minor render thread refactor

rendering/framebufferobject.cpp

@@ -0,0 +1,81 @@
+#include "framebufferobject.h"
+
+#include <QOpenGLFunctions>
+
+FramebufferObject::FramebufferObject() :
+  buffer_(0),
+  texture_(0),
+  ctx_(nullptr)
+{}
+
+FramebufferObject::~FramebufferObject()
+{
+  Destroy();
+}
+
+bool FramebufferObject::IsCreated()
+{
+  return ctx_ != nullptr;
+}
+
+void FramebufferObject::Create(QOpenGLContext *ctx, int width, int height)
+{
+  // free any previous textures
+  Destroy();
+
+  // set context to new context provided
+  ctx_ = ctx;
+
+  // create framebuffer object
+  ctx->functions()->glGenFramebuffers(1, &buffer_);
+
+  // create texture
+  ctx->functions()->glGenTextures(1, &texture_);
+
+  // bind framebuffer for attaching
+  ctx->functions()->glBindFramebuffer(GL_DRAW_FRAMEBUFFER, buffer_);
+
+  // bind texture
+  ctx->functions()->glBindTexture(GL_TEXTURE_2D, texture_);
+
+  // allocate storage for texture
+  ctx->functions()->glTexImage2D(
+        GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr
+        );
+
+  // set texture filtering to bilinear
+  ctx->functions()->glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+  ctx->functions()->glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+
+  // attach texture to framebuffer
+  ctx->functions()->glFramebufferTexture2D(
+        GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, texture_, 0
+        );
+
+  // release texture
+  ctx->functions()->glBindTexture(GL_TEXTURE_2D, 0);
+
+  // release framebuffer
+  ctx->functions()->glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
+}
+
+void FramebufferObject::Destroy()
+{
+  if (ctx_ != nullptr) {
+    ctx_->functions()->glDeleteFramebuffers(1, &buffer_);
+
+    ctx_->functions()->glDeleteTextures(1, &texture_);
+  }
+
+  ctx_ = nullptr;
+}
+
+const GLuint &FramebufferObject::buffer()
+{
+  return buffer_;
+}
+
+const GLuint &FramebufferObject::texture()
+{
+  return texture_;
+}