Basic fog lighting, refactoring

res/shaders/light.wgsl

@@ -1,26 +1,29 @@
-#include globals.wgsl
+fn sample_direct_light(index: i32, light_coords: vec4<f32>) -> f32 {
+    if (light_coords.w <= 0.0) {
+        return 0.0;
+    }
 
-struct LightVertexInput {
-    @location(0) position: vec3<f32>,
-};
+    let flip_correction = vec2<f32>(0.5, -0.5);
+    let proj_correction = 1.0 / light_coords.w;
+    let light_local = light_coords.xy * flip_correction * proj_correction + vec2<f32>(0.5, 0.5);
+    let bias = 0.000001;
+    let reference_depth = light_coords.z * proj_correction - bias;
 
-struct LightVertexOutput {
-    @builtin(position) clip_position: vec4<f32>,
-    @location(0) color: vec3<f32>,
-};
+    var total_sample = 0.0;
+    for (var x: i32 = -SHADOW_SAMPLES; x < SHADOW_SAMPLES; x++) {
+        for (var y: i32 = -SHADOW_SAMPLES; y < SHADOW_SAMPLES; y++) {
+            let texelSize = vec2<f32>(textureDimensions(t_light_depth));
+            let offset = vec2<f32>(f32(x), f32(y)) / texelSize.xy;
+            let s = textureSampleCompare(
+                t_light_depth,
+                s_light_depth,
+                light_local + offset,
+                index,
+                reference_depth
+            );
+            total_sample += s * INV_SHADOW_SAMPLES;
+        }
+    }
 
-@vertex
-fn vs_main(
-    model: LightVertexInput,
-) -> LightVertexOutput {
-    let scale = 10.0;
-    var out: LightVertexOutput;
-    out.clip_position = camera.proj * camera.view * vec4<f32>(model.position * scale + light.position, 1.0);
-    out.color = light.color.xyz;
-    return out;
-}
-
-@fragment
-fn fs_main(in: LightVertexOutput) -> @location(0) vec4<f32> {
-    return vec4<f32>(in.color, 1.0);
+    return total_sample;
 }