Files
jsix_import/src/drivers/fb/screen.cpp
Justin C. Miller dcb8a3f3fb [fb] Use double-buffering in fb driver
Allocate and use a back buffer, so that draws to the screen are always a
single memcpy()
2021-01-18 13:49:59 -08:00

51 lines
1003 B
C++

#include <stdlib.h>
#include <string.h>
#include "screen.h"
screen::screen(void *addr, unsigned hres, unsigned vres, pixel_order order) :
m_fb(static_cast<pixel_t *>(addr)),
m_order(order),
m_resx(hres),
m_resy(vres)
{
m_back = reinterpret_cast<pixel_t*>(malloc(hres*vres*sizeof(pixel_t)));
}
screen::pixel_t
screen::color(uint8_t r, uint8_t g, uint8_t b) const
{
switch (m_order) {
case pixel_order::bgr8:
return
(static_cast<uint32_t>(b) << 0) |
(static_cast<uint32_t>(g) << 8) |
(static_cast<uint32_t>(r) << 16);
case pixel_order::rgb8:
return
(static_cast<uint32_t>(r) << 0) |
(static_cast<uint32_t>(g) << 8) |
(static_cast<uint32_t>(b) << 16);
}
}
void
screen::fill(pixel_t color)
{
const size_t len = m_resx * m_resy;
for (size_t i = 0; i < len; ++i)
m_back[i] = color;
}
void
screen::draw_pixel(unsigned x, unsigned y, pixel_t color)
{
m_back[x + y * m_resx] = color;
}
void
screen::update()
{
memcpy(m_fb, m_back, m_resx*m_resy*sizeof(pixel_t));
}