Initial commit

Ray3f.c

@@ -0,0 +1,195 @@
+#include "CgeMath.h"
+#include <string.h>
+#include <math.h>
+
+#define EPSILON 0.00001f
+#define PI      3.14159265358979323846f
+
+int CgeRay3fIntersectPlane(const float start[3], const float direction[3],
+                           const float plane[4], float *t, float out[3]) {
+    float tmp1[3];
+    float denom, time;
+
+    /* Calculate intersection time */
+    denom = CgeVec3fDot(direction, plane);
+    time = (plane[3] - CgeVec3fDot(plane, start)) / denom;
+
+    /* Check for ray/plane parallel to each other or point is behing the ray. */
+    if (fabsf(denom) < EPSILON || time < 0.0f)
+        return 0;
+
+    /* Compute intersection point */
+    CgeVec3fScale(direction, time, tmp1);
+    CgeVec3fAdd(start, tmp1, out);
+    *t = time;
+    return 1;
+}
+
+int CgeRay3fIntersectTriangle(const float start[3], const float direction[3],
+                              const float a[3], const float b[3],
+                              const float c[3], float *t, float out[3]) {
+    float plane[4];
+    float tmp1[3], tmp2[3], tmp3[3];
+    float time;
+
+    /* Compute plane */
+    if (CgePlaneFromPoints(a, b, c, plane))
+        return 0;
+
+    /* Compute intersection point in ray against plane */
+    if (CgeRay3fIntersectPlane(start, direction, plane, &time, tmp3))
+        return 0;
+
+    /* Check if point inside rectangle */
+    CgeVec3fSub(b, a, tmp1);
+    CgeVec3fSub(tmp3, a, tmp2);
+    CgeVec3fCross(tmp2, tmp1, tmp1);
+    if (CgeVec3fDot(tmp1, plane) < 0.0f)
+        return 0;
+
+    CgeVec3fSub(c, b, tmp1);
+    CgeVec3fSub(tmp3, b, tmp2);
+    CgeVec3fCross(tmp2, tmp1, tmp1);
+    if (CgeVec3fDot(tmp1, plane) < 0.0f)
+        return 0;
+
+    CgeVec3fSub(a, c, tmp1);
+    CgeVec3fSub(tmp3, c, tmp2);
+    CgeVec3fCross(tmp2, tmp1, tmp1);
+    if (CgeVec3fDot(tmp1, plane) < 0.0f)
+        return 0;
+
+    /* Copy intersection point */
+    memcpy(out, tmp3, sizeof(tmp3));
+    *t = time;
+    return 1;
+}
+
+int CgeSegment3fIntersectPlane(const float start[3], const float end[3],
+                               const float plane[4], float *t, float out[3]) {
+    float tmp[3];
+    float denom, time;
+
+    /* Calculate intersection time */
+    CgeVec3fSub(end, start, tmp);
+    denom = CgeVec3fDot(tmp, plane);
+    time = (plane[3] - CgeVec3fDot(plane, start)) / denom;
+
+    /* Check for ray/plane parallel to each other or point is behing the ray. */
+    if (fabsf(denom) < EPSILON || time < 0.0f || time > 1.0f)
+        return 0;
+
+    /* Compute intersection point */
+    CgeVec3fScale(tmp, time, tmp);
+    CgeVec3fAdd(start, tmp, out);
+    *t = time;
+    return 1;
+}
+
+int CgeSegment3fIntersectTriangle(const float start[3], const float end[3],
+                                  const float a[3], const float b[3],
+                                  const float c[3], float *t, float out[3]) {
+    float plane[4];
+    float tmp1[3], tmp2[3], tmp3[3];
+    float time;
+
+    /* Compute plane */
+    if (CgePlaneFromPoints(a, b, c, plane))
+        return 0;
+
+    /* Compute intersection point in ray against plane */
+    if (CgeSegment3fIntersectPlane(start, end, plane, &time, tmp3))
+        return 0;
+
+    /* Check if point inside rectangle */
+    CgeVec3fSub(b, a, tmp1);
+    CgeVec3fSub(tmp3, a, tmp2);
+    CgeVec3fCross(tmp2, tmp1, tmp1);
+    if (CgeVec3fDot(tmp1, plane) < 0.0f)
+        return 0;
+
+    CgeVec3fSub(c, b, tmp1);
+    CgeVec3fSub(tmp3, b, tmp2);
+    CgeVec3fCross(tmp2, tmp1, tmp1);
+    if (CgeVec3fDot(tmp1, plane) < 0.0f)
+        return 0;
+
+    CgeVec3fSub(a, c, tmp1);
+    CgeVec3fSub(tmp3, c, tmp2);
+    CgeVec3fCross(tmp2, tmp1, tmp1);
+    if (CgeVec3fDot(tmp1, plane) < 0.0f)
+        return 0;
+
+    /* Copy intersection point */
+    memcpy(out, tmp3, sizeof(tmp3));
+    *t = time;
+    return 1;
+}
+
+int CgeRay3fIntersectBox3f(const float aStart[3], const float aDirection[3],
+                           const float bMin[3], const float bMax[3], float *t,
+                           float out[3]) {
+    float timeNear, timeFar, hitNear, hitFar, denom, tmp;
+    int i;
+
+    timeNear = -1.0f / 0.0f;
+    timeFar  =  1.0f / 0.0f;
+
+    /* Check if origin inside box */
+    if (!CgeBox3fContains(bMin, bMax, aStart)) {
+        memcpy(out, aStart, sizeof(float) * 3);
+        *t = 0.0f;
+        return 1;
+    }
+
+    /* Check each axis for the minimal and maximum intersection time */
+    for (i = 0; i < 3; i++) {
+        if (fabsf(aDirection[i]) < EPSILON) {
+            if (aStart[i] < bMin[i] || aStart[i] > bMax[i])
+                return 0;
+            continue;
+        }
+
+        denom = 1.0f / aDirection[i];
+        hitNear = (bMin[i] - aStart[i]) * denom;
+        hitFar  = (bMax[i] - aStart[i]) * denom;
+
+        if (hitNear > hitFar) {
+            tmp = hitNear;
+            hitNear = hitFar;
+            hitFar = tmp;
+        }
+
+        if (hitNear > timeNear)
+            timeNear = hitNear;
+        if (hitFar < timeFar)
+            timeFar = hitFar;
+
+        if (timeNear > timeFar || timeFar < 0.0f)
+            return 0;
+    }
+
+    out[0] = aStart[0] + aDirection[0] * timeNear;
+    out[1] = aStart[1] + aDirection[1] * timeNear;
+    out[2] = aStart[2] + aDirection[2] * timeNear;
+    *t = timeNear;
+
+    return 1;
+}
+
+int CgeSegment3fIntersectBox3f(const float aStart[3], const float aEnd[3],
+                               const float bMin[3], const float bMax[3],
+                               float *t, float out[3]) {
+    float tmp[3];
+    float time;
+
+    CgeVec3fSub(aEnd, aStart, tmp);
+    if (CgeRay3fIntersectBox3f(aStart, tmp, bMin, bMax, &time, out))
+        return 0;
+
+    if (time > 1.0f)
+        return 0;
+
+    *t = time;
+    return 1;
+}