Test007
Last update: 16.07.2025
/// <script src="./ansys251/nexus/viewer-loader.js"></script>
///
Instancing.
This example demonstrates a couple of different ways to do instancing. They both involve the re-using of Mesh object.
- Create a node and add it to a parent node, then add the parent node to its parent, ...
- Create a node and add it to a parent node, then create another node and add it to the same parent node, ...
The visibility selector in the first case will be multiple levels deep, and only a single level deep in the second case.
In either case the matrix associated with each node must be different so that the nodes do not draw in the same location as an other node.
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#include <vector>
#include <sstream>
#include "GLTFWriter.h"
#include "test.h"
using namespace ANSYS::AVZ;
// Replicated nodes
TESTFUNC(Instancing)
{
if (!gltf)
throw std::runtime_error("Can't create GLTF");
// SCENE
GLTFWriter::Scene *scene = GLTFWriter::Scene::Create(gltf, "TestScene", "m", 1.0, GLTFWriter::Scene::BT_SOLID, 0.5, 0.5, 0.5);
if (!scene) {
GLTFWriter::GLTF::Destroy(gltf);
throw std::runtime_error("Can't create scene");
}
// LIGHTS
{
// LIGHT NODE
GLTFWriter::Node *lightNode = GLTFWriter::Node::CreateLight(gltf);
GLTFWriter::GLTF::Destroy(gltf);
throw std::runtime_error("Can't create light");
}
// LIGHTS
GLTFWriter::Light *light1 = GLTFWriter::Light::CreateAmbient(gltf);
lightNode->AppendLight(light1);
GLTFWriter::Light *light2 = GLTFWriter::Light::CreateDirectional(gltf, 1, 1, 1, 0, 0, -1);
lightNode->AppendLight(light2);
}
// CAMERA
{
// CAMERA
GLTFWriter::Camera *camera = GLTFWriter::Camera::CreatePerspective(gltf);
// CAMERA NODE
std::vector<double> mat(16);
mat[0] = 3;
mat[1] = 0;
mat[2] = 0;
mat[3] = 0;
mat[4] = 0;
mat[5] = 3;
mat[6] = 0;
mat[7] = 0;
mat[8] = 0;
mat[9] = 0;
mat[10] = 3;
mat[11] = 0;
mat[12] = 0;
mat[13] = 0;
mat[14] = 0;
mat[15] = 1;
GLTFWriter::Node *cameraNode = GLTFWriter::Node::CreateCamera(gltf, camera, "TestCamera", &mat[0]);
scene->SetCamera(cameraNode);
}
// CENTER
{
// NODE
GLTFWriter::Node *node = GLTFWriter::Node::CreateMesh(gltf, "Center");
GLTFWriter::GLTF::Destroy(gltf);
throw std::runtime_error("Can't create mesh node");
}
// MESH
GLTFWriter::Mesh *mesh = GLTFWriter::Mesh::Create(gltf);
GLTFWriter::GLTF::Destroy(gltf);
throw std::runtime_error("Can't create mesh");
}
// PRIMITIVE
std::pair<GLTFWriter::Primitive *, GLTFWriter::Material *> pm = GLTFWriter::Test::CreateSolidColoredSpherePrimitive(gltf, 0, 0, 0, 0.05F, 16, 1, 1, 1, 1);
mesh->AppendPrimitive(pm.first);
}
const unsigned int numInstances = 6;
// ONE WAY TO DO INSTANCING
{
// MESH
GLTFWriter::Mesh *mesh = GLTFWriter::Mesh::Create(gltf);
{
// PRIMITIVE
std::pair<GLTFWriter::Primitive *, GLTFWriter::Material *> pm = GLTFWriter::Test::CreateColoredSpherePrimitive(gltf, 1, 0, 0, 0.5, 6);
if (!pm.first || !pm.second || !mesh->AppendPrimitive(pm.first)) {
GLTFWriter::GLTF::Destroy(gltf);
throw std::runtime_error("Can't CreateColoredSpherePrimitive");
}
// this is a solid object, that we want to have an interior color so when it is clipped we see the solid interior color
pm.second->AppendValue(GLTFWriter::Value::Create(gltf, "solidColor", 0.4, 0.2, 0.4, 1.0));
}
GLTFWriter::Node *lastNode = 0;
for (unsigned int i = numInstances; i > 0; --i) {
GLTFWriter::Test::Matrix4 mat; // identity
GLTFWriter::Test::Matrix4 rot;
if (i > 1) {
rot.LoadRotation(GLTFWriter::Test::Vector3(0, 0, 0), GLTFWriter::Test::Vector3(0, 0, 1), DegreesToRadians(360.0 / numInstances));
mat *= rot;
}
std::ostringstream oss;
oss << "Node " << i << " + ";
const std::string name = oss.str();
GLTFWriter::Node *node = GLTFWriter::Node::CreateMesh(gltf, name.c_str(), true, &(mat.Get())[0]);
if (!node || !node->AppendMesh(mesh)) {
GLTFWriter::GLTF::Destroy(gltf);
throw std::runtime_error("Can't create mesh node");
}
if (i != numInstances)
node->AppendChild(lastNode);
lastNode = node;
}
// NODE
GLTFWriter::Node *node = GLTFWriter::Node::CreateMesh(gltf, "INSTANCING 1");
if (!node || !scene->AppendMesh(node)) {
GLTFWriter::GLTF::Destroy(gltf);
throw std::runtime_error("Can't create mesh node");
}
node->AppendChild(lastNode);
}
// ANOTHER WAY TO DO INSTANCING
{
// NODE
GLTFWriter::Node *node = GLTFWriter::Node::CreateMesh(gltf, "INSTANCING 2");
if (!node || !scene->AppendMesh(node)) {
GLTFWriter::GLTF::Destroy(gltf);
throw std::runtime_error("Can't create mesh node");
}
GLTFWriter::Mesh *mesh = GLTFWriter::Mesh::Create(gltf);
if (!mesh) {
GLTFWriter::GLTF::Destroy(gltf);
throw std::runtime_error("Can't create mesh");
}
{
// PRIMITIVE
std::pair<GLTFWriter::Primitive *, GLTFWriter::Material *> pm = GLTFWriter::Test::CreateColoredSpherePrimitive(gltf, 2, 0, 0, 0.5, 6);
if (!pm.first || !pm.second || !mesh->AppendPrimitive(pm.first)) {
GLTFWriter::GLTF::Destroy(gltf);
throw std::runtime_error("Can't CreateColoredSpherePrimitive");
}
// this is a solid object, that we want to have an interior color so when it is clipped we see the solid interior color
pm.second->AppendValue(GLTFWriter::Value::Create(gltf, "solidColor", 0.5, 0.5, 0.5, 1.0));
}
GLTFWriter::Test::Matrix4 mat; // identity
GLTFWriter::Test::Matrix4 rot;
rot.LoadRotation(GLTFWriter::Test::Vector3(0, 0, 0), GLTFWriter::Test::Vector3(0, 0, 1), DegreesToRadians(360.0 / numInstances));
for (unsigned int i = 0; i < numInstances; ++i) {
if (i > 0)
mat *= rot;
std::ostringstream oss;
oss << "Node " << i + 1;
const std::string name = oss.str();
GLTFWriter::Node *lastNode = GLTFWriter::Node::CreateMesh(gltf, name.c_str(), true, &(mat.Get())[0]);
GLTFWriter::GLTF::Destroy(gltf);
throw std::runtime_error("Can't create mesh");
}
}
}
GLTFWriter::GLTF::Destroy(gltf);
throw std::runtime_error("Error creating file");
}
GLTFWriter::GLTF::Destroy(gltf);
if (error != GLTFWriter::GLTF::GLTF_ERROR_NONE)
throw std::runtime_error("Error creating file");
}
Cameras define an orthographic or perspective projection of the scene.
Definition GLTFCamera.h:28
virtual bool Write(bool formatJSON=false)=0
virtual GLTFError GetError()=0
Lights define the light objects that can be added to a light node.
Definition GLTFLight.h:31
Meshes define the renderable objects that can be added to a node.
Definition GLTFMesh.h:104
virtual bool AppendPrimitive(Primitive *primitive)=0
Nodes are the GLTFWriter class that contain the data that is defined in the GLTF file.
Definition GLTFNode.h:31
virtual bool AppendLight(Light *light)=0
virtual bool AppendMesh(Mesh *mesh)=0
virtual bool AppendChild(Node *node)=0
Scenes are the GLTFWriter class that create the view of the data that is defined in the GLTF file.
Definition GLTFScene.h:29
virtual bool AppendMesh(Node *mesh)=0
virtual bool SetLight(Node *light)=0
virtual bool SetCamera(Node *camera)=0
