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Implement iterative rendering function. (#15)
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- Just an interesting task that I wanted to implement.
- Also this is a prerequisite to using OpenCL to parallel the rendering to GPU.
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@Morozov-5F
Morozov-5F authored Nov 10, 2021
1 parent 788680e commit 96aab79
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Showing 2 changed files with 56 additions and 7 deletions.
61 changes: 55 additions & 6 deletions main.c
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Original file line number Diff line number Diff line change
Expand Up @@ -17,6 +17,8 @@
#include <assert.h>
#include <rt_sync.h>

typedef colour_t (*render_fn_t)(const ray_t *ray, const rt_hittable_list_t *list, const rt_skybox_t *skybox, int child_rays);

typedef struct worker_arg_s
{
struct
Expand All @@ -39,6 +41,7 @@ typedef struct worker_arg_s
{
int child_rays;
long number_of_samples;
render_fn_t render_function;
} rendering;

struct
Expand All @@ -60,7 +63,7 @@ static void render_worker(void *args);
static void render_worker_complete(int status, void *args);
static void render_chunk(vec3_t *image, int image_width, int image_height, long number_of_samples, int child_rays,
int column_start, int width, int row_start, int height, const rt_hittable_list_t *world,
const rt_skybox_t *skybox, const rt_camera_t *camera);
const rt_skybox_t *skybox, const rt_camera_t *camera, render_fn_t render_function);

static void show_usage(const char *program_name, int err);

Expand All @@ -87,6 +90,38 @@ static colour_t ray_colour(const ray_t *ray, const rt_hittable_list_t *list, con
return emitted;
}

static colour_t ray_color_iterative(const ray_t *ray, const rt_hittable_list_t *list, const rt_skybox_t *skybox, int child_rays)
{
colour_t resulting_color = colour(0, 0, 0);
colour_t global_attenuation = colour(1, 1, 1);

ray_t current_ray = *ray;

for (int ray_hop = 0; ray_hop < child_rays; ray_hop++)
{
rt_hit_record_t record;
if (!rt_hittable_list_hit_test(list, &current_ray, 0.001, INFINITY, &record))
{
vec3_add(&resulting_color, vec3_multiply(rt_skybox_value(skybox, &current_ray), global_attenuation));
break;
}

colour_t emitted = rt_material_emit(record.material, record.u, record.v, &record.p);
vec3_add(&resulting_color, vec3_multiply(emitted, global_attenuation));

ray_t scattered;
colour_t attenuation;
bool ray_scattered = rt_material_scatter(record.material, &current_ray, &record, &attenuation, &scattered);
global_attenuation = vec3_multiply(attenuation, global_attenuation);
if (!ray_scattered)
{
break;
}
current_ray = scattered;
}
return resulting_color;
}

int main(int argc, char const *argv[])
{
const char *number_of_samples_str = NULL;
Expand All @@ -96,6 +131,7 @@ int main(int argc, char const *argv[])
const char *image_width_str = NULL;
const char *image_height_str = NULL;
bool verbose = false;
bool render_recursive = true;

// Parse console arguments
for (int i = 1; i < argc; ++i)
Expand Down Expand Up @@ -159,6 +195,11 @@ int main(int argc, char const *argv[])
{
show_usage(argv[0], EXIT_SUCCESS);
}
else if (0 == strcmp(argv[i], "-i"))
{
render_recursive = false;
continue;
}
else if ('-' == *argv[i])
{
fprintf(stderr, "Fatal error: Unknown argument '%s'\n", argv[i]);
Expand All @@ -181,6 +222,7 @@ int main(int argc, char const *argv[])
fprintf(stderr, "\t- image width: %s\n", image_width_str);
fprintf(stderr, "\t- image height: %s\n", image_width_str);
fprintf(stderr, "\t- file_name: %s\n", file_name);
fprintf(stderr, "\t- renderer: %s\n", render_recursive ? "recursive" : "iterative");
}

// Parse resulting parameters
Expand Down Expand Up @@ -248,7 +290,11 @@ int main(int argc, char const *argv[])
show_usage(argv[0], EXIT_FAILURE);
}
}

render_fn_t render_function = ray_colour;
if (!render_recursive)
{
render_function = ray_color_iterative;
}

if (verbose)
{
Expand All @@ -259,6 +305,7 @@ int main(int argc, char const *argv[])
fprintf(stderr, "\t- image width: %d\n", image_width);
fprintf(stderr, "\t- image height: %d\n", image_height);
fprintf(stderr, "\t- file_name: %s\n", file_name);
fprintf(stderr, "\t- render function: %s\n", render_function == ray_colour ? "ray_colour" : "ray_colou_iterative");
}

// Image parameters
Expand Down Expand Up @@ -420,6 +467,7 @@ int main(int argc, char const *argv[])

arg->rendering.number_of_samples = number_of_samples;
arg->rendering.child_rays = CHILD_RAYS;
arg->rendering.render_function = render_function;

arg->chunk.x_start = j * CHUNK_SIZE;
arg->chunk.y_start = i * CHUNK_SIZE;
Expand Down Expand Up @@ -474,7 +522,7 @@ static void show_usage(const char *program_name, int err)
{
// clang-format off
fprintf(stderr, "Usage:\n");
fprintf(stderr, "%s [-s|--samples N] [--scene SCENE] [-v|--verbose] [-t|--threads THREADS] [--width WIDTH] [--height HEIGHT] [output_file_name]\n", program_name);
fprintf(stderr, "%s [-s|--samples N] [--scene SCENE] [-v|--verbose] [-t|--threads THREADS] [--width WIDTH] [--height HEIGHT] [-i] [output_file_name]\n", program_name);
fprintf(stderr, "Options:\n");
fprintf(stderr, "\t-s | --samples <int> Number of rays to cast for each pixel\n");
fprintf(stderr, "\t--scene <string> ID of the scene to render. List of available scenes is printed below.\n");
Expand All @@ -483,6 +531,7 @@ static void show_usage(const char *program_name, int err)
fprintf(stderr, "\t--height <int> Image height in pixels. Should be used with --width option.\n");
fprintf(stderr, "\t-v | --verbose Enable verbose output\n");
fprintf(stderr, "\t-h Show this message and exit\n");
fprintf(stderr, "\t-i Use iterative rendering loop instead of recursive\n");
fprintf(stderr, "Positional arguments:\n");
fprintf(stderr, "\toutput_file_name Name of the output file. Outputs image to console if not specified.\n");
fprintf(stderr, "Available scenes:\n");
Expand All @@ -494,7 +543,7 @@ static void show_usage(const char *program_name, int err)

static void render_chunk(vec3_t *image, int image_width, int image_height, long number_of_samples, int child_rays,
int column_start, int width, int row_start, int height, const rt_hittable_list_t *world,
const rt_skybox_t *skybox, const rt_camera_t *camera)
const rt_skybox_t *skybox, const rt_camera_t *camera, render_fn_t render_function)
{
for (int j = row_start + height - 1; j >= row_start; --j)
{
Expand All @@ -507,7 +556,7 @@ static void render_chunk(vec3_t *image, int image_width, int image_height, long
double v = (double)(j + rt_random_double(0, 1)) / (image_height - 1);

ray_t ray = rt_camera_get_ray(camera, u, v);
vec3_add(&pixel, ray_colour(&ray, world, skybox, child_rays));
vec3_add(&pixel, render_function(&ray, world, skybox, child_rays));
}
image[j * image_width + i] = pixel;
}
Expand All @@ -522,7 +571,7 @@ static void render_worker(void *args)
render_chunk(worker_arg->image.pixels, worker_arg->image.width, worker_arg->image.height,
worker_arg->rendering.number_of_samples, worker_arg->rendering.child_rays, worker_arg->chunk.x_start,
worker_arg->chunk.width, worker_arg->chunk.y_start, worker_arg->chunk.height, worker_arg->scene.world,
worker_arg->scene.skybox, worker_arg->scene.camera);
worker_arg->scene.skybox, worker_arg->scene.camera, worker_arg->rendering.render_function);
}

static void render_worker_complete(int status, void *args)
Expand Down
2 changes: 1 addition & 1 deletion materials/rt_material.c
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Original file line number Diff line number Diff line change
Expand Up @@ -71,7 +71,7 @@ void rt_material_delete(rt_material_t *material)
return;
}

material->delete (material);
material->delete(material);
}

static bool scatter_base(const rt_material_t *material, const ray_t *incoming_ray, const rt_hit_record_t *hit_record,
Expand Down

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