remember and restore previoulsy bound texture state in Texture::getImageData

src/ACGL/OpenGL/Objects/Texture.cc

@@ -79,6 +79,17 @@ SharedTextureData Texture::getImageData(GLint _lod, GLenum _type) const
 {
     if(_type == GL_INVALID_ENUM) _type = mType;
 
+    // remember the previously bound texture
+    GLint prevTexture;
+    if     (mTarget == GL_TEXTURE_1D)                   glGetIntegerv(GL_TEXTURE_BINDING_1D,                   &prevTexture);
+    else if(mTarget == GL_TEXTURE_2D)                   glGetIntegerv(GL_TEXTURE_BINDING_2D,                   &prevTexture);
+    else if(mTarget == GL_TEXTURE_3D)                   glGetIntegerv(GL_TEXTURE_BINDING_3D,                   &prevTexture);
+    else if(mTarget == GL_TEXTURE_1D_ARRAY)             glGetIntegerv(GL_TEXTURE_BINDING_1D_ARRAY,             &prevTexture);
+    else if(mTarget == GL_TEXTURE_2D_ARRAY)             glGetIntegerv(GL_TEXTURE_BINDING_2D_ARRAY,             &prevTexture);
+    else if(mTarget == GL_TEXTURE_RECTANGLE)            glGetIntegerv(GL_TEXTURE_BINDING_RECTANGLE,            &prevTexture);
+    else if(mTarget == GL_TEXTURE_2D_MULTISAMPLE)       glGetIntegerv(GL_TEXTURE_BINDING_2D_MULTISAMPLE,       &prevTexture);
+    else if(mTarget == GL_TEXTURE_2D_MULTISAMPLE_ARRAY) glGetIntegerv(GL_TEXTURE_BINDING_2D_MULTISAMPLE_ARRAY, &prevTexture);
+
     // determine the required buffer size to hold the requested LOD level
     bind();
     GLint width, height, depth;
@@ -93,6 +104,9 @@ SharedTextureData Texture::getImageData(GLint _lod, GLenum _type) const
     GLubyte* imageData = new GLubyte[width * height * getGLTypeSize(_type) * channels];
     glGetTexImage(mTarget, _lod, GL_RGB, _type, (GLvoid*)imageData);
 
+    // revert to the previously bound texture
+    glBindTexture(mTarget, prevTexture);
+
     // store the image data and meta information in a TextureData object
     SharedTextureData dataObject = SharedTextureData(new TextureData());
     dataObject->setWidth(width);