7200 based systems = Any Apple 7200/xx system and any PowerComputing system based on the 7200.
Graphics Driver used for motherboard video on PowerMac 7200 based systems. This driver will also work on the motherboard video of PowerComputing's systems that are based on the 7200.
Fixes potential sparkles or "snow" that occur during palette animation and rapidly changing cursors. The driver in System 7.5.5 and earlier would sometimes hit the hardware that updated the CLUT during active video. This resulted in sparkles or snow.
The CLUT is changed by the Graphics Driver with the control routines SetEntries and DirectSetEntries. Previous drivers, when updating the CLUT would "spin loop" until the next VBL occurred and then update the hardware. A VBL occurs every 15 ms for a monitor with a resolution of 640x480@67Hz. So on average, the driver would spend 7 ms inside the spin loop each time the palette was changed.
The new driver saves the changes to a global variable and updates the hardware at the next VBL. The driver now spends about .2 ms in the SetEntries/DirectSetEntries code for each SetEntries or DirectSetEntries call.
Side Effect: Apps that fade the screen to black may now jump to black immediately. Previous Graphics Drivers would not return from SetEntries/DirectSetEntries until the hardware was updated. With this new behavior, an App can call SetEntries/DirectSetEntries multiple times and fade the CLUT to black before a VBL has occurred. Hence the monitor turns black immediately.
The 7200 Graphics Driver will be included in the next System Update AFTER 7.5.5. You can throw this extension away after you get the new System.
Kevin Williams
System
out of 10 (0 vote)
2 / 
2023-12-23 / 
2024-09-10 / 
602b0b9e854c02a7ce95cdf491a5be292f85c198 / 
/ 
7200GraphicsDriver1.3f0.hqx
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