diff options
| -rw-r--r-- | 3dmath.c | 36 | ||||
| -rw-r--r-- | 3dmath.h | 3 | ||||
| -rw-r--r-- | Makefile | 3 | ||||
| -rw-r--r-- | ray.c | 100 |
4 files changed, 63 insertions, 79 deletions
diff --git a/3dmath.c b/3dmath.c new file mode 100644 index 0000000..d729323 --- /dev/null +++ b/3dmath.c @@ -0,0 +1,36 @@ +#include <math.h> + +#define POW2(x) ((x) * (x)) + +float +dot(float x[3], float y[3]) { + return x[0] * y[0] + x[1] * y[1] + x[2] * y[2]; +} + +void +normalize(float x[3]) { + float len; + int i; + + len = sqrt(dot(x, x)); + + for(i = 0; i < 3; ++i) + x[i] /= len; +} + +float +sphere_intersect(float s[3], float d[3], float c[3], float r) { + int i; + float D; + float v[3]; + + for(i = 0; i < 3; ++i) + v[i] = s[i] - c[i]; + + D = POW2(dot(v, d)) - 4 * (dot(v, v) - POW2(r)); + + if(D < 0) + return -1; + + return 1; +} diff --git a/3dmath.h b/3dmath.h new file mode 100644 index 0000000..6714da5 --- /dev/null +++ b/3dmath.h @@ -0,0 +1,3 @@ +float dot(float x[3], float y[3]); +void normalize(float x[3]); +float sphere_intersect(float s[3], float d[3], float c[3], float r); @@ -9,6 +9,9 @@ OBJECTS = $(BINARY).o all: $(BINARY) +$(BINARY): $(BINARY).c 3dmath.c + $(CC) $(CFLAGS) $(LDFLAGS) -o $(BINARY) 3dmath.c $(BINARY).c + clean: rm -f $(BINARY).o $(BINARY) @@ -6,17 +6,15 @@ #include <string.h> #include <math.h> +#include "3dmath.h" + #define WIDTH 1080 #define HEIGHT 1080 #define BUFFER_SIZE (WIDTH * HEIGHT * 4) -#define LENGTH(array) (sizeof(array) / sizeof(array[0])) +#define LENGTH(array) (sizeof(array) / sizeof(array[0])) #define MAX(x, y) (x > y ? x : y) #define MIN(x, y) (x < y ? x : y) -#define POW2(x) ((x) * (x)) -#define POW3(x) ((x) * (x) * (x)) -#define POW4(x) ((x) * (x) * (x) * (x)) -#define POW5(x) ((x) * (x) * (x) * (x) * (x)) typedef struct { float position[3]; @@ -29,85 +27,26 @@ typedef struct { float diffuse[3]; } Light; -static Object objects[2] = {{.position={1.5, 0, -20}, .radius=.1, .diffuse={0, 0, .3}}, - {.position={-1.5, 0, -30}, .radius=.1, .diffuse={0, 0, .3}}}; -static Light lights[1] = {{.position={0, 2, -4}, .diffuse={0, .7, .7}}}; static unsigned char buffer[BUFFER_SIZE]; - -static float -dot(float x[3], float y[3]) { - return x[0] * y[0] + x[1] * y[1] + x[2] * y[2]; -} - -static void -normalize(float x[3]) { - float len; - int i; - - len = sqrt(dot(x, x)); - - for(i = 0; i < 3; ++i) - x[i] /= len; -} +static Object objects[2] = {{.position={0, 0, 2}, .radius=1, .diffuse={0, 0, .3}}, + {.position={-1.5, 0, -30}, .radius=.1, .diffuse={0, 0, .3}}}; static void -trace(float s[3], float d[3], float pixel[3], int N) { - int i, j; - float D; - float l[3]; - float n[3]; - float t; - float v[3]; - float vd, vv; - float y[3]; - Object *object = objects; - Light *light = lights; - - for(j = 0; j < LENGTH(objects); ++j) { - object = &objects[j]; - - for(i = 0; i < 3; ++i) - v[i] = s[i] - object->position[i]; - - vd = dot(v, d); - vv = dot(v, v); - - D = POW2(2 * vd) - 4 * (vv - POW2(object->radius)); - - if(D < 0) { - pixel[0] += .3; - pixel[1] += .15; - pixel[2] += .075; - } else { - - t = MIN(-vd + sqrt(D), -vd - sqrt(D)); - - for(i = 0; i < 3; ++i) { - y[i] = s[i] + t * d[i]; - n[i] = y[i] - object->position[i]; - l[i] = light->position[i] - object->position[i]; - } - - normalize(n); - normalize(l); - - for(i = 0; i < 3; ++i) { - n[i] = (object->diffuse[i] + light->diffuse[i]) * dot(n, l); - //n[i] = object->diffuse[i]; - pixel[i] += n[i]; - } - - if(N) - trace(y, n, pixel, N - 1); - } - } +trace(float s[3], float d[3], float pixel[3]) { + float t = sphere_intersect(s, d, objects[0].position, objects[0].radius); + + //printf("%f.\n", objects[0].position[0]); + if(t > 0) + pixel[1] = .5; + else + pixel[2] = .5; } static void display(void) { int i, j; float x, y; - float s[3] = {0, 0, 1}; + float s[3] = {0, 0, 0}; float d[3]; float pixel[3]; @@ -119,12 +58,15 @@ display(void) { d[0] = x / (WIDTH / 2); d[1] = y / (HEIGHT / 2); - d[2] = -1; + d[2] = 1; - memset(pixel, '\0', sizeof(pixel)); - trace(s, d, pixel, 0); + normalize(d); + + //if(!(i % 256)) + //printf("%f, %f, %f.\n", d[0], d[1], d[2]); - //printf("%f %f %f\n", pixel[0], pixel[1], pixel[2]); + memset(pixel, '\0', sizeof(pixel)); + trace(s, d, pixel); for(j = 0; j < 3; ++j) buffer[i + j] = MIN(255 * pixel[j], 255); |