SpaceCadetPinball/SpaceCadetPinball/proj.cpp
oz a143b820af TBall, nudge v1, ready.
render occlude list.
2020-12-27 18:19:36 +03:00

63 lines
1.6 KiB
C++

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