Check OpenGL readback byte counts

src/renderer_gl/opengl_capabilities.cpp

@@ -1,6 +1,7 @@
 #include "renderer_gl/opengl_capabilities.h"
 
 #include <array>
+#include <limits>
 
 namespace pp::renderer::gl {
 
@@ -284,7 +285,22 @@ std::uint64_t readback_byte_count(
     std::uint32_t width,
     std::uint32_t height) noexcept
 {
-    return static_cast<std::uint64_t>(width) * height * format.bytes_per_pixel;
+    if (format.bytes_per_pixel == 0U) {
+        return 0U;
+    }
+
+    const auto wide_width = static_cast<std::uint64_t>(width);
+    const auto wide_height = static_cast<std::uint64_t>(height);
+    if (wide_width != 0U && wide_height > std::numeric_limits<std::uint64_t>::max() / wide_width) {
+        return 0U;
+    }
+
+    const auto pixels = wide_width * wide_height;
+    if (pixels != 0U && format.bytes_per_pixel > std::numeric_limits<std::uint64_t>::max() / pixels) {
+        return 0U;
+    }
+
+    return pixels * format.bytes_per_pixel;
 }
 
 std::uint32_t pixel_pack_buffer_target() noexcept