How do I move a point in a specific direction in 3d Space?

Question

I know how to move a point in a direction in 2d space it's like this:

pointX += sin(angle) * movementSpeed;
pointY += cos(angle) * movementSpeed;

but how do I do the same in 3d space assuming the angle variable is replaced with pitch, yaw, and roll variables?

(btw I'm making a ray marching algorithm)

Answer 1

To move a point in 3D space using pitch, yaw, and roll angles, you need to convert these angles into a direction vector. The direction vector describes the direction in which the point will move.

1. Convert Angles to Radians: Make sure your pitch, yaw, and roll angles are in radians. If they are in degrees, convert them to radians
2. Compute the Direction Vector: Calculate the direction vector based on pitch and yaw.
3. Move the Point: Use the direction vector to update the point's position.

#include <cmath>

// Convert degrees to radians if needed
constexpr float DEG_TO_RAD = M_PI / 180.0f;

// Function to move a point in 3D space
void movePointIn3DSpace(float& pointX, float& pointY, float& pointZ, float pitch, float yaw, float movementSpeed) {
    // Convert angles to radians if they are in degrees
    float pitchRad = pitch * DEG_TO_RAD;
    float yawRad = yaw * DEG_TO_RAD;

    // Calculate the direction vector
    float dirX = cos(pitchRad) * sin(yawRad);
    float dirY = sin(pitchRad);
    float dirZ = cos(pitchRad) * cos(yawRad);

    // Update the point's position
    pointX += dirX * movementSpeed;
    pointY += dirY * movementSpeed;
    pointZ += dirZ * movementSpeed;
}

// Example usage
int main() {
    float pointX = 0.0f, pointY = 0.0f, pointZ = 0.0f;
    float pitch = 30.0f;  // degrees
    float yaw = 45.0f;    // degrees
    float movementSpeed = 1.0f;

    movePointIn3DSpace(pointX, pointY, pointZ, pitch, yaw, movementSpeed);

    // Output the new position
    printf("New position: (%f, %f, %f)\n", pointX, pointY, pointZ);

    return 0;
}

(This is coded in cpp btw)