1 files changed, 63 insertions, 0 deletions

diff --git a/src/Frustum.cpp b/src/Frustum.cpp
new file mode 100644
index 0000000..dbad920
--- /dev/null
+++ b/src/Frustum.cpp
@@ -0,0 +1,63 @@
+#include "Frustum.hpp"
+
+#include <glm/gtc/type_ptr.hpp>
+
+void Frustum::NormalizePlane(FrustumSide side) {
+    float magnitude = (float)sqrt(frustum[side][A] * frustum[side][A] + frustum[side][B] * frustum[side][B] + frustum[side][C] * frustum[side][C]);
+
+    frustum[side][A] /= magnitude;
+    frustum[side][B] /= magnitude;
+    frustum[side][C] /= magnitude;
+    frustum[side][D] /= magnitude;
+}
+
+void Frustum::UpdateFrustum(const glm::mat4& vpmat) {
+    vp = vpmat;
+    float *clip = glm::value_ptr(vp);
+
+    frustum[RIGHT][A] = clip[3] - clip[0];
+    frustum[RIGHT][B] = clip[7] - clip[4];
+    frustum[RIGHT][C] = clip[11] - clip[8];
+    frustum[RIGHT][D] = clip[15] - clip[12];
+    NormalizePlane(RIGHT);
+
+
+    frustum[LEFT][A] = clip[3] + clip[0];
+    frustum[LEFT][B] = clip[7] + clip[4];
+    frustum[LEFT][C] = clip[11] + clip[8];
+    frustum[LEFT][D] = clip[15] + clip[12];
+    NormalizePlane(LEFT);
+
+    frustum[BOTTOM][A] = clip[3] + clip[1];
+    frustum[BOTTOM][B] = clip[7] + clip[5];
+    frustum[BOTTOM][C] = clip[11] + clip[9];
+    frustum[BOTTOM][D] = clip[15] + clip[13];
+    NormalizePlane(BOTTOM);
+
+    frustum[TOP][A] = clip[3] - clip[1];
+    frustum[TOP][B] = clip[7] - clip[5];
+    frustum[TOP][C] = clip[11] - clip[9];
+    frustum[TOP][D] = clip[15] - clip[13];
+    NormalizePlane(TOP);
+
+    frustum[BACK][A] = clip[3] - clip[2];
+    frustum[BACK][B] = clip[7] - clip[6];
+    frustum[BACK][C] = clip[11] - clip[10];
+    frustum[BACK][D] = clip[15] - clip[14];
+    NormalizePlane(BACK);
+
+    frustum[FRONT][A] = clip[3] + clip[2];
+    frustum[FRONT][B] = clip[7] + clip[6];
+    frustum[FRONT][C] = clip[11] + clip[10];
+    frustum[FRONT][D] = clip[15] + clip[14];
+    NormalizePlane(FRONT);
+}
+
+bool Frustum::TestPoint(VectorF point) {
+    for (int i = 0; i < 6; i++) {
+        if (frustum[i][A] * point.x + frustum[i][B] * point.y + frustum[i][C] * point.z + frustum[i][D] <= 0) {
+            return false;
+        }
+    }
+    return true;
+}
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