Improvement Request: add VBI hook capability

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I'd like TVout to have the ability to call a hook during the vertical blanking 
interval.  I am using this capability to communicate with an I2C device.

Example implementation

TVout.h:
// declaration of set_vbi_hook function
void set_vbi_hook(void (*func)());

TVout.cpp:
// implementation of set_vbi_hook
void TVout::set_vbi_hook(void (*func)()) {
  vbi_hook = func;
}

video_gen.h:
// extern declaration of vbi_hook function pointer
extern void (*vbi_hook)();

video_gen.cpp:
// declaration of vbi_hook function pointer and invocation of function at 
beginning of VBI
void (*vbi_hook)();

// in active_line()...
    if ((display.scanLine + 1) == display.stop_render) {
        line_handler = &blank_line;
        if (vbi_hook != 0) {
          vbi_hook();
        }
    }

Let me know if you have any questions; this should be pretty self explanatory 
for you.

Original issue reported on code.google.com by nootropi...@gmail.com on 15 Oct 2010 at 9:02

[GoogleCodeExporter]

Original comment by mdmetzle@gmail.com on 15 Oct 2010 at 9:59

• Added labels: Type-Enhancement
• Removed labels: Type-Defect

[GoogleCodeExporter]

Original comment by mdmetzle@gmail.com on 15 Oct 2010 at 11:23

• Changed state: Accepted

[GoogleCodeExporter]

Original comment by mdmetzle@gmail.com on 17 Oct 2010 at 4:29

• Added labels: Milestone-Release1.0

[GoogleCodeExporter]

Original comment by mdmetzle@gmail.com on 21 Oct 2010 at 2:23

• Changed state: Fixed