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Move rendering logic into camera module

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This commit is contained in:
Camden Dixie O'Brien
2025-09-21 13:24:08 +01:00
parent bf05f1df59
commit 7400228c0c
3 changed files with 69 additions and 56 deletions
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58
demo.c
View File

@@ -1,27 +1,16 @@
#include "camera.h"
#include "ff.h"
#include "obj.h"
#include "ray.h"
#include "vec3.h"
#include <float.h>
#include <limits.h>
#include <math.h>
#include <stdio.h>
#include <unistd.h>
#define W 800
#define H 600
#define FOCAL_LEN 1.0
#define VIEWPORT_H 2.0
#define NELEMS(arr) (sizeof(arr) / sizeof(arr[0]))
static const vec3_t lightblue = { 0.4, 0.6, 1.0 };
static const vec3_t white = { 1.0, 1.0, 1.0 };
static const vec3_t red = { 1.0, 0.1, 0.2 };
static const vec3_t camera_pos = { 0.0, 0.0, 0.0 };
static const obj_t scene[] = {
@@ -32,54 +21,11 @@ static const obj_t scene[] = {
static pix_t pixbuf[W * H];
static vec3_t raycol(ray_t ray)
{
bool got_hit = false;
hit_t hit = { .t = DBL_MAX };
for (unsigned i = 0; i < NELEMS(scene); ++i) {
if (scene[i].intersect(scene[i].params, ray, &hit, 0.0, hit.t))
got_hit = true;
}
if (got_hit)
return vec3_scale(vec3_add(hit.normal, white), 0.5);
const double a = (ray.dir.y + 1.0) / 2.0;
return vec3_add(vec3_scale(lightblue, a), vec3_scale(white, 1 - a));
}
static void setpix(vec3_t col, pix_t *out)
{
out->r = UINT16_MAX * col.x;
out->g = UINT16_MAX * col.y;
out->b = UINT16_MAX * col.z;
out->a = UINT16_MAX;
}
int main()
{
img_t img = { .w = W, .h = H, .pix = pixbuf };
img_t img = { .pix = pixbuf };
camera_t camera = camera_init(camera_pos, FOCAL_LEN, VIEWPORT_H, W, H);
for (unsigned y = 0; y < H; ++y) {
fprintf(stderr, "\r[%3d/%3d]", y, H);
fflush(stderr);
const vec3_t row
= vec3_add(camera.pix_origin, vec3_scale(camera.y_step, y));
for (unsigned x = 0; x < W; ++x) {
const vec3_t pix = vec3_add(row, vec3_scale(camera.x_step, x));
const ray_t ray = {
.orig = camera.pos,
.dir = vec3_unit(pix),
};
const vec3_t col = raycol(ray);
setpix(col, img.pix + (W * y + x));
}
}
fprintf(stderr, "\r[%3d/%3d]\n", H, H);
camera_render(&camera, scene, NELEMS(scene), &img);
ff_write(STDOUT_FILENO, img);
return 0;
}

7
include/camera.h
View File

@@ -1,6 +1,8 @@
#ifndef CAMERA_H
#define CAMERA_H
#include "img.h"
#include "obj.h"
#include "vec3.h"
#include <stdint.h>
@@ -8,10 +10,15 @@
typedef struct {
vec3_t pos;
vec3_t pix_origin, x_step, y_step;
uint32_t img_width, img_height;
} camera_t;
camera_t camera_init(
vec3_t pos, double focal_len, double viewport_height, uint32_t img_width,
uint32_t img_height);
void camera_render(
const camera_t *camera, const obj_t *scene, unsigned scene_count,
img_t *img_out);
#endif

60
src/camera.c
View File

@@ -1,5 +1,36 @@
#include "camera.h"
#include "ray.h"
#include <float.h>
#include <stdio.h>
static const vec3_t lightblue = { 0.4, 0.6, 1.0 };
static const vec3_t white = { 1.0, 1.0, 1.0 };
static vec3_t trace(ray_t ray, const obj_t *scene, unsigned scene_count)
{
bool got_hit = false;
hit_t hit = { .t = DBL_MAX };
for (unsigned i = 0; i < scene_count; ++i) {
if (scene[i].intersect(scene[i].params, ray, &hit, 0.0, hit.t))
got_hit = true;
}
if (got_hit)
return vec3_scale(vec3_add(hit.normal, white), 0.5);
const double a = (ray.dir.y + 1.0) / 2.0;
return vec3_add(vec3_scale(lightblue, a), vec3_scale(white, 1 - a));
}
static void setpix(vec3_t col, pix_t *out)
{
out->r = UINT16_MAX * col.x;
out->g = UINT16_MAX * col.y;
out->b = UINT16_MAX * col.z;
out->a = UINT16_MAX;
}
camera_t camera_init(
vec3_t pos, double focal_len, double viewport_height, uint32_t img_width,
uint32_t img_height)
@@ -22,5 +53,34 @@ camera_t camera_init(
.pix_origin = pix_origin,
.x_step = x_step,
.y_step = y_step,
.img_width = img_width,
.img_height = img_height,
};
}
void camera_render(
const camera_t *camera, const obj_t *scene, unsigned scene_count,
img_t *img_out)
{
const uint32_t w = img_out->w = camera->img_width;
const uint32_t h = img_out->h = camera->img_height;
for (unsigned y = 0; y < h; ++y) {
fprintf(stderr, "\r[%3d/%3d]", y, h);
fflush(stderr);
const vec3_t row
= vec3_add(camera->pix_origin, vec3_scale(camera->y_step, y));
for (unsigned x = 0; x < w; ++x) {
const vec3_t pix = vec3_add(row, vec3_scale(camera->x_step, x));
const ray_t ray = {
.orig = camera->pos,
.dir = vec3_unit(pix),
};
const vec3_t col = trace(ray, scene, scene_count);
setpix(col, img_out->pix + (w * y + x));
}
}
fprintf(stderr, "\r[%3d/%3d]\n", h, h);
}