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37 lines
1.3 KiB
37 lines
1.3 KiB
#include"Camera.h"
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#include"Ray.h"
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#include<math.h>
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Camera::Camera(float fov, float aspect) {
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mFOV = fov;
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mAspect = aspect;
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mNearPlaneWidth = 0.0f;
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mNearPlaneHeight = 0.0f;
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}
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void Camera::LookAt(const Vector3& position, const Vector3& center, const Vector3& up) {
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Vector3 camera_to_view_point = center - position;
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float distance = camera_to_view_point.Magnitude();
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float half_fov = mFOV / 2.0f;
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float radian_half_fov = half_fov * 3.14159f / 180.0f;
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float half_height = atanf(radian_half_fov)*distance;
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float half_width = half_height * mAspect;
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mNearPlaneWidth = half_width * 2.0f;
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mNearPlaneHeight = half_height * 2.0f;
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camera_to_view_point.Normalize();
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Vector3 right_direction = Cross(camera_to_view_point, up);
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right_direction.Normalize();
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Vector3 up_direction = Cross(right_direction, camera_to_view_point);
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up_direction.Normalize();
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mUVector = right_direction;
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mVVector = up_direction;
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mUSpanVector = mNearPlaneWidth * mUVector;
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mVSpanVector = mNearPlaneHeight * mVVector;
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mCenter = center;
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mPosition = position;
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mUp = up;
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}
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Ray Camera::GetRay(float u, float v) {
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u = u * 2.0f - 1.0f;
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v = v * 2.0f - 1.0f;
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Vector3 point_on_near_plane = mCenter + 0.5f*u*mUSpanVector + 0.5f*v*mVSpanVector;
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return Ray(mPosition, point_on_near_plane - mPosition, Vector3(1.0f, 1.0f, 1.0f));
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}
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