Initial commit

Ray2f.c

@@ -0,0 +1,193 @@
+#include "CgeMath.h"
+#include <string.h>
+#include <math.h>
+
+#define EPSILON 0.00001f
+#define PI      3.14159265358979323846f
+
+int CgeRay2fIntersectLine(const float start[2], const float direction[2],
+                          const float line[3], float *t, float out[2]) {
+    float tmp1[2];
+    float denom, time;
+
+    /* Calculate intersection time */
+    denom = CgeVec2fDot(direction, line);
+    time = (line[2] - CgeVec2fDot(line, 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 */
+    CgeVec2fScale(direction, time, tmp1);
+    CgeVec2fAdd(start, tmp1, out);
+    *t = time;
+    return 1;
+}
+
+int CgeRay2fIntersectTime(const float aStart[2], const float aDirection[2],
+                          const float bStart[2], const float bDirection[2],
+                          float *time1, float *time2) {
+    float tmp1[2], tmp2[2], tmp3[2];
+    float denom;
+
+    /* Rotate directions by 90 degrees and caluclate denom */
+    tmp1[0] = -aDirection[1]; tmp1[1] = aDirection[0];
+    tmp2[0] = -bDirection[1]; tmp2[1] = bDirection[0];
+    denom = CgeVec2fDot(tmp1, bDirection);
+
+    if (fabsf(denom) < EPSILON)
+        return 0;
+
+    /* Calculate segments offset and intersection times */
+    CgeVec2fSub(aStart, bStart, tmp3);
+    *time1 = CgeVec2fDot(tmp3, tmp2) / denom;
+    *time2 = CgeVec2fDot(tmp3, tmp1) / denom;
+
+    return 1;
+}
+
+int CgeRay2fIntersectRay(const float aStart[2], const float aDirection[2],
+                         const float bStart[2], const float bDirection[2],
+                         float *t, float out[2]) {
+    float tmp[2];
+    float time1, time2;
+
+    if (CgeRay2fIntersectTime(aStart, aDirection, bStart, bDirection, &time1, &time2))
+        return 0;
+
+    if (time1 < 0.0f || time2 < 0.0f)
+        return 0;
+
+    CgeVec2fScale(aDirection, time1, tmp);
+    CgeVec2fAdd(aStart, tmp, out);
+    *t = time1;
+    return 1;
+}
+
+int CgeRay2fIntersectSegment(const float aStart[2], const float aDirection[2],
+                             const float bStart[2], const float bEnd[2],
+                             float *t, float out[2]) {
+    float tmp[2];
+    float time1, time2;
+
+    CgeVec2fSub(bEnd, bStart, tmp);
+    if (CgeRay2fIntersectTime(aStart, aDirection, bStart, tmp, &time1, &time2))
+        return 0;
+
+    if (time1 < 0.0f || time2 < 0.0f || time2 > 1.0f)
+        return 0;
+
+    CgeVec2fScale(aDirection, time1, tmp);
+    CgeVec2fAdd(aStart, tmp, out);
+    *t = time1;
+    return 1;
+}
+
+int CgeSegment2fIntersectLine(const float start[2], const float end[2],
+                              const float line[3], float *t, float out[2]) {
+    float tmp[2];
+    float denom, time;
+
+    /* Calculate intersection time */
+    CgeVec2fSub(end, start, tmp);
+    denom = CgeVec2fDot(tmp, line);
+    time = (line[2] - CgeVec2fDot(line, 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 */
+    CgeVec2fScale(tmp, time, tmp);
+    CgeVec2fAdd(start, tmp, out);
+    *t = time;
+    return 1;
+}
+
+int CgeSegment2fIntersectSegment(const float aStart[2], const float aEnd[2],
+                                 const float bStart[2], const float bEnd[2],
+                                 float *t, float out[2]) {
+    float tmp1[2], tmp2[2];
+    float time1, time2;
+
+    CgeVec2fSub(aEnd, aStart, tmp1);
+    CgeVec2fSub(bEnd, bStart, tmp2);
+    if (CgeRay2fIntersectTime(aStart, tmp1, bStart, tmp2, &time1, &time2))
+        return 0;
+
+    if (time1 < 0.0f || time1 > 1.0f || time2 < 0.0f || time2 > 1.0f)
+        return 0;
+
+    CgeVec2fLerp(aStart, aEnd, time1, out);
+    *t = time1;
+
+    return 1;
+}
+
+int CgeRay2fIntersectBox2f(const float aStart[2], const float aDirection[2],
+                           const float bMin[2], const float bMax[2],
+                           float *t, float out[2]) {
+    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 (!CgeBox2fContains(bMin, bMax, aStart)) {
+        memcpy(out, aStart, sizeof(float) * 2);
+        *t = 0.0f;
+        return 1;
+    }
+
+    /* Check each axis for the minimal and maximum intersection time */
+    for (i = 0; i < 2; 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;
+    *t = timeNear;
+
+    return 1;
+}
+
+int CgeSegment2fIntersectBox2f(const float aStart[2], const float aEnd[2],
+                               const float bMin[2], const float bMax[2],
+                               float *t, float out[2]) {
+    float tmp[3];
+    float time;
+
+    CgeVec2fSub(aEnd, aStart, tmp);
+    if (CgeRay2fIntersectBox2f(aStart, tmp, bMin, bMax, &time, out))
+        return 0;
+
+    if (time > 1.0f)
+        return 0;
+
+    *t = time;
+    return 1;
+}