// 0 < distance <= infinity
// 0 <= split < 1
// split = 2f means no collision
internal void GetCollisionData(WallData *wall, out float cur_dist, out float cur_split)
{
// Medium performance impact.
float
drx = wall->geom_direction.x,
dry = wall->geom_direction.y;
float det = direction.x * dry - direction.y * drx; // Caching can only be used here
if (det == 0) // Parallel
{
cur_dist = float.PositiveInfinity;
cur_split = 2f;
return;
}
float spldet = direction.x * (start.y - wall->geom_start.y) - direction.y * (start.x - wall->geom_start.x);
float dstdet = wall->geom_direction.x * (start.y - wall->geom_start.y) - wall->geom_direction.y * (start.x - wall->geom_start.x);
float spltmp = spldet / det;
float dsttmp = dstdet / det;
if (spltmp < 0 || spltmp >= 1 || dsttmp <= 0) // dsttmp = 0 means column height = x/0.
{
cur_dist = float.PositiveInfinity;
cur_split = 2f;
return;
}
cur_split = spltmp;
cur_dist = dsttmp;
}
internal Texture texture; // Yes, by value.
internal static WallData *Create(Vector start, Vector end, Texture texture)
{
WallData *result = (WallData *)Marshal.AllocHGlobal(sizeof(WallData));
result->texture = texture;
result->geom_direction = end - start;
result->geom_start = start;
return(result);
}
internal static WallData *Create(Vector start, float angle, float length, Texture texture)
{
WallData *result = (WallData *)Marshal.AllocHGlobal(sizeof(WallData));
Vector dir = new Vector(angle) * length;
result->texture = texture;
result->geom_direction = dir;
result->geom_start = start;
return(result);
}
private WallData *NearestWallTest(SceneData *map, out float nearest_dist, out float nearest_hratio)
{
nearest_dist = float.PositiveInfinity;
nearest_hratio = 2f;
WallData * nearest = null;
WallData **pptr = map->walls;
while (*pptr != null)
{
//Medium performance impact.
GetCollisionData(*pptr, out float cur_dist, out float cur_split);
if (cur_dist < nearest_dist)
{
nearest_hratio = cur_split;
nearest_dist = cur_dist;
nearest = *pptr;
}
pptr++;
}
return(nearest);
}
internal WallData *NearestWall(SceneData *map, out float nearest_dist, out float nearest_ratio)
{
nearest_dist = float.PositiveInfinity;
nearest_ratio = 2f;
int wallcount = map->wall_count;
WallData **cur = map->walls;
WallData * nearest = null;
for (int i = 0; i < wallcount; i++)
{
//walls cannot be null.
GetCollisionData(*cur, out float cur_dist, out float cur_ratio);
if (cur_dist < nearest_dist)
{
nearest_ratio = cur_ratio;
nearest_dist = cur_dist;
nearest = *cur;
}
cur++;
}
return(nearest);
}
private unsafe static void CLRRender(PixelBuffer target, SceneData *scene) // Must be changed
{
//Caching frequently used values.
uint * buffer = target.uint0;
int width = target.width;
int height = target.height;
Texture background = scene->background;
if (ParallelRendering)
{
Parallel.For(0, width, Loop);
}
else
{
for (int i = 0; i < width; i++)
{
Loop(i);
}
}
void Loop(int ray_id)
//for (int ray_id = 0; ray_id < rendererData->bitmap_width; ray_id++)
{
//Caching
float ray_cos = cache->cosines[ray_id];
float ray_angle = cache->angles[ray_id] + scene->activeObserver->rotation;
Ray ray = new Ray(scene->activeObserver->position, ray_angle);
//Cast the ray towards every wall.
WallData *nearest = ray.NearestWall(scene, out float nearest_dist, out float nearest_ratio);
if (nearest_ratio != 2f)
{
float columnHeight = (cache->colHeight1 / (ray_cos * nearest_dist)); //Wall column size in pixels
float column_start = (height - columnHeight) / 2f;
float column_end = (height + columnHeight) / 2f;
int draw_column_start = (int)column_start;
int draw_column_end = (int)column_end;
if (draw_column_start < 0)
{
draw_column_start = 0;
}
if (draw_column_end > height)
{
draw_column_end = height;
}
for (int line = 0; line < draw_column_start; line++)
{
//PURPOSELY REPEATED CODE!
float background_hratio = ray_angle / 360 + 1; //Temporary bugfix to avoid hratio being < 0
float screenVratio = (float)line / height;
float background_vratio = (1 - ray_cos) / 2 + ray_cos * screenVratio;
uint color = background.MapPixel(background_hratio, background_vratio);
buffer[width * line + ray_id] = color;
}
for (int line = draw_column_start; line < draw_column_end; line++)
{
float vratio = (line - column_start) / columnHeight;
uint pixel = nearest->texture.MapPixel(nearest_ratio, vratio);
buffer[width * line + ray_id] = pixel;
}
for (int line = draw_column_end; line < height; line++)
{
//PURPOSELY REPEATED CODE!
float background_hratio = ray_angle / 360 + 1; //Temporary bugfix to avoid hratio being < 0
float screenVratio = (float)line / height;
float background_vratio = (1 - ray_cos) / 2 + ray_cos * screenVratio;
uint color = background.MapPixel(background_hratio, background_vratio);
buffer[width * line + ray_id] = color;
}
}
else
{
for (int line = 0; line < height; line++)
{
//Critical performance impact.
//PURPOSELY REPEATED CODE!
float background_hratio = ray_angle / 360 + 1;
float screenVratio = (float)line / height;
float background_vratio = (1 - ray_cos) / 2 + ray_cos * screenVratio;
uint color = background.MapPixel(background_hratio, background_vratio);
buffer[width * line + ray_id] = color;
}
}
}
}
internal void Add(WallData *wall)
{
walls[wall_count++] = wall;
walls[wall_count] = null;
}
internal static void Delete(WallData *item)
{
Marshal.FreeHGlobal((IntPtr)item);
}