rpi4-osdev/part12-wgt/examples/wgt02.c
2021-03-12 22:02:57 +00:00

104 lines
2.2 KiB
C

#include "wgt.h"
// ######## REQUIRED FUNCTIONS ########
unsigned long state0 = 1;
unsigned long state1 = 2;
unsigned long rand(void)
{
unsigned long s1 = state0;
unsigned long s0 = state1;
state0 = s0;
s1 ^= s1 << 23;
s1 ^= s1 >> 17;
s1 ^= s0;
s1 ^= s0 >> 26;
state1 = s1;
return state0 + state1;
}
void wait_msec(unsigned int n)
{
register unsigned long f, t, r;
// Get the current counter frequency
asm volatile ("mrs %0, cntfrq_el0" : "=r"(f));
// Read the current counter
asm volatile ("mrs %0, cntpct_el0" : "=r"(t));
// Calculate expire value for counter
t+=((f/1000)*n)/1000;
do{asm volatile ("mrs %0, cntpct_el0" : "=r"(r));}while(r<t);
}
// ######## STUB FUNCTIONS ########
unsigned int kb = 0;
unsigned int kbhit(void) {
kb++;
return kb / 500;
}
void getch(void) {
wait_msec(0x500000);
}
// ######## WGT EXAMPLES ########
void wgt02()
{
short x;
short y;
short i;
vga256 ();
wcls (vgapal[0]); /* Clear screen with color 0 */
/* Put randomly coloured pixels in random screen coordinates */
do {
wsetcolor (vgapal[rand () % 255]);
x = rand () % 320;
y = rand() % 200;
wputpixel (x, y);
} while (kbhit () == 0);
getch ();
wcls (vgapal[0]); /* Clear screen with color 0 */
wsetcolor (vgapal[10]); /* Now we will draw with #10 */
for (x = 0; x < 320; x++)
for (y = 0; y < 200; y++)
wfastputpixel (x, y); /* Fast due to no clipping checking */
getch ();
wcls (vgapal[0]); /* Clears screen with color 0 */
/* Put randomly coloured pixels in the top left corner of the screen */
for (i = 0; i < 15000; i++)
{
wsetcolor (vgapal[rand () % 255]);
x = rand () % 160;
y = rand () % 100;
wputpixel (x, y);
}
/* Now use wgetpixel to read image off screen */
for (y = 0; y < 100; y++)
for (x = 0; x < 160; x++)
{
wsetcolor (wgetpixel (x, y));
wputpixel (x + 160, y + 100);
}
getch ();
while (1);
}
void main()
{
wgt02();
while (1);
}