diff options
Diffstat (limited to 'Minecraft.Client/Frustum.cpp')
| -rw-r--r-- | Minecraft.Client/Frustum.cpp | 149 |
1 files changed, 149 insertions, 0 deletions
diff --git a/Minecraft.Client/Frustum.cpp b/Minecraft.Client/Frustum.cpp new file mode 100644 index 00000000..c40f7c6f --- /dev/null +++ b/Minecraft.Client/Frustum.cpp @@ -0,0 +1,149 @@ +#include "stdafx.h" +#include "..\Minecraft.World\FloatBuffer.h" +#include "Frustum.h" + +Frustum *Frustum::frustum = new Frustum(); + +Frustum::Frustum() +{ + _proj = MemoryTracker::createFloatBuffer(16); + _modl = MemoryTracker::createFloatBuffer(16); + _clip = MemoryTracker::createFloatBuffer(16); +} + +Frustum::~Frustum() +{ + delete _proj; + delete _modl; + delete _clip; +} + + +FrustumData *Frustum::getFrustum() +{ + frustum->calculateFrustum(); + return frustum; +} + + + ///////////////////////////////// NORMALIZE PLANE \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\* + ///// + ///// This normalizes a plane (A side) from a given frustum. + ///// + ///////////////////////////////// NORMALIZE PLANE \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\* + +void Frustum::normalizePlane(float **frustum, int side) +{ + float magnitude = (float) sqrt(frustum[side][A] * frustum[side][A] + frustum[side][B] * frustum[side][B] + frustum[side][C] * frustum[side][C]); + + // Then we divide the plane's values by it's magnitude. + // This makes it easier to work with. + frustum[side][A] /= magnitude; + frustum[side][B] /= magnitude; + frustum[side][C] /= magnitude; + frustum[side][D] /= magnitude; +} + +void Frustum::calculateFrustum() +{ + _proj->clear(); + _modl->clear(); + _clip->clear(); + + // glGetFloatv() is used to extract information about our OpenGL world. + // Below, we pass in GL_PROJECTION_MATRIX to abstract our projection matrix. + // It then stores the matrix into an array of [16]. + glGetFloat(GL_PROJECTION_MATRIX, _proj); + + // By passing in GL_MODELVIEW_MATRIX, we can abstract our model view matrix. + // This also stores it in an array of [16]. + glGetFloat(GL_MODELVIEW_MATRIX, _modl); + + _proj->flip()->limit(16); + _proj->get(&proj); + _modl->flip()->limit(16); + _modl->get(&modl); + + // Now that we have our modelview and projection matrix, if we combine these 2 matrices, + // it will give us our clipping planes. To combine 2 matrices, we multiply them. + + clip[0] = modl[0] * proj[0] + modl[1] * proj[4] + modl[2] * proj[8] + modl[3] * proj[12]; + clip[1] = modl[0] * proj[1] + modl[1] * proj[5] + modl[2] * proj[9] + modl[3] * proj[13]; + clip[2] = modl[0] * proj[2] + modl[1] * proj[6] + modl[2] * proj[10] + modl[3] * proj[14]; + clip[3] = modl[0] * proj[3] + modl[1] * proj[7] + modl[2] * proj[11] + modl[3] * proj[15]; + + clip[4] = modl[4] * proj[0] + modl[5] * proj[4] + modl[6] * proj[8] + modl[7] * proj[12]; + clip[5] = modl[4] * proj[1] + modl[5] * proj[5] + modl[6] * proj[9] + modl[7] * proj[13]; + clip[6] = modl[4] * proj[2] + modl[5] * proj[6] + modl[6] * proj[10] + modl[7] * proj[14]; + clip[7] = modl[4] * proj[3] + modl[5] * proj[7] + modl[6] * proj[11] + modl[7] * proj[15]; + + clip[8] = modl[8] * proj[0] + modl[9] * proj[4] + modl[10] * proj[8] + modl[11] * proj[12]; + clip[9] = modl[8] * proj[1] + modl[9] * proj[5] + modl[10] * proj[9] + modl[11] * proj[13]; + clip[10] = modl[8] * proj[2] + modl[9] * proj[6] + modl[10] * proj[10] + modl[11] * proj[14]; + clip[11] = modl[8] * proj[3] + modl[9] * proj[7] + modl[10] * proj[11] + modl[11] * proj[15]; + + clip[12] = modl[12] * proj[0] + modl[13] * proj[4] + modl[14] * proj[8] + modl[15] * proj[12]; + clip[13] = modl[12] * proj[1] + modl[13] * proj[5] + modl[14] * proj[9] + modl[15] * proj[13]; + clip[14] = modl[12] * proj[2] + modl[13] * proj[6] + modl[14] * proj[10] + modl[15] * proj[14]; + clip[15] = modl[12] * proj[3] + modl[13] * proj[7] + modl[14] * proj[11] + modl[15] * proj[15]; + + // Now we actually want to get the sides of the frustum. To do this we take + // the clipping planes we received above and extract the sides from them. + + // This will extract the RIGHT side of the frustum + m_Frustum[RIGHT][A] = clip[3] - clip[0]; + m_Frustum[RIGHT][B] = clip[7] - clip[4]; + m_Frustum[RIGHT][C] = clip[11] - clip[8]; + m_Frustum[RIGHT][D] = clip[15] - clip[12]; + + // Now that we have a normal (A,B,C) and a distance (D) to the plane, + // we want to normalize that normal and distance. + + // Normalize the RIGHT side + normalizePlane(m_Frustum, RIGHT); + + // This will extract the LEFT side of the frustum + m_Frustum[LEFT][A] = clip[3] + clip[0]; + m_Frustum[LEFT][B] = clip[7] + clip[4]; + m_Frustum[LEFT][C] = clip[11] + clip[8]; + m_Frustum[LEFT][D] = clip[15] + clip[12]; + + // Normalize the LEFT side + normalizePlane(m_Frustum, LEFT); + + // This will extract the BOTTOM side of the frustum + m_Frustum[BOTTOM][A] = clip[3] + clip[1]; + m_Frustum[BOTTOM][B] = clip[7] + clip[5]; + m_Frustum[BOTTOM][C] = clip[11] + clip[9]; + m_Frustum[BOTTOM][D] = clip[15] + clip[13]; + + // Normalize the BOTTOM side + normalizePlane(m_Frustum, BOTTOM); + + // This will extract the TOP side of the frustum + m_Frustum[TOP][A] = clip[3] - clip[1]; + m_Frustum[TOP][B] = clip[7] - clip[5]; + m_Frustum[TOP][C] = clip[11] - clip[9]; + m_Frustum[TOP][D] = clip[15] - clip[13]; + + // Normalize the TOP side + normalizePlane(m_Frustum, TOP); + + // This will extract the BACK side of the frustum + m_Frustum[BACK][A] = clip[3] - clip[2]; + m_Frustum[BACK][B] = clip[7] - clip[6]; + m_Frustum[BACK][C] = clip[11] - clip[10]; + m_Frustum[BACK][D] = clip[15] - clip[14]; + + // Normalize the BACK side + normalizePlane(m_Frustum, BACK); + + // This will extract the FRONT side of the frustum + m_Frustum[FRONT][A] = clip[3] + clip[2]; + m_Frustum[FRONT][B] = clip[7] + clip[6]; + m_Frustum[FRONT][C] = clip[11] + clip[10]; + m_Frustum[FRONT][D] = clip[15] + clip[14]; + + // Normalize the FRONT side + normalizePlane(m_Frustum, FRONT); +}
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