83 lines
2.1 KiB
C
83 lines
2.1 KiB
C
#define _POSIX_C_SOURCE 200809L
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#include <assert.h>
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#include <fcntl.h>
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#include <stdint.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/ioctl.h>
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#include <sys/mman.h>
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#include <unistd.h>
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#include <xf86drm.h>
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#include <xf86drmMode.h>
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int main()
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{
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int err;
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const int fd = open("/dev/dri/card1", O_RDWR | O_CLOEXEC);
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assert(fd != -1);
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drmModeRes *res = drmModeGetResources(fd);
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assert(res != nullptr);
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drmModeConnector *conn = drmModeGetConnector(fd, res->connectors[0]);
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assert(conn != nullptr);
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drmModeModeInfo mode = conn->modes[0];
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uint32_t conn_id = conn->connector_id;
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struct drm_mode_create_dumb create_req = {
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.width = mode.hdisplay,
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.height = mode.vdisplay,
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.bpp = 32,
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};
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err = ioctl(fd, DRM_IOCTL_MODE_CREATE_DUMB, &create_req);
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assert(err != -1);
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uint32_t fb_id;
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err = drmModeAddFB(
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fd, create_req.width, create_req.height, 24, 32, create_req.pitch,
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create_req.handle, &fb_id);
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assert(err == 0);
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err = drmModeSetCrtc(fd, res->crtcs[0], fb_id, 0, 0, &conn_id, 1, &mode);
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assert(err == 0);
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drmModeCrtc *crtc = drmModeGetCrtc(fd, res->crtcs[0]);
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assert(crtc != nullptr);
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struct drm_mode_map_dumb map_req = { .handle = create_req.handle };
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err = ioctl(fd, DRM_IOCTL_MODE_MAP_DUMB, &map_req);
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assert(err != -1);
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uint32_t *const fb = mmap(
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0, create_req.size, PROT_READ | PROT_WRITE, MAP_SHARED, fd,
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map_req.offset);
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assert(fb != MAP_FAILED);
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for (int y = 0; y < mode.vdisplay; ++y) {
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for (int x = 0; x < mode.hdisplay; ++x) {
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const uint8_t r = (x * 255) / mode.hdisplay;
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const uint8_t g = (y * 255) / mode.vdisplay;
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const uint8_t b = 128;
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fb[y * (create_req.pitch / 4) + x] = (r << 16) | (g << 8) | b;
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}
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}
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getchar();
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munmap(fb, create_req.size);
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struct drm_mode_destroy_dumb delete_req
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= { .handle = create_req.handle };
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ioctl(fd, DRM_IOCTL_MODE_DESTROY_DUMB, &delete_req);
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drmModeSetCrtc(
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fd, crtc->crtc_id, crtc->buffer_id, crtc->x, crtc->y, &conn_id, 1,
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&crtc->mode);
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drmModeFreeCrtc(crtc);
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drmModeFreeConnector(conn);
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drmModeFreeResources(res);
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close(fd);
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return 0;
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}
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