From dbbdcf4be06c05f60798b322890c88b79d802bd8 Mon Sep 17 00:00:00 2001
From: 3gg <3gg@shellblade.net>
Date: Sat, 11 Feb 2023 09:13:18 -0800
Subject: Create default material for meshes that do not specify one.
---
gfx/src/util/scene.c | 101 +++++++++++++++++++++++++++++++++++----------------
1 file changed, 70 insertions(+), 31 deletions(-)
diff --git a/gfx/src/util/scene.c b/gfx/src/util/scene.c
index 49e661d..6f34922 100644
--- a/gfx/src/util/scene.c
+++ b/gfx/src/util/scene.c
@@ -803,13 +803,44 @@ static bool load_materials(
return true;
}
+/// Create a default material for meshes that do not have a material.
+static Material* make_default_material() {
+ MaterialDesc desc = (MaterialDesc){0};
+
+ assert(desc.num_uniforms < GFX_MAX_UNIFORMS_PER_MATERIAL);
+ desc.uniforms[desc.num_uniforms++] = (ShaderUniform){
+ .name = sstring_make(UNIFORM_BASE_COLOR_FACTOR),
+ .type = UniformVec4,
+ .value.vec4 = vec4_make(1, 1, 1, 1)};
+
+ assert(desc.num_uniforms < GFX_MAX_UNIFORMS_PER_MATERIAL);
+ desc.uniforms[desc.num_uniforms++] = (ShaderUniform){
+ .name = sstring_make(UNIFORM_METALLIC_FACTOR),
+ .type = UniformFloat,
+ .value.scalar = 0};
+
+ assert(desc.num_uniforms < GFX_MAX_UNIFORMS_PER_MATERIAL);
+ desc.uniforms[desc.num_uniforms++] = (ShaderUniform){
+ .name = sstring_make(UNIFORM_ROUGHNESS_FACTOR),
+ .type = UniformFloat,
+ .value.scalar = 1};
+
+ assert(desc.num_uniforms < GFX_MAX_UNIFORMS_PER_MATERIAL);
+ desc.uniforms[desc.num_uniforms++] = (ShaderUniform){
+ .name = sstring_make(UNIFORM_EMISSIVE_FACTOR),
+ .type = UniformVec3,
+ .value.vec3 = vec3_make(0, 0, 0)};
+
+ return gfx_make_material(&desc);
+}
+
/// Load all meshes from the glTF scene.
static bool load_meshes(
const cgltf_data* data, Gfx* gfx, Buffer** buffers,
Buffer** tangent_buffers, const cgltfTangentBuffer* cgltf_tangent_buffers,
- cgltf_size num_tangent_buffers, Material** materials, ShaderProgram* shader,
- size_t primitive_count, Geometry** geometries, Mesh** meshes,
- SceneObject** scene_objects) {
+ cgltf_size num_tangent_buffers, Material** materials,
+ ShaderProgram* const shader, size_t primitive_count, Geometry** geometries,
+ Mesh** meshes, SceneObject** scene_objects) {
// Walk through the mesh primitives to create Meshes. A GLTF mesh primitive
// has a material (Mesh) and vertex data (Geometry). A GLTF mesh maps to
// a SceneObject.
@@ -852,16 +883,21 @@ static bool load_meshes(
const cgltf_primitive* prim = &mesh->primitives[p];
const cgltf_material* mat = prim->material;
- MeshPermutation perm = {0};
- perm.has_normal_map = mat->normal_texture.texture != 0;
- perm.has_occlusion_map = mat->occlusion_texture.texture != 0;
- perm.has_emissive_map = mat->emissive_texture.texture != 0;
- // TODO: specular/glossiness and other material parameters.
- if (mat->has_pbr_metallic_roughness) {
- const cgltf_pbr_metallic_roughness* pbr = &mat->pbr_metallic_roughness;
- perm.has_albedo_map = pbr->base_color_texture.texture != 0;
- perm.has_metallic_roughness_map =
- pbr->metallic_roughness_texture.texture != 0;
+ MeshPermutation perm = {0};
+ if (mat) {
+ perm.has_normal_map = mat->normal_texture.texture != 0;
+ perm.has_occlusion_map = mat->occlusion_texture.texture != 0;
+ perm.has_emissive_map = mat->emissive_texture.texture != 0;
+
+ if (mat->has_pbr_metallic_roughness) {
+ const cgltf_pbr_metallic_roughness* pbr =
+ &mat->pbr_metallic_roughness;
+ perm.has_albedo_map = pbr->base_color_texture.texture != 0;
+ perm.has_metallic_roughness_map =
+ pbr->metallic_roughness_texture.texture != 0;
+ } else {
+ // TODO: specular/glossiness and other material parameters.
+ }
}
GeometryDesc geometry_desc = {
@@ -1034,36 +1070,39 @@ static bool load_meshes(
CHECK_COUNT(weights.u16, uint16_t, 4);
CHECK_COUNT(weights.floats, float, 4);
- const cgltf_size material_index = prim->material - data->materials;
- assert(material_index < data->materials_count);
- Material* material = materials[material_index];
+ Material* material = 0;
+ if (mat) {
+ const cgltf_size material_index = mat - data->materials;
+ assert(material_index < data->materials_count);
+ material = materials[material_index];
+ } else {
+ // Create a default material for meshes that do not specify one.
+ material = make_default_material();
+ }
+ assert(material);
geometries[next_mesh] = gfx_make_geometry(render_backend, &geometry_desc);
if (!geometries[next_mesh]) {
return false;
}
- // If the user specifies a custom shader, use that instead.
- // else TODO: Build a shader based on permutation.
+ // If the user specifies a custom shader, use that instead. Otherwise
+ // compile a shader based on the mesh's permutation.
//
- // TODO: We should cache shader permutations to re-use shader programs.
- // Caching should not be done locally here because a caller may call
- // gfx_load_scene() multiple times to load multiple scenes, and we want
- // shader re-use across scenes too.
+ // Note that Gfx takes care of caching shaders and shader programs.
//
- // On the other hand, caching materials is not necessary since, provided
- // they can share shaders, the renderer can check later whether uniforms
- // have the same values. Also, changing uniforms is much faster than
- // swapping shaders, so shader caching is the most important thing here.
- if (!shader) {
- shader = make_shader_permutation(render_backend, perm);
- }
- assert(shader);
+ // Caching materials could be useful, but, provided they can share
+ // shaders, the renderer can check later whether uniforms have the same
+ // values. Also, changing uniforms is much faster than swapping shaders,
+ // so shader caching is the most important thing here.
+ ShaderProgram* mesh_shader =
+ shader ? shader : make_shader_permutation(render_backend, perm);
+ assert(mesh_shader);
meshes[next_mesh] = gfx_make_mesh(&(MeshDesc){
.geometry = geometries[next_mesh],
.material = material,
- .shader = shader});
+ .shader = mesh_shader});
if (!meshes[next_mesh]) {
return false;
--
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