1 files changed, 21 insertions, 1 deletions
diff --git a/src/shader/instance.wgsl b/src/shader/instance.wgsl
index a549801..4b921ab 100644
--- a/src/shader/instance.wgsl
+++ b/src/shader/instance.wgsl
@@ -1,8 +1,16 @@
+const AMBIENT_LIGHT = vec4f(0.4, 0.4, 0.4, 1.0);
+const LIGHT_RESOLUTION = 1.0;
+
 struct Camera {
     scale: vec2f,
     centre: vec2f,
 };
 
+struct Lighting {
+    origin: vec2f,
+    _padding: vec2f,
+};
+
 struct Instance {
     centre: vec2f,
     cos_sin: vec2f,
@@ -15,6 +23,9 @@ struct Instance {
 @group(0) @binding(1) var<storage, read> palette: array<vec4f>;
 @group(0) @binding(2) var<storage, read> instances: array<Instance>;
 @group(0) @binding(3) var<storage, read> cells: array<u32>;
+@group(0) @binding(4) var lighting: texture_2d_array<f32>;
+@group(0) @binding(5) var light_sampler: sampler;
+@group(0) @binding(6) var<uniform> light_params: Lighting;
 
 struct VertexOutput {
     @builtin(position) clip_position: vec4f,
@@ -67,5 +78,14 @@ fn fs_main(in: VertexOutput) -> @location(0) vec4f {
         discard;
     }
 
-    return palette[material];
+    var total = vec3f(0.0);
+    let light_dims = vec2f(textureDimensions(lighting));
+    let light_texel = (in.world - light_params.origin) * LIGHT_RESOLUTION;
+    let light_uv = light_texel / light_dims;
+    for (var d = 0u; d < 4u; d++) {
+        total += textureSample(lighting, light_sampler, light_uv, d).rgb;
+    }
+    let light = vec4f(total.r, total.g, total.b, 1.0);
+
+    return palette[material] * (light + AMBIENT_LIGHT);
 }