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Add mapping function

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This commit is contained in:
Miloslav Číž 2018-09-04 11:42:27 +02:00
parent 695f921c2d
commit 12cfd9f0fb
1 changed files with 54 additions and 0 deletions
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54
raycastlib.h
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@ -126,6 +126,11 @@ typedef void
*/
HitResult castRay(Ray ray, ArrayFunction arrayFunc);
/**
Maps a single point in the world to the screen (2D position + depth).
*/
PixelInfo mapToScreen(Vector2D worldPosition, Unit height, Camera camera);
/**
Casts a single ray and returns a list of collisions.
*/
@ -753,6 +758,52 @@ Unit vectorsAngleCos(Vector2D v1, Vector2D v2)
return (v1.x * v2.x + v1.y * v2.y) / UNITS_PER_SQUARE;
}
PixelInfo mapToScreen(Vector2D worldPosition, Unit height, Camera camera)
{
// TODO: precompute some stuff that's constant in the frame
PixelInfo result;
Unit d = dist(worldPosition,camera.position);
Vector2D toPoint;
toPoint.x = worldPosition.x - camera.position.x;
toPoint.y = worldPosition.y - camera.position.y;
Vector2D cameraDir = angleToDirection(camera.direction);
result.depth = // adjusted distance
(d * vectorsAngleCos(cameraDir,toPoint)) / UNITS_PER_SQUARE;
result.position.y = camera.resolution.y / 2 -
(camera.resolution.y *
perspectiveScale(height - camera.height,result.depth)) / UNITS_PER_SQUARE;
Unit middleColumn = camera.resolution.x / 2;
Unit a = sqrtInt(d * d - result.depth * result.depth);
Ray r;
r.start = camera.position;
r.direction = cameraDir;
if (!pointIsLeftOfRay(worldPosition,r))
a *= -1;
Unit alpha = camera.fovAngle / 2;
Unit cos = cosInt(alpha);
Unit b =
(result.depth * sinInt(alpha)) / (cos == 0 ? 1 : cos); // sin/cos = tan
result.position.x = (a * middleColumn) / b;
result.position.x = 2 * (middleColumn - result.position.x);
return result;
}
Unit degreesToUnitsAngle(int16_t degrees)
{
return (degrees * UNITS_PER_SQUARE) / 360;
@ -760,6 +811,9 @@ Unit degreesToUnitsAngle(int16_t degrees)
Unit perspectiveScale(Unit originalSize, Unit distance)
{
if (distance == 0)
return 0;
return (originalSize * UNITS_PER_SQUARE) /
((VERTICAL_FOV * 2 * distance) / UNITS_PER_SQUARE);
// ^ approximation of tan function