dump state

bin/defocus.c

@@ -1,6 +1,7 @@
 /* Main command line executable. */
 
 #include <defocus/defocus.h>
+#include <defocus/df_math.h>
 
 #define STB_IMAGE_WRITE_IMPLEMENTATION
 #include <stb_image_write.h>
@@ -49,17 +50,43 @@ int main(int argc, char **argv) {
 
     df_image_handle input_image = df_load_image("../test_image.png", &image_width, &image_height);
     float aspect = (float)image_width / (float)image_height;
-    df_plane plane = get_image_filling_plane(image_width, image_height, input_image, focal_length);
+    
+    
+    df_plane plane;
+    plane.base_x = 0.f;
+    plane.base_y = 0.f;
+    plane.base_z = -2;
+    plane.normal_x = 0.f;
+    plane.normal_y = 0.f;
+    plane.normal_z = 1.f;
+    plane.img_p0_x = -aspect;
+    plane.img_p0_y = -1.f;
+    plane.img_p0_z = plane.base_z;
+    plane.img_w = 2.f * aspect;
+    plane.img_h = 2.f;
+    plane.img_ax0_x = 1.f;
+    plane.img_ax0_y = 0.f;
+    plane.img_ax0_z = 0.f;
+    plane.img_ax1_x = 0.f;
+    plane.img_ax1_y = 1.f;
+    plane.img_ax1_z = 0.f;
+    plane.image = input_image;
 
     uint8_t *image = NULL;
     
-    df_thin_lense_camera_data camera_data = df_create_thin_lense_camera_data(image_width, image_height, 42.f, focal_length);
+    df_v3 look_from = {1, 1.5, 5};
+    df_v3 look_at = {0, 0, -2};
+    df_v3 up = {0, 1, 0};
+
+    float dist_to_focus = df_len_v3(df_sub_v3(look_at, look_from));
+
+    df_thin_lense_camera_data camera_data = df_create_thin_lense_camera_data(look_from, look_at, up, 45.f, aspect, 2.0, dist_to_focus);
 
     df_trace_rays((df_trace_rays_settings){
             .image_width = image_width,
             .image_height = image_height,
             .samples_per_pixel = 64,
-            .camera = df_thin_lense_camera,
+            .camera = df_pinhole_camera,
             .camera_data = &camera_data,
         },
         spheres, 0,

include/defocus/defocus.h

@@ -26,6 +26,9 @@
 #define DF_PIF32 3.1415926f
 #define DF_PI_OVER_4F32 (DF_PIF32 / 4.f)
 #define DF_PI_OVER_2F32 (DF_PIF32 / 2.f)
+#define DF_PI_OVER_180F32 (DF_PIF32 / 180.f)
+
+#define DF_DEGREES_TO_RADIANS(deg) ((deg) * DF_PI_OVER_180F32)
 
 #define DF_ARRAY_COUNT(A) (sizeof((A)) / sizeof((A)[0]))
 #define DF_UNUSED(x) ((void)sizeof((x)))
@@ -58,6 +61,12 @@ DF_API df_image_handle df_load_image(const char *path, int *w, int *h);
 
 /* cameras */
 
+/* The camera data structs (df_pinhole_camera_data etc.) are defined here
+ * to enable you to store these on the stack.
+ * However - unless you know what you are doing (-: - you should treat these
+ * structs as opaque.
+ */
+
 typedef struct
 {
     df_v3 origin;
@@ -70,25 +79,31 @@ typedef df_ray (*df_camera_fn)(float u, float v, unsigned int sample_idx, void *
 
 typedef struct
 {
-    df_v2 viewport_size;
+    df_v3 horizontal;
+    df_v3 vertical;
     df_v3 lower_left;
+    df_v3 origin;
 } df_pinhole_camera_data;
 
-DF_API df_pinhole_camera_data df_create_pinhole_camera_data(int image_width, int image_height, float focal_length);
+/* Creates data for a pinhole camera.
+ * The vertical fov (vfov) is given in degrees.
+ */
+DF_API df_pinhole_camera_data df_create_pinhole_camera_data(df_v3 look_from, df_v3 look_at, df_v3 up,
+    float vfov, float aspect);
 
 DF_API df_ray df_pinhole_camera(float u, float v, unsigned int sample_idx, void *camera_data);
 
 typedef struct
 {
-    df_v2 viewport_size;
+    df_v3 horizontal;
+    df_v3 vertical;
     df_v3 lower_left;
+    df_v3 origin;
     float lens_radius;
 } df_thin_lense_camera_data;
 
-DF_API df_thin_lense_camera_data df_create_thin_lense_camera_data(int image_width,
+DF_API df_thin_lense_camera_data df_create_thin_lense_camera_data(df_v3 look_from, df_v3 look_at, df_v3 up,
-                                                                  int image_height,
+    float vfov, float aspect, float aperture, float focal_distance);
-                                                                  float aperture,
-                                                                  float focal_distance);
 
 DF_API df_ray df_thin_lense_camera(float u, float v, unsigned int sample_idx, void *camera_data);
 
@@ -100,6 +115,9 @@ typedef struct
     int image_height;
     int samples_per_pixel;
 
+    df_v3 look_from;
+    df_v3 look_at;
+
     df_camera_fn camera;
     void *camera_data;
 } df_trace_rays_settings;

lib/raytracer.c

@@ -1,4 +1,5 @@
 #include <defocus/defocus.h>
+#include <defocus/df_math.h>
 
 #include <math.h>
 #include <stdlib.h>
@@ -9,23 +10,6 @@
 
 #include "pcg/pcg_basic.h"
 
-/* ************* *
- *               *
- *    Vectors    *
- *               *
- * ************* */
-
-static df_v3 normalize(df_v3 v)
-{
-    float l = sqrtf(v.x * v.x + v.y * v.y + v.z * v.z);
-    return (df_v3){v.x / l, v.y / l, v.z / l};
-}
-
-static float dot(df_v3 a, df_v3 b) { return a.x * b.x + a.y * b.y + a.z * b.z; }
-
-static float v2_len(df_v2 v) { return sqrtf(v.x * v.x + v.y * v.y); }
-
-
 /* ********************* *
  *                       *
  *    Image functions    *
@@ -72,22 +56,32 @@ DF_API df_image_handle df_load_image(const char *path, int *w, int *h)
  *                             *
  * *************************** */
 
-DF_API df_pinhole_camera_data df_create_pinhole_camera_data(int image_width, int image_height, float focal_length)
+DF_API df_pinhole_camera_data
+df_create_pinhole_camera_data(df_v3 look_from, df_v3 look_at, df_v3 up, float vfov, float aspect)
 {
-    float aspect_ratio = (float)image_width / (float)image_height;
+    float theta = DF_DEGREES_TO_RADIANS(vfov);
-    float viewport_height = 2.f;
+    float h = tanf(theta * .5f);
-    float viewport_width = aspect_ratio * viewport_height;
+    float viewport_height = 2.f * h;
+    float viewport_width = aspect * viewport_height;
 
-    /* Simple perspective projection.
+    df_v3 view_vec = df_sub_v3(look_from, look_at);
-     * The lens is placed at (0, 0, 0)
+    df_v3 w = df_normalize_v3(view_vec);
-     */
+    df_v3 u = df_normalize_v3(df_cross(up, w));
-    float lower_left_x = -viewport_width / 2.f;
+    df_v3 v = df_cross(w, u);
-    float lower_left_y = -viewport_height / 2.f;
+
-    float lower_left_z = -focal_length;
+    df_v3 horizontal = df_mul_v3(viewport_width, u);
+    df_v3 vertical = df_mul_v3(viewport_height, v);
+    df_v3 lower_left = {
+        .x = look_from.x - horizontal.x / 2.f - vertical.x / 2.f - w.x,
+        .y = look_from.y - horizontal.y / 2.f - vertical.y / 2.f - w.y,
+        .z = look_from.z - horizontal.z / 2.f - vertical.z / 2.f - w.z,
+    };
 
     return (df_pinhole_camera_data){
-        .viewport_size = {.x = viewport_width, .y = viewport_height},
+        .origin = look_from,
-        .lower_left = { .x = lower_left_x, .y = lower_left_y, .z = lower_left_z },
+        .horizontal = horizontal,
+        .vertical = vertical,
+        .lower_left = lower_left,
     };
 }
 
@@ -96,11 +90,14 @@ DF_API df_ray df_pinhole_camera(float u, float v, unsigned int sample_idx, void
     DF_UNUSED(sample_idx);
     df_pinhole_camera_data *data = camera_data;
 
-    df_v3 origin = {0.f, 0.f, 0.f};
+    df_v3 origin = data->origin;
+    df_v3 horizontal = data->horizontal;
+    df_v3 vertical = data->vertical;
+
     df_v3 target = {
-        data->lower_left.x + u * data->viewport_size.x, 
+        data->lower_left.x + u * horizontal.x + v * vertical.x - origin.x, 
-        data->lower_left.y + v * data->viewport_size.y,
+        data->lower_left.y + u * horizontal.y + v * vertical.y - origin.y,
-        data->lower_left.z
+        data->lower_left.z + u * horizontal.z + v * vertical.z - origin.z,
     };
 
     return (df_ray){
@@ -116,40 +113,38 @@ static df_v2 random_point_on_disk(unsigned int i)
 
     while (1) {
         df_v2 p = {.x = (float)pcg32_boundedrand(1024) / 1023.f, .y = (float)pcg32_boundedrand(1024) / 1023.f};
-        if (v2_len(p) <= 1.f)
+        if (df_len_v2(p) <= 1.f)
             return p;
     }
 }
 
-DF_API df_thin_lense_camera_data df_create_thin_lense_camera_data(int image_width,
+DF_API df_thin_lense_camera_data df_create_thin_lense_camera_data(
-                                                                  int image_height,
+    df_v3 look_from, df_v3 look_at, df_v3 up, float vfov, float aspect, float aperture, float focal_distance)
-                                                                  float aperture,
-                                                                  float focal_distance)
 {
-    float aspect_ratio = (float)image_width / (float)image_height;
+    float theta = DF_DEGREES_TO_RADIANS(vfov);
-    float viewport_height = 2.f;
+    float h = tanf(theta * .5f);
-    float viewport_width = aspect_ratio * viewport_height;
+    float viewport_height = 2.f * h;
+    float viewport_width = aspect * viewport_height;
 
-    /* Simple perspective projection.
+    df_v3 view_vec = df_sub_v3(look_from, look_at);
-     * The lens is placed at (0, 0, 0)
+    df_v3 w = df_normalize_v3(view_vec);
-     */
+    df_v3 u = df_normalize_v3(df_cross(up, w));
-    float lower_left_x = -viewport_width / 2.f;
+    df_v3 v = df_cross(w, u);
-    float lower_left_y = -viewport_height / 2.f;
-    float lower_left_z = -focal_distance;
 
-    float lens_radius = aperture / 2.f;
+    df_v3 horizontal = df_mul_v3(viewport_width, u);
+    df_v3 vertical = df_mul_v3(viewport_height, v);
+    df_v3 lower_left = {
+        .x = look_from.x - horizontal.x / 2.f - vertical.x / 2.f - focal_distance * w.x,
+        .y = look_from.y - horizontal.y / 2.f - vertical.y / 2.f - focal_distance * w.y,
+        .z = look_from.z - horizontal.z / 2.f - vertical.z / 2.f - focal_distance * w.z,
+    };
 
     return (df_thin_lense_camera_data){
-        .lens_radius = lens_radius,
+        .origin = look_from,
-        .lower_left = {
+        .horizontal = horizontal,
-            .x = lower_left_x,
+        .vertical = vertical,
-            .y = lower_left_y,
+        .lower_left = lower_left,
-            .z = lower_left_z,
+        .lens_radius = aperture / 2.f,
-        },
-        .viewport_size = {
-            .x = viewport_width,
-            .y = viewport_height
-        }
     };
 }
 
@@ -162,12 +157,20 @@ DF_API df_ray df_thin_lense_camera(float u, float v, unsigned int sample_idx, vo
     lensp.y *= data->lens_radius;
 
     df_v3 offset = {u * lensp.x, v * lensp.y, .z = 0.f};
+    df_v3 origin = df_add_v3(data->origin, offset);
+    df_v3 horizontal = data->horizontal;
+    df_v3 vertical = data->vertical;
 
-    df_v3 origin = offset;
+    df_v3 target = {
-    df_v3 target = {data->lower_left.x + u * data->viewport_size.x + offset.x,
+        data->lower_left.x + u * horizontal.x + v * vertical.x - origin.x,
-                    data->lower_left.y + v * data->viewport_size.y + offset.y,
+        data->lower_left.y + u * horizontal.y + v * vertical.y - origin.y,
-                    data->lower_left.z + offset.z};
+        data->lower_left.z + u * horizontal.z + v * vertical.z - origin.z,
-    return (df_ray){.origin = origin, .dir = target};
+    };
+
+    return (df_ray){
+        .origin = origin,
+        .dir = target,
+    };
 }
 
 
@@ -305,17 +308,17 @@ DF_API int df_trace_rays(df_trace_rays_settings settings,
         return 0;
     void *camera_data = settings.camera_data;
 
-    uint8_t *pixels = malloc(image_width * image_height * 3);
+    float *fpixels = malloc(sizeof(float) * image_width * image_height * 3);
-    if (!pixels)
+    if (!fpixels)
         return 0;
-    memset(pixels, 0, image_width * image_height * 3);
+    memset(fpixels, 0, sizeof(float) * image_width * image_height * 3);
 
     df_ray_packet packet;
     packet.samples_per_pixel = samples_per_pixel;
     packet.ray_count = image_width * image_height * samples_per_pixel;
     void *packet_mem = malloc(packet.ray_count * (2 * sizeof(df_v3) + sizeof(df_v2i)));
     if (!packet_mem) {
-        free(pixels);
+        free(fpixels);
         return 0;
     }
     packet.ray_origins = (df_v3 *)packet_mem;
@@ -329,7 +332,6 @@ DF_API int df_trace_rays(df_trace_rays_settings settings,
     unsigned int ray_idx = 0;
     for (int y = 0; y < image_height; ++y) {
         /* TODO(Kevin): SIMD */
-        uint8_t *row = pixels + y * image_width * 3;
         for (int x = 0; x < image_width; ++x) {
             float u = (float)x / (float)(image_width - 1);
             float v = (float)y / (float)(image_height - 1);
@@ -418,11 +420,12 @@ DF_API int df_trace_rays(df_trace_rays_settings settings,
         }
     }
     
+    float fsamples = (float)samples_per_pixel;
     /* Trace the rays */
     for (unsigned int i = 0; i < packet.ray_count; ++i) {
         df_v2i pixelp = packet.ray_pixels[i];
 
-        uint8_t *row = pixels + pixelp.y * image_width * 3;
+        float *row = fpixels + pixelp.y * image_width * 3;
 
         df_hit plane_hit = plane_test(packet.ray_origins[i], packet.ray_deltas[i], planes, plane_count);
 
@@ -438,13 +441,30 @@ DF_API int df_trace_rays(df_trace_rays_settings settings,
                 stbi_uc *pixel = _image_table.images[plane_hit.image].pixels +
                                  4 * (pixely * _image_table.images[plane_hit.image].w + pixelx);
 
-                row[pixelp.x * 3 + 0] += pixel[0] / samples_per_pixel;
+                row[pixelp.x * 3 + 0] += (float)pixel[0];
-                row[pixelp.x * 3 + 1] += pixel[1] / samples_per_pixel;
+                row[pixelp.x * 3 + 1] += (float)pixel[1];
-                row[pixelp.x * 3 + 2] += pixel[2] / samples_per_pixel;
+                row[pixelp.x * 3 + 2] += (float)pixel[2];
             }
         }
     }
 
+    /* Map down to 8bit rgb */
+    uint8_t *pixels = malloc(image_width * image_height * 3);
+    if (!pixels) {
+        free(packet_mem);
+        free(fpixels);
+        return 0;
+    }
+    for (unsigned int i = 0; i < image_width * image_height; ++i) {
+        float *fp = &fpixels[i * 3];
+        uint8_t *p = &pixels[i * 3];
+
+        p[0] = (uint8_t)(fp[0] / fsamples);
+        p[1] = (uint8_t)(fp[1] / fsamples);
+        p[2] = (uint8_t)(fp[2] / fsamples);
+    }
+
+    free(fpixels);
     free(packet_mem);
     *result = pixels;
     return 1;

meson.build

@@ -13,7 +13,9 @@ endif
 lib = library('df',
               'lib/raytracer.c',
               'lib/utils.c',
+              'lib/df_math.c',
 	          'include/defocus/defocus.h',
+              'include/defocus/df_math.h',
               '3p/stb_image.h',
               '3p/pcg/pcg_basic.c',
               '3p/pcg/pcg_basic.h',