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1 files changed, 1173 insertions, 0 deletions

diff --git a/contrib/cgltf/cgltf_write.h b/contrib/cgltf/cgltf_write.h
new file mode 100644
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+++ b/contrib/cgltf/cgltf_write.h
@@ -0,0 +1,1173 @@
+/**
+ * cgltf_write - a single-file glTF 2.0 writer written in C99.
+ *
+ * Version: 1.7
+ *
+ * Website: https://github.com/jkuhlmann/cgltf
+ *
+ * Distributed under the MIT License, see notice at the end of this file.
+ *
+ * Building:
+ * Include this file where you need the struct and function
+ * declarations. Have exactly one source file where you define
+ * `CGLTF_WRITE_IMPLEMENTATION` before including this file to get the
+ * function definitions.
+ *
+ * Reference:
+ * `cgltf_result cgltf_write_file(const cgltf_options* options, const char*
+ * path, const cgltf_data* data)` writes JSON to the given file path. Buffer
+ * files and external images are not written out. `data` is not deallocated.
+ *
+ * `cgltf_size cgltf_write(const cgltf_options* options, char* buffer,
+ * cgltf_size size, const cgltf_data* data)` writes JSON into the given memory
+ * buffer. Returns the number of bytes written to `buffer`, including a null
+ * terminator. If buffer is null, returns the number of bytes that would have
+ * been written. `data` is not deallocated.
+ *
+ * To write custom JSON into the `extras` field, aggregate all the custom JSON
+ * into a single buffer, then set `file_data` to this buffer. By supplying
+ * start_offset and end_offset values for various objects, you can select a
+ * range of characters within the aggregated buffer.
+ */
+#ifndef CGLTF_WRITE_H_INCLUDED__
+#define CGLTF_WRITE_H_INCLUDED__
+
+#include "cgltf.h"
+
+#include <stddef.h>
+#include <stdbool.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+cgltf_result cgltf_write_file(const cgltf_options* options, const char* path, const cgltf_data* data);
+cgltf_size cgltf_write(const cgltf_options* options, char* buffer, cgltf_size size, const cgltf_data* data);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* #ifndef CGLTF_WRITE_H_INCLUDED__ */
+
+/*
+ *
+ * Stop now, if you are only interested in the API.
+ * Below, you find the implementation.
+ *
+ */
+
+#if defined(__INTELLISENSE__) || defined(__JETBRAINS_IDE__)
+/* This makes MSVC/CLion intellisense work. */
+#define CGLTF_IMPLEMENTATION
+#endif
+
+#ifdef CGLTF_WRITE_IMPLEMENTATION
+
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define CGLTF_EXTENSION_FLAG_TEXTURE_TRANSFORM      (1 << 0)
+#define CGLTF_EXTENSION_FLAG_MATERIALS_UNLIT        (1 << 1)
+#define CGLTF_EXTENSION_FLAG_SPECULAR_GLOSSINESS    (1 << 2)
+#define CGLTF_EXTENSION_FLAG_LIGHTS_PUNCTUAL        (1 << 3)
+#define CGLTF_EXTENSION_FLAG_DRACO_MESH_COMPRESSION (1 << 4)
+#define CGLTF_EXTENSION_FLAG_MATERIALS_CLEARCOAT    (1 << 5)
+#define CGLTF_EXTENSION_FLAG_MATERIALS_IOR          (1 << 6)
+#define CGLTF_EXTENSION_FLAG_MATERIALS_SPECULAR     (1 << 7)
+#define CGLTF_EXTENSION_FLAG_MATERIALS_TRANSMISSION (1 << 8)
+
+typedef struct {
+        char* buffer;
+        cgltf_size buffer_size;
+        cgltf_size remaining;
+        char* cursor;
+        cgltf_size tmp;
+        cgltf_size chars_written;
+        const cgltf_data* data;
+        int depth;
+        const char* indent;
+        int needs_comma;
+        uint32_t extension_flags;
+        uint32_t required_extension_flags;
+} cgltf_write_context;
+
+#define CGLTF_MIN(a, b) (a < b ? a : b)
+
+#define CGLTF_SPRINTF(...) { \
+                context->tmp = snprintf ( context->cursor, context->remaining, __VA_ARGS__ ); \
+                context->chars_written += context->tmp; \
+                if (context->cursor) { \
+                        context->cursor += context->tmp; \
+                        context->remaining -= context->tmp; \
+                } }
+
+#define CGLTF_SNPRINTF(length, ...) { \
+                context->tmp = snprintf ( context->cursor, CGLTF_MIN(length + 1, context->remaining), __VA_ARGS__ ); \
+                context->chars_written += length; \
+                if (context->cursor) { \
+                        context->cursor += length; \
+                        context->remaining -= length; \
+                } }
+
+#define CGLTF_WRITE_IDXPROP(label, val, start) if (val) { \
+                cgltf_write_indent(context); \
+                CGLTF_SPRINTF("\"%s\": %d", label, (int) (val - start)); \
+                context->needs_comma = 1; }
+
+#define CGLTF_WRITE_IDXARRPROP(label, dim, vals, start) if (vals) { \
+                cgltf_write_indent(context); \
+                CGLTF_SPRINTF("\"%s\": [", label); \
+                for (int i = 0; i < (int)(dim); ++i) { \
+                        int idx = (int) (vals[i] - start); \
+                        if (i != 0) CGLTF_SPRINTF(","); \
+                        CGLTF_SPRINTF(" %d", idx); \
+                } \
+                CGLTF_SPRINTF(" ]"); \
+                context->needs_comma = 1; }
+
+#define CGLTF_WRITE_TEXTURE_INFO(label, info) if (info.texture) { \
+                cgltf_write_line(context, "\"" label "\": {"); \
+                CGLTF_WRITE_IDXPROP("index", info.texture, context->data->textures); \
+                cgltf_write_intprop(context, "texCoord", info.texcoord, 0); \
+                cgltf_write_floatprop(context, "scale", info.scale, 1.0f); \
+                if (info.has_transform) { \
+                        context->extension_flags |= CGLTF_EXTENSION_FLAG_TEXTURE_TRANSFORM; \
+                        cgltf_write_texture_transform(context, &info.transform); \
+                } \
+                cgltf_write_extras(context, &info.extras); \
+                cgltf_write_line(context, "}"); }
+
+static void cgltf_write_indent(cgltf_write_context* context)
+{
+        if (context->needs_comma)
+        {
+                CGLTF_SPRINTF(",\n");
+                context->needs_comma = 0;
+        }
+        else
+        {
+                CGLTF_SPRINTF("\n");
+        }
+        for (int i = 0; i < context->depth; ++i)
+        {
+                CGLTF_SPRINTF("%s", context->indent);
+        }
+}
+
+static void cgltf_write_line(cgltf_write_context* context, const char* line)
+{
+        if (line[0] == ']' || line[0] == '}')
+        {
+                --context->depth;
+                context->needs_comma = 0;
+        }
+        cgltf_write_indent(context);
+        CGLTF_SPRINTF("%s", line);
+        cgltf_size last = (cgltf_size)(strlen(line) - 1);
+        if (line[0] == ']' || line[0] == '}')
+        {
+                context->needs_comma = 1;
+        }
+        if (line[last] == '[' || line[last] == '{')
+        {
+                ++context->depth;
+                context->needs_comma = 0;
+        }
+}
+
+static void cgltf_write_strprop(cgltf_write_context* context, const char* label, const char* val)
+{
+        if (val)
+        {
+                cgltf_write_indent(context);
+                CGLTF_SPRINTF("\"%s\": \"%s\"", label, val);
+                context->needs_comma = 1;
+        }
+}
+
+static void cgltf_write_extras(cgltf_write_context* context, const cgltf_extras* extras)
+{
+        cgltf_size length = extras->end_offset - extras->start_offset;
+        if (length > 0 && context->data->file_data)
+        {
+                char* json_string = ((char*) context->data->file_data) + extras->start_offset;
+                cgltf_write_indent(context);
+                CGLTF_SPRINTF("%s", "\"extras\": ");
+                CGLTF_SNPRINTF(length, "%s", json_string);
+                context->needs_comma = 1;
+        }
+}
+
+static void cgltf_write_stritem(cgltf_write_context* context, const char* item)
+{
+        cgltf_write_indent(context);
+        CGLTF_SPRINTF("\"%s\"", item);
+        context->needs_comma = 1;
+}
+
+static void cgltf_write_intprop(cgltf_write_context* context, const char* label, int val, int def)
+{
+        if (val != def)
+        {
+                cgltf_write_indent(context);
+                CGLTF_SPRINTF("\"%s\": %d", label, val);
+                context->needs_comma = 1;
+        }
+}
+
+static void cgltf_write_floatprop(cgltf_write_context* context, const char* label, float val, float def)
+{
+        if (val != def)
+        {
+                cgltf_write_indent(context);
+                CGLTF_SPRINTF("\"%s\": ", label);
+                CGLTF_SPRINTF("%g", val);
+                context->needs_comma = 1;
+
+                if (context->cursor)
+                {
+                        char *decimal_comma = strchr(context->cursor - context->tmp, ',');
+                        if (decimal_comma)
+                        {
+                                *decimal_comma = '.';
+                        }
+                }
+        }
+}
+
+static void cgltf_write_boolprop_optional(cgltf_write_context* context, const char* label, bool val, bool def)
+{
+        if (val != def)
+        {
+                cgltf_write_indent(context);
+                CGLTF_SPRINTF("\"%s\": %s", label, val ? "true" : "false");
+                context->needs_comma = 1;
+        }
+}
+
+static void cgltf_write_floatarrayprop(cgltf_write_context* context, const char* label, const cgltf_float* vals, cgltf_size dim)
+{
+        cgltf_write_indent(context);
+        CGLTF_SPRINTF("\"%s\": [", label);
+        for (cgltf_size i = 0; i < dim; ++i)
+        {
+                if (i != 0)
+                {
+                        CGLTF_SPRINTF(", %g", vals[i]);
+                }
+                else
+                {
+                        CGLTF_SPRINTF("%g", vals[i]);
+                }
+        }
+        CGLTF_SPRINTF("]");
+        context->needs_comma = 1;
+}
+
+static bool cgltf_check_floatarray(const float* vals, int dim, float val) {
+        while (dim--)
+        {
+                if (vals[dim] != val)
+                {
+                        return true;
+                }
+        }
+        return false;
+}
+
+static int cgltf_int_from_component_type(cgltf_component_type ctype)
+{
+        switch (ctype)
+        {
+                case cgltf_component_type_r_8: return 5120;
+                case cgltf_component_type_r_8u: return 5121;
+                case cgltf_component_type_r_16: return 5122;
+                case cgltf_component_type_r_16u: return 5123;
+                case cgltf_component_type_r_32u: return 5125;
+                case cgltf_component_type_r_32f: return 5126;
+                default: return 0;
+        }
+}
+
+static const char* cgltf_str_from_alpha_mode(cgltf_alpha_mode alpha_mode)
+{
+        switch (alpha_mode)
+        {
+                case cgltf_alpha_mode_mask: return "MASK";
+                case cgltf_alpha_mode_blend: return "BLEND";
+                default: return NULL;
+        }
+}
+
+static const char* cgltf_str_from_type(cgltf_type type)
+{
+        switch (type)
+        {
+                case cgltf_type_scalar: return "SCALAR";
+                case cgltf_type_vec2: return "VEC2";
+                case cgltf_type_vec3: return "VEC3";
+                case cgltf_type_vec4: return "VEC4";
+                case cgltf_type_mat2: return "MAT2";
+                case cgltf_type_mat3: return "MAT3";
+                case cgltf_type_mat4: return "MAT4";
+                default: return NULL;
+        }
+}
+
+static cgltf_size cgltf_dim_from_type(cgltf_type type)
+{
+        switch (type)
+        {
+                case cgltf_type_scalar: return 1;
+                case cgltf_type_vec2: return 2;
+                case cgltf_type_vec3: return 3;
+                case cgltf_type_vec4: return 4;
+                case cgltf_type_mat2: return 4;
+                case cgltf_type_mat3: return 9;
+                case cgltf_type_mat4: return 16;
+                default: return 0;
+        }
+}
+
+static const char* cgltf_str_from_camera_type(cgltf_camera_type camera_type)
+{
+        switch (camera_type)
+        {
+                case cgltf_camera_type_perspective: return "perspective";
+                case cgltf_camera_type_orthographic: return "orthographic";
+                default: return NULL;
+        }
+}
+
+static const char* cgltf_str_from_light_type(cgltf_light_type light_type)
+{
+        switch (light_type)
+        {
+                case cgltf_light_type_directional: return "directional";
+                case cgltf_light_type_point: return "point";
+                case cgltf_light_type_spot: return "spot";
+                default: return NULL;
+        }
+}
+
+static void cgltf_write_texture_transform(cgltf_write_context* context, const cgltf_texture_transform* transform)
+{
+        cgltf_write_line(context, "\"extensions\": {");
+        cgltf_write_line(context, "\"KHR_texture_transform\": {");
+        if (cgltf_check_floatarray(transform->offset, 2, 0.0f))
+        {
+                cgltf_write_floatarrayprop(context, "offset", transform->offset, 2);
+        }
+        cgltf_write_floatprop(context, "rotation", transform->rotation, 0.0f);
+        if (cgltf_check_floatarray(transform->scale, 2, 1.0f))
+        {
+                cgltf_write_floatarrayprop(context, "scale", transform->scale, 2);
+        }
+        cgltf_write_intprop(context, "texCoord", transform->texcoord, 0);
+        cgltf_write_line(context, "}");
+        cgltf_write_line(context, "}");
+}
+
+static void cgltf_write_asset(cgltf_write_context* context, const cgltf_asset* asset)
+{
+        cgltf_write_line(context, "\"asset\": {");
+        cgltf_write_strprop(context, "copyright", asset->copyright);
+        cgltf_write_strprop(context, "generator", asset->generator);
+        cgltf_write_strprop(context, "version", asset->version);
+        cgltf_write_strprop(context, "min_version", asset->min_version);
+        cgltf_write_extras(context, &asset->extras);
+        cgltf_write_line(context, "}");
+}
+
+static void cgltf_write_primitive(cgltf_write_context* context, const cgltf_primitive* prim)
+{
+        cgltf_write_intprop(context, "mode", (int) prim->type, 4);
+        CGLTF_WRITE_IDXPROP("indices", prim->indices, context->data->accessors);
+        CGLTF_WRITE_IDXPROP("material", prim->material, context->data->materials);
+        cgltf_write_line(context, "\"attributes\": {");
+        for (cgltf_size i = 0; i < prim->attributes_count; ++i)
+        {
+                const cgltf_attribute* attr = prim->attributes + i;
+                CGLTF_WRITE_IDXPROP(attr->name, attr->data, context->data->accessors);
+        }
+        cgltf_write_line(context, "}");
+
+        if (prim->targets_count)
+        {
+                cgltf_write_line(context, "\"targets\": [");
+                for (cgltf_size i = 0; i < prim->targets_count; ++i)
+                {
+                        cgltf_write_line(context, "{");
+                        for (cgltf_size j = 0; j < prim->targets[i].attributes_count; ++j)
+                        {
+                                const cgltf_attribute* attr = prim->targets[i].attributes + j;
+                                CGLTF_WRITE_IDXPROP(attr->name, attr->data, context->data->accessors);
+                        }
+                        cgltf_write_line(context, "}");
+                }
+                cgltf_write_line(context, "]");
+        }
+        cgltf_write_extras(context, &prim->extras);
+
+        cgltf_bool has_extensions = prim->has_draco_mesh_compression;
+        if (has_extensions) {
+                cgltf_write_line(context, "\"extensions\": {");
+
+                if (prim->has_draco_mesh_compression) {
+                        context->extension_flags |= CGLTF_EXTENSION_FLAG_DRACO_MESH_COMPRESSION;
+                        if (prim->attributes_count == 0 || prim->indices == 0) {
+                                context->required_extension_flags |= CGLTF_EXTENSION_FLAG_DRACO_MESH_COMPRESSION;                                
+                        }
+
+                        cgltf_write_line(context, "\"KHR_draco_mesh_compression\": {");
+                        CGLTF_WRITE_IDXPROP("bufferView", prim->draco_mesh_compression.buffer_view, context->data->buffer_views);
+                        cgltf_write_line(context, "\"attributes\": {");
+                        for (cgltf_size i = 0; i < prim->draco_mesh_compression.attributes_count; ++i)
+                        {
+                                const cgltf_attribute* attr = prim->draco_mesh_compression.attributes + i;
+                                CGLTF_WRITE_IDXPROP(attr->name, attr->data, context->data->accessors);
+                        }
+                        cgltf_write_line(context, "}");
+                        cgltf_write_line(context, "}");
+                }
+
+                cgltf_write_line(context, "}");
+        }
+}
+
+static void cgltf_write_mesh(cgltf_write_context* context, const cgltf_mesh* mesh)
+{
+        cgltf_write_line(context, "{");
+        cgltf_write_strprop(context, "name", mesh->name);
+
+        cgltf_write_line(context, "\"primitives\": [");
+        for (cgltf_size i = 0; i < mesh->primitives_count; ++i)
+        {
+                cgltf_write_line(context, "{");
+                cgltf_write_primitive(context, mesh->primitives + i);
+                cgltf_write_line(context, "}");
+        }
+        cgltf_write_line(context, "]");
+
+        if (mesh->weights_count > 0)
+        {
+                cgltf_write_floatarrayprop(context, "weights", mesh->weights, mesh->weights_count);
+        }
+        cgltf_write_extras(context, &mesh->extras);
+        cgltf_write_line(context, "}");
+}
+
+static void cgltf_write_buffer_view(cgltf_write_context* context, const cgltf_buffer_view* view)
+{
+        cgltf_write_line(context, "{");
+        CGLTF_WRITE_IDXPROP("buffer", view->buffer, context->data->buffers);
+        cgltf_write_intprop(context, "byteLength", (int)view->size, -1);
+        cgltf_write_intprop(context, "byteOffset", (int)view->offset, 0);
+        cgltf_write_intprop(context, "byteStride", (int)view->stride, 0);
+        // NOTE: We skip writing "target" because the spec says its usage can be inferred.
+        cgltf_write_extras(context, &view->extras);
+        cgltf_write_line(context, "}");
+}
+
+
+static void cgltf_write_buffer(cgltf_write_context* context, const cgltf_buffer* buffer)
+{
+        cgltf_write_line(context, "{");
+        cgltf_write_strprop(context, "uri", buffer->uri);
+        cgltf_write_intprop(context, "byteLength", (int)buffer->size, -1);
+        cgltf_write_extras(context, &buffer->extras);
+        cgltf_write_line(context, "}");
+}
+
+static void cgltf_write_material(cgltf_write_context* context, const cgltf_material* material)
+{
+        cgltf_write_line(context, "{");
+        cgltf_write_strprop(context, "name", material->name);
+        cgltf_write_floatprop(context, "alphaCutoff", material->alpha_cutoff, 0.5f);
+        cgltf_write_boolprop_optional(context, "doubleSided", material->double_sided, false);
+        // cgltf_write_boolprop_optional(context, "unlit", material->unlit, false);
+
+        if (material->unlit)
+        {
+                context->extension_flags |= CGLTF_EXTENSION_FLAG_MATERIALS_UNLIT;
+        }
+
+        if (material->has_pbr_specular_glossiness)
+        {
+                context->extension_flags |= CGLTF_EXTENSION_FLAG_SPECULAR_GLOSSINESS;
+        }
+
+        if (material->has_clearcoat)
+        {
+                context->extension_flags |= CGLTF_EXTENSION_FLAG_MATERIALS_CLEARCOAT;
+        }
+
+        if (material->has_transmission)
+        {
+                context->extension_flags |= CGLTF_EXTENSION_FLAG_MATERIALS_TRANSMISSION;
+        }
+
+        if (material->has_ior)
+        {
+                context->extension_flags |= CGLTF_EXTENSION_FLAG_MATERIALS_IOR;
+        }
+
+        if (material->has_specular)
+        {
+                context->extension_flags |= CGLTF_EXTENSION_FLAG_MATERIALS_SPECULAR;
+        }
+
+        if (material->has_pbr_metallic_roughness)
+        {
+                const cgltf_pbr_metallic_roughness* params = &material->pbr_metallic_roughness;
+                cgltf_write_line(context, "\"pbrMetallicRoughness\": {");
+                CGLTF_WRITE_TEXTURE_INFO("baseColorTexture", params->base_color_texture);
+                CGLTF_WRITE_TEXTURE_INFO("metallicRoughnessTexture", params->metallic_roughness_texture);
+                cgltf_write_floatprop(context, "metallicFactor", params->metallic_factor, 1.0f);
+                cgltf_write_floatprop(context, "roughnessFactor", params->roughness_factor, 1.0f);
+                if (cgltf_check_floatarray(params->base_color_factor, 4, 1.0f))
+                {
+                        cgltf_write_floatarrayprop(context, "baseColorFactor", params->base_color_factor, 4);
+                }
+                cgltf_write_extras(context, &params->extras);
+                cgltf_write_line(context, "}");
+        }
+
+        if (material->unlit || material->has_pbr_specular_glossiness || material->has_clearcoat || material->has_ior || material->has_specular || material->has_transmission)
+        {
+                cgltf_write_line(context, "\"extensions\": {");
+                if (material->has_clearcoat)
+                {
+                        const cgltf_clearcoat* params = &material->clearcoat;
+                        cgltf_write_line(context, "\"KHR_materials_clearcoat\": {");
+                        CGLTF_WRITE_TEXTURE_INFO("clearcoatTexture", params->clearcoat_texture);
+                        CGLTF_WRITE_TEXTURE_INFO("clearcoatRoughnessTexture", params->clearcoat_roughness_texture);
+                        CGLTF_WRITE_TEXTURE_INFO("clearcoatNormalTexture", params->clearcoat_normal_texture);
+                        cgltf_write_floatprop(context, "clearcoatFactor", params->clearcoat_factor, 0.0f);
+                        cgltf_write_floatprop(context, "clearcoatRoughnessFactor", params->clearcoat_roughness_factor, 0.0f);
+                        cgltf_write_line(context, "}");
+                }
+                if (material->has_ior)
+                {
+                        const cgltf_ior* params = &material->ior;
+                        cgltf_write_line(context, "\"KHR_materials_ior\": {");
+                        cgltf_write_floatprop(context, "ior", params->ior, 1.5f);
+                        cgltf_write_line(context, "}");
+                }
+                if (material->has_specular)
+                {
+                        const cgltf_specular* params = &material->specular;
+                        cgltf_write_line(context, "\"KHR_materials_specular\": {");
+                        CGLTF_WRITE_TEXTURE_INFO("specularTexture", params->specular_texture);
+                        cgltf_write_floatprop(context, "specularFactor", params->specular_factor, 1.0f);
+                        if (cgltf_check_floatarray(params->specular_color_factor, 3, 1.0f))
+                        {
+                                cgltf_write_floatarrayprop(context, "specularColorFactor", params->specular_color_factor, 3);
+                        }
+                        cgltf_write_line(context, "}");
+                }
+                if (material->has_transmission)
+                {
+                        const cgltf_transmission* params = &material->transmission;
+                        cgltf_write_line(context, "\"KHR_materials_transmission\": {");
+                        CGLTF_WRITE_TEXTURE_INFO("transmissionTexture", params->transmission_texture);
+                        cgltf_write_floatprop(context, "transmissionFactor", params->transmission_factor, 0.0f);
+                        cgltf_write_line(context, "}");
+                }
+                if (material->has_pbr_specular_glossiness)
+                {
+                        const cgltf_pbr_specular_glossiness* params = &material->pbr_specular_glossiness;
+                        cgltf_write_line(context, "\"KHR_materials_pbrSpecularGlossiness\": {");
+                        CGLTF_WRITE_TEXTURE_INFO("diffuseTexture", params->diffuse_texture);
+                        CGLTF_WRITE_TEXTURE_INFO("specularGlossinessTexture", params->specular_glossiness_texture);
+                        if (cgltf_check_floatarray(params->diffuse_factor, 4, 1.0f))
+                        {
+                                cgltf_write_floatarrayprop(context, "dffuseFactor", params->diffuse_factor, 4);
+                        }
+                        if (cgltf_check_floatarray(params->specular_factor, 3, 1.0f))
+                        {
+                                cgltf_write_floatarrayprop(context, "specularFactor", params->specular_factor, 3);
+                        }
+                        cgltf_write_floatprop(context, "glossinessFactor", params->glossiness_factor, 1.0f);
+                        cgltf_write_line(context, "}");
+                }
+                if (material->unlit)
+                {
+                        cgltf_write_line(context, "\"KHR_materials_unlit\": {}");
+                }
+                cgltf_write_line(context, "}");
+        }
+
+        CGLTF_WRITE_TEXTURE_INFO("normalTexture", material->normal_texture);
+        CGLTF_WRITE_TEXTURE_INFO("occlusionTexture", material->occlusion_texture);
+        CGLTF_WRITE_TEXTURE_INFO("emissiveTexture", material->emissive_texture);
+        if (cgltf_check_floatarray(material->emissive_factor, 3, 0.0f))
+        {
+                cgltf_write_floatarrayprop(context, "emissiveFactor", material->emissive_factor, 3);
+        }
+        cgltf_write_strprop(context, "alphaMode", cgltf_str_from_alpha_mode(material->alpha_mode));
+        cgltf_write_extras(context, &material->extras);
+        cgltf_write_line(context, "}");
+}
+
+static void cgltf_write_image(cgltf_write_context* context, const cgltf_image* image)
+{
+        cgltf_write_line(context, "{");
+        cgltf_write_strprop(context, "name", image->name);
+        cgltf_write_strprop(context, "uri", image->uri);
+        CGLTF_WRITE_IDXPROP("bufferView", image->buffer_view, context->data->buffer_views);
+        cgltf_write_strprop(context, "mimeType", image->mime_type);
+        cgltf_write_extras(context, &image->extras);
+        cgltf_write_line(context, "}");
+}
+
+static void cgltf_write_texture(cgltf_write_context* context, const cgltf_texture* texture)
+{
+        cgltf_write_line(context, "{");
+        cgltf_write_strprop(context, "name", texture->name);
+        CGLTF_WRITE_IDXPROP("source", texture->image, context->data->images);
+        CGLTF_WRITE_IDXPROP("sampler", texture->sampler, context->data->samplers);
+        cgltf_write_extras(context, &texture->extras);
+        cgltf_write_line(context, "}");
+}
+
+static void cgltf_write_skin(cgltf_write_context* context, const cgltf_skin* skin)
+{
+        cgltf_write_line(context, "{");
+        CGLTF_WRITE_IDXPROP("skeleton", skin->skeleton, context->data->nodes);
+        CGLTF_WRITE_IDXPROP("inverseBindMatrices", skin->inverse_bind_matrices, context->data->accessors);
+        CGLTF_WRITE_IDXARRPROP("joints", skin->joints_count, skin->joints, context->data->nodes);
+        cgltf_write_strprop(context, "name", skin->name);
+        cgltf_write_extras(context, &skin->extras);
+        cgltf_write_line(context, "}");
+}
+
+static const char* cgltf_write_str_path_type(cgltf_animation_path_type path_type)
+{
+        switch (path_type)
+        {
+        case cgltf_animation_path_type_translation:
+                return "translation";
+        case cgltf_animation_path_type_rotation:
+                return "rotation";
+        case cgltf_animation_path_type_scale:
+                return "scale";
+        case cgltf_animation_path_type_weights:
+                return "weights";
+        case cgltf_animation_path_type_invalid:
+                break;
+        }
+        return "invalid";
+}
+
+static const char* cgltf_write_str_interpolation_type(cgltf_interpolation_type interpolation_type)
+{
+        switch (interpolation_type)
+        {
+        case cgltf_interpolation_type_linear:
+                return "LINEAR";
+        case cgltf_interpolation_type_step:
+                return "STEP";
+        case cgltf_interpolation_type_cubic_spline:
+                return "CUBICSPLINE";
+        }
+        return "invalid";
+}
+
+static void cgltf_write_path_type(cgltf_write_context* context, const char *label, cgltf_animation_path_type path_type)
+{
+        cgltf_write_strprop(context, label, cgltf_write_str_path_type(path_type));
+}
+
+static void cgltf_write_interpolation_type(cgltf_write_context* context, const char *label, cgltf_interpolation_type interpolation_type)
+{
+        cgltf_write_strprop(context, label, cgltf_write_str_interpolation_type(interpolation_type));
+}
+
+static void cgltf_write_animation_sampler(cgltf_write_context* context, const cgltf_animation_sampler* animation_sampler)
+{
+        cgltf_write_line(context, "{");
+        cgltf_write_interpolation_type(context, "interpolation", animation_sampler->interpolation);
+        CGLTF_WRITE_IDXPROP("input", animation_sampler->input, context->data->accessors);
+        CGLTF_WRITE_IDXPROP("output", animation_sampler->output, context->data->accessors);
+        cgltf_write_extras(context, &animation_sampler->extras);
+        cgltf_write_line(context, "}");
+}
+
+static void cgltf_write_animation_channel(cgltf_write_context* context, const cgltf_animation* animation, const cgltf_animation_channel* animation_channel)
+{
+        cgltf_write_line(context, "{");
+        CGLTF_WRITE_IDXPROP("sampler", animation_channel->sampler, animation->samplers);
+        cgltf_write_line(context, "\"target\": {");
+        CGLTF_WRITE_IDXPROP("node", animation_channel->target_node, context->data->nodes);
+        cgltf_write_path_type(context, "path", animation_channel->target_path);
+        cgltf_write_line(context, "}");
+        cgltf_write_extras(context, &animation_channel->extras);
+        cgltf_write_line(context, "}");
+}
+
+static void cgltf_write_animation(cgltf_write_context* context, const cgltf_animation* animation)
+{
+        cgltf_write_line(context, "{");
+        cgltf_write_strprop(context, "name", animation->name);
+
+        if (animation->samplers_count > 0)
+        {
+                cgltf_write_line(context, "\"samplers\": [");
+                for (cgltf_size i = 0; i < animation->samplers_count; ++i)
+                {
+                        cgltf_write_animation_sampler(context, animation->samplers + i);
+                }
+                cgltf_write_line(context, "]");
+        }
+        if (animation->channels_count > 0)
+        {
+                cgltf_write_line(context, "\"channels\": [");
+                for (cgltf_size i = 0; i < animation->channels_count; ++i)
+                {
+                        cgltf_write_animation_channel(context, animation, animation->channels + i);
+                }
+                cgltf_write_line(context, "]");
+        }
+        cgltf_write_extras(context, &animation->extras);
+        cgltf_write_line(context, "}");
+}
+
+static void cgltf_write_sampler(cgltf_write_context* context, const cgltf_sampler* sampler)
+{
+        cgltf_write_line(context, "{");
+        cgltf_write_intprop(context, "magFilter", sampler->mag_filter, 0);
+        cgltf_write_intprop(context, "minFilter", sampler->min_filter, 0);
+        cgltf_write_intprop(context, "wrapS", sampler->wrap_s, 10497);
+        cgltf_write_intprop(context, "wrapT", sampler->wrap_t, 10497);
+        cgltf_write_extras(context, &sampler->extras);
+        cgltf_write_line(context, "}");
+}
+
+static void cgltf_write_node(cgltf_write_context* context, const cgltf_node* node)
+{
+        cgltf_write_line(context, "{");
+        CGLTF_WRITE_IDXARRPROP("children", node->children_count, node->children, context->data->nodes);
+        CGLTF_WRITE_IDXPROP("mesh", node->mesh, context->data->meshes);
+        cgltf_write_strprop(context, "name", node->name);
+        if (node->has_matrix)
+        {
+                cgltf_write_floatarrayprop(context, "matrix", node->matrix, 16);
+        }
+        if (node->has_translation)
+        {
+                cgltf_write_floatarrayprop(context, "translation", node->translation, 3);
+        }
+        if (node->has_rotation)
+        {
+                cgltf_write_floatarrayprop(context, "rotation", node->rotation, 4);
+        }
+        if (node->has_scale)
+        {
+                cgltf_write_floatarrayprop(context, "scale", node->scale, 3);
+        }
+        if (node->skin)
+        {
+                CGLTF_WRITE_IDXPROP("skin", node->skin, context->data->skins);
+        }
+
+        if (node->light)
+        {
+                context->extension_flags |= CGLTF_EXTENSION_FLAG_LIGHTS_PUNCTUAL;
+                cgltf_write_line(context, "\"extensions\": {");
+                cgltf_write_line(context, "\"KHR_lights_punctual\": {");
+                CGLTF_WRITE_IDXPROP("light", node->light, context->data->lights);
+                cgltf_write_line(context, "}");
+                cgltf_write_line(context, "}");
+        }
+
+        if (node->weights_count > 0)
+        {
+                cgltf_write_floatarrayprop(context, "weights", node->weights, node->weights_count);
+        }
+
+        if (node->camera)
+        {
+                CGLTF_WRITE_IDXPROP("camera", node->camera, context->data->cameras);
+        }
+
+        cgltf_write_extras(context, &node->extras);
+        cgltf_write_line(context, "}");
+}
+
+static void cgltf_write_scene(cgltf_write_context* context, const cgltf_scene* scene)
+{
+        cgltf_write_line(context, "{");
+        cgltf_write_strprop(context, "name", scene->name);
+        CGLTF_WRITE_IDXARRPROP("nodes", scene->nodes_count, scene->nodes, context->data->nodes);
+        cgltf_write_extras(context, &scene->extras);
+        cgltf_write_line(context, "}");
+}
+
+static void cgltf_write_accessor(cgltf_write_context* context, const cgltf_accessor* accessor)
+{
+        cgltf_write_line(context, "{");
+        CGLTF_WRITE_IDXPROP("bufferView", accessor->buffer_view, context->data->buffer_views);
+        cgltf_write_intprop(context, "componentType", cgltf_int_from_component_type(accessor->component_type), 0);
+        cgltf_write_strprop(context, "type", cgltf_str_from_type(accessor->type));
+        cgltf_size dim = cgltf_dim_from_type(accessor->type);
+        cgltf_write_boolprop_optional(context, "normalized", accessor->normalized, false);
+        cgltf_write_intprop(context, "byteOffset", (int)accessor->offset, 0);
+        cgltf_write_intprop(context, "count", (int)accessor->count, -1);
+        if (accessor->has_min)
+        {
+                cgltf_write_floatarrayprop(context, "min", accessor->min, dim);
+        }
+        if (accessor->has_max)
+        {
+                cgltf_write_floatarrayprop(context, "max", accessor->max, dim);
+        }
+        if (accessor->is_sparse)
+        {
+                cgltf_write_line(context, "\"sparse\": {");
+                cgltf_write_intprop(context, "count", (int)accessor->sparse.count, 0);
+                cgltf_write_line(context, "\"indices\": {");
+                cgltf_write_intprop(context, "byteOffset", (int)accessor->sparse.indices_byte_offset, 0);
+                CGLTF_WRITE_IDXPROP("bufferView", accessor->sparse.indices_buffer_view, context->data->buffer_views);
+                cgltf_write_intprop(context, "componentType", cgltf_int_from_component_type(accessor->sparse.indices_component_type), 0);
+                cgltf_write_extras(context, &accessor->sparse.indices_extras);
+                cgltf_write_line(context, "}");
+                cgltf_write_line(context, "\"values\": {");
+                cgltf_write_intprop(context, "byteOffset", (int)accessor->sparse.values_byte_offset, 0);
+                CGLTF_WRITE_IDXPROP("bufferView", accessor->sparse.values_buffer_view, context->data->buffer_views);
+                cgltf_write_extras(context, &accessor->sparse.values_extras);
+                cgltf_write_line(context, "}");
+                cgltf_write_extras(context, &accessor->sparse.extras);
+                cgltf_write_line(context, "}");
+        }
+        cgltf_write_extras(context, &accessor->extras);
+        cgltf_write_line(context, "}");
+}
+
+static void cgltf_write_camera(cgltf_write_context* context, const cgltf_camera* camera)
+{
+        cgltf_write_line(context, "{");
+        cgltf_write_strprop(context, "type", cgltf_str_from_camera_type(camera->type));
+        if (camera->name)
+        {
+                cgltf_write_strprop(context, "name", camera->name);
+        }
+
+        if (camera->type == cgltf_camera_type_orthographic)
+        {
+                cgltf_write_line(context, "\"orthographic\": {");
+                cgltf_write_floatprop(context, "xmag", camera->data.orthographic.xmag, -1.0f);
+                cgltf_write_floatprop(context, "ymag", camera->data.orthographic.ymag, -1.0f);
+                cgltf_write_floatprop(context, "zfar", camera->data.orthographic.zfar, -1.0f);
+                cgltf_write_floatprop(context, "znear", camera->data.orthographic.znear, -1.0f);
+                cgltf_write_extras(context, &camera->data.orthographic.extras);
+                cgltf_write_line(context, "}");
+        }
+        else if (camera->type == cgltf_camera_type_perspective)
+        {
+                cgltf_write_line(context, "\"perspective\": {");
+                cgltf_write_floatprop(context, "aspectRatio", camera->data.perspective.aspect_ratio, -1.0f);
+                cgltf_write_floatprop(context, "yfov", camera->data.perspective.yfov, -1.0f);
+                cgltf_write_floatprop(context, "zfar", camera->data.perspective.zfar, -1.0f);
+                cgltf_write_floatprop(context, "znear", camera->data.perspective.znear, -1.0f);
+                cgltf_write_extras(context, &camera->data.perspective.extras);
+                cgltf_write_line(context, "}");
+        }
+        cgltf_write_extras(context, &camera->extras);
+        cgltf_write_line(context, "}");
+}
+
+static void cgltf_write_light(cgltf_write_context* context, const cgltf_light* light)
+{
+        cgltf_write_line(context, "{");
+        cgltf_write_strprop(context, "type", cgltf_str_from_light_type(light->type));
+        if (light->name)
+        {
+                cgltf_write_strprop(context, "name", light->name);
+        }
+        if (cgltf_check_floatarray(light->color, 3, 1.0f))
+        {
+                cgltf_write_floatarrayprop(context, "color", light->color, 3);
+        }
+        cgltf_write_floatprop(context, "intensity", light->intensity, 1.0f);
+        cgltf_write_floatprop(context, "range", light->range, 0.0f);
+
+        if (light->type == cgltf_light_type_spot)
+        {
+                cgltf_write_line(context, "\"spot\": {");
+                cgltf_write_floatprop(context, "innerConeAngle", light->spot_inner_cone_angle, 0.0f);
+                cgltf_write_floatprop(context, "outerConeAngle", light->spot_outer_cone_angle, 3.14159265358979323846f/4.0f);
+                cgltf_write_line(context, "}");
+        }
+        cgltf_write_line(context, "}");
+}
+
+cgltf_result cgltf_write_file(const cgltf_options* options, const char* path, const cgltf_data* data)
+{
+        cgltf_size expected = cgltf_write(options, NULL, 0, data);
+        char* buffer = (char*) malloc(expected);
+        cgltf_size actual = cgltf_write(options, buffer, expected, data);
+        if (expected != actual) {
+                fprintf(stderr, "Error: expected %zu bytes but wrote %zu bytes.\n", expected, actual);
+        }
+        FILE* file = fopen(path, "wt");
+        if (!file)
+        {
+                return cgltf_result_file_not_found;
+        }
+        // Note that cgltf_write() includes a null terminator, which we omit from the file content.
+        fwrite(buffer, actual - 1, 1, file);
+        fclose(file);
+        free(buffer);
+        return cgltf_result_success;
+}
+
+static void cgltf_write_extensions(cgltf_write_context* context, uint32_t extension_flags)
+{
+        if (extension_flags & CGLTF_EXTENSION_FLAG_TEXTURE_TRANSFORM) {
+                cgltf_write_stritem(context, "KHR_texture_transform");
+        }
+        if (extension_flags & CGLTF_EXTENSION_FLAG_MATERIALS_UNLIT) {
+                cgltf_write_stritem(context, "KHR_materials_unlit");
+        }
+        if (extension_flags & CGLTF_EXTENSION_FLAG_SPECULAR_GLOSSINESS) {
+                cgltf_write_stritem(context, "KHR_materials_pbrSpecularGlossiness");
+        }
+        if (extension_flags & CGLTF_EXTENSION_FLAG_LIGHTS_PUNCTUAL) {
+                cgltf_write_stritem(context, "KHR_lights_punctual");
+        }
+        if (extension_flags & CGLTF_EXTENSION_FLAG_DRACO_MESH_COMPRESSION) {
+                cgltf_write_stritem(context, "KHR_draco_mesh_compression");
+        }
+        if (extension_flags & CGLTF_EXTENSION_FLAG_MATERIALS_CLEARCOAT) {
+                cgltf_write_stritem(context, "KHR_materials_clearcoat");
+        }
+        if (extension_flags & CGLTF_EXTENSION_FLAG_MATERIALS_IOR) {
+                cgltf_write_stritem(context, "KHR_materials_ior");
+        }
+        if (extension_flags & CGLTF_EXTENSION_FLAG_MATERIALS_SPECULAR) {
+                cgltf_write_stritem(context, "KHR_materials_specular");
+        }
+        if (extension_flags & CGLTF_EXTENSION_FLAG_MATERIALS_TRANSMISSION) {
+                cgltf_write_stritem(context, "KHR_materials_transmission");
+        }
+}
+
+cgltf_size cgltf_write(const cgltf_options* options, char* buffer, cgltf_size size, const cgltf_data* data)
+{
+        (void)options;
+        cgltf_write_context ctx;
+        ctx.buffer = buffer;
+        ctx.buffer_size = size;
+        ctx.remaining = size;
+        ctx.cursor = buffer;
+        ctx.chars_written = 0;
+        ctx.data = data;
+        ctx.depth = 1;
+        ctx.indent = "  ";
+        ctx.needs_comma = 0;
+        ctx.extension_flags = 0;
+        ctx.required_extension_flags = 0;
+
+        cgltf_write_context* context = &ctx;
+
+        CGLTF_SPRINTF("{");
+
+        if (data->accessors_count > 0)
+        {
+                cgltf_write_line(context, "\"accessors\": [");
+                for (cgltf_size i = 0; i < data->accessors_count; ++i)
+                {
+                        cgltf_write_accessor(context, data->accessors + i);
+                }
+                cgltf_write_line(context, "]");
+        }
+
+        cgltf_write_asset(context, &data->asset);
+
+        if (data->buffer_views_count > 0)
+        {
+                cgltf_write_line(context, "\"bufferViews\": [");
+                for (cgltf_size i = 0; i < data->buffer_views_count; ++i)
+                {
+                        cgltf_write_buffer_view(context, data->buffer_views + i);
+                }
+                cgltf_write_line(context, "]");
+        }
+
+        if (data->buffers_count > 0)
+        {
+                cgltf_write_line(context, "\"buffers\": [");
+                for (cgltf_size i = 0; i < data->buffers_count; ++i)
+                {
+                        cgltf_write_buffer(context, data->buffers + i);
+                }
+                cgltf_write_line(context, "]");
+        }
+
+        if (data->images_count > 0)
+        {
+                cgltf_write_line(context, "\"images\": [");
+                for (cgltf_size i = 0; i < data->images_count; ++i)
+                {
+                        cgltf_write_image(context, data->images + i);
+                }
+                cgltf_write_line(context, "]");
+        }
+
+        if (data->meshes_count > 0)
+        {
+                cgltf_write_line(context, "\"meshes\": [");
+                for (cgltf_size i = 0; i < data->meshes_count; ++i)
+                {
+                        cgltf_write_mesh(context, data->meshes + i);
+                }
+                cgltf_write_line(context, "]");
+        }
+
+        if (data->materials_count > 0)
+        {
+                cgltf_write_line(context, "\"materials\": [");
+                for (cgltf_size i = 0; i < data->materials_count; ++i)
+                {
+                        cgltf_write_material(context, data->materials + i);
+                }
+                cgltf_write_line(context, "]");
+        }
+
+        if (data->nodes_count > 0)
+        {
+                cgltf_write_line(context, "\"nodes\": [");
+                for (cgltf_size i = 0; i < data->nodes_count; ++i)
+                {
+                        cgltf_write_node(context, data->nodes + i);
+                }
+                cgltf_write_line(context, "]");
+        }
+
+        if (data->samplers_count > 0)
+        {
+                cgltf_write_line(context, "\"samplers\": [");
+                for (cgltf_size i = 0; i < data->samplers_count; ++i)
+                {
+                        cgltf_write_sampler(context, data->samplers + i);
+                }
+                cgltf_write_line(context, "]");
+        }
+
+        CGLTF_WRITE_IDXPROP("scene", data->scene, data->scenes);
+
+        if (data->scenes_count > 0)
+        {
+                cgltf_write_line(context, "\"scenes\": [");
+                for (cgltf_size i = 0; i < data->scenes_count; ++i)
+                {
+                        cgltf_write_scene(context, data->scenes + i);
+                }
+                cgltf_write_line(context, "]");
+        }
+
+        if (data->textures_count > 0)
+        {
+                cgltf_write_line(context, "\"textures\": [");
+                for (cgltf_size i = 0; i < data->textures_count; ++i)
+                {
+                        cgltf_write_texture(context, data->textures + i);
+                }
+                cgltf_write_line(context, "]");
+        }
+
+        if (data->skins_count > 0)
+        {
+                cgltf_write_line(context, "\"skins\": [");
+                for (cgltf_size i = 0; i < data->skins_count; ++i)
+                {
+                        cgltf_write_skin(context, data->skins + i);
+                }
+                cgltf_write_line(context, "]");
+        }
+
+        if (data->animations_count > 0)
+        {
+                cgltf_write_line(context, "\"animations\": [");
+                for (cgltf_size i = 0; i < data->animations_count; ++i)
+                {
+                        cgltf_write_animation(context, data->animations + i);
+                }
+                cgltf_write_line(context, "]");
+        }
+
+        if (data->cameras_count > 0)
+        {
+                cgltf_write_line(context, "\"cameras\": [");
+                for (cgltf_size i = 0; i < data->cameras_count; ++i)
+                {
+                        cgltf_write_camera(context, data->cameras + i);
+                }
+                cgltf_write_line(context, "]");
+        }
+
+        if (data->lights_count > 0)
+        {
+                cgltf_write_line(context, "\"extensions\": {");
+
+                cgltf_write_line(context, "\"KHR_lights_punctual\": {");
+                cgltf_write_line(context, "\"lights\": [");
+                for (cgltf_size i = 0; i < data->lights_count; ++i)
+                {
+                        cgltf_write_light(context, data->lights + i);
+                }
+                cgltf_write_line(context, "]");
+                cgltf_write_line(context, "}");
+
+                cgltf_write_line(context, "}");
+        }
+
+        if (context->extension_flags != 0) {
+                cgltf_write_line(context, "\"extensionsUsed\": [");
+                cgltf_write_extensions(context, context->extension_flags);
+                cgltf_write_line(context, "]");
+        }
+
+        if (context->required_extension_flags != 0) {
+                cgltf_write_line(context, "\"extensionsRequired\": [");
+                cgltf_write_extensions(context, context->required_extension_flags);
+                cgltf_write_line(context, "]");
+        }
+
+        cgltf_write_extras(context, &data->extras);
+
+        CGLTF_SPRINTF("\n}\n");
+
+        // snprintf does not include the null terminator in its return value, so be sure to include it
+        // in the returned byte count.
+        return 1 + ctx.chars_written;
+}
+
+#endif /* #ifdef CGLTF_WRITE_IMPLEMENTATION */
+
+/* cgltf is distributed under MIT license:
+ *
+ * Copyright (c) 2019 Philip Rideout
+
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */