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

test/functions.zig

@@ -108,3 +108,90 @@ test "Nested function calls" {
         });
     }
 }
+
+test "Function params" {
+    const allocator = std.testing.allocator;
+    const shader =
+        \\ [nzsl_version("1.1")]
+        \\ module;
+        \\
+        \\ struct FragOut
+        \\ {
+        \\     [location(0)] color: vec4[f32]
+        \\ }
+        \\
+        \\ fn affine(value: f32, scale: f32, bias: f32) -> f32
+        \\ {
+        \\     return value * scale + bias;
+        \\ }
+        \\
+        \\ fn combine(a: vec2[f32], b: vec2[f32]) -> vec4[f32]
+        \\ {
+        \\     let left = affine(a.x, b.x, b.y);
+        \\     let right = affine(a.y, b.y, b.x);
+        \\     return vec4[f32](left, right, left + right, left - right);
+        \\ }
+        \\
+        \\ [entry(frag)]
+        \\ fn main() -> FragOut
+        \\ {
+        \\     let output: FragOut;
+        \\     output.color = combine(vec2[f32](2.0, 3.0), vec2[f32](4.0, 5.0));
+        \\     return output;
+        \\ }
+    ;
+    const code = try compileNzsl(allocator, shader);
+    defer allocator.free(code);
+
+    try case.expect(.{
+        .source = code,
+        .expected_outputs = &.{
+            std.mem.asBytes(&[_]f32{ 13.0, 19.0, 32.0, -6.0 }),
+        },
+    });
+}
+
+test "Struct logic" {
+    const allocator = std.testing.allocator;
+    const shader =
+        \\ [nzsl_version("1.1")]
+        \\ module;
+        \\
+        \\ struct Pair
+        \\ {
+        \\     a: f32,
+        \\     b: f32
+        \\ }
+        \\
+        \\ struct FragOut
+        \\ {
+        \\     [location(0)] color: vec4[f32]
+        \\ }
+        \\
+        \\ fn eval(pair: Pair) -> vec2[f32]
+        \\ {
+        \\     return vec2[f32](pair.a + pair.b, pair.a * pair.b);
+        \\ }
+        \\
+        \\ [entry(frag)]
+        \\ fn main() -> FragOut
+        \\ {
+        \\     let pair: Pair;
+        \\     pair.a = 3.0;
+        \\     pair.b = 4.0;
+        \\     let v = eval(pair);
+        \\     let output: FragOut;
+        \\     output.color = vec4[f32](v.x, v.y, v.y - v.x, v.x + v.y);
+        \\     return output;
+        \\ }
+    ;
+    const code = try compileNzsl(allocator, shader);
+    defer allocator.free(code);
+
+    try case.expect(.{
+        .source = code,
+        .expected_outputs = &.{
+            std.mem.asBytes(&[_]f32{ 7.0, 12.0, 5.0, 19.0 }),
+        },
+    });
+}