New TFT Extension Library

Development Libraries
62

small test - // cos = sqrt(1-sin*sin); to calculate a faster cos()
"draw" your conclusions.

// Released to the public domain
uint32_t start;
uint32_t stop;
float deg_to_rad = 3.14159265/180;
int x;
int y;


void setup() 
{
  Serial.begin(115200);
  Serial.println("Start ");

  start = micros();
  drawGauge(100, 10); 
  stop = micros();
  Serial.println(stop - start);

  start = micros();
  drawGauge1(100, 10); 
  stop = micros();
  Serial.println(stop - start);
  Serial.println(x);
  Serial.println(y);
}

void loop() 
{
}

void drawGauge(int value, int rad)
{
  x = sin((value-90) * deg_to_rad) * (rad-2);
  y = cos((value-90) * deg_to_rad) * (rad-2);	
}

void drawGauge1(int value, int rad)
{
  x = sin((value-90) * deg_to_rad);
  y = sqrt(1-x*x) * (rad-2);            // cos = sqrt(1-sin*sin)
  x = x * (rad-2);
}