46 lines
1.2 KiB
C
46 lines
1.2 KiB
C
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#include "fb.h"
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#include <linux/fb.h>
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#include <sys/mman.h>
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#include <sys/ioctl.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include <assert.h>
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Framebuffer newFramebuffer(const char* device) {
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Framebuffer fb;
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// Open the framebuffer file descriptor
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fb.fd = open(device, O_RDWR);
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assert(fb.fd >= 0 && "Invalid framebuffer device, please ensure your user is in the 'video' group.");
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// Get information about framebuffer
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ioctl(fb.fd, FBIOGET_VSCREENINFO, &fb.vinfo);
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// Get size of screen for writing pixels in bounds
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fb.screensize = fb.vinfo.xres * fb.vinfo.yres * fb.vinfo.bits_per_pixel / 8;
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fb.data = mmap(0, fb.screensize, PROT_READ | PROT_WRITE, MAP_SHARED, fb.fd, 0);
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return fb;
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}
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void writeColourToFramebuffer(Framebuffer* fb, Pixel pixel, Colour colour) {
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int offset = (pixel.y * fb->vinfo.xres + pixel.x) * (fb->vinfo.bits_per_pixel / 8);
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fb->data[offset + 0] = colour.red;
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fb->data[offset + 1] = colour.green;
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fb->data[offset + 2] = colour.blue;
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fb->data[offset + 3] = colour.alpha;
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munmap(fb->data, fb->screensize);
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}
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void destroyFramebuffer(Framebuffer* fb) {
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close(fb->fd);
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// NOTE: Do not free fb->data, this is not memory owned by us.
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// Will cause a segfault
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}
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