tutorial_nel_3 - ryzom/ryzomcore GitHub Wiki

title: Tutorial NeL Part 3 description: published: true date: 2023-03-18T02:05:43.089Z tags: editor: markdown dateCreated: 2023-03-18T02:04:46.908Z

Rendering Basic 3D Shapes in NeL

Introduction

In this tutorial, we will cover how to render basic 3D shapes in a NeL project. This will involve loading and creating 3D shapes using NeL's UShape and UInstance classes, setting up the camera and projection matrix, and rendering the shapes in the main rendering loop.

Prerequisites

Before starting this tutorial, make sure you have completed the following steps:

  1. Set up a NeL game project as described in the Creating a Blank NeL Game Project section.
  2. Initialize the NeL driver as described in the Initializing the NeL Driver section.

Step-by-step Instructions

  1. Include necessary headers: Add the following headers to your source code to handle 3D shapes in NeL:
#include <nel/3d/u_shape_bank.h>
#include <nel/3d/u_instance.h>
#include <nel/3d/u_camera.h>
  1. Create a cube shape: Define a function to create a cube shape using the UShape class. This function will be called later in the main function:
NL3D::UShape createCube(NL3D::UDriver *driver)
{
    // Add the code to create a cube shape
}
  1. Create a scene: In the main function

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  • Before starting this tutorial, make sure you have completed the following steps:
  1. Set up a NeL game project as described in the Creating a Blank NeL Game Project section.
  2. Initialize the NeL driver as described in the Initializing the NeL Driver section.

Step-by-step Instructions

  1. Include necessary headers: Add the following headers to your source code to handle 3D shapes in NeL:
#include <nel/3d/u_shape_bank.h>
#include <nel/3d/u_instance.h>
#include <nel/3d/u_camera.h>
  1. Create a cube shape: Define a function to create a cube shape using the UShape class. This function will be called later in the main function:
NL3D::UShape createCube(NL3D::UDriver *driver)
{
    // Add the code to create a cube shape
}
  1. Create a scene: In the main function, create a scene using the createScene method of the UDriver class:
NL3D::UScene *scene = driver->createScene(true);
  1. Check for scene creation errors: If the scene cannot be created, display an error message and exit the application:
if (!scene)
{
    nlerror("Failed to create scene.");
    delete driver;
    return 1;
}
  1. Create a cube instance: In the main function, call the createCube function you defined earlier to create a cube shape. Then, create a cube instance using the createInstance method of the UScene class:
NL3D::UShape cubeShape = createCube(driver);
NL3D::UInstance cubeInstance = scene->createInstance(cubeShape);
  1. Check for instance creation errors: If the cube instance cannot be created, display an error message and exit the application:
if (!cubeInstance.isValid())
{
    nlerror("Failed to create cube instance.");
    delete driver;
    return 1;
}
  1. Set up the camera: Set up the camera's perspective and position by calling the setPerspective and setMatrix methods of the UCamera class:
NL3D::UCamera camera = scene->getCam();
camera.setTransformMode(NL3D::UTransformable::DirectMatrix);
camera.setPerspective(fovInDegrees, aspectRatio, nearPlane, farPlane);
camera.setMatrix(matrixToPlaceCamera);
  1. Main rendering loop: In your main rendering loop, clear the screen, update the scene, render the scene, and swap the buffers:
// Clear the screen
driver->clearBuffers();

// Update the scene
scene->animate(TAnimationTime(CTime::ticksToSecond(CTime::getPerformanceTime())));

// Render the scene
scene->render();

// Swap buffers
driver->swapBuffers();

Congratulations! You have successfully rendered a basic 3D shape in your NeL project.

Rendering Basic 3D Shapes in NeL

In this tutorial, we will cover how to render basic 3D shapes in a NeL project. This will involve loading and creating 3D shapes using NeL's UShape and UInstance classes, setting up the camera and projection matrix, and rendering the shapes in the main rendering loop.

Prerequisites

Before starting this tutorial, make sure you have completed the following steps:

  1. Set up a NeL game project as described in the Creating a Blank NeL Game Project section.
  2. Initialize the NeL driver as described in the Initializing the NeL Driver section.

Source Code

Here's the complete source code for rendering basic 3D shapes in a NeL project:

#include <nel/misc/app_context.h>
#include <nel/misc/debug.h>
#include <nel/misc/path.h>
#include <nel/misc/file.h>
#include <nel/misc/config_file.h>
#include <nel/3d/u_driver.h>
#include <nel/3d/u_text_context.h>
#include <nel/3d/u_shape_bank.h>
#include <nel/3d/u_instance.h>
#include <nel/3d/u_camera.h>
#include <nel/3d/u_scene.h>

using namespace std;
using namespace NLMISC;
using namespace NL3D;

// Function to create a cube shape
UShape createCube(UDriver *driver)
{
    // [Add the code to create a cube shape]
}

int main(int argc, char *argv[])
{
    // Create the application context
    CApplicationContext applicationContext;

    // Initialize the driver
    UDriver *driver = nullptr;

    try
    {
        driver = UDriver::createDriver(0, nullptr, true);
        if (!driver)
        {
            nlerror("Unable to create a NeL driver.");
            return 1;
        }

        // Set up the display mode
        UDriver::CMode mode;
        mode.Width = 800;
        mode.Height = 600;
        mode.Depth = 32;

        // Initialize the window
        driver->setDisplay(mode, 32, false, "NeL 3D Shapes");
    }
    catch (const Exception &e)
    {
        nlerror("NeL driver initialization error: %s", e.what());
        return 1;
    }

    // Create a scene
    UScene *scene = driver->createScene(true);
    if (!scene)
    {
        nlerror("Failed to create scene.");
        delete driver;
        return 1;
    }

    // Create a cube shape
    UShape cubeShape = createCube(driver);

    // Create a cube instance
    UInstance cubeInstance = scene->createInstance(cubeShape);
    if (!cubeInstance.isValid())
    {
        nlerror("Failed to create cube instance.");
        delete driver;
        return 1;
    }

    // Set up the camera
    UCamera camera = scene->getCam();
    camera.setTransformMode(UTransformable::DirectMatrix);
    camera.setPerspective(fovInDegrees, aspectRatio, nearPlane, farPlane);
    camera.setMatrix(matrixToPlaceCamera);

    // Main rendering loop
    while (!driver->AsyncDownloader->isTerminated() && !driver->AsyncTextureUploader->isTerminated() && !driver->Exit)
    {
        // Clear the screen
        driver->clearBuffers();

        // Update the scene
        scene->animate(TAnimationTime(CTime::ticksToSecond(CTime::getPerformanceTime())));

        // Render the scene
        scene->render();

        // Swap buffers
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