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Example of how to build a gltf file from scratch with tiny_gltf.h
// An example of how to generate a gltf file from scratch. This example
// was translated from the pygltlib documentation in the pypi project page,
// which in turn is based on the Khronos Sample Models at:
//
// https://github.com/KhronosGroup/glTF-Sample-Models
//
// This example is released under the MIT license.
//
// 2021-02-25 Thu
// Dov Grobgeld <dov.grobgeld@gmail.com>
// Define these only in *one* .cc file.
#define TINYGLTF_IMPLEMENTATION
#define STB_IMAGE_IMPLEMENTATION
#define STB_IMAGE_WRITE_IMPLEMENTATION
// #define TINYGLTF_NOEXCEPTION // optional. disable exception handling.
#include "tiny_gltf.h"
int main(int argc, char **argv)
{
// Create a model with a single mesh and save it as a gltf file
tinygltf::Model m;
tinygltf::Scene scene;
tinygltf::Mesh mesh;
tinygltf::Primitive primitive;
tinygltf::Node node;
tinygltf::Buffer buffer;
tinygltf::BufferView bufferView1;
tinygltf::BufferView bufferView2;
tinygltf::Accessor accessor1;
tinygltf::Accessor accessor2;
tinygltf::Asset asset;
// This is the raw data buffer.
buffer.data = {
// 6 bytes of indices and two bytes of padding
0x00,0x00,0x01,0x00,0x02,0x00,0x00,0x00,
// 36 bytes of floating point numbers
0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
0x00,0x00,0x00,0x00,0x00,0x00,0x80,0x3f,
0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
0x00,0x00,0x00,0x00,0x00,0x00,0x80,0x3f,
0x00,0x00,0x00,0x00};
// "The indices of the vertices (ELEMENT_ARRAY_BUFFER) take up 6 bytes in the
// start of the buffer.
bufferView1.buffer = 0;
bufferView1.byteOffset=0;
bufferView1.byteLength=6;
bufferView1.target = TINYGLTF_TARGET_ELEMENT_ARRAY_BUFFER;
// The vertices take up 36 bytes (3 vertices * 3 floating points * 4 bytes)
// at position 8 in the buffer and are of type ARRAY_BUFFER
bufferView2.buffer = 0;
bufferView2.byteOffset=8;
bufferView2.byteLength=36;
bufferView2.target = TINYGLTF_TARGET_ARRAY_BUFFER;
// Describe the layout of bufferView1, the indices of the vertices
accessor1.bufferView = 0;
accessor1.byteOffset = 0;
accessor1.componentType = TINYGLTF_COMPONENT_TYPE_UNSIGNED_SHORT;
accessor1.count = 3;
accessor1.type = TINYGLTF_TYPE_SCALAR;
accessor1.maxValues.push_back(2);
accessor1.minValues.push_back(0);
// Describe the layout of bufferView2, the vertices themself
accessor2.bufferView = 1;
accessor2.byteOffset = 0;
accessor2.componentType = TINYGLTF_COMPONENT_TYPE_FLOAT;
accessor2.count = 3;
accessor2.type = TINYGLTF_TYPE_VEC3;
accessor2.maxValues = {1.0, 1.0, 0.0};
accessor2.minValues = {0.0, 0.0, 0.0};
// Build the mesh primitive and add it to the mesh
primitive.indices = 0; // The index of the accessor for the vertex indices
primitive.attributes["POSITION"] = 1; // The index of the accessor for positions
primitive.material = 0;
primitive.mode = TINYGLTF_MODE_TRIANGLES;
mesh.primitives.push_back(primitive);
// Other tie ups
node.mesh = 0;
scene.nodes.push_back(0); // Default scene
// Define the asset. The version is required
asset.version = "2.0";
asset.generator = "tinygltf";
// Now all that remains is to tie back all the loose objects into the
// our single model.
m.scenes.push_back(scene);
m.meshes.push_back(mesh);
m.nodes.push_back(node);
m.buffers.push_back(buffer);
m.bufferViews.push_back(bufferView1);
m.bufferViews.push_back(bufferView2);
m.accessors.push_back(accessor1);
m.accessors.push_back(accessor2);
m.asset = asset;
// Create a simple material
tinygltf::Material mat;
mat.pbrMetallicRoughness.baseColorFactor = {1.0f, 0.9f, 0.9f, 1.0f};
mat.doubleSided = true;
m.materials.push_back(mat);
// Save it to a file
tinygltf::TinyGLTF gltf;
gltf.WriteGltfSceneToFile(&m, "triangle.gltf",
true, // embedImages
true, // embedBuffers
true, // pretty print
false); // write binary
exit(0);
}
project('gltf-examples','cpp')
exe = executable('create_triangle_gltf',
['create_triangle_gltf.cpp'])
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