144 lines
3.1 KiB
C
144 lines
3.1 KiB
C
#include "renderer.h"
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#include "fb.h"
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#include <assert.h>
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#include <fcntl.h>
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#include <math.h>
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#include <stdio.h>
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#include <string.h>
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#include <unistd.h>
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#include <xf86drm.h>
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#define MAX_VERTS_PER_DRAW 8U
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static int drm_fd;
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static drmModeConnector *conn;
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static drmModeCrtc *crtc;
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static uint32_t conn_id;
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static fb_info_t fbs[2];
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static int front, back;
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static uint32_t width, height;
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static mat3_t view;
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static vec3_t vert_buf[MAX_VERTS_PER_DRAW];
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static void page_flip_handler(int, unsigned, unsigned, unsigned, void *)
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{
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}
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static void set_pixel(uint32_t x, uint32_t y)
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{
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x %= width;
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y %= height;
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const uint32_t offset = y * (fbs[back].pitch / 4) + x;
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fbs[back].buf[offset] = 0xff'ff'ff;
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}
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static void draw_line(vec3_t v1, vec3_t v2)
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{
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const float delta_x = v2.x - v1.x;
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const float delta_y = v2.y - v1.y;
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const float step = fmaxf(fabsf(delta_x), fabsf(delta_y));
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if (step != 0.0) {
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const float step_x = delta_x / step;
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const float step_y = delta_y / step;
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for (unsigned i = 0; i <= step; ++i)
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set_pixel(roundf(v1.x + i * step_x), roundf(v1.y + i * step_y));
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} else {
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set_pixel(roundf(v1.x), roundf(v1.y));
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}
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}
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renderer_params_t renderer_init()
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{
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drm_fd = open("/dev/dri/card1", O_RDWR | O_CLOEXEC);
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assert(drm_fd != -1);
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drmModeRes *res = drmModeGetResources(drm_fd);
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assert(res != nullptr);
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conn = drmModeGetConnector(drm_fd, res->connectors[0]);
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assert(conn != nullptr);
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drmModeModeInfo mode = conn->modes[0];
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conn_id = conn->connector_id;
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fbs[0] = fb_init(drm_fd, mode);
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fbs[1] = fb_init(drm_fd, mode);
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front = 0;
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back = 1;
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const int err = drmModeSetCrtc(
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drm_fd, res->crtcs[0], fbs[front].id, 0, 0, &conn_id, 1, &mode);
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assert(err == 0);
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crtc = drmModeGetCrtc(drm_fd, res->crtcs[0]);
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assert(crtc != nullptr);
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drmModeFreeResources(res);
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width = mode.hdisplay;
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height = mode.vdisplay;
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const float aspect = (float)width / (float)height;
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const float scale = (float)height / 2.0f;
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view = (mat3_t) {
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{ scale, 0, 0 },
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{ 0, -scale, 0 },
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{ aspect * scale, scale, 1 },
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};
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return (renderer_params_t) {
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.drm_fd = drm_fd,
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.aspect = aspect,
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};
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}
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void renderer_cleanup()
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{
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drmModeSetCrtc(
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drm_fd, crtc->crtc_id, crtc->buffer_id, crtc->x, crtc->y, &conn_id,
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1, &crtc->mode);
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fb_cleanup(drm_fd, fbs[0]);
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fb_cleanup(drm_fd, fbs[1]);
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drmModeFreeCrtc(crtc);
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drmModeFreeConnector(conn);
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close(drm_fd);
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}
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void renderer_handle()
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{
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drmEventContext ev = {
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.version = DRM_EVENT_CONTEXT_VERSION,
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.page_flip_handler = page_flip_handler,
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};
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drmHandleEvent(drm_fd, &ev);
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}
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void renderer_clear()
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{
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memset(fbs[back].buf, 0, fbs[back].size);
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}
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void renderer_swap()
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{
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const int err = drmModePageFlip(
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drm_fd, crtc->crtc_id, fbs[back].id, DRM_MODE_PAGE_FLIP_EVENT,
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nullptr);
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assert(err == 0);
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front = (front + 1) & 1;
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back = (back + 1) & 1;
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}
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void renderer_draw(const vec2_t *vs, unsigned count)
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{
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assert(count < MAX_VERTS_PER_DRAW);
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for (unsigned i = 0; i < count; ++i)
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vert_buf[i] = mat3_mul_vec3(view, vec2_extend(vs[i]));
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for (unsigned i = 1; i < count; ++i)
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draw_line(vert_buf[i - 1], vert_buf[i]);
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draw_line(vert_buf[count - 1], vert_buf[0]);
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}
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