63 lines
1.6 KiB
C++
63 lines
1.6 KiB
C++
#include "pch.h"
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#include "proj.h"
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mat4_row_major proj::matrix;
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float proj::d_, proj::centerx, proj::centery;
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void proj::init(float* mat4x3, float d, float centerX, float centerY)
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{
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/*for (auto colIndex = 0; colIndex < 4; ++colIndex)
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{
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// Todo: out of bounds read from mat4x3?
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for (int rowIndex = colIndex, i = 4; i > 0; rowIndex += 4, --i)
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{
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((float*)&matrix)[rowIndex] = mat4x3[rowIndex];
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}
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}*/
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memcpy(&matrix, mat4x3, sizeof(float) * 4 * 3);
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matrix.Row3.X = 0.0;
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matrix.Row3.Y = 0.0;
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matrix.Row3.Z = 0.0;
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matrix.Row3.W = 1.0;
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d_ = d;
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centerx = centerX;
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centery = centerY;
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}
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void proj::matrix_vector_multiply(mat4_row_major* mat, vector_type* vec, vector_type* dstVec)
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{
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const float x = vec->X, y = vec->Y, z = vec->Z;
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dstVec->X = z * mat->Row0.Z + y * mat->Row0.Y + x * mat->Row0.X + mat->Row0.W;
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dstVec->Y = z * mat->Row1.Z + y * mat->Row1.Y + x * mat->Row1.X + mat->Row1.W;
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dstVec->Z = z * mat->Row2.Z + y * mat->Row2.Y + x * mat->Row2.X + mat->Row2.W;
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}
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float proj::z_distance(vector_type* vec)
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{
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vector_type dstVec{};
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matrix_vector_multiply(&matrix, vec, &dstVec);
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return maths::magnitude(&dstVec);
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}
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void proj::xform_to_2d(vector_type* vec, int* dst)
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{
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float projCoef;
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vector_type dstVec2{};
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matrix_vector_multiply(&matrix, vec, &dstVec2);
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if (0.0 == dstVec2.Z)
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projCoef = 999999.88f;
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else
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projCoef = d_ / dstVec2.Z;
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dst[0] = static_cast<int>(dstVec2.X * projCoef + centerx);
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dst[1] = static_cast<int>(dstVec2.Y * projCoef + centery);
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}
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void proj::recenter(float centerX, float centerY)
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{
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centerx = centerX;
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centery = centerY;
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}
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