Add gltfskinning rust shader

Author: LegNeato

shaders/rust/Cargo.lock

@@ -35,6 +35,7 @@ members = [
     "gears",
     "gltfloading/mesh",
     "gltfscenerendering/scene",
+    "gltfskinning/skinnedmodel",
     "hdr/bloom",
     "hdr/composition",
     "hdr/gbuffer",

shaders/rust/Cargo.toml

@@ -0,0 +1,10 @@
+[package]
+name = "gltfskinning-skinnedmodel"
+version = "0.1.0"
+edition.workspace = true
+
+[lib]
+crate-type = ["dylib"]
+
+[dependencies]
+spirv-std = { workspace = true }

shaders/rust/gltfskinning/skinnedmodel.frag.spv

@@ -0,0 +1,95 @@
+#![cfg_attr(target_arch = "spirv", no_std)]
+#![allow(clippy::missing_safety_doc)]
+
+use spirv_std::{spirv, glam::{mat3, vec3, vec4, Mat4, Vec2, Vec3, Vec4}, Image, num_traits::Float};
+use spirv_std::image::SampledImage;
+
+#[repr(C)]
+#[derive(Copy, Clone)]
+pub struct UboScene {
+    pub projection: Mat4,
+    pub view: Mat4,
+    pub light_pos: Vec4,
+}
+
+#[repr(C)]
+#[derive(Copy, Clone)]
+pub struct PushConsts {
+    pub model: Mat4,
+}
+
+#[spirv(vertex)]
+pub fn main_vs(
+    in_pos: Vec3,
+    in_normal: Vec3,
+    in_uv: Vec2,
+    in_color: Vec3,
+    in_joint_indices: Vec4,
+    in_joint_weights: Vec4,
+    #[spirv(uniform, descriptor_set = 0, binding = 0)] ubo_scene: &UboScene,
+    #[spirv(push_constant)] push_consts: &PushConsts,
+    #[spirv(storage_buffer, descriptor_set = 1, binding = 0)] joint_matrices: &[Mat4],
+    #[spirv(position)] out_position: &mut Vec4,
+    out_normal: &mut Vec3,
+    out_color: &mut Vec3,
+    out_uv: &mut Vec2,
+    out_view_vec: &mut Vec3,
+    out_light_vec: &mut Vec3,
+) {
+    *out_normal = in_normal;
+    *out_color = in_color;
+    *out_uv = in_uv;
+
+    // Calculate skinned matrix from weights and joint indices of the current vertex
+    let skin_mat = 
+        in_joint_weights.x * joint_matrices[in_joint_indices.x as usize] +
+        in_joint_weights.y * joint_matrices[in_joint_indices.y as usize] +
+        in_joint_weights.z * joint_matrices[in_joint_indices.z as usize] +
+        in_joint_weights.w * joint_matrices[in_joint_indices.w as usize];
+
+    *out_position = ubo_scene.projection * ubo_scene.view * push_consts.model * skin_mat * vec4(in_pos.x, in_pos.y, in_pos.z, 1.0);
+    
+    // Transform normal with model and skin matrices (matching slang version)
+    let model_mat3 = mat3(
+        push_consts.model.x_axis.truncate(),
+        push_consts.model.y_axis.truncate(),
+        push_consts.model.z_axis.truncate(),
+    );
+    let skin_mat3 = mat3(
+        skin_mat.x_axis.truncate(),
+        skin_mat.y_axis.truncate(),
+        skin_mat.z_axis.truncate(),
+    );
+    *out_normal = model_mat3 * skin_mat3 * in_normal;
+
+    let pos = ubo_scene.view * vec4(in_pos.x, in_pos.y, in_pos.z, 1.0);
+    let view_mat3 = mat3(
+        ubo_scene.view.x_axis.truncate(),
+        ubo_scene.view.y_axis.truncate(),
+        ubo_scene.view.z_axis.truncate(),
+    );
+    let l_pos = view_mat3 * ubo_scene.light_pos.truncate();
+    *out_light_vec = l_pos - pos.truncate();
+    *out_view_vec = -pos.truncate();
+}
+
+#[spirv(fragment)]
+pub fn main_fs(
+    in_normal: Vec3,
+    in_color: Vec3,
+    in_uv: Vec2,
+    in_view_vec: Vec3,
+    in_light_vec: Vec3,
+    #[spirv(descriptor_set = 2, binding = 0)] sampler_color_map: &SampledImage<Image!(2D, type=f32, sampled)>,
+    out_frag_color: &mut Vec4,
+) {
+    let color = sampler_color_map.sample(in_uv) * vec4(in_color.x, in_color.y, in_color.z, 1.0);
+
+    let n = in_normal.normalize();
+    let l = in_light_vec.normalize();
+    let v = in_view_vec.normalize();
+    let r = (-l).reflect(n);
+    let diffuse = n.dot(l).max(0.5) * in_color;
+    let specular = v.dot(r).max(0.0).powf(16.0) * vec3(0.75, 0.75, 0.75);
+    *out_frag_color = vec4(diffuse.x * color.x + specular.x, diffuse.y * color.y + specular.y, diffuse.z * color.z + specular.z, 1.0);
+}