camera.cpp

#include "camera.h"

CAMERA::CAMERA() {
  float IdentityMatrix[4][4]{
      {1, 0, 0, 0}, {0, 1, 0, 0}, {0, 0, 1, 0}, {0, 0, 0, 1}};
  viewMatrix = new MATRIX(&IdentityMatrix[0][0]);
  projMatrix = new MATRIX(&IdentityMatrix[0][0]);
}

CAMERA::~CAMERA() {
  delete viewMatrix;
  delete projMatrix;
}

void CAMERA::SetAspectRatio(float width, float height) {
  aspectRatio = height / width;
}

void CAMERA::SetFOV(float degrees) { vFOV = degrees; }

void CAMERA::SetViewMatrix(float *position) {
  viewMatrix = new MATRIX(position);
}

MATRIX *CAMERA::GetViewMatrix() { return viewMatrix; }

void CAMERA::SetProjMatrix(float zNear, float zFar) {
  float rad = vFOV * 0.01744f;
  float yScale = 1.0f / tan(rad / 2);
  float xScale = yScale * aspectRatio;
  nearPlane = zNear;
  farPlane = zFar;

  float projMat[4][4]{{yScale * aspectRatio, 0, 0, 0},
                      {0, yScale, 0, 0},
                      {0, 0, zFar / (zFar - zNear), 1},
                      {0, 0, -(zFar * zNear) / (zFar - zNear), 0}};
  projMatrix->Pos(&projMat[0][0]);
}

MATRIX *CAMERA::GetProjMatrix() { return projMatrix; }

void CAMERA::Invert() {
  VECTOR_3 tempVert{*(viewMatrix->GetMatrix() + 12),
                    *(viewMatrix->GetMatrix() + 13),
                    *(viewMatrix->GetMatrix() + 14)};
  float subMatrix[3][3]{
      {*(viewMatrix->GetMatrix() + 0), *(viewMatrix->GetMatrix() + 1),
       *(viewMatrix->GetMatrix() + 2)},
      {*(viewMatrix->GetMatrix() + 4), *(viewMatrix->GetMatrix() + 5),
       *(viewMatrix->GetMatrix() + 6)},
      {*(viewMatrix->GetMatrix() + 8), *(viewMatrix->GetMatrix() + 9),
       *(viewMatrix->GetMatrix() + 10)},
  };
  // Transpose the matrix.
  float transMatrix[4][4]{
      {1, 0, 0, 0}, {0, 1, 0, 0}, {0, 0, 1, 0}, {0, 0, 0, 1}};
  for (int j = 0; j < 3; j++) {
    for (int i = 0; i < 3; i++) {
      transMatrix[i][j] = subMatrix[j][i];
    }
  }
  MATRIX *tempMatrix = new MATRIX(&transMatrix[0][0]);
  ShaderUtil::MultVertByMatrix(&tempVert, tempMatrix);
  // Negate the vector.
  tempVert.x = -tempVert.x;
  tempVert.y = -tempVert.y;
  tempVert.z = -tempVert.z;
  tempMatrix->SetCoord(0, tempVert.x);
  tempMatrix->SetCoord(1, tempVert.y);
  tempMatrix->SetCoord(2, tempVert.z);
  viewMatrix = tempMatrix;
}

float CAMERA::GetNearPlane() { return nearPlane; }

float CAMERA::GetFarPlane() { return farPlane; }