From da90b580737857e5a508ec704bdf3ac834cd2972 Mon Sep 17 00:00:00 2001 From: Arseny Kapoulkine Date: Fri, 16 Feb 2024 13:16:39 -0800 Subject: [PATCH] Implement support for KHR_materials_dispersion Specification: https://github.com/KhronosGroup/gltf/tree/main/extensions/2.0/Khronos/KHR_materials_dispersion --- cgltf.h | 43 +++++++++++++++++++++++++++++++++++++++++++ cgltf_write.h | 18 +++++++++++++++++- 2 files changed, 60 insertions(+), 1 deletion(-) diff --git a/cgltf.h b/cgltf.h index f6d01cd..3231201 100644 --- a/cgltf.h +++ b/cgltf.h @@ -505,6 +505,11 @@ typedef struct cgltf_anisotropy cgltf_texture_view anisotropy_texture; } cgltf_anisotropy; +typedef struct cgltf_dispersion +{ + cgltf_float dispersion; +} cgltf_dispersion; + typedef struct cgltf_material { char* name; @@ -519,6 +524,7 @@ typedef struct cgltf_material cgltf_bool has_emissive_strength; cgltf_bool has_iridescence; cgltf_bool has_anisotropy; + cgltf_bool has_dispersion; cgltf_pbr_metallic_roughness pbr_metallic_roughness; cgltf_pbr_specular_glossiness pbr_specular_glossiness; cgltf_clearcoat clearcoat; @@ -530,6 +536,7 @@ typedef struct cgltf_material cgltf_emissive_strength emissive_strength; cgltf_iridescence iridescence; cgltf_anisotropy anisotropy; + cgltf_dispersion dispersion; cgltf_texture_view normal_texture; cgltf_texture_view occlusion_texture; cgltf_texture_view emissive_texture; @@ -4297,6 +4304,37 @@ static int cgltf_parse_json_anisotropy(cgltf_options* options, jsmntok_t const* return i; } +static int cgltf_parse_json_dispersion(jsmntok_t const* tokens, int i, const uint8_t* json_chunk, cgltf_dispersion* out_dispersion) +{ + CGLTF_CHECK_TOKTYPE(tokens[i], JSMN_OBJECT); + int size = tokens[i].size; + ++i; + + + for (int j = 0; j < size; ++j) + { + CGLTF_CHECK_KEY(tokens[i]); + + if (cgltf_json_strcmp(tokens + i, json_chunk, "dispersion") == 0) + { + ++i; + out_dispersion->dispersion = cgltf_json_to_float(tokens + i, json_chunk); + ++i; + } + else + { + i = cgltf_skip_json(tokens, i + 1); + } + + if (i < 0) + { + return i; + } + } + + return i; +} + static int cgltf_parse_json_image(cgltf_options* options, jsmntok_t const* tokens, int i, const uint8_t* json_chunk, cgltf_image* out_image) { CGLTF_CHECK_TOKTYPE(tokens[i], JSMN_OBJECT); @@ -4690,6 +4728,11 @@ static int cgltf_parse_json_material(cgltf_options* options, jsmntok_t const* to out_material->has_anisotropy = 1; i = cgltf_parse_json_anisotropy(options, tokens, i + 1, json_chunk, &out_material->anisotropy); } + else if (cgltf_json_strcmp(tokens + i, json_chunk, "KHR_materials_dispersion") == 0) + { + out_material->has_dispersion = 1; + i = cgltf_parse_json_dispersion(tokens, i + 1, json_chunk, &out_material->dispersion); + } else { i = cgltf_parse_json_unprocessed_extension(options, tokens, i, json_chunk, &(out_material->extensions[out_material->extensions_count++])); diff --git a/cgltf_write.h b/cgltf_write.h index 0c6da06..d5615cd 100644 --- a/cgltf_write.h +++ b/cgltf_write.h @@ -86,6 +86,7 @@ cgltf_size cgltf_write(const cgltf_options* options, char* buffer, cgltf_size si #define CGLTF_EXTENSION_FLAG_MESH_GPU_INSTANCING (1 << 14) #define CGLTF_EXTENSION_FLAG_MATERIALS_IRIDESCENCE (1 << 15) #define CGLTF_EXTENSION_FLAG_MATERIALS_ANISOTROPY (1 << 16) +#define CGLTF_EXTENSION_FLAG_MATERIALS_DISPERSION (1 << 17) typedef struct { char* buffer; @@ -659,6 +660,11 @@ static void cgltf_write_material(cgltf_write_context* context, const cgltf_mater context->extension_flags |= CGLTF_EXTENSION_FLAG_MATERIALS_ANISOTROPY; } + if (material->has_dispersion) + { + context->extension_flags |= CGLTF_EXTENSION_FLAG_MATERIALS_DISPERSION; + } + if (material->has_pbr_metallic_roughness) { const cgltf_pbr_metallic_roughness* params = &material->pbr_metallic_roughness; @@ -674,7 +680,7 @@ static void cgltf_write_material(cgltf_write_context* context, const cgltf_mater cgltf_write_line(context, "}"); } - if (material->unlit || material->has_pbr_specular_glossiness || material->has_clearcoat || material->has_ior || material->has_specular || material->has_transmission || material->has_sheen || material->has_volume || material->has_emissive_strength || material->has_iridescence || material->has_anisotropy) + if (material->unlit || material->has_pbr_specular_glossiness || material->has_clearcoat || material->has_ior || material->has_specular || material->has_transmission || material->has_sheen || material->has_volume || material->has_emissive_strength || material->has_iridescence || material->has_anisotropy || material->has_dispersion) { cgltf_write_line(context, "\"extensions\": {"); if (material->has_clearcoat) @@ -794,6 +800,13 @@ static void cgltf_write_material(cgltf_write_context* context, const cgltf_mater CGLTF_WRITE_TEXTURE_INFO("anisotropyTexture", params->anisotropy_texture); cgltf_write_line(context, "}"); } + if (material->has_dispersion) + { + cgltf_write_line(context, "\"KHR_materials_dispersion\": {"); + const cgltf_dispersion* params = &material->dispersion; + cgltf_write_floatprop(context, "dispersion", params->dispersion, 0.f); + cgltf_write_line(context, "}"); + } cgltf_write_line(context, "}"); } @@ -1279,6 +1292,9 @@ static void cgltf_write_extensions(cgltf_write_context* context, uint32_t extens if (extension_flags & CGLTF_EXTENSION_FLAG_MESH_GPU_INSTANCING) { cgltf_write_stritem(context, "EXT_mesh_gpu_instancing"); } + if (extension_flags & CGLTF_EXTENSION_FLAG_MATERIALS_DISPERSION) { + cgltf_write_stritem(context, "KHR_materials_dispersion"); + } } cgltf_size cgltf_write(const cgltf_options* options, char* buffer, cgltf_size size, const cgltf_data* data)