added underdeveloped but working image support (no freeing or samplers)

src/render/shader.wgsl

@@ -1,9 +1,29 @@
 const RECT: u32 = 0;
+const TEXTURE: u32 = 1;
 
 @group(0) @binding(0)
 var<uniform> window: WindowUniform;
 @group(1) @binding(RECT)
-var<storage> rects: array<RoundedRect>;
+var<storage> rects: array<Rect>;
+@group(1) @binding(TEXTURE)
+var<storage> textures: array<TextureInfo>;
+
+struct Rect {
+    color: u32,
+    radius: f32,
+    thickness: f32,
+    inner_radius: f32,
+}
+
+struct TextureInfo {
+    view_idx: u32,
+    sampler_idx: u32,
+}
+
+@group(2) @binding(0)
+var views: binding_array<texture_2d<f32>>;
+@group(2) @binding(1)
+var samplers: binding_array<sampler>;
 
 struct WindowUniform {
     dim: vec2<f32>,
@@ -18,23 +38,18 @@ struct InstanceInput {
     @location(5) idx: u32,
 }
 
-struct RoundedRect {
-    color: u32,
-    radius: f32,
-    thickness: f32,
-    inner_radius: f32,
-}
-
 struct VertexOutput {
     @location(0) top_left: vec2<f32>,
     @location(1) bot_right: vec2<f32>,
-    @location(2) binding: u32,
-    @location(3) idx: u32,
+    @location(2) uv: vec2<f32>,
+    @location(3) binding: u32,
+    @location(4) idx: u32,
     @builtin(position) clip_position: vec4<f32>,
 };
 
 struct Region {
     pos: vec2<f32>,
+    uv: vec2<f32>,
     top_left: vec2<f32>,
     bot_right: vec2<f32>,
 }
@@ -50,12 +65,13 @@ fn vs_main(
     let bot_right = in.bottom_right_anchor * window.dim + in.bottom_right_offset;
     let size = bot_right - top_left;
 
-    var pos = top_left + vec2<f32>(
+    let uv = vec2<f32>(
         f32(vi % 2u),
         f32(vi / 2u)
-    ) * size;
-    pos = pos / window.dim * 2.0 - 1.0;
+    );
+    let pos = (top_left + uv * size) / window.dim * 2.0 - 1.0;
     out.clip_position = vec4<f32>(pos.x, -pos.y, 0.0, 1.0);
+    out.uv = uv;
     out.binding = in.binding;
     out.idx = in.idx;
     out.top_left = top_left;
@@ -69,19 +85,27 @@ fn fs_main(
     in: VertexOutput
 ) -> @location(0) vec4<f32> {
     let pos = in.clip_position.xy;
-    let region = Region(pos, in.top_left, in.bot_right);
+    let region = Region(pos, in.uv, in.top_left, in.bot_right);
     let i = in.idx;
     switch in.binding {
         case RECT: {
             return draw_rounded_rect(region, rects[i]);
         }
+        case TEXTURE: {
+            return draw_texture(region, textures[i]);
+        }
         default: {
             return vec4(1.0, 0.0, 1.0, 1.0);
         }
     }
 }
 
-fn draw_rounded_rect(region: Region, rect: RoundedRect) -> vec4<f32> {
+// TODO: this seems really inefficient (per frag indexing)?
+fn draw_texture(region: Region, info: TextureInfo) -> vec4<f32> {
+    return textureSample(views[info.view_idx], samplers[info.sampler_idx], region.uv);
+}
+
+fn draw_rounded_rect(region: Region, rect: Rect) -> vec4<f32> {
     var color = read_color(rect.color);
 
     let edge = 0.5;
@@ -106,7 +130,7 @@ fn distance_from_rect(pixel_pos: vec2<f32>, rect_center: vec2<f32>, rect_corner:
     let p = pixel_pos - rect_center;
     // vec from inner rect corner to pixel
     let q = abs(p) - (rect_corner - radius);
-    return length(max(q, vec2<f32>(0.0, 0.0))) - radius;
+    return length(max(q, vec2(0.0))) - radius;
 }
 
 fn read_color(c: u32) -> vec4<f32> {