Refactor to allow running examples

blog/2025-03-30-draw-compute-shader/draw-compute/shader/src/lib.rs

@@ -1,15 +1,25 @@
 #![no_std]
-
 use glam::Vec4Swizzles;
 use spirv_std::spirv;
 
+pub trait DrawSettings: Copy + Sized + bytemuck::Pod + bytemuck::Zeroable {}
+
 #[derive(Copy, Clone, bytemuck::Pod, bytemuck::Zeroable)]
 #[repr(C)]
-pub struct Viewport {
-    pub offset: glam::UVec2,
-    pub size: glam::UVec2,
-    pub image: glam::UVec2,
+pub struct DrawSized {
+    pub image_size: glam::UVec2,
+    pub viewport_size: glam::UVec2,
 }
+impl DrawSettings for DrawSized {}
+
+#[derive(Copy, Clone, bytemuck::Pod, bytemuck::Zeroable)]
+#[repr(C)]
+pub struct DrawRect {
+    pub image_size: glam::UVec2,
+    pub viewport_size: glam::UVec2,
+    pub viewport_offset: glam::UVec2,
+}
+impl DrawSettings for DrawRect {}
 
 const BLOCK_SIZE: usize = 16;
 const BLACK: glam::Vec4 = glam::vec4(0.0, 0.0, 0.0, 1.0);
@@ -19,13 +29,37 @@ fn image_index(x: usize, y: usize, width: usize) -> usize {
     y * width + x
 }
 
+fn in_bounds(image_coordinate: glam::Vec2, image_size: glam::Vec2) -> bool {
+    image_coordinate.cmpge(glam::Vec2::ZERO).all() && image_coordinate.cmplt(image_size).all()
+}
+
 #[spirv(compute(threads(1)))]
-pub fn main_cs(
-    #[spirv(uniform, descriptor_set = 0, binding = 0)] viewport: &Viewport,
+pub fn main_cs_bounding(
+    #[spirv(uniform, descriptor_set = 0, binding = 0)] viewport: &DrawSized,
     #[spirv(storage_buffer, descriptor_set = 0, binding = 1)] image: &mut [glam::Vec4],
 ) {
-    let width = viewport.image.x as usize;
-    let height = viewport.image.y as usize;
+    let width = viewport.image_size.x as usize;
+    let height = viewport.image_size.y as usize;
+
+    for x in 0..width {
+        for y in 0..height {
+            image[image_index(x, y, width)] =
+                if x == 0 || x == width - 1 || y == 0 || y == height - 1 {
+                    WHITE
+                } else {
+                    BLACK
+                }
+        }
+    }
+}
+
+#[spirv(compute(threads(1)))]
+pub fn main_cs_blocks(
+    #[spirv(uniform, descriptor_set = 0, binding = 0)] viewport: &DrawSized,
+    #[spirv(storage_buffer, descriptor_set = 0, binding = 1)] image: &mut [glam::Vec4],
+) {
+    let width = viewport.image_size.x as usize;
+    let height = viewport.image_size.y as usize;
     for x in 0..width {
         let x_even = x / BLOCK_SIZE % 2 == 0;
         for y in 0..height {
@@ -48,24 +82,50 @@ pub fn main_vs(
 }
 
 #[spirv(fragment)]
-pub fn main_fs(
+pub fn main_fs_size(
     #[spirv(frag_coord)] frag_coord: glam::Vec4,
-    #[spirv(uniform, descriptor_set = 0, binding = 0)] viewport: &Viewport,
+    #[spirv(uniform, descriptor_set = 0, binding = 0)] draw_settings: &DrawSized,
     #[spirv(storage_buffer, descriptor_set = 0, binding = 1)] image: &mut [glam::Vec4],
     output: &mut glam::Vec4,
 ) {
-    let vp_size = viewport.size.as_vec2();
-    let img_size = viewport.image.as_vec2();
+    let vp_size = draw_settings.viewport_size.as_vec2();
+    let img_size = draw_settings.image_size.as_vec2();
 
     let scale = (vp_size / img_size).min_element();
     let img_offset = (vp_size / scale - img_size) / 2.0;
-    let img_coord = (frag_coord.xy() - viewport.offset.as_vec2()) / scale - img_offset;
+    let img_coord = frag_coord.xy() / scale - img_offset;
 
-    *output = if img_coord.cmpge(glam::Vec2::ZERO).all() && img_coord.cmple(img_size).all() {
+    *output = if in_bounds(img_coord, img_size) {
         image[image_index(
             img_coord.x as usize,
             img_coord.y as usize,
-            viewport.image.x as usize,
+            img_size.x as usize,
+        )]
+    } else {
+        BLACK
+    }
+}
+
+#[spirv(fragment)]
+pub fn main_fs_rect(
+    #[spirv(frag_coord)] frag_coord: glam::Vec4,
+    #[spirv(uniform, descriptor_set = 0, binding = 0)] draw_settings: &DrawRect,
+    #[spirv(storage_buffer, descriptor_set = 0, binding = 1)] image: &mut [glam::Vec4],
+    output: &mut glam::Vec4,
+) {
+    let vp_size = draw_settings.viewport_size.as_vec2();
+    let img_size = draw_settings.image_size.as_vec2();
+
+    let scale = (vp_size / img_size).min_element();
+    let img_offset = (vp_size / scale - img_size) / 2.0;
+    let img_coord =
+        (frag_coord.xy() - draw_settings.viewport_offset.as_vec2()) / scale - img_offset;
+
+    *output = if in_bounds(img_coord, img_size) {
+        image[image_index(
+            img_coord.x as usize,
+            img_coord.y as usize,
+            img_size.x as usize,
         )]
     } else {
         BLACK