Add texture3d rust shader

Author: LegNeato

shaders/rust/Cargo.lock

@@ -61,6 +61,7 @@ members = [
     "instancing/instancing",
     "instancing/planet",
     "instancing/starfield",
+    "texture3d",
 ]
 
 [workspace.dependencies]

shaders/rust/Cargo.toml

@@ -0,0 +1,10 @@
+[package]
+name = "texture3d"
+version = "0.1.0"
+edition = "2021"
+
+[lib]
+crate-type = ["dylib"]
+
+[dependencies]
+spirv-std = { workspace = true }

shaders/rust/texture3d/Cargo.toml

@@ -0,0 +1,80 @@
+#![cfg_attr(target_arch = "spirv", no_std)]
+
+use spirv_std::spirv;
+use spirv_std::glam::{vec3, vec4, Mat4, Vec2, Vec3, Vec4};
+use spirv_std::num_traits::Float;
+
+#[repr(C)]
+pub struct UBO {
+    projection: Mat4,
+    model: Mat4,
+    view_pos: Vec4,
+    depth: f32,
+}
+
+#[spirv(vertex)]
+pub fn main_vs(
+    in_pos: Vec3,
+    in_uv: Vec2,
+    in_normal: Vec3,
+    #[spirv(uniform, descriptor_set = 0, binding = 0)] ubo: &UBO,
+    #[spirv(position)] out_position: &mut Vec4,
+    out_uv: &mut Vec3,
+    out_lod_bias: &mut f32,
+    out_normal: &mut Vec3,
+    out_view_vec: &mut Vec3,
+    out_light_vec: &mut Vec3,
+) {
+    *out_uv = vec3(in_uv.x, in_uv.y, ubo.depth);
+    
+    let world_pos = (ubo.model * vec4(in_pos.x, in_pos.y, in_pos.z, 1.0)).truncate();
+    
+    *out_position = ubo.projection * ubo.model * vec4(in_pos.x, in_pos.y, in_pos.z, 1.0);
+    
+    let pos = ubo.model * vec4(in_pos.x, in_pos.y, in_pos.z, 1.0);
+    
+    // Transform normal by inverse transpose of model matrix
+    let normal_matrix = ubo.model.inverse().transpose();
+    *out_normal = normal_matrix.transform_vector3(in_normal);
+    
+    let light_pos = Vec3::ZERO;
+    let l_pos = ubo.model.transform_vector3(light_pos);
+    *out_light_vec = l_pos - pos.truncate();
+    *out_view_vec = ubo.view_pos.truncate() - pos.truncate();
+    
+    // Note: out_lod_bias is not used in the GLSL shader, leaving uninitialized
+    *out_lod_bias = 0.0;
+}
+
+// Reflect function
+fn reflect(i: Vec3, n: Vec3) -> Vec3 {
+    i - 2.0 * n.dot(i) * n
+}
+
+#[spirv(fragment)]
+pub fn main_fs(
+    in_uv: Vec3,
+    _in_lod_bias: f32,
+    in_normal: Vec3,
+    in_view_vec: Vec3,
+    in_light_vec: Vec3,
+    #[spirv(descriptor_set = 0, binding = 1)] sampler_color: &spirv_std::image::SampledImage<spirv_std::image::Image3d>,
+    out_color: &mut Vec4,
+) {
+    let color = sampler_color.sample(in_uv);
+    
+    let n = in_normal.normalize();
+    let l = in_light_vec.normalize();
+    let v = in_view_vec.normalize();
+    let r = reflect(-l, n);
+    
+    let diffuse = n.dot(l).max(0.0) * vec3(1.0, 1.0, 1.0);
+    let specular = r.dot(v).max(0.0).powf(16.0) * color.x;
+    
+    *out_color = vec4(
+        diffuse.x * color.x + specular,
+        diffuse.y * color.x + specular,
+        diffuse.z * color.x + specular,
+        1.0
+    );
+}