Add renderer scissor state contract

src/renderer_api/renderer_api.cpp

@@ -131,6 +131,38 @@ pp::foundation::Status validate_viewport(Viewport viewport, Extent2D target_exte
     return pp::foundation::Status::success();
 }
 
+pp::foundation::Status validate_scissor(ScissorRect scissor, Extent2D target_extent) noexcept
+{
+    const auto extent_status = validate_extent(target_extent);
+    if (!extent_status.ok()) {
+        return extent_status;
+    }
+
+    if (!scissor.enabled) {
+        return pp::foundation::Status::success();
+    }
+
+    if (scissor.x < 0 || scissor.y < 0) {
+        return pp::foundation::Status::invalid_argument("scissor origin must be non-negative");
+    }
+
+    if (scissor.width == 0 || scissor.height == 0) {
+        return pp::foundation::Status::invalid_argument("scissor size must be greater than zero");
+    }
+
+    const auto x = static_cast<std::uint32_t>(scissor.x);
+    const auto y = static_cast<std::uint32_t>(scissor.y);
+    if (x > target_extent.width || y > target_extent.height) {
+        return pp::foundation::Status::out_of_range("scissor origin is outside the render target");
+    }
+
+    if (scissor.width > target_extent.width - x || scissor.height > target_extent.height - y) {
+        return pp::foundation::Status::out_of_range("scissor exceeds render target bounds");
+    }
+
+    return pp::foundation::Status::success();
+}
+
 pp::foundation::Status validate_blend_factor(BlendFactor factor) noexcept
 {
     switch (factor) {