glviewer.cpp

#include <iostream>
#include <algorithm>
#include "glviewer.h"
using namespace std;
using namespace MaxLib;

namespace GLViewer {

Viewer::Viewer() 
  : camera(Window::GetWidth(), Window::GetHeight(), glm::vec3(0.0f, 0.0f, 0.0f), 80.0f), buffers(this)
    
{ 
    // Setup events
    Event<Event_WindowResize>::RegisterPersistantHandler([&](Event_WindowResize& data) {
        camera.SetViewport(0, 0, data.Width, data.Height);
    });
    Event<Event_MouseScroll>::RegisterPersistantHandler([&](Event_MouseScroll& data) {
        if(!ActiveItem::IsViewportHovered(camera))
            return;
        camera.ProcessMouseScroll(data.OffsetY);
    });
    Event<Event_MouseMove>::RegisterPersistantHandler([&](Event_MouseMove& data) {
        // we can just use the data already sent to mouse
        (void)data;
        // ignore if a window is hovered over
        if(ImGui::GetIO().WantCaptureMouse)
            return;
        
        // rotate on mouse click
        if(Mouse::IsLeftClicked() && ActiveItem::IsViewport(camera)) {
            camera.ChangeDirection(Mouse::GetPositionDif());
        } 
        // pan on mouse middle click
        else if(Mouse::IsMiddleClicked() && ActiveItem::IsViewport(camera)) { 
            camera.Move(camera.GetWorldVector(Mouse::GetPositionDif()));		
        } 
    });

	// blending (allows translucence)
	GLCall(glEnable(GL_BLEND));
	// what to do with source (overlapping item) / what to do with destination (item we are overlapping)
	GLCall(glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA));
	// dont draw triangles facing the wrong way 
	glEnable(GL_CULL_FACE);  
	// dont draw vertices outside of our visible depth
	glEnable(GL_DEPTH_TEST);
}
 
void Viewer::Render()
{    
    m_Proj = camera.GetProjectionMatrix();
    m_View = camera.GetViewMatrix();
    // Clear old render data
    Renderer::Clear();
    // Render each of the buffers 
    buffers.RenderBuffers(m_Proj, m_View);
}


void Viewer::RenderLoop(GLSystem& glsys, std::function<void()> cb_Configure, std::function<void()> cb_Draw_ImGui, std::function<void()> cb_Set_DynamicBuffers, std::function<void()> cb_Finalise)
{
    // Loop until the user closes the window
    while (!glfwWindowShouldClose(glsys.GetWindow()))
    {    
        // Poll for and process glfw events 
        GLCall(glfwPollEvents());
        
        // Configure using custon callback
        cb_Configure();
       
        // Draw ImGui
        glsys.imgui_NewFrame();
        cb_Draw_ImGui();

        // Render viewer buffers
        cb_Set_DynamicBuffers();
        Render(); 
        
        // Render ImGui
        glsys.imgui_Render();
        
        // Final functions using custon callback
        if(cb_Finalise) { cb_Finalise(); }
        
        // Swap front and back buffers 
        GLCall(glfwSwapBuffers(glsys.GetWindow()));
    }
}
    
    
} // End namespace GLViewer