLTextureCube::unbind()
  {
      glBindTexture(GL_TEXTURE_CUBE_MAP, 0);
      glDisable(GL_TEXTURE_CUBE_MAP);
  }

  //============================================================================//
  //                            GLFrameBufferObject                             //
  //============================================================================//

  GLFrameBufferObject::GLFrameBufferObject(int width, int height)
      : m_fbo(0)
      , m_depthBuffer(0)
      , m_width(width)
      , m_height(height)
      , m_failed(false)
  {
      GLBUFFERS_ASSERT_OPENGL("GLFrameBufferObject::GLFrameBufferObject",
          glGenFramebuffersEXT && glGenRenderbuffersEXT && glBindRenderbufferEXT && glRenderbufferStorageEXT, return)

      // TODO: share depth buffers of same size
      glGenFramebuffersEXT(1, &m_fbo);
      //glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, m_fbo);
      glGenRenderbuffersEXT(1, &m_depthBuffer);
      glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, m_depthBuffer);
      glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_DEPTH_COMPONENT, m_width, m_height);
      //glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT, GL_RENDERBUFFER_EXT, m_depthBuffer);
      //glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
  }

  GLFrameBufferObject::~GLFrameBufferObject()
  {
      GLBUFFERS_ASSERT_OPENGL("GLFrameBufferObject::~GLFrameBufferObject",
          glDeleteFramebuffersEXT && glDeleteRenderbuffersEXT, return)

      glDeleteFramebuffersEXT(1, &m_fbo);
      glDeleteRenderbuffersEXT(1, &m_depthBuffer);
  }

  void GLFrameBufferObject::setAsRenderTarget(bool state)
  {
      GLBUFFERS_ASSERT_OPENGL("GLFrameBufferObject::setAsRenderTarget", glBindFramebufferEXT, return)

      if (state) {
          glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, m_fbo);
          glPushAttrib(GL_VIEWPORT_BIT);
          glViewport(0, 0, m_width, m_height);
      } else {
          glPopAttrib();
          glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
      }
  }

  bool GLFrameBufferObject::isComplete()
  {
      GLBUFFERS_ASSERT_OPENGL("GLFrameBufferObject::isComplete", glCheckFramebufferStatusEXT, return false)

      return GL_FRAMEBUFFER_COMPLETE_EXT == glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT);
  }

  //============================================================================//
  //                             GLRenderTargetCube                             //
  //============================================================================//

  GLRenderTargetCube::GLRenderTargetCube(int size)
      : GLTextureCube(size)
      , m_fbo(size, size)
  {
  }

  void GLRenderTargetCube::begin(int face)
  {
      GLBUFFERS_ASSERT_OPENGL("GLRenderTargetCube::begin",
          glFramebufferTexture2DEXT && glFramebufferRenderbufferEXT, return)

      m_fbo.setAsRenderTarget(true);
      glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT,
          GL_TEXTURE_CUBE_MAP_POSITIVE_X + face, m_texture, 0);
      glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT, GL_RENDERBUFFER_EXT, m_fbo.m_depthBuffer);
  }

  void GLRenderTargetCube::end()
  {
      m_fbo.setAsRenderTarget(false);
  }

  void GLRenderTargetCube::getViewMatrix(QMatrix4x4& mat, int face)
  {
      if (face < 0 || face >= 6) {
          qWarning("GLRenderTargetCube::getViewMatrix: 'face' must be in the range [0, 6). (face == %d)", face);
          return;
      }

      static int perm[6][3] = {
          {2, 1, 0},
          {2, 1, 0},
          {0, 2, 1},
          {0, 2, 1},
          {0, 1, 2},
          {0, 1, 2},
      };

      static float signs[6][3] = {
          {-1.0f, -1.0f, -1.0f},
          {+1.0f, -1.0f, +1.0f},
          {+1.0f, +1.0f, -1.0f},
          {+1.0f, -1.0f, +1.0f},
          {+1.0f, -1.0f, -1.0f},
          {-1.0f, -1.0f, +1.0f},
      };

      mat.fill(0.0f);
      for (int i = 0; i < 3; ++i)
          mat(i, perm[face][i]) = signs[face][i];
      mat(3, 3) = 1.0f;
  }

  void GLRenderTargetCube::getProjectionMatrix(QMatrix4x4& mat, float nearZ, float farZ)
  {
      static const QMatrix4x4 reference(
              1.0f, 0.0f, 0.0f, 0.0f,
              0.0f, 1.0f, 0.0f, 0.0f,
              0.0f, 0.0f, 0.0f, 0.0f,
              0.0f, 0.0f, -1.0f, 0.0f);

      mat = reference;
      mat(2, 2) = (nearZ+farZ)/(nearZ-farZ);
      mat(2, 3) = 2.0f*nearZ*farZ/(nearZ-farZ);
  }