glbuffers.cpp Example File | Qt Widgets 5.6

Qt 5.6 | Qt Widgets | Boxes | glbuffers.cpp Example File

Qt 5.6.2 Reference Documentation

# glbuffers.cpp Example File

graphicsview/boxes/glbuffers.cpp

      /****************************************************************************
      **
      ** Copyright (C) 2015 The Qt Company Ltd.
      ** Contact: http://www.qt.io/licensing/
      **
      ** This file is part of the demonstration applications of the Qt Toolkit.
      **
      ** $QT_BEGIN_LICENSE:LGPL21$
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      ** Licensees holding valid commercial Qt licenses may use this file in
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      **
      ** GNU Lesser General Public License Usage
      ** Alternatively, this file may be used under the terms of the GNU Lesser
      ** General Public License version 2.1 or version 3 as published by the Free
      ** Software Foundation and appearing in the file LICENSE.LGPLv21 and
      ** LICENSE.LGPLv3 included in the packaging of this file. Please review the
      ** following information to ensure the GNU Lesser General Public License
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      ** $QT_END_LICENSE$
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      ****************************************************************************/

      #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);
      }