OpenGl在3D中绘制鼠标选择框2D

以下代码实现：当空格键按下时，点击鼠标进行框选，屏幕中出现选择框。

//绘制3D选框
void xxxRender3D::DrawSelectionRectangle3D(){
	if (m_bSpaceKeyDown){
		if (m_bLBDown && m_bMouseMove){
			glm::vec3 firPoint = m_RectSelPt1;//鼠标的第一个点
			glm::vec3 secPoint = m_RectSelPt2;//鼠标的第二个点
			if (abs(firPoint.x - secPoint.x) > 1e-3)
			{
				glDisable(GL_LIGHTING);

				//绘制选择框
				glColor3f(1, 0, 0);

				//glm::vec3 viewdir = m_pDataManager->m_pCamera3D->GetDirection();
				//glm::vec3 offset = glm::vec3(1000 * viewdir.x, 1000 * viewdir.y, 1000 * viewdir.z);

				glm::vec3 upLeftPt, upRightPt, downLeftPt, downRightPt;

				/*upLeftPt = m_pDataManager->m_pCamera3D->ScreenToWorld(glm::vec3(firPoint.x, firPoint.y,0.0)) + offset;
				upRightPt = m_pDataManager->m_pCamera3D->ScreenToWorld(glm::vec3(secPoint.x, firPoint.y,0.0)) + offset;
				downRightPt = m_pDataManager->m_pCamera3D->ScreenToWorld(glm::vec3(secPoint.x, secPoint.y,0.0)) + offset;
				downLeftPt = m_pDataManager->m_pCamera3D->ScreenToWorld(glm::vec3(firPoint.x, secPoint.y, 0.0)) + offset;*/
				upLeftPt = m_pDataManager->m_pCamera3D->ScreenToWorld(glm::vec3(firPoint.x, firPoint.y, 0.0));
				upRightPt = m_pDataManager->m_pCamera3D->ScreenToWorld(glm::vec3(secPoint.x, firPoint.y, 0.0));
				downRightPt = m_pDataManager->m_pCamera3D->ScreenToWorld(glm::vec3(secPoint.x, secPoint.y, 0.0));
				downLeftPt = m_pDataManager->m_pCamera3D->ScreenToWorld(glm::vec3(firPoint.x, secPoint.y, 0.0));


				GLDrawLine(upLeftPt, upRightPt);
				GLDrawLine(upRightPt, downRightPt);
				GLDrawLine(downRightPt, downLeftPt);
				GLDrawLine(downLeftPt, upLeftPt);
				glEnable(GL_LIGHTING);
			}
		}
	}
}