#include<graphics.h>#include<conio.h>#include <math.h> // fabsf(), fminf(), fmaxf(), sinf(), cosf(), sqrt()#include <stdlib.h> // rand(), RAND_MAX
#define TWO_PI 6.28318530718f#define W 512#define H 512#define N 64#define MAX_STEP 64#define MAX_DISTANCE 5.0f#define EPSILON 1e-6f#define BIAS 1e-4f#define MAX_DEPTH 3
typedef struct { float sd, emissive, reflectivity; } Result;
unsigned char img[W * H * 3];
float circleSDF(float x, float y, float cx, float cy, float r) { float ux = x - cx, uy = y - cy; return sqrtf(ux * ux + uy * uy) - r;}
float boxSDF(float x, float y, float cx, float cy, float theta, float sx, float sy) { float costheta = cosf(theta), sintheta = sinf(theta); float dx = fabs((x - cx) * costheta + (y - cy) * sintheta) - sx; float dy = fabs((y - cy) * costheta - (x - cx) * sintheta) - sy; float ax = fmaxf(dx, 0.0f), ay = fmaxf(dy, 0.0f); return fminf(fmaxf(dx, dy), 0.0f) + sqrtf(ax * ax + ay * ay);}
float planeSDF(float x, float y, float px, float py, float nx, float ny) { return (x - px) * nx + (y - py) * ny;}
Result unionOp(Result a, Result b) { return a.sd < b.sd ? a : b;}
Result intersectOp(Result a, Result b) { return a.sd > b.sd ? a : b;}
Result subtractOp(Result a, Result b) { Result r = a; r.sd = (a.sd > -b.sd) ? a.sd : -b.sd; return r;}
Result scene(float x, float y) { Result a = { circleSDF(x, y, 0.4f, 0.2f, 0.1f), 2.0f, 0.0f }; Result b = { boxSDF(x, y, 0.5f, 0.8f, TWO_PI / 16.0f, 0.1f, 0.1f), 0.0f, 0.9f }; Result c = { boxSDF(x, y, 0.8f, 0.5f, TWO_PI / 16.0f, 0.1f, 0.1f), 0.0f, 0.9f }; Result d = { planeSDF(x, y, 0.0f, 0.5f, 0.0f, -1.0f), 0.0f, 0.9f }; Result e = { circleSDF(x, y, 0.5f, 0.5f, 0.4f), 0.0f, 0.9f }; return unionOp(a, subtractOp(d, e));}
void gradient(float x, float y, float* nx, float* ny) { *nx = (scene(x + EPSILON, y).sd - scene(x - EPSILON, y).sd) * (0.5f / EPSILON); *ny = (scene(x, y + EPSILON).sd - scene(x, y - EPSILON).sd) * (0.5f / EPSILON);}
void reflect(float ix, float iy, float nx, float ny, float* rx, float* ry) { float idotn2 = (ix * nx + iy * ny) * 2.0f; *rx = ix - idotn2 * nx; *ry = iy - idotn2 * ny;}
float trace(float ox, float oy, float dx, float dy, int depth) { float t = 0.0f; for (int i = 0; i < MAX_STEP && t < MAX_DISTANCE; i++) { float x = ox + dx * t, y = oy + dy * t; Result r = scene(x, y); if (r.sd < EPSILON) { float sum = r.emissive; if (depth < MAX_DEPTH && r.reflectivity > 0.0f) { float nx, ny, rx, ry; gradient(x, y, &nx, &ny); reflect(dx, dy, nx, ny, &rx, &ry); sum += r.reflectivity * trace(x + nx * BIAS, y + ny * BIAS, rx, ry, depth + 1); } return sum; } t += r.sd; } return 0.0f;}
float sample(float x, float y) { float sum = 0.0f; for (int i = 0; i < N; i++) { float a = TWO_PI * (i + (float)rand() / RAND_MAX) / N; sum += trace(x, y, cosf(a), sinf(a), 0); } return sum / N;}
int main() { initgraph(W,H); unsigned char* p = img; for (int y = 0; y < H; y++) { for (int x = 0; x < W; x++, p += 3) { p[0] = p[1] = p[2] = (int)(fminf(sample((float)x / W, (float)y / H) * 255.0f, 255.0f)); putpixel(x,y,RGB(p[0],p[1],p[2])); } } _getch();}
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#include<graphics.h>#include<conio.h>#include <math.h> // fminf(), sinf(), cosf(), sqrt()#include <stdlib.h> // rand(), RAND_MAX
#define TWO_PI 6.28318530718f#define W 512#define H 512#define N 64#define MAX_STEP 64#define MAX_DISTANCE 2.0f#define EPSILON 1e-6f
typedef struct { float sd, emissive; } Result;
unsigned char img[W * H * 3];
float circleSDF(float x, float y, float cx, float cy, float r) { float ux = x - cx, uy = y - cy; return sqrtf(ux * ux + uy * uy) - r;}
float planeSDF(float x, float y, float px, float py, float nx, float ny) { return (x - px) * nx + (y - py) * ny;}
float segmentSDF(float x, float y, float ax, float ay, float bx, float by) { float vx = x - ax, vy = y - ay, ux = bx - ax, uy = by - ay; float t = fmaxf(fminf((vx * ux + vy * uy) / (ux * ux + uy * uy), 1.0f), 0.0f); float dx = vx - ux * t, dy = vy - uy * t; return sqrtf(dx * dx + dy * dy);}
float capsuleSDF(float x, float y, float ax, float ay, float bx, float by, float r) { return segmentSDF(x, y, ax, ay, bx, by) - r;}
float boxSDF(float x, float y, float cx, float cy, float theta, float sx, float sy) { float costheta = cosf(theta), sintheta = sinf(theta); float dx = fabs((x - cx) * costheta + (y - cy) * sintheta) - sx; float dy = fabs((y - cy) * costheta - (x - cx) * sintheta) - sy; float ax = fmaxf(dx, 0.0f), ay = fmaxf(dy, 0.0f); return fminf(fmaxf(dx, dy), 0.0f) + sqrtf(ax * ax + ay * ay);}
float triangleSDF(float x, float y, float ax, float ay, float bx, float by, float cx, float cy) { float d = fminf(fminf( segmentSDF(x, y, ax, ay, bx, by), segmentSDF(x, y, bx, by, cx, cy)), segmentSDF(x, y, cx, cy, ax, ay)); return (bx - ax) * (y - ay) > (by - ay) * (x - ax) && (cx - bx) * (y - by) > (cy - by) * (x - bx) && (ax - cx) * (y - cy) > (ay - cy) * (x - cx) ? -d : d;}
Result intersectOp(Result a, Result b) { return a.sd > b.sd ? a : b;}
Result scene(float x, float y) { Result a = { circleSDF(x, y, 0.5f, 0.5f, 0.2f), 1.0f }; Result b = { planeSDF(x, y, 0.0f, 0.5f, 0.0f, 1.0f), 0.8f }; Result c = { capsuleSDF(x, y, 0.4f, 0.4f, 0.6f, 0.6f, 0.1f), 1.0f }; Result d = { boxSDF(x, y, 0.5f, 0.5f, TWO_PI / 16.0f, 0.3f, 0.1f), 1.0f }; Result e = { boxSDF(x, y, 0.5f, 0.5f, TWO_PI / 16.0f, 0.3f, 0.1f) - 0.1f, 1.0f }; Result f = { triangleSDF(x, y, 0.5f, 0.2f, 0.8f, 0.8f, 0.3f, 0.6f), 1.0f }; Result g = { triangleSDF(x, y, 0.5f, 0.2f, 0.8f, 0.8f, 0.3f, 0.6f) - 0.1f, 1.0f }; return intersectOp(a, b); }
float trace(float ox, float oy, float dx, float dy) { float t = 0.0f; for (int i = 0; i < MAX_STEP && t < MAX_DISTANCE; i++) { Result r = scene(ox + dx * t, oy + dy * t); if (r.sd < EPSILON) return r.emissive; t += r.sd; } return 0.0f;}
float sample(float x, float y) { float sum = 0.0f; for (int i = 0; i < N; i++) { float a = TWO_PI * (i + (float)rand() / RAND_MAX) / N; sum += trace(x, y, cosf(a), sinf(a)); } return sum / N;}
int main() { initgraph(W,H); unsigned char* p = img; for (int y = 0; y < H; y++) { for (int x = 0; x < W; x++, p += 3) { p[0] = p[1] = p[2] = (int)(fminf(sample((float)x / W, (float)y / H) * 255.0f, 255.0f)); putpixel(x,y,RGB(p[0],p[1],p[2])); } } _getch();}
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