Add shadowmappingcascade rust shaders

Author: LegNeato

shaders/rust/Cargo.lock

@@ -136,6 +136,9 @@ members = [
     "vulkanscene/logo",
     "vulkanscene/mesh",
     "vulkanscene/skybox",
+    "shadowmappingcascade/depthpass",
+    "shadowmappingcascade/debugshadowmap",
+    "shadowmappingcascade/scene",
 ]
 
 [workspace.package]

shaders/rust/Cargo.toml

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

shaders/rust/shadowmappingcascade/debugshadowmap.frag.spv

@@ -0,0 +1,41 @@
+#![no_std]
+
+use spirv_std::glam::{Vec2, Vec3, Vec4};
+use spirv_std::spirv;
+use spirv_std::{Image, Sampler};
+
+#[repr(C)]
+#[derive(Copy, Clone)]
+pub struct PushConsts {
+    pub position: Vec4,
+    pub cascade_index: u32,
+}
+
+#[spirv(vertex)]
+pub fn main_vs(
+    #[spirv(vertex_index)] vertex_index: u32,
+    #[spirv(push_constant)] push_consts: &PushConsts,
+    #[spirv(position)] out_position: &mut Vec4,
+    out_uv: &mut Vec2,
+    #[spirv(flat)] out_cascade_index: &mut u32,
+) {
+    let uv = Vec2::new(
+        ((vertex_index << 1) & 2) as f32,
+        (vertex_index & 2) as f32,
+    );
+    *out_uv = uv;
+    *out_cascade_index = push_consts.cascade_index;
+    *out_position = Vec4::new(uv.x * 2.0 - 1.0, uv.y * 2.0 - 1.0, 0.0, 1.0);
+}
+
+#[spirv(fragment)]
+pub fn main_fs(
+    in_uv: Vec2,
+    #[spirv(flat)] in_cascade_index: u32,
+    #[spirv(descriptor_set = 0, binding = 1)] shadow_map: &Image!(2D, type=f32, sampled, arrayed),
+    #[spirv(descriptor_set = 0, binding = 1)] sampler: &Sampler,
+    out_frag_color: &mut Vec4,
+) {
+    let depth = shadow_map.sample(*sampler, Vec3::new(in_uv.x, in_uv.y, in_cascade_index as f32)).x;
+    *out_frag_color = Vec4::new(depth, depth, depth, 1.0);
+}

shaders/rust/shadowmappingcascade/debugshadowmap.vert.spv

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

shaders/rust/shadowmappingcascade/debugshadowmap/Cargo.toml

@@ -0,0 +1,46 @@
+#![no_std]
+
+use spirv_std::glam::{Mat4, Vec2, Vec3, Vec4, Vec4Swizzles};
+use spirv_std::spirv;
+use spirv_std::{Image, Sampler};
+
+const SHADOW_MAP_CASCADE_COUNT: usize = 4;
+
+#[repr(C)]
+#[derive(Copy, Clone)]
+pub struct PushConsts {
+    pub position: Vec4,
+    pub cascade_index: u32,
+}
+
+#[repr(C)]
+#[derive(Copy, Clone)]
+pub struct UBO {
+    pub cascade_view_proj_mat: [Mat4; SHADOW_MAP_CASCADE_COUNT],
+}
+
+#[spirv(vertex)]
+pub fn main_vs(
+    in_pos: Vec3,
+    in_uv: Vec2,
+    #[spirv(push_constant)] push_consts: &PushConsts,
+    #[spirv(uniform, descriptor_set = 0, binding = 3)] ubo: &UBO,
+    #[spirv(position)] out_position: &mut Vec4,
+    out_uv: &mut Vec2,
+) {
+    *out_uv = in_uv;
+    let pos = in_pos + push_consts.position.xyz();
+    *out_position = ubo.cascade_view_proj_mat[push_consts.cascade_index as usize] * Vec4::from((pos, 1.0));
+}
+
+#[spirv(fragment)]
+pub fn main_fs(
+    in_uv: Vec2,
+    #[spirv(descriptor_set = 1, binding = 0)] color_map: &Image!(2D, type=f32, sampled),
+    #[spirv(descriptor_set = 1, binding = 0)] sampler: &Sampler,
+) {
+    let alpha = color_map.sample(*sampler, in_uv).w;
+    if alpha < 0.5 {
+        spirv_std::arch::kill();
+    }
+}