mirror of https://github.com/AxioDL/zeus.git
70 lines
1.9 KiB
C++
70 lines
1.9 KiB
C++
#include "zeus/CProjection.hpp"
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#include <cassert>
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#include <cmath>
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namespace zeus {
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void CProjection::_updateCachedMatrix() {
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assert(m_projType == EProjType::Orthographic || m_projType == EProjType::Perspective);
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if (m_projType == EProjType::Orthographic) {
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float tmp;
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tmp = 1.0f / (m_ortho.right - m_ortho.left);
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m_mtx.m[0][0] = 2.0f * tmp;
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m_mtx.m[1][0] = 0.0f;
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m_mtx.m[2][0] = 0.0f;
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m_mtx.m[3][0] = -(m_ortho.right + m_ortho.left) * tmp;
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tmp = 1.0f / (m_ortho.top - m_ortho.bottom);
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m_mtx.m[0][1] = 0.0f;
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m_mtx.m[1][1] = 2.0f * tmp;
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m_mtx.m[2][1] = 0.0f;
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m_mtx.m[3][1] = -(m_ortho.top + m_ortho.bottom) * tmp;
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tmp = 1.0f / (m_ortho.zfar - m_ortho.znear);
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m_mtx.m[0][2] = 0.0f;
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m_mtx.m[1][2] = 0.0f;
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m_mtx.m[2][2] = -tmp;
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m_mtx.m[3][2] = -m_ortho.zfar * tmp;
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m_mtx.m[0][3] = 0.0f;
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m_mtx.m[1][3] = 0.0f;
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m_mtx.m[2][3] = 0.0f;
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m_mtx.m[3][3] = 1.0f;
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} else if (m_projType == EProjType::Perspective) {
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float tfov = std::tan(m_persp.fov * 0.5f);
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float top = m_persp.znear * tfov;
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float bottom = -top;
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float right = m_persp.aspect * m_persp.znear * tfov;
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float left = -right;
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float rml = right - left;
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float rpl = right + left;
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float tmb = top - bottom;
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float tpb = top + bottom;
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float fpn = m_persp.zfar + m_persp.znear;
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float fmn = m_persp.zfar - m_persp.znear;
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m_mtx.m[0][0] = 2.f * m_persp.znear / rml;
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m_mtx.m[1][0] = 0.0f;
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m_mtx.m[2][0] = rpl / rml;
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m_mtx.m[3][0] = 0.0f;
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m_mtx.m[0][1] = 0.0f;
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m_mtx.m[1][1] = 2.f * m_persp.znear / tmb;
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m_mtx.m[2][1] = tpb / tmb;
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m_mtx.m[3][1] = 0.0f;
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m_mtx.m[0][2] = 0.0f;
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m_mtx.m[1][2] = 0.0f;
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m_mtx.m[2][2] = -fpn / fmn;
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m_mtx.m[3][2] = -2.f * m_persp.zfar * m_persp.znear / fmn;
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m_mtx.m[0][3] = 0.0f;
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m_mtx.m[1][3] = 0.0f;
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m_mtx.m[2][3] = -1.0f;
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m_mtx.m[3][3] = 0.0f;
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}
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}
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} // namespace zeus
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