blankhex/CgeMath
1
0
Fork 0
Code Issues Pull Requests Actions Packages Releases Activity

Add more functions, add example, fix ray collision detection
All checks were successful
CI / build-and-analyze (push) Successful in 41s
Details

Browse Source
This commit is contained in:
Mikhail Romanko
2026-07-03 23:28:17 +03:00
parent aef2932ce4
commit b6481a26bc
12 changed files with 500 additions and 14 deletions
Download Patch File Download Diff File Expand all files Collapse all files

205
examples/demo.c Normal file
View File

@@ -0,0 +1,205 @@
#include <stdio.h>
#include <math.h>
#include "CgeMath.h"
#define WIDTH 640
#define HEIGHT 480
#define BG_R 0.05f
#define BG_G 0.05f
#define BG_B 0.1f
#define MAX_BOUNCES 7
static int toInt(float x) {
return (int)(x * 255.0f);
}
typedef struct {
float center[3];
float radius;
const float *color;
float reflectivity;
float shininess;
float specular;
} Sphere;
static const float gRed[3] = {1.0f, 0.0f, 0.0f};
static const float gGreen[3] = {0.0f, 1.0f, 0.0f};
static const float gBlue[3] = {0.0f, 0.0f, 1.0f};
static const Sphere gSpheres[] = {
{{-2.0f, 0.0f, -5.0f}, 1.0f, gRed, 0.1f, 20.0f, 0.5f},
{{ 0.0f, 2.0f, -4.0f}, 1.0f, gGreen, 0.5f, 50.0f, 0.8f},
{{ 2.0f, 0.0f, -5.0f}, 1.0f, gBlue, 0.95f, 100.0f, 1.0f}
};
static const int gNumSpheres = 3;
static const float gLightPos[3] = {0.0f, 3.0f, -2.0f};
static const float gAmbient = 0.2f;
static const float gOrigin[3] = {0.0f, 0.5f, 0.0f};
int traceRay(const float origin[3], const float direction[3], float *t,
int *hitIndex, float hitPoint[3], float normal[3]) {
float t0, closest;
float p[3];
int i, hit;
closest = 1e10f;
hit = -1;
for (i = 0; i < gNumSpheres; i++) {
if (CgeRay3fIntersectSphere(origin, direction, gSpheres[i].center, gSpheres[i].radius, &t0, p) == 1) {
if (t0 > 0.001f && t0 < closest) {
closest = t0;
hit = i;
CgeVec3fSub(p, gSpheres[i].center, normal);
CgeVec3fNormal(normal, normal);
}
}
}
if (direction[1] != 0.0f) {
float t_plane;
t_plane = (-1.0f - origin[1]) / direction[1];
if (t_plane > 0.001f && t_plane < closest) {
closest = t_plane;
hit = -2;
}
}
if (closest == 1e10f) {
return -1;
}
*t = closest;
*hitIndex = hit;
hitPoint[0] = origin[0] + closest * direction[0];
hitPoint[1] = origin[1] + closest * direction[1];
hitPoint[2] = origin[2] + closest * direction[2];
if (hit >= 0) {
CgeVec3fSub(hitPoint, gSpheres[hit].center, normal);
CgeVec3fNormal(normal, normal);
} else if (hit == -2) {
normal[0] = 0.0f; normal[1] = 1.0f; normal[2] = 0.0f;
}
return 1;
}
void traceColor(const float origin[3], const float direction[3], float color[3],
int depth) {
float viewDir[3], halfVec[3], reflectDir[3], offset[3], reflectOrigin[3];
float hitPoint[3], normal[3], localColor[3], reflectColor[3];
float toLight[3], lightDir[3], dummyPoint[3], dummyNormal[3];
float t, NdotL, diffuse, specular, brightness, tile, NdotH, reflectivity;
float shadow, tShadow;
const float *surf;
int hitIndex, dummyIdx, ix, iz;
if (depth >= MAX_BOUNCES) {
color[0] = color[1] = color[2] = 0.0f;
return;
}
if (traceRay(origin, direction, &t, &hitIndex, hitPoint, normal) >= 0) {
CgeVec3fSub(gLightPos, hitPoint, toLight);
CgeVec3fNormal(toLight, lightDir);
shadow = 1.0f;
if (traceRay(hitPoint, lightDir, &tShadow, &dummyIdx, dummyPoint, dummyNormal) >= 0) {
float lightDist = CgeVec3fDistance(gLightPos, hitPoint);
if (tShadow < lightDist) {
shadow = 0.0f;
}
}
NdotL = CgeVec3fDot(normal, lightDir);
diffuse = (NdotL > 0.0f) ? NdotL : 0.0f;
specular = 0.0f;
if (hitIndex >= 0 && NdotL > 0.0f) {
CgeVec3fSub(gOrigin, hitPoint, viewDir);
CgeVec3fNormal(viewDir, viewDir);
CgeVec3fAdd(viewDir, lightDir, halfVec);
CgeVec3fNormal(halfVec, halfVec);
NdotH = CgeVec3fDot(normal, halfVec);
if (NdotH > 0.0f) {
specular = powf(NdotH, gSpheres[hitIndex].shininess) * gSpheres[hitIndex].specular;
}
}
brightness = gAmbient + diffuse * shadow + specular * shadow;
if (hitIndex == -2) {
ix = (int)floorf(hitPoint[0]);
iz = (int)floorf(hitPoint[2]);
tile = ((ix + iz) % 2 == 0) ? 1.0f : 0.3f;
localColor[0] = localColor[1] = localColor[2] = tile * brightness;
} else {
surf = gSpheres[hitIndex].color;
localColor[0] = surf[0] * brightness;
localColor[1] = surf[1] * brightness;
localColor[2] = surf[2] * brightness;
}
reflectivity = (hitIndex >= 0) ? gSpheres[hitIndex].reflectivity : 0.0f;
if (reflectivity > 0.0f) {
CgeVec3fReflect(direction, normal, reflectDir);
CgeVec3fScale(reflectDir, 0.001f, offset);
CgeVec3fAdd(hitPoint, offset, reflectOrigin);
traceColor(reflectOrigin, reflectDir, reflectColor, depth + 1);
localColor[0] = localColor[0] * (1.0f - reflectivity) + reflectColor[0] * reflectivity;
localColor[1] = localColor[1] * (1.0f - reflectivity) + reflectColor[1] * reflectivity;
localColor[2] = localColor[2] * (1.0f - reflectivity) + reflectColor[2] * reflectivity;
}
color[0] = localColor[0];
color[1] = localColor[1];
color[2] = localColor[2];
} else {
color[0] = BG_R;
color[1] = BG_G;
color[2] = BG_B;
}
}
int main() {
int x, y;
float u, v, aspect, fov;
float direction[3], color[3];
printf("P3\n%d %d\n255\n", WIDTH, HEIGHT);
aspect = (float)WIDTH / (float)HEIGHT;
fov = 1.0f;
for (y = 0; y < HEIGHT; y++) {
for (x = 0; x < WIDTH; x++) {
u = (2.0f * (x + 0.5f) / (float)WIDTH - 1.0f) * aspect;
v = (2.0f * (HEIGHT - y - 0.5f) / (float)HEIGHT - 1.0f);
direction[0] = u;
direction[1] = v;
direction[2] = -fov;
CgeVec3fNormal(direction, direction);
traceColor(gOrigin, direction, color, 0);
if (color[0] < 0.0f) color[0] = 0.0f; else if (color[0] > 1.0f) color[0] = 1.0f;
if (color[1] < 0.0f) color[1] = 0.0f; else if (color[1] > 1.0f) color[1] = 1.0f;
if (color[2] < 0.0f) color[2] = 0.0f; else if (color[2] > 1.0f) color[2] = 1.0f;
color[0] = powf(color[0], 1.0f / 2.2f);
color[1] = powf(color[1], 1.0f / 2.2f);
color[2] = powf(color[2], 1.0f / 2.2f);
printf("%d %d %d\n", toInt(color[0]), toInt(color[1]), toInt(color[2]));
}
}
return 0;
}