SCAN_RATE in AIPlayer::isSupplySourceAttacked() uses frames instead of seconds, causing AI to "forget" attacks after 0.33 seconds #2386

Prerequisites

• I have searched for similar issues and confirmed this is not a duplicate

Game Version

• Command & Conquer Generals
• Command & Conquer Generals: Zero Hour
• Other (please specify below)

Bug Description

In AIPlayer::isSupplySourceAttacked(), the constant SCAN_RATE is set to 10 with a comment stating "don't scan more often than every 10 seconds". However, this value is used directly with frame numbers without multiplying by LOGICFRAMES_PER_SECOND, resulting in a 10-frame window (~0.33 seconds) instead of the intended 10-second window.

File: GeneralsGameCode/Generals/Code/GameEngine/Source/GameLogic/AI/AIPlayer.cpp

const Int SCAN_RATE = 10; // don't scan more often than every 10 seconds.

How SCAN_RATE is Used

Player attack recency check:

if (m_player->getAttackedFrame() + SCAN_RATE < curFrame) {
    return false; // haven't been attacked recently.
}

Object damage recency check:

if (body->getLastDamageTimestamp() + SCAN_RATE > curFrame) {
    m_attackedSupplyCenter = obj->getID();
    return true;
}

Expected vs Actual Behavior

Calculation

• Game logic runs at 30 FPS (LOGICFRAMES_PER_SECOND = 30)
• SCAN_RATE = 10 frames
• 10 frames / 30 FPS = 0.33 seconds

Impact on Gameplay

Most units fire every 2-3 seconds. If an enemy attacks the AI's harvester:

1. Frame 1000: Enemy hits harvester. getLastDamageTimestamp() = 1000
2. Frame 1011 (~0.36 sec later): AI checks isSupplySourceAttacked()
3. 1000 + 10 = 1010, but 1010 < 1011 → AI thinks attack is over
4. AI does not send guards, while harvester continues to be destroyed

The AI only detects an attack if the check happens within 0.33 seconds of the last hit. With typical AI script intervals of 5+ seconds, the probability of detection is approximately 6-7%.

Comparison with Other Timers in AIPlayer.cpp

All other second-based timers in the same file correctly use multiplication:

• m_teamTimer = m_teamSeconds * LOGICFRAMES_PER_SECOND
• m_structureTimer = TheAI->getAiData()->m_structureSeconds * LOGICFRAMES_PER_SECOND
• team->m_frameStarted + 60 * LOGICFRAMES_PER_SECOND

Only SCAN_RATE is missing the multiplier.

Suggested Fix

const Int SCAN_RATE = 10 * LOGICFRAMES_PER_SECOND; // 300 frames = 10 seconds

Reproduction Steps

1. Start a skirmish game against an AI opponent (any difficulty)
2. Wait for the AI to build harvesters and begin collecting resources
3. Send a single slow-firing unit (e.g., Tank, Missile Defender) to attack the AI's harvester
4. Observe that the AI rarely or never sends units to defend the harvester
5. The harvester is destroyed with minimal AI response

Note: This bug is in the source code logic and affects AI behavior probabilistically. The AI will occasionally respond if the timing aligns with the 0.33-second window, but in most cases it will not react appropriately to sustained harassment.

Additional Context

No response