adding lots of unit tests, improving image sampling, adding image sampling deref

test/ssbo.zig

@@ -3,7 +3,7 @@ const root = @import("root.zig");
 const compileNzsl = root.compileNzsl;
 const case = root.case;
 
-test "Simple SSBO" {
+test "SSBO read" {
     const allocator = std.testing.allocator;
     const shader =
         \\ [nzsl_version("1.1")]
@@ -58,3 +58,51 @@ test "Simple SSBO" {
         },
     });
 }
+
+test "SSBO write" {
+    const allocator = std.testing.allocator;
+    const shader =
+        \\ [nzsl_version("1.1")]
+        \\ module;
+        \\
+        \\ [layout(std430)]
+        \\ struct SSBO
+        \\ {
+        \\     data: dyn_array[u32]
+        \\ }
+        \\
+        \\ external
+        \\ {
+        \\     [set(0), binding(0)] ssbo: storage[SSBO],
+        \\ }
+        \\
+        \\ [entry(compute)]
+        \\ [workgroup(1, 1, 1)]
+        \\ fn main()
+        \\ {
+        \\     for i in u32(2) -> u32(8)
+        \\     {
+        \\         ssbo.data[i] = ssbo.data[i - u32(1)] + ssbo.data[i - u32(2)];
+        \\     }
+        \\ }
+    ;
+    const code = try compileNzsl(allocator, shader);
+    defer allocator.free(code);
+
+    var ssbo = [_]u32{ 1, 1, 0, 0, 0, 0, 0, 0 };
+    const expected = [_]u32{ 1, 1, 2, 3, 5, 8, 13, 21 };
+
+    try case.expect(.{
+        .source = code,
+        .descriptor_sets = &.{
+            &.{
+                std.mem.asBytes(&ssbo),
+            },
+        },
+        .expected_descriptor_sets = &.{
+            &.{
+                std.mem.asBytes(&expected),
+            },
+        },
+    });
+}