Raw source
#include <math.h>
#include <stdio.h>
#include <stdint.h>
#include <float.h>
#include <limits.h>
#include <stdlib.h>
#include <windows.h>
#include <sysinfoapi.h>
#include <curand_kernel.h>
#define w 960
#define h 540
#define BPP 3
struct Vec {
float x;
float y;
float z;
__device__ Vec(float v = 0) {
x = y = z = v;
}
__device__ Vec(float a, float b, float c = 0) {
x = a;
y = b;
z = c;
}
__device__ Vec operator+(const Vec r) const { return Vec(x + r.x , y + r.y , z + r.z); }
__device__ Vec operator*(const Vec r) const { return Vec(x * r.x , y * r.y , z * r.z); }
__device__ float operator%(const Vec r) const {return x * r.x + y * r.y + z * r.z;}
__device__ Vec operator!() { return *this * rsqrtf(*this % *this); }
};
__shared__ curandState_t states[w];
__device__ float randomVal() {
return curand_uniform(&states[threadIdx.x]);
}
// Rectangle CSG equation. Returns minimum signed distance from
// space carved by
// lowerLeft vertex and opposite rectangle vertex upperRight.
__device__ float BoxTest(const Vec& position, Vec lowerLeft, Vec upperRight) {
lowerLeft = position + lowerLeft * -1.0f;
upperRight = upperRight + position * -1.0f;
return -fminf(
fminf(fminf(lowerLeft.x, upperRight.x), fminf(lowerLeft.y, upperRight.y)),
fminf(lowerLeft.z, upperRight.z));
}
#define HIT_NONE 0
#define HIT_LETTER 1
#define HIT_WALL 2
#define HIT_SUN 3
// Sample the world using Signed Distance Fields.
__device__ float QueryDatabase(const Vec& position, int &hitType) {
float distance = 1e9;//FLT_MAX;
Vec f = position; // Flattened position (z=0)
f.z = 0;
char letters[15*4+1] = // 15 two points lines
"5O5_" "5W9W" "5_9_" // P (without curve)
"AOEO" "COC_" "A_E_" // I
"IOQ_" "I_QO" // X
"UOY_" "Y_]O" "WW[W" // A
"aOa_" "aWeW" "a_e_" "cWiO"; // R (without curve)
for (int i = 0; i < sizeof(letters); i += 4) {
Vec begin = Vec(letters[i] - 79, letters[i + 1] - 79) * .5;
Vec e = Vec(letters[i + 2] - 79, letters[i + 3] - 79) * .5 + begin * -1;
Vec o = f + (begin + e * fminf(-fminf((begin + f * -1) % e / (e % e), 0), 1)) * -1;
distance = fminf(distance, o % o); // compare squared distance.
}
distance = sqrtf(distance); // Get real distance, not square distance.
// Two curves (for P and R in PixaR) with hard-coded locations.
Vec curves[] = {Vec(-11, 6), Vec(11, 6)};
for (int i = 2; i--;) {
Vec o = f + curves[i] * -1;
distance = fminf(distance, o.x > 0 ? fabsf(sqrtf(o % o) - 2)
: (o.y += o.y > 0 ? -2 : 2, sqrtf(o % o)));
}
// distance = p(p(distance, 8.0f) + p(position.z, 8.0f), 0.125f) - 0.5f;
distance = __powf(
distance * distance * distance * distance *
distance * distance * distance * distance
+
position.z * position.z * position.z * position.z *
position.z * position.z * position.z * position.z
, 0.125f) - 0.5f;
hitType = HIT_LETTER;
float roomDist ;
roomDist = fminf( // min(A,B) = Union with Constructive solid geometry
//-min carves an empty space
-fminf( // Lower room
BoxTest(position, Vec(-30, -.5, -30), Vec(30, 18, 30)),
// Upper room
BoxTest(position, Vec(-25, 17, -25), Vec(25, 20, 25))
),
BoxTest( // Ceiling "planks" spaced 8 units apart.
Vec(fmodf(fabsf(position.x), 8), position.y, position.z),
Vec(1.5, 18.5, -25),
Vec(6.5, 20, 25)
)
);
if (roomDist < distance)
distance = roomDist, hitType = HIT_WALL;
float sun = 19.9 - position.y; // Everything above 19.9 is light source.
if (sun < distance)
distance = sun, hitType = HIT_SUN;
return distance;
}
// Perform signed sphere marching
// Returns hitType 0, 1, 2, or 3 and update hit position/normal
__device__ int RayMarching(const Vec& origin, const Vec& direction, Vec& hitPos, Vec& hitNorm) {
int hitType = HIT_NONE;
int noHitCount = 0;
// Signed distance marching
float d; // distance from closest object in world.
for (float total_d = 0; total_d < 100; total_d += d) {
if ((d = QueryDatabase(hitPos = origin + direction * total_d, hitType)) < .01 || ++noHitCount > 99)
return hitNorm =
!Vec(QueryDatabase(hitPos + Vec(.01, 0), noHitCount) - d,
QueryDatabase(hitPos + Vec(0, .01), noHitCount) - d,
QueryDatabase(hitPos + Vec(0, 0, .01), noHitCount) - d),
hitType; // Weird return statement where a variable is also
// updated.
}
return 0;
}
__device__ Vec Trace(Vec origin, Vec direction) {
Vec sampledPosition;
Vec normal;
Vec color = 0;
Vec attenuation = 1;
Vec lightDirection(!Vec(0.6f, 0.6f, 1.0f)); // Directional light
for (int bounceCount = 3; bounceCount--;) {
int hitType = RayMarching(origin, direction, sampledPosition, normal);
if (hitType == HIT_NONE)
break; // No hit. This is over, return color.
if (hitType == HIT_LETTER) { // Specular bounce on a letter. No color acc.
direction = direction + normal * (normal % direction * -2);
origin = sampledPosition + direction * 0.1f;
attenuation = attenuation * 0.2f; // Attenuation via distance traveled.
}
if (hitType == HIT_WALL) { // Wall hit uses color yellow?
float incidence = normal % lightDirection;
float p = 6.283185f * randomVal();
float c = randomVal();
float s = sqrtf(1 - c);
float g = normal.z < 0 ? -1 : 1;
float u = -1 / (g + normal.z);
float v = normal.x * normal.y * u;
float cosp;
float sinp;
__sincosf(p, &sinp, &cosp);
direction =
Vec(v, g + normal.y * normal.y * u, -normal.y) * (cosp * s) +
Vec(1 + g * normal.x * normal.x * u, g * v, -g * normal.x) *
(sinp * s) +
normal * sqrtf(c);
origin = sampledPosition + direction * 0.1f;
attenuation = attenuation * 0.2f;
if (incidence > 0.0f &&
RayMarching(sampledPosition + normal * 0.1f, lightDirection,
sampledPosition, normal) == HIT_SUN)
color = color + attenuation * Vec(500, 400, 100) * incidence;
}
if (hitType == HIT_SUN) { //
color = color + attenuation * Vec(50, 80, 100);
break; // Sun Color
}
}
return color;
}
__global__ void GetColor(unsigned char *img, int samplesCount) {
int x = blockIdx.x;
int y = threadIdx.x;
curand_init( blockIdx.x * threadIdx.x, 0, 0 , &states[threadIdx.x]);
const Vec position(-22.0f, 5.0f, 25.0f);
const Vec goal = !(Vec(-3.0f, 4.0f, 0.0f) + position * -1.0f);
const Vec left = !Vec(goal.z, 0, -goal.x) * (1.0f / w);
// Cross-product to get the up vector
const Vec up(goal.y *left.z - goal.z * left.y, goal.z *left.x - goal.x * left.z,
goal.x *left.y - goal.y * left.x);
Vec color;
for (int p = samplesCount; p--;) {
color = color + Trace(position,
!(goal + left * (x - w / 2.0f + randomVal()) + up * (y - h / 2.0f + randomVal())));
}
// Reinhard tone mapping
color = color * (1.0f / samplesCount) + 14.0f / 241.0f;
Vec o = color + 1.0f;
color = Vec(color.x / o.x, color.y / o.y, color.z / o.z) * 255.0f;
img[(y * w + x) * BPP] = color.x;
img[(y * w + x) * BPP + 1] = color.y;
img[(y * w + x) * BPP + 2] = color.z;
}
#define gpuErrchk(ans) { gpuAssert((ans), __FILE__, __LINE__); }
inline void gpuAssert(cudaError_t code, const char *file, int line, bool abort=true) {
if (code != cudaSuccess) {
fprintf(stderr,"GPUassert: %s %s %d\n", cudaGetErrorString(code), file, line);
if (abort) exit(code);
}
}
int main(int argc, char **argv) {
DWORD start_time = GetTickCount();
unsigned char *dev_bitmap;
cudaMalloc( (void**)&dev_bitmap, (w * h * BPP) );
gpuErrchk( cudaPeekAtLastError() );
int samplesCount = 1 << 10;
if (argc > 1 ) {
samplesCount = atoi(argv[1]);
}
GetColor<<<w,h>>>(dev_bitmap, samplesCount);
gpuErrchk( cudaDeviceSynchronize() );
char* bitmap = new char[w * h * BPP];
cudaMemcpy( bitmap, dev_bitmap, (w * h * BPP), cudaMemcpyDeviceToHost );
gpuErrchk( cudaPeekAtLastError() );
DWORD elapsed_ms = GetTickCount() - start_time;
fprintf(stderr, "Time: %dms\n", elapsed_ms);
printf("P6 %d %d 255 ", w, h);
char* c = bitmap;
for (int y = h; y--;) {
for (int x = w; x--;) {
c = &bitmap[y * w * BPP + x * BPP];
printf("%c%c%c", c[0], c[1], c[2]);
c += BPP;
}
}
delete bitmap;
return EXIT_SUCCESS;
}
// Andrew Kensler