I've been writing a raycaster in C++ and to render stuff I use GDI/GDI+. I know that using WGDI to render graphics is not the best idea in the world and I should probably use OpenGL, SFML and etc. but this raycaster does not involve any super-high-level real-time graphics, so in this case WGDI does the job. Besides I probably will be showing this in my school and installing OpenGL there would be a huge pain.
Okay, so the actual problem I wanted to talk about is that whenever I change the map grid from 8x8 to e.g. 8x16, the way that some walls are rendered is pretty bizzarre:
If someone can explain why such issue occurrs I would be very happy to discover what's wrong with my code.
main.cpp
/*
* Pseudo-code of the void renderer():
* Horizontal gridline check:
* Set horizontal distance to a pretty high value, horizontal coordinates to camera coordinates
* Calculate negative inverse of tangent
* Set DOF variable to 0
* If ray angle is bigger than PI calculate ray Y-coordinate to be as close as possible to the gridline position and subtract 0.0001 for precision, calculate ray X-coordinate and offset coordinates for the ray moovement over the gridline
* If ray angle is smaller than PI do the same as if ray angle < PI but add whatever the size of the map is to ray Y-coordinate
* If ray angle is straight up or down set ray coordinates to camera coordinates and DOF to map size
* Loop only if DOF is smaller than map size:
* Calculate actual gridline coordinates
* If the grid cell at [X, Y] is a wall break out from the loop, save the current ray coordinates, calculate the distance between the camera and the wall
* Else update ray coordinates with the earlier calculated offsets
*
* Vertical gridline check:
* Set vertical distance to a pretty high value, vertical coordinates to camera coordinates
* Calculate inverse of tangent
* Set DOF variable to 0
* If ray angle is bigger than PI / 2 and smaller than 3 * PI / 2 calculate ray X-coordinate to be as close as possible to the gridline position and subtract 0.0001 for precision, calculate ray Y-coordinate and offset coordinates for the ray moovement over the gridline
* If ray angle is smaller than PI / 2 or bigger than 3 * PI / 2 do the same as if ray angle > PI / 2 && < 3 * PI / 2 but add whatever the size of the map is to ray X-coordinate
* If ray angle is straight left or right set ray coordinates to camera coordinates and DOF to map size
* Loop only if DOF is smaller than map size:
* Calculate actual gridline coordinates
* If the grid cell at [X, Y] is a wall break out from the loop, save the current ray coordinates, calculate the distance between the camera and the wall
* Else update ray coordinates with the earlier calculated offsets
*
* If the vertical distance is smaller than the horizontal one update ray coordinates to the horizontal ones and set final distance to the horizontal one
* Else update ray coordinates to the vertical ones and set final distance to the vertical one
* Fix fisheye effect
* Add one radian to the ray angle
* Calculate line height by multiplying constant integer 400 by the map size and dividing that by the final distance
* Calculate line offset (to make it more centered) by subtracting half of the line height from constant integer 400
* Draw 8-pixels wide column at [ray index * 8, camera Z-offset + line offset] and [ray index * 8, camera Z-offset + line offset + line height] (the color doesn't matter i think)
*/
#include "../../LIB/wsgl.hpp"
#include "res/maths.hpp"
#include <memory>
using namespace std;
const int window_x = 640, window_y = 640;
float camera_x = 256, camera_y = 256, camera_z = 75;
float camera_a = 0.001;
int camera_fov = 80;
int map_x;
int map_y;
int map_s;
shared_ptr<int[]> map_w;
void controls()
{
if(wsgl::is_key_down(wsgl::key::w))
{
int mx = (camera_x + 30 * cos(camera_a)) / map_s;
int my = (camera_y + 30 * sin(camera_a)) / map_s;
int mp = my * map_x + mx;
if(mp >= 0 && mp < map_s && !map_w[mp])
{camera_x += 15 * cos(camera_a); camera_y += 15 * sin(camera_a);}
}
if(wsgl::is_key_down(wsgl::key::s))
{
int mx = (camera_x - 30 * cos(camera_a)) / map_s;
int my = (camera_y - 30 * sin(camera_a)) / map_s;
int mp = my * map_x + mx;
if(mp >= 0 && mp < map_s && !map_w[mp])
{camera_x -= 5 * cos(camera_a); camera_y -= 5 * sin(camera_a);}
}
if(wsgl::is_key_down(wsgl::key::a_left))
{camera_a = reset_ang(camera_a - 5 * RAD);}
if(wsgl::is_key_down(wsgl::key::a_right))
{camera_a = reset_ang(camera_a + 5 * RAD);}
if(wsgl::is_key_down(wsgl::key::a_up))
{camera_z += 15;}
if(wsgl::is_key_down(wsgl::key::a_down))
{camera_z -= 15;}
}
void renderer()
{
int map_x_pos, map_y_pos, map_cell, dof;
float ray_x, ray_y, ray_a = reset_ang(camera_a - deg_to_rad(camera_fov / 2));
float x_offset, y_offset, tangent, distance_h, distance_v, h_x, h_y, v_x, v_y;
float final_distance, line_height, line_offset;
wsgl::clear_window();
for(int i = 0; i < camera_fov; i++)
{
distance_h = 1000000, h_x = camera_x, h_y = camera_y;
tangent = -1 / tan(ray_a);
dof = 0;
if(ray_a > PI)
{ray_y = (((int)camera_y / map_s) * map_s) - 0.0001; ray_x = (camera_y - ray_y) * tangent + camera_x; y_offset = -map_s; x_offset = -y_offset * tangent;}
if(ray_a < PI)
{ray_y = (((int)camera_y / map_s) * map_s) + map_s; ray_x = (camera_y - ray_y) * tangent + camera_x; y_offset = map_s; x_offset = -y_offset * tangent;}
if(ray_a == 0 || ray_a == PI)
{ray_x = camera_x; ray_y = camera_y; dof = map_s;}
for(dof; dof < map_s; dof++)
{
map_x_pos = (int)(ray_x) / map_s;
map_y_pos = (int)(ray_y) / map_s;
map_cell = map_y_pos * map_x + map_x_pos;
if(map_cell >= 0 && map_cell < map_s && map_w[map_cell])
{dof = map_s; h_x = ray_x; h_y = ray_y; distance_h = distance(camera_x, camera_y, h_x, h_y);}
else
{ray_x += x_offset; ray_y += y_offset;}
}
distance_v = 1000000, v_x = camera_x, v_y = camera_y;
tangent = -tan(ray_a);
dof = 0;
if(ray_a > PI2 && ray_a < PI3)
{ray_x = (((int)camera_x / map_s) * map_s) - 0.0001; ray_y = (camera_x - ray_x) * tangent + camera_y; x_offset = -map_s; y_offset = -x_offset * tangent;}
if(ray_a < PI2 || ray_a > PI3)
{ray_x = (((int)camera_x / map_s) * map_s) + map_s; ray_y = (camera_x - ray_x) * tangent + camera_y; x_offset = map_s; y_offset = -x_offset * tangent;}
if(ray_a == PI2 || ray_a == PI3)
{ray_x = camera_x; ray_y = camera_y; dof = map_s;}
for(dof; dof < map_s; dof++)
{
map_x_pos = (int)(ray_x) / map_s;
map_y_pos = (int)(ray_y) / map_s;
map_cell = map_y_pos * map_x + map_x_pos;
if(map_cell >= 0 && map_cell < map_s && map_w[map_cell])
{dof = map_s; v_x = ray_x; v_y = ray_y; distance_v = distance(camera_x, camera_y, v_x, v_y);}
else
{ray_x += x_offset; ray_y += y_offset;}
}
if(distance_v < distance_h)
{ray_x = v_x; ray_y = v_y; final_distance = distance_v;}
else
{ray_x = h_x; ray_y = h_y; final_distance = distance_h;}
final_distance *= cos(reset_ang(camera_a - ray_a));
ray_a = reset_ang(ray_a + RAD);
line_height = (map_s * 400) / final_distance;
line_offset = 200 - line_height / 2;
wsgl::draw_line({i * 8, camera_z + line_offset}, {i * 8, camera_z + line_offset + line_height}, {0, 255 / (final_distance / 250 + 1), 0}, 8);
if(i == camera_fov / 2)
{wsgl::draw_text({0, 0}, {255, 255, 255}, L"Final distance: " + to_wstring(final_distance) + L" Line height: " + to_wstring(line_height) + L" X: " + to_wstring(camera_x) + L" Y: " + to_wstring(camera_y));}
}
wsgl::render_frame();
}
void load_map(wsgl::wide_str wstr, int cell_size = 1)
{
shared_ptr<wsgl::bmp> map = shared_ptr<wsgl::bmp>(wsgl::bmp::FromFile(wstr.c_str(), true));
map_x = map->GetWidth();
map_y = map->GetHeight();
map_s = map_x * map_y;
map_w = shared_ptr<int[]>(new int[map_s]);
wsgl::color color;
for(int y = 0; y < map_y; y += cell_size)
{
for(int x = 0; x < map_x; x += cell_size)
{
map->GetPixel(x, y, &color);
if(color.GetR() == 255 && color.GetG() == 255 && color.GetB() == 255)
{*(map_w.get() + ((y / cell_size) * map_x + (x / cell_size))) = 0;}
else
{*(map_w.get() + ((y / cell_size) * map_x + (x / cell_size))) = 1;}
}
}
}
int main()
{
wsgl::session sess = wsgl::startup(L"raycaster", {window_x, window_y});
load_map(L"res/map.png");
while(true)
{controls(); renderer();}
}
maths.hpp
#include <cmath>
const float PI = 3.14159265359;
const float PI2 = PI / 2;
const float PI3 = 3 * PI2;
const float RAD = PI / 180;
float deg_to_rad(float deg)
{return deg * RAD;}
float distance(float ax, float ay, float bx, float by)
{
float dx = bx - ax;
float dy = by - ay;
return sqrt(dx * dx + dy * dy);
}
float reset_ang(float ang)
{
if(ang < 0)
{ang += 2 * PI;}
if(ang > 2 * PI)
{ang -= 2 * PI;}
return ang;
}
If someone asks whats wsgl.hpp thats just my wrapper library over some WGDI routines and etc.
I think the problem lies here:
map_x_pos = (int)(ray_x) / map_s;
map_y_pos = (int)(ray_y) / map_s;
map_cell = map_y_pos * map_x + map_x_pos;
You need to change the order of operations:
map_x_pos = (int)(ray_x / map_s);
map_y_pos = (int)(ray_y / map_s);
map_cell = map_y_pos * map_x + map_x_pos;
With your current implementation, you first truncate ray_x and ray_y, then divide by map_s (which should probably be a floating point value, but is an integer in your current implementation), then truncate again to integer values. Your current implementation needlessly sacrifices precision and will be unpredictable for small map_s values.
Additionally, map_s seems incorrect. You set map_s to represent the total area of your map, but in the above code, you use it like it was the side length of the map.
To be correct, you would need something like
#include <cmath>
map_x_pos = (int)(ray_x / sqrtf(map_s));
map_y_pos = (int)(ray_y / sqrtf(map_s));
map_cell = map_y_pos * map_x + map_x_pos;
Related
I am learning opengl and in the code for creating a circle or any circular shape.
Why do we multiply by 2 PI ?
for (int i = 0; i < iSegments + 1; i++)
{
float angle = 2.0f * M_PI * i / iSegments;
}
Because a total circle radian is 2 * PI？
the angle = ratio * total_radian
So I have the following code that works fine
I've taken it from https://codereview.stackexchange.com/questions/192477/circle-line-segment-collision
I am now trying to figure out where along this function I can determine the angle in which the circle is hitting the line. Instead of returning true I'd like it to return the angle, since I didn't write the function myself going through it to try and figure this out myself has been a bit of a struggle. Wondering if someone excellent at math can help me figure this out at first glance. Thank you!
// Function to check intercept of line seg and circle
// A,B end points of line segment
// C center of circle
// radius of circle
// returns true if touching or crossing else false
function doesLineInterceptCircle(A, B, C, radius) {
var dist;
const v1x = B.x - A.x;
const v1y = B.y - A.y;
const v2x = C.x - A.x;
const v2y = C.y - A.y;
// get the unit distance along the line of the closest point to
// circle center
const u = (v2x * v1x + v2y * v1y) / (v1y * v1y + v1x * v1x);
// if the point is on the line segment get the distance squared
// from that point to the circle center
if(u >= 0 && u <= 1){
dist = (A.x + v1x * u - C.x) ** 2 + (A.y + v1y * u - C.y) ** 2;
} else {
// if closest point not on the line segment
// use the unit distance to determine which end is closest
// and get dist square to circle
dist = u < 0 ?
(A.x - C.x) ** 2 + (A.y - C.y) ** 2 :
(B.x - C.x) ** 2 + (B.y - C.y) ** 2;
}
return dist < radius * radius;
}
double shootx = vx + dx / t0;
double shooty = vy + dy / t0;
double radians = atan2((double)-shooty, shootx);
deg_to_aim = (int)((radians * 360) / (2 * 3.141592653589793238462));
myprintf("(A) radians = %f deg to aim = %d\n", radians, deg_to_aim);
radians 3.14 = 180 should be 0
radians 0 = 0 should be 180
radians -1.584827 = -90 should be 90
radians -1579912 = 90 should be -90
how do I make the values show up properly for all sides.
At the moment if I spin around the dot it will show a out wards motion like behind actual point when it should have the point always pointing at the dot.
Also it goes from 179 to -179 never hitting the 180.
Full code looks like this
/* Relative player position */
float const dx = (MyShip.XCoordinate + 18) - (Enemy.XCoordinate + 18);
float const dy = (MyShip.YCoordinate + 18) - (Enemy.YCoordinate + 18);
/* Relative player velocity */
float const vx = MyShip.XSpeed - Enemy.XSpeed;
float const vy = MyShip.YSpeed - Enemy.YSpeed;
float const a = vx * vx + vy * vy - bulletSpeed * bulletSpeed;
float const b = 2.f * (vx * dx + vy * dy);
float const c = dx * dx + dy * dy;
float const discriminant = b * b - 4.f * a * c;
int deg_to_aim = 0;
if (discriminant >= 0) {
float t0 = (float)(-b + sqrt(discriminant)) / (2 * a);
float t1 = (float)(-b - sqrt(discriminant)) / (2 * a);
if (t0 < 0.f || (t1 < t0 && t1 >= 0.f))
t0 = t1;
if (t0 >= 0.f)
{
// Aim at
double shootx = vx + dx / t0;
double shooty = vy + dy / t0;
double radians = atan2((double)-shooty, shootx);
deg_to_aim = (int)((radians * 360) / (2 * 3.141592653589793238462));
myprintf("(A) radians = %f deg to aim = %d\n", radians, deg_to_aim);
}
}
else {
myprintf("Error found!!!!!!! no solution\n");
}
Fixed it just Flip the MyShip Enemy values around.
Instead of MyShip - Enemy
you do Enemy - MyShip
I am trying to make an animated 3D wave with Three.js and Points. It is kind of working. It is starting slow and then the applitude is increasing. But after some time it gets too high and unsteady.
This is how it should be looking. However after some time it is loosing it's shape. The problem is the decreasing period of the sine and increasing amplitude. But I am failing to fix it.
Here is some code.
Creating of the points mesh.
this.particleGeometry = new Geometry()
for (let ix = 0; ix < this.WIDTH; ix++) {
for (let iz = 0; iz < this.HEIGHT; iz++) {
let vert = new Vector3()
vert.x = ix * this.SEPERATION - ((this.WIDTH * this.SEPERATION) / 2)
vert.y = (Math.cos((ix / this.WIDTH) * Math.PI * 6) + Math.sin((iz / this.HEIGHT) * Math.PI * 6))
vert.z = iz * this.SEPERATION - ((this.HEIGHT * this.SEPERATION) / 2)
this.particleGeometry.vertices.push(vert)
}
}
this.particleCloud = new Points(this.particleGeometry, this.material)
this.scene.add(this.particleCloud)
The initial generation is pretty good. But the updating is buggy.
animate() code:
render () {
let index = 0
let time = Date.now() * 0.00005
let h = (360 * (1.0 + time) % 360) / 360
this.theta += 0.0008
this.material.color.setHSL(h, 0.5, 0.5)
for (let ix = 0; ix < this.WIDTH; ix++) {
for (let iz = 0; iz < this.HEIGHT; iz++) {
this.particleCloud.geometry.vertices[index].y = (Math.cos((ix * this.theta / this.WIDTH) * Math.PI * 6) + Math.sin((iz * this.theta / this.HEIGHT) * Math.PI * 6))
index++
}
}
this.particleCloud.geometry.verticesNeedUpdate = true
this.updateGuiSettings()
this.renderer.render(this.scene, this.camera)
},
this.theta starts at 0 and then slowly increasing.
Okay, got it working with (Math.cos((ix / this.WIDTH * PI * 8 + this.theta)) + Math.sin((iz / this.HEIGHT * PI * 8 + this.theta)))
Now it is steady. However will tweak it maybe more.
I needed to draw sphere on OpenGL without using gluSphere() function. I have found somewhere this function:
void drawSphere(double r, int lats, int longs) {
int i, j;
for(i = 0; i <= lats; i++) {
double lat0 = M_PI * (-0.5 + (double) (i - 1) / lats);
double z0 = sin(lat0);
double zr0 = cos(lat0);
double lat1 = M_PI * (-0.5 + (double) i / lats);
double z1 = sin(lat1);
double zr1 = cos(lat1);
glBegin(GL_QUAD_STRIP);
for(j = 0; j <= longs; j++) {
double lng = 2 * M_PI * (double) (j - 1) / longs;
double x = cos(lng);
double y = sin(lng);
glNormal3f(x * zr0, y * zr0, z0);
glVertex3f(x * zr0, y * zr0, z0);
glNormal3f(x * zr1, y * zr1, z1);
glVertex3f(x * zr1, y * zr1, z1);
}
glEnd();
}
}
But I can't understand what it does. I think it draws polyhedron that looks like sphere.
Also, I think lat0, lat1 used to determine how far from Z axis vertices will be located.