diff --git a/.vscode/settings.json b/.vscode/settings.json
index d909400..74f4b13 100644
--- a/.vscode/settings.json
+++ b/.vscode/settings.json
@@ -8,6 +8,9 @@
         "generation.h": "c",
         "time.h": "c",
         "limits": "c",
-        "sdl.h": "c"
+        "sdl.h": "c",
+        "triangles.h": "c",
+        "base.h": "c",
+        "move.h": "c"
     }
 }
\ No newline at end of file
diff --git a/bin/back b/bin/back
index b2da8bc..6f16127 100755
Binary files a/bin/back and b/bin/back differ
diff --git a/obj/base.o b/obj/base.o
index a955de7..3fef6e4 100644
Binary files a/obj/base.o and b/obj/base.o differ
diff --git a/obj/display.o b/obj/display.o
index 145d470..a1e0e96 100644
Binary files a/obj/display.o and b/obj/display.o differ
diff --git a/obj/entities.o b/obj/entities.o
index 63a0e5e..778c1d2 100644
Binary files a/obj/entities.o and b/obj/entities.o differ
diff --git a/obj/generation.o b/obj/generation.o
index 87bbab4..8c3c53d 100644
Binary files a/obj/generation.o and b/obj/generation.o differ
diff --git a/obj/main.o b/obj/main.o
index 88b382c..4267838 100644
Binary files a/obj/main.o and b/obj/main.o differ
diff --git a/obj/move.o b/obj/move.o
index 8f6b7c1..20a86aa 100644
Binary files a/obj/move.o and b/obj/move.o differ
diff --git a/obj/triangles.o b/obj/triangles.o
index e578db8..8507888 100644
Binary files a/obj/triangles.o and b/obj/triangles.o differ
diff --git a/src/base.c b/src/base.c
index 82d9ba9..9f7973a 100644
--- a/src/base.c
+++ b/src/base.c
@@ -95,6 +95,10 @@ int convex_seg(int x1, int x2, double theta) {
     return (int)(((1.0f - theta) * x1 + theta * x2));
 }
 
+double convex_tri(double a, double tha, double b, double thb, double c, double thc) {
+    return (a*tha + b*thb + c*thc);
+}
+
 bool is_an_integer(char c) {
     return ((int)c >= 48 && (int)c <= 57);
 }
@@ -339,6 +343,29 @@ void project_to_cube(double x0, double y0, double z0, double* rx, double* ry, do
     if(rz != NULL) {*rz = zry*cos(c.vt_angle) + yry*sin(c.vt_angle);}
 }
 
+double dist_to_cam_cube(double x0, double y0, double z0, cube_0 c) {
+    double px0, py0, pz0;
+    project_to_cube(x0, y0, z0, &px0, &py0, &pz0, c);
+    return distance_pt_pt_3d(px0 + c.x + c.w/2.0, py0 + c.y + c.h/2.0, pz0 + c.z + c.d/2.0, camx, camy, camz);
+}
+
+bool pt_equal_3D(pt_2d p1, pt_2d p2) {
+    return (p1.x == p2.x && p1.y == p2.y && p1.z == p2.z);
+}
+
+bool pt_equal_2D(pt_2d p1, pt_2d p2) {
+    return (p1.x == p2.x && p1.y == p2.y);
+}
+
+bool pt_equal_3D_eps(pt_2d p1, pt_2d p2, double epsilon) {
+    return (absf(p1.x - p2.x) <= epsilon && absf(p1.y - p2.y) <= epsilon && absf(p1.z - p2.z) <= epsilon);
+}
+
+bool pt_equal_2D_eps(pt_2d p1, pt_2d p2, double epsilon, bool debug0) {
+    if(debug0) {printf("(%lf, %lf)\n", absf(p1.x - p2.x), absf(p1.y - p2.y));}
+    return (absf(p1.x - p2.x) <= epsilon && absf(p1.y - p2.y) <= epsilon);
+}
+
 // ------------------------------------------------------------------------------------------------ //
 
 void remove_entity(entity** arr, int* memlen, int* len, int index) {
diff --git a/src/base.h b/src/base.h
index a00fa31..87d09c0 100644
--- a/src/base.h
+++ b/src/base.h
@@ -11,12 +11,17 @@ double mind(double a, double b);
 double maxd(double a, double b);
 double absf(double n);
 int convex_seg(int x1, int x2, double theta);
+double convex_tri(double a, double tha, double b, double thb, double c, double thc);
 bool is_an_integer(char c);
 double to_double(int n);
 int to_int(double n);
 int line_count(char* filename);
 int str_to_int(char* s);
 bool str_equal(char* s1, char* s2);
+bool pt_equal_3D(pt_2d p1, pt_2d p2);
+bool pt_equal_2D(pt_2d p1, pt_2d p2);
+bool pt_equal_3D_eps(pt_2d p1, pt_2d p2, double epsilon);
+bool pt_equal_2D_eps(pt_2d p1, pt_2d p2, double epsilon, bool debug0);
 
 cube_0 create_cube_0(double x, double y, double z, double w, double h, double d, double hz_a, double vt_a, int r, int g, int b);
 cube create_cube(double x, double y, double z, double w, double h, double d, double hz_a, double vt_a, int r, int g, int b);
@@ -51,6 +56,7 @@ void add_entity(entity** arr, int* memlen, int* len, entity ent);
 double distance_pt_cube_3d(double x0, double y0, double z0, cube cb);
 void project_to_camera(double x0, double y0, double z0, double* rx, double* ry, double* rz);
 void project_to_cube(double x0, double y0, double z0, double* rx, double* ry, double* rz, cube_0 c);
+double dist_to_cam_cube(double x0, double y0, double z0, cube_0 c);
 
 void import_digits(SDL_Renderer* renderer);
 void import_letters(SDL_Renderer* renderer);
diff --git a/src/display.c b/src/display.c
index 876d58a..aeb18d1 100644
--- a/src/display.c
+++ b/src/display.c
@@ -24,8 +24,17 @@ int* drawOrder;
 
 double draw_constant ;
 
+int* cubeDrawOrder;
+bool* seen ;
+
 void init_draworder() {
     drawOrder = malloc(sizeof(int)*6) ;
+    cubeDrawOrder = malloc(sizeof(int)*2048);
+    seen = malloc(sizeof(bool)*2048);
+    for(int k = 0; k < 2048; k++) {
+        cubeDrawOrder[k] = 0;
+        seen[k] = false;
+    }
     draw_constant = 0.4 ;
 }
 
@@ -420,12 +429,12 @@ int surfaceDrawOrder(double x0, double y0, double z0, cube_0 cb) {
     }
 }
 
-SDL_Vertex construct_vertex(double px, double py, int r, int g, int b) {
+SDL_Vertex construct_vertex(double px, double py, int r, int g, int b, int a) {
     SDL_Vertex vtx ;
     vtx.color.r = r ;
     vtx.color.g = g ;
     vtx.color.b = b ;
-    vtx.color.a = SDL_ALPHA_OPAQUE;
+    vtx.color.a = a ;
     vtx.position.x = (float)px ;
     vtx.position.y = (float)py ;
     vtx.tex_coord.x = 0.0f;
@@ -433,22 +442,51 @@ SDL_Vertex construct_vertex(double px, double py, int r, int g, int b) {
     return vtx ;
 }
 
+void renderTriangleNoProject(
+    SDL_Renderer* renderer,
+    double px0, double py0, double pz0,
+    double px1, double py1, double pz1,
+    double px2, double py2, double pz2,
+    int red, int green, int blue, bool debug
+) {
+
+    const SDL_Vertex vtxs[3] = {
+        construct_vertex(px0, py0, red, green, blue, 128),
+        construct_vertex(px1, py1, red, green, blue, 128),
+        construct_vertex(px2, py2, red, green, blue, 128),
+    };
+    if(debug) {   
+        printf("P[*] : (%f, %f), (%f, %f), (%f, %f)\n", vtxs[0].position.x,  vtxs[0].position.y,  vtxs[1].position.x,  vtxs[1].position.y,  vtxs[2].position.x,  vtxs[2].position.y);
+    }
+    SDL_RenderGeometry(renderer, NULL, vtxs, 3, NULL, 0);
+}
+
 void renderTriangle(
     SDL_Renderer* renderer,
     double x0, double y0, double z0,
     double x1, double y1, double z1,
     double x2, double y2, double z2,
-    int red, int green, int blue
+    int red, int green, int blue, bool debug
 ) {
+    double px0; double py0; double pz0;
+    double px1; double py1; double pz1;
+    double px2; double py2; double pz2;
+    double fpx0; double fpy0; double fpz0;
+    double fpx1; double fpy1; double fpz1;
+    double mpx0; double mpy0; double mpz0;
+    double mpx1; double mpy1; double mpz1;
     project_to_camera(x0, y0, z0, &px0, &py0, &pz0);
     project_to_camera(x1, y1, z1, &px1, &py1, &pz1);
     project_to_camera(x2, y2, z2, &px2, &py2, &pz2);
     if(pz0 >= draw_constant && pz1 >= draw_constant && pz2 >= draw_constant) {
         const SDL_Vertex vtxs[3] = {
-            construct_vertex(1500.0 * (1.0 + (px0 / (1.5 * pz0 * tan_fov))) / 2.0, 1000.0 * (1.0 + (py0 / (pz0 * tan_fov))) / 2.0, red, green, blue),
-            construct_vertex(1500.0 * (1.0 + (px1 / (1.5 * pz1 * tan_fov))) / 2.0, 1000.0 * (1.0 + (py1 / (pz1 * tan_fov))) / 2.0, red, green, blue),
-            construct_vertex(1500.0 * (1.0 + (px2 / (1.5 * pz2 * tan_fov))) / 2.0, 1000.0 * (1.0 + (py2 / (pz2 * tan_fov))) / 2.0, red, green, blue),
+            construct_vertex(1500.0 * (1.0 + (px0 / (1.5 * pz0 * tan_fov))) / 2.0, 1000.0 * (1.0 + (py0 / (pz0 * tan_fov))) / 2.0, red, green, blue, 255),
+            construct_vertex(1500.0 * (1.0 + (px1 / (1.5 * pz1 * tan_fov))) / 2.0, 1000.0 * (1.0 + (py1 / (pz1 * tan_fov))) / 2.0, red, green, blue, 255),
+            construct_vertex(1500.0 * (1.0 + (px2 / (1.5 * pz2 * tan_fov))) / 2.0, 1000.0 * (1.0 + (py2 / (pz2 * tan_fov))) / 2.0, red, green, blue, 255),
         };
+        if(debug) {
+            printf("P[3] : (%f, %f), (%f, %f), (%f, %f)\n", vtxs[0].position.x,  vtxs[0].position.y,  vtxs[1].position.x,  vtxs[1].position.y,  vtxs[2].position.x,  vtxs[2].position.y);
+        }
         SDL_RenderGeometry(renderer, NULL, vtxs, 3, NULL, 0);
     } else if((pz0 >= draw_constant) + (pz1 >= draw_constant) + (pz2 >= draw_constant) == 2) {
         if(pz0 < draw_constant) {     
@@ -505,13 +543,17 @@ void renderTriangle(
         }
 
         const SDL_Vertex vtxs[6] = {
-            construct_vertex(1500.0 * (1.0 + (fpx0 / (1.5 * fpz0 * tan_fov))) / 2.0, 1000.0 * (1.0 + (fpy0 / (fpz0 * tan_fov))) / 2.0, red, green, blue),
-            construct_vertex(1500.0 * (1.0 + (mpx0 / (1.5 * mpz0 * tan_fov))) / 2.0, 1000.0 * (1.0 + (mpy0 / (mpz0 * tan_fov))) / 2.0, red, green, blue),
-            construct_vertex(1500.0 * (1.0 + (fpx1 / (1.5 * fpz1 * tan_fov))) / 2.0, 1000.0 * (1.0 + (fpy1 / (fpz1 * tan_fov))) / 2.0, red, green, blue),
-            construct_vertex(1500.0 * (1.0 + (mpx0 / (1.5 * mpz0 * tan_fov))) / 2.0, 1000.0 * (1.0 + (mpy0 / (mpz0 * tan_fov))) / 2.0, red, green, blue),
-            construct_vertex(1500.0 * (1.0 + (mpx1 / (1.5 * mpz1 * tan_fov))) / 2.0, 1000.0 * (1.0 + (mpy1 / (mpz1 * tan_fov))) / 2.0, red, green, blue),
-            construct_vertex(1500.0 * (1.0 + (fpx1 / (1.5 * fpz1 * tan_fov))) / 2.0, 1000.0 * (1.0 + (fpy1 / (fpz1 * tan_fov))) / 2.0, red, green, blue),
+            construct_vertex(1500.0 * (1.0 + (fpx0 / (1.5 * fpz0 * tan_fov))) / 2.0, 1000.0 * (1.0 + (fpy0 / (fpz0 * tan_fov))) / 2.0, red, green, blue, 255),
+            construct_vertex(1500.0 * (1.0 + (mpx0 / (1.5 * mpz0 * tan_fov))) / 2.0, 1000.0 * (1.0 + (mpy0 / (mpz0 * tan_fov))) / 2.0, red, green, blue, 255),
+            construct_vertex(1500.0 * (1.0 + (fpx1 / (1.5 * fpz1 * tan_fov))) / 2.0, 1000.0 * (1.0 + (fpy1 / (fpz1 * tan_fov))) / 2.0, red, green, blue, 255),
+            construct_vertex(1500.0 * (1.0 + (mpx0 / (1.5 * mpz0 * tan_fov))) / 2.0, 1000.0 * (1.0 + (mpy0 / (mpz0 * tan_fov))) / 2.0, red, green, blue, 255),
+            construct_vertex(1500.0 * (1.0 + (mpx1 / (1.5 * mpz1 * tan_fov))) / 2.0, 1000.0 * (1.0 + (mpy1 / (mpz1 * tan_fov))) / 2.0, red, green, blue, 255),
+            construct_vertex(1500.0 * (1.0 + (fpx1 / (1.5 * fpz1 * tan_fov))) / 2.0, 1000.0 * (1.0 + (fpy1 / (fpz1 * tan_fov))) / 2.0, red, green, blue, 255),
         };
+        if(debug) {
+            printf("P[2] : (%f, %f), (%f, %f), (%f, %f)\n", vtxs[0].position.x,  vtxs[0].position.y,  vtxs[1].position.x,  vtxs[1].position.y,  vtxs[2].position.x,  vtxs[2].position.y);
+            printf("       (%f, %f), (%f, %f), (%f, %f)\n", vtxs[3].position.x,  vtxs[3].position.y,  vtxs[4].position.x,  vtxs[4].position.y,  vtxs[5].position.x,  vtxs[5].position.y);
+        }
         SDL_RenderGeometry(renderer, NULL, vtxs, 6, NULL, 0);
     } else if((pz0 >= draw_constant) + (pz1 >= draw_constant) + (pz2 >= draw_constant) == 1) {
         if(pz0 >= draw_constant) {
@@ -549,11 +591,18 @@ void renderTriangle(
             &px1, &py1, &pz1);
         }
         const SDL_Vertex vtxs[3] = {
-            construct_vertex(1500.0 * (1.0 + (px0 / (1.5 * pz0 * tan_fov))) / 2.0, 1000.0 * (1.0 + (py0 / (pz0 * tan_fov))) / 2.0, red, green, blue),
-            construct_vertex(1500.0 * (1.0 + (px1 / (1.5 * pz1 * tan_fov))) / 2.0, 1000.0 * (1.0 + (py1 / (pz1 * tan_fov))) / 2.0, red, green, blue),
-            construct_vertex(1500.0 * (1.0 + (px2 / (1.5 * pz2 * tan_fov))) / 2.0, 1000.0 * (1.0 + (py2 / (pz2 * tan_fov))) / 2.0, red, green, blue),
+            construct_vertex(1500.0 * (1.0 + (px0 / (1.5 * pz0 * tan_fov))) / 2.0, 1000.0 * (1.0 + (py0 / (pz0 * tan_fov))) / 2.0, red, green, blue, 255),
+            construct_vertex(1500.0 * (1.0 + (px1 / (1.5 * pz1 * tan_fov))) / 2.0, 1000.0 * (1.0 + (py1 / (pz1 * tan_fov))) / 2.0, red, green, blue, 255),
+            construct_vertex(1500.0 * (1.0 + (px2 / (1.5 * pz2 * tan_fov))) / 2.0, 1000.0 * (1.0 + (py2 / (pz2 * tan_fov))) / 2.0, red, green, blue, 255),
         };
+        if(debug) {
+            printf("P[1] : (%f, %f), (%f, %f), (%f, %f)\n", vtxs[0].position.x,  vtxs[0].position.y,  vtxs[1].position.x,  vtxs[1].position.y,  vtxs[2].position.x,  vtxs[2].position.y);
+        }
         SDL_RenderGeometry(renderer, NULL, vtxs, 3, NULL, 0);
+    } else {
+        if(debug) {
+            printf("P[0] : (-)\n");
+        }
     }
 }
 
@@ -565,13 +614,16 @@ void renderTriangleRotated(
     int red, int green, int blue,
     cube_0 cb
 ) {
+    double px0; double py0; double pz0;
+    double px1; double py1; double pz1;
+    double px2; double py2; double pz2;
     /*double px0; double py0; double pz0;
     double px1; double py1; double pz1;
     double px2; double py2; double pz2;*/
     rotate_cube(x0, y0, z0, &px0, &py0, &pz0, cb);
     rotate_cube(x1, y1, z1, &px1, &py1, &pz1, cb);
     rotate_cube(x2, y2, z2, &px2, &py2, &pz2, cb);
-    renderTriangle(renderer, px0, py0, pz0, px1, py1, pz1, px2, py2, pz2, red, green, blue);
+    renderTriangle(renderer, px0, py0, pz0, px1, py1, pz1, px2, py2, pz2, red, green, blue, false);
 }
 
 void drawSfOfCube(SDL_Renderer* renderer, int sf, cube_0 c) {
@@ -703,10 +755,35 @@ void insertionSort_ent(entity* arr, int len) {
     }
 }
 
+void visit(SDL_Renderer* renderer, int k, cube_0* arr, int len, bool vflag, int* retptr) {
+    double overlap = 0.0;
+    if(seen[k] != vflag) {
+        seen[k] = vflag;
+        for(int k2 = 0; k2 < len; k2++) {
+            if(k != k2 && seen[k2] != vflag) {
+                if(cubeOverlap(renderer, arr[k], arr[k2], &overlap) && overlap > 0.0) {
+                    visit(renderer, k2, arr, len, vflag, retptr);
+                }
+            }
+        }
+        cubeDrawOrder[*retptr] = k;
+        *retptr += 1;
+    }
+}
+
+void insertionDepthSort(SDL_Renderer* renderer, cube_0* arr, int len) {
+    bool vflag = !seen[0];
+    int rptr = 0;
+    for(int k = 0; k < len; k++) {
+        visit(renderer, k, arr, len, vflag, &rptr);   
+    }
+}
+
 void drawCurrentRoom(SDL_Renderer* renderer) {
     insertionSort_cb(current_room->map, current_room->map_size);
     insertionSort_tp(current_room->tps, current_room->tps_size);
     insertionSort_ent(current_room->ents, current_room->ent_len);
+    insertionDepthSort(NULL, current_room->map, current_room->map_size);
 
     /*for(int k1 = 0; k1 < current_room->map_size; k1++) {
         current_room->map[k1].red = 188 ;
@@ -728,7 +805,8 @@ void drawCurrentRoom(SDL_Renderer* renderer) {
 
     if(true || draw_type == 0) {
         for(int k = 0; k < current_room->map_size; k++) {
-            drawFullCube(renderer, current_room->map[k]);
+            //drawFullCube(renderer, current_room->map[k]);
+            drawFullCube(renderer, current_room->map[cubeDrawOrder[k]]);
         }
         for(int k = 0; k < current_room->ent_len; k++) {
             drawFullCube(renderer, *(current_room->ents[k].pos));
diff --git a/src/display.h b/src/display.h
index cba0a79..e27a30e 100644
--- a/src/display.h
+++ b/src/display.h
@@ -49,7 +49,14 @@ void renderTriangle(
     double x0, double y0, double z0,
     double x1, double y1, double z1,
     double x2, double y2, double z2,
-    int red, int green, int blue
+    int red, int green, int blue, bool debug
+);
+void renderTriangleNoProject(
+    SDL_Renderer* renderer,
+    double x0, double y0, double z0,
+    double x1, double y1, double z1,
+    double x2, double y2, double z2,
+    int red, int green, int blue, bool debug
 );
 void renderTriangleRotated(
     SDL_Renderer* renderer,
diff --git a/src/main.c b/src/main.c
index 41b4e26..3b53fae 100644
--- a/src/main.c
+++ b/src/main.c
@@ -15,6 +15,7 @@
 #include "structure.h"
 #include "base.h"
 #include "move.h"
+#include "triangles.h"
 #include "entities.h"
 #include "display.h"
 #include "generation.h"
@@ -55,7 +56,7 @@ int main(int argc, char** argv) {
     init_hashtbl() ;
     init_draworder() ;
     trInit();
-    parse_rooms(3);
+    parse_rooms(4);
     import_digits(rend) ;
     import_letters(rend) ;
     sim_time = 0.0 ;
diff --git a/src/structure.h b/src/structure.h
index 9a8bcb1..e533dad 100644
--- a/src/structure.h
+++ b/src/structure.h
@@ -115,12 +115,5 @@ extern int draw_type ;
 
 extern double draw_constant ;
 
-extern double px0; extern double py0; extern double pz0;
-extern double px1; extern double py1; extern double pz1;
-extern double px2; extern double py2; extern double pz2;
-extern double fpx0; extern double fpy0; extern double fpz0;
-extern double fpx1; extern double fpy1; extern double fpz1;
-extern double mpx0; extern double mpy0; extern double mpz0;
-extern double mpx1; extern double mpy1; extern double mpz1;
 
 #endif
\ No newline at end of file
diff --git a/src/triangles.c b/src/triangles.c
index 24e2a7f..38b4b0d 100644
--- a/src/triangles.c
+++ b/src/triangles.c
@@ -14,15 +14,10 @@
 #include "hash.h"
 #include "structure.h"
 #include "base.h"
+#include "display.h"
 #include "triangles.h"
 
-double px0; double py0; double pz0;
-double px1; double py1; double pz1;
-double px2; double py2; double pz2;
-double fpx0; double fpy0; double fpz0;
-double fpx1; double fpy1; double fpz1;
-double mpx0; double mpy0; double mpz0;
-double mpx1; double mpy1; double mpz1;
+double draw_incr = 0.0 ;
 
 int errno = 0;
 pt_2d* triangle_1 ;
@@ -132,7 +127,7 @@ bool triTri2D(pt_2d* t1, pt_2d* t2, double eps, bool allowReversed, bool onBound
 }
 
 bool triangleIntersection(pt_2d* tri1, pt_2d* tri2) {
-    return triTri2D(tri1, tri2, 0.0, false, true);
+    return triTri2D(tri1, tri2, 0.0, false, false);
 }
 
 bool triangleIntersectionDec(pt_2d t1_1, pt_2d t1_2, pt_2d t1_3, pt_2d t2_1, pt_2d t2_2, pt_2d t2_3) {
@@ -145,10 +140,12 @@ bool triangleIntersectionDec(pt_2d t1_1, pt_2d t1_2, pt_2d t1_3, pt_2d t2_1, pt_
     return triangleIntersection(triangle_1, triangle_2);
 }
 
-bool multipleTrianglesIntersection(pt_2d* tri1, int len1, pt_2d* tri2, int len2) {
+bool multipleTrianglesIntersection(pt_2d* tri1, int len1, pt_2d* tri2, int len2, int* ret1, int* ret2) {
     for(int k1 = 0; k1 < len1; k1+=3) {
         for(int k2 = 0; k2 < len2; k2+=3) {
             if(triangleIntersection(&tri1[k1], &tri2[k2])) {
+                if(ret1 != NULL) {*ret1 = k1;}
+                if(ret2 != NULL) {*ret2 = k2;}
                 return true;
             }
         }
@@ -170,17 +167,24 @@ int returnTriangle(
     double x2, double y2, double z2,
     pt_2d* retarr
 ) {
+    double px0; double py0; double pz0;
+    double px1; double py1; double pz1;
+    double px2; double py2; double pz2;
+    double fpx0; double fpy0; double fpz0;
+    double fpx1; double fpy1; double fpz1;
+    double mpx0; double mpy0; double mpz0;
+    double mpx1; double mpy1; double mpz1;
     project_to_camera(x0, y0, z0, &px0, &py0, &pz0);
     project_to_camera(x1, y1, z1, &px1, &py1, &pz1);
     project_to_camera(x2, y2, z2, &px2, &py2, &pz2);
-    if(pz0 >= draw_constant && pz1 >= draw_constant && pz2 >= draw_constant) {
+    if(pz0 >= (draw_constant + draw_incr) && pz1 >= (draw_constant + draw_incr) && pz2 >= (draw_constant + draw_incr)) {
         retarr[0] = to_fpoint(1500.0 * (1.0 + (px0 / (1.5 * pz0 * tan_fov))) / 2.0, 1000.0 * (1.0 + (py0 / (pz0 * tan_fov))) / 2.0, pz0);
         retarr[1] = to_fpoint(1500.0 * (1.0 + (px1 / (1.5 * pz1 * tan_fov))) / 2.0, 1000.0 * (1.0 + (py1 / (pz1 * tan_fov))) / 2.0, pz1);
         retarr[2] = to_fpoint(1500.0 * (1.0 + (px2 / (1.5 * pz2 * tan_fov))) / 2.0, 1000.0 * (1.0 + (py2 / (pz2 * tan_fov))) / 2.0, pz2);
         return 3;
-    } else if((pz0 >= draw_constant) + (pz1 >= draw_constant) + (pz2 >= draw_constant) == 2) {
-        if(pz0 < draw_constant) {     
-            // pz1 >= draw_constant and pz2 >+ draw_constant
+    } else if((pz0 >= (draw_constant + draw_incr)) + (pz1 >= (draw_constant + draw_incr)) + (pz2 >= (draw_constant + draw_incr)) == 2) {
+        if(pz0 < (draw_constant + draw_incr)) {     
+            // pz1 >= (draw_constant + draw_incr) and pz2 >+ (draw_constant + draw_incr)
             fpx0 = px1 ; fpy0 = py1 ; fpz0 = pz1 ;
             fpx1 = px2 ; fpy1 = py2 ; fpz1 = pz2 ;
             // 1-0 segment
@@ -196,8 +200,8 @@ int returnTriangle(
                 convex_pt(y2, y0, (pz2 - draw_constant)/(pz2 - pz0)), 
                 convex_pt(z2, z0, (pz2 - draw_constant)/(pz2 - pz0)), 
             &mpx1, &mpy1, &mpz1) ;
-        } else if(pz1 < draw_constant) {     
-            // pz0 >= draw_constant and pz2 >+ draw_constant
+        } else if(pz1 < (draw_constant + draw_incr)) {     
+            // pz0 >= (draw_constant + draw_incr) and pz2 >+ (draw_constant + draw_incr)
             fpx0 = px0 ; fpy0 = py0 ; fpz0 = pz0 ;
             fpx1 = px2 ; fpy1 = py2 ; fpz1 = pz2 ;
             // 0-1 segment
@@ -213,8 +217,8 @@ int returnTriangle(
                 convex_pt(y2, y1, (pz2 - draw_constant)/(pz2 - pz1)), 
                 convex_pt(z2, z1, (pz2 - draw_constant)/(pz2 - pz1)), 
             &mpx1, &mpy1, &mpz1) ;
-        } else /*if(pz2 < draw_constant)*/ {     
-            // pz1 >= draw_constant and pz0 >+ draw_constant
+        } else /*if(pz2 < (draw_constant + draw_incr))*/ {     
+            // pz1 >= (draw_constant + draw_incr) and pz0 >+ (draw_constant + draw_incr)
             fpx0 = px0 ; fpy0 = py0 ; fpz0 = pz0 ;
             fpx1 = px1 ; fpy1 = py1 ; fpz1 = pz1 ;
             // 0-2 segment
@@ -239,8 +243,8 @@ int returnTriangle(
         retarr[4] = to_fpoint(1500.0 * (1.0 + (mpx1 / (1.5 * mpz1 * tan_fov))) / 2.0, 1000.0 * (1.0 + (mpy1 / (mpz1 * tan_fov))) / 2.0, mpz1);
         retarr[5] = to_fpoint(1500.0 * (1.0 + (fpx1 / (1.5 * fpz1 * tan_fov))) / 2.0, 1000.0 * (1.0 + (fpy1 / (fpz1 * tan_fov))) / 2.0, fpz1);
         return 6;
-    } else if((pz0 >= draw_constant) + (pz1 >= draw_constant) + (pz2 >= draw_constant) == 1) {
-        if(pz0 >= draw_constant) {
+    } else if((pz0 >= (draw_constant + draw_incr)) + (pz1 >= (draw_constant + draw_incr)) + (pz2 >= (draw_constant + draw_incr)) == 1) {
+        if(pz0 >= (draw_constant + draw_incr)) {
             project_to_camera(
                 convex_pt(x0, x1, (pz0 - draw_constant)/(pz0 - pz1)),
                 convex_pt(y0, y1, (pz0 - draw_constant)/(pz0 - pz1)),
@@ -251,7 +255,7 @@ int returnTriangle(
                 convex_pt(y0, y2, (pz0 - draw_constant)/(pz0 - pz2)),
                 convex_pt(z0, z2, (pz0 - draw_constant)/(pz0 - pz2)),
             &px2, &py2, &pz2);
-        } else if(pz1 >= draw_constant) {
+        } else if(pz1 >= (draw_constant + draw_incr)) {
             project_to_camera(
                 convex_pt(x1, x0, (pz1 - draw_constant)/(pz1 - pz0)),
                 convex_pt(y1, y0, (pz1 - draw_constant)/(pz1 - pz0)),
@@ -262,7 +266,7 @@ int returnTriangle(
                 convex_pt(y1, y2, (pz1 - draw_constant)/(pz1 - pz2)),
                 convex_pt(z1, z2, (pz1 - draw_constant)/(pz1 - pz2)),
             &px2, &py2, &pz2);
-        } else if(pz2 >= draw_constant) {
+        } else if(pz2 >= (draw_constant + draw_incr)) {
             project_to_camera(
                 convex_pt(x2, x0, (pz2 - draw_constant)/(pz2 - pz0)),
                 convex_pt(y2, y0, (pz2 - draw_constant)/(pz2 - pz0)),
@@ -389,63 +393,150 @@ int visibleSurfaces(double x0, double y0, double z0, cube_0 cb, int* dOrd) {
     }
 }
 
-void get_zdepths(cube_0 c, int sf, double* ret) {
-    pt_2d campt = to_fpoint(camx, camy, camz);
-    if(sf == 0 || sf == 1) {        // x
-        ret[0] = zdepth_of_pt(c.x + c.w*(sf==0), c.y,       c.z      );
-        ret[1] = zdepth_of_pt(c.x + c.w*(sf==0), c.y + c.h, c.z      );
-        ret[2] = zdepth_of_pt(c.x + c.w*(sf==0), c.y      , c.z + c.d);
-        ret[3] = zdepth_of_pt(c.x + c.w*(sf==0), c.y + c.h, c.z + c.d);
-    } else if(sf == 2 || sf == 3) { // y
-        ret[0] = zdepth_of_pt(c.x,       c.y + c.h*(sf==2), c.z      );
-        ret[1] = zdepth_of_pt(c.x + c.w, c.y + c.h*(sf==2), c.z      );
-        ret[2] = zdepth_of_pt(c.x      , c.y + c.h*(sf==2), c.z + c.d);
-        ret[3] = zdepth_of_pt(c.x + c.w, c.y + c.h*(sf==2), c.z + c.d);
-    } else {                        // z
-        ret[0] = zdepth_of_pt(c.x,       c.y,       c.z + c.d*(sf==4));
-        ret[1] = zdepth_of_pt(c.x + c.w, c.y,       c.z + c.d*(sf==4));
-        ret[2] = zdepth_of_pt(c.x      , c.y + c.h, c.z + c.d*(sf==4));
-        ret[3] = zdepth_of_pt(c.x + c.w, c.y + c.h, c.z + c.d*(sf==4));
-    }
+bool noWT;
+double sign_triangle(pt_2d p1, pt_2d p2, pt_2d p3) {
+    return (p1.x - p3.x) * (p2.y - p3.y) - (p2.x - p3.x) * (p1.y - p3.y);
 }
 
-bool is_all_behind(double* back, double* front) {
-    for(int k = 0; k < 3; k++) {
-        if(back[k] > front[k]) {
-            return false;
+pt_2d to_pt2d(double x0, double y0, double z0) {
+    pt_2d res;
+    res.x = x0;
+    res.y = y0;
+    res.z = z0;
+    return res;
+}
+
+double dot_product_3D(pt_2d p1, pt_2d p2) {
+    return p1.x*p2.x + p1.y*p2.y + p1.z*p2.z ;
+}
+
+double dot_product_2D(pt_2d p1, pt_2d p2) {
+    return p1.x*p2.x + p1.y*p2.y ;
+}
+
+void return_barycentric(pt_2d p, pt_2d a, pt_2d b, pt_2d c, double* u, double* v, double* w) {
+    // get barycentric coords of p inside ABC triangle
+    pt_2d v0 = to_pt2d(b.x - a.x, b.y - a.y, b.z - a.z);
+    pt_2d v1 = to_pt2d(c.x - a.x, c.y - a.y, c.z - a.z);
+    pt_2d v2 = to_pt2d(p.x - a.x, p.y - a.y, p.z - a.z);
+    double d00 = dot_product_2D(v0, v0);
+    double d01 = dot_product_2D(v0, v1);
+    double d11 = dot_product_2D(v1, v1);
+    double d20 = dot_product_2D(v2, v0);
+    double d21 = dot_product_2D(v2, v1);
+    double denom = d00 * d11 - d01 * d01;
+    if(v != NULL) {*v = (d11 * d20 - d01 * d21) / denom;}
+    if(w != NULL) {*w = (d00 * d21 - d01 * d20) / denom;}
+    if(u != NULL && v != NULL && w != NULL) {*u = 1.0 - *v - *w;}
+}
+
+bool point_in_triangle(pt_2d pt, pt_2d v1, pt_2d v2, pt_2d v3, double* thetaA, double* thetaB, double* thetaC) {
+    double d1, d2, d3;
+    bool has_neg, has_pos;
+
+    d1 = sign_triangle(pt, v1, v2);
+    d2 = sign_triangle(pt, v2, v3);
+    d3 = sign_triangle(pt, v3, v1);
+
+    has_neg = (d1 < 0) || (d2 < 0) || (d3 < 0);
+    has_pos = (d1 > 0) || (d2 > 0) || (d3 > 0);
+
+    if(!(has_neg && has_pos)) {
+        return_barycentric(pt, v1, v2, v3, thetaA, thetaB, thetaC);
+        return true;
+    }
+    return false;
+}
+
+bool seg_seg_inter(pt_2d p1, pt_2d p2, pt_2d p3, pt_2d p4, double* ret0, double* ret1) {
+    double deno = (p4.x - p3.x)*(p2.y - p1.y) - (p4.y - p3.y)*(p2.x - p1.x);
+    if(0.0 <= deno && deno <= 0.001) {
+        //printf("%lf -->", deno);
+        deno = 0.001 ;
+    } else if(-0.001 <= deno && deno <= 0.0) {
+        //printf("%lf -->", deno);
+        deno = -0.001 ;
+    }
+    //printf("%lf\n", deno);
+    double alpha = 
+        ((p4.x - p3.x)*(p3.y - p1.y) - (p4.y - p3.y)*(p3.x - p1.x))/
+        (deno) ;
+
+    double beta = 
+        ((p2.x - p1.x)*(p3.y - p1.y) - (p2.y - p1.y)*(p3.x - p1.x))/
+        (deno) ;
+
+    if(ret0 != NULL) {*ret0 = alpha;}
+    if(ret1 != NULL) {*ret1 = beta;}
+    return (alpha >= 0.0 && alpha <= 1.0 && beta >= 0.0 && beta <= 1.0);
+}
+
+void print_tri(pt_2d* t) {
+    printf("T :\n    (%lf, %lf, %lf)\n    (%lf, %lf, %lf)\n    (%lf, %lf, %lf)\n", t[0].x, t[0].y, t[0].z, t[1].x, t[1].y, t[1].z, t[2].x, t[2].y, t[2].z);
+}
+
+bool delta_get(pt_2d* tri1, pt_2d* tri2, double* ret) {
+    double th1 = 0.0;
+    double th2 = 0.0;
+    double th3 = 0.0;
+    for(int k = 0; k < 3; k++) {        // pt
+        if(point_in_triangle(tri1[k], tri2[0], tri2[1], tri2[2], &th1, &th2, &th3)) {
+            //printf("%lf, %lf, %lf\n", th1, th2, th3);
+            //if(ret != NULL) {*ret = convex_tri(tri2[0].z, th1, tri2[1].z, th2, tri2[2].z, th3) - tri1[k].z;}
+            return true;
+        }
+        if(point_in_triangle(tri2[k], tri1[0], tri1[1], tri1[2], &th1, &th2, &th3)) {
+            //printf("%lf, %lf, %lf\n", th1, th2, th3);
+            //if(ret != NULL) {*ret = tri2[k].z - convex_tri(tri1[0].z, th1, tri1[1].z, th2, tri1[2].z, th3);}
+            return true;
         }
     }
-    return true;
-}
-
-int which_is_in_front(cube_0 c1, int sfc1, cube_0 c2, int sfc2) {
-    int nVis1 = visibleSurfaces(camx, camy, camz, c1, dOrder1);
-    int nVis2 = visibleSurfaces(camx, camy, camz, c2, dOrder2);
-    for(int k1 = 0; k1 < nVis1; k1++) {
-        for(int k2 = 0; k2 < nVis2; k2++) {
-            get_zdepths(c1, dOrder1[k1], zdepths1);
-            get_zdepths(c2, dOrder2[k2], zdepths2);
-            if(is_all_behind(zdepths1, zdepths2)) {
-                return 1;
-            } else if(is_all_behind(zdepths2, zdepths1)) {
-                return -1;
+    for(int k1 = 0; k1 < 3; k1++) {     // seg
+        for(int k2 = 0; k2 < 3; k2++) {
+            if(seg_seg_inter(tri1[k1], tri1[(k1+1)%3], tri2[k2], tri2[(k2+1)%3], &th1, &th2)) {
+                print_tri(tri1);
+                print_tri(tri2);
+                printf("%lf, %lf\n\n", th1, th2);
+                if(ret != NULL) {*ret = convex_pt(tri2[k2].z, tri2[(k2+1)%3].z, th2) - convex_pt(tri1[k1].z, tri1[(k1+1)%3].z, th1);} //no
+                return true;
             }
         }
     }
-    return 0;
+    return false;
 }
 
-bool cubeOverlap(cube_0 c1, cube_0 c2, int* retval) {
+bool cubeOverlap(SDL_Renderer* renderer, cube_0 c1, cube_0 c2, double* retval) {
     int len1 = 0;
     int len2 = 0;
+    int id1, id2;
+    double dz = 0.0;
     for(int i1 = 0; i1 < 6; i1++) {
-        for(int i2 = i1+1; i2 < 6; i2++) {
+        for(int i2 = i1; i2 < 6; i2++) {
             for(int n = 0; n < 4; n++) {
                 len1 = fillPolygon(i1, c1, n%2, cube_t1);
                 len2 = fillPolygon(i2, c2, n/2, cube_t2);
-                if(multipleTrianglesIntersection(cube_t1, len1, cube_t2, len2)) {
-                    if(retval != NULL) {*retval = which_is_in_front(c1, i1, c2, i2);}
-                    return true;
+                if(multipleTrianglesIntersection(cube_t1, len1, cube_t2, len2, &id1, &id2)) {
+                    if(delta_get(&(cube_t1[id1]), &(cube_t2[id2]), &dz) && absf(dz) >= 0.001) {
+                        if(retval != NULL) {*retval = dz;; printf("%lf\n", dz);}
+                        return true;
+                    } else if(renderer != NULL) {
+                        // debug things //
+                        SDL_SetRenderDrawColor(renderer, 255, 255, 255, SDL_ALPHA_OPAQUE);
+                        printf("ids : 1 = (%d / %d), 2 = (%d / %d)\n", id1, len1, id2, len2);
+                        renderTriangleNoProject(renderer, 
+                            cube_t1[id1].x, cube_t1[id1].y, cube_t1[id1].z,
+                            cube_t1[id1+1].x, cube_t1[id1+1].y, cube_t1[id1+1].z,
+                            cube_t1[id1+2].x, cube_t1[id1+2].y, cube_t1[id1+2].z,
+                            255, 0, 0, true);
+                        renderTriangleNoProject(renderer, 
+                            cube_t2[id2].x, cube_t2[id2].y, cube_t2[id2].z,
+                            cube_t2[id2+1].x, cube_t2[id2+1].y, cube_t2[id2+1].z,
+                            cube_t2[id2+2].x, cube_t2[id2+2].y, cube_t2[id2+2].z,
+                            0, 255, 0, true);
+                        updateRenderer(renderer);
+                        usleep(2000000);
+                        exit(1);
+                    }
                 }
             }
         }
diff --git a/src/triangles.h b/src/triangles.h
index 631d81f..55c2348 100644
--- a/src/triangles.h
+++ b/src/triangles.h
@@ -11,10 +11,11 @@ bool boundaryDoesntCollideChk(pt_2d *p1, pt_2d *p2, pt_2d *p3, double eps) ;
 bool triTri2D(pt_2d* t1, pt_2d* t2, double eps, bool allowReversed, bool onBoundary) ;
 bool triangleIntersection(pt_2d* tri1, pt_2d* tri2);
 bool triangleIntersectionDec(pt_2d t1_1, pt_2d t1_2, pt_2d t1_3, pt_2d t2_1, pt_2d t2_2, pt_2d t2_3);
+bool multipleTrianglesIntersection(pt_2d* tri1, int len1, pt_2d* tri2, int len2, int* ret1, int* ret2);
 
 int returnTriangle(double x0, double y0, double z0, double x1, double y1, double z1, double x2, double y2, double z2, pt_2d* retarr);
 int fillPolygon(int sf, cube_0 c, int trig, pt_2d* ret);
 
-bool cubeOverlap(cube_0 c1, cube_0 c2, int* retval);
+bool cubeOverlap(SDL_Renderer* renderer, cube_0 c1, cube_0 c2, double* retval);
 
 #endif
\ No newline at end of file
diff --git a/templates/room_3 b/templates/room_3
new file mode 100644
index 0000000..0248989
--- /dev/null
+++ b/templates/room_3
@@ -0,0 +1,16 @@
+Blocks :
+[-10.0, 0.0, -10.0, 20.0, 0.9, 20.0, 0.0, 0.0, 192, 192, 192]
+[-10.0, 7.1, -10.0, 20.0, 0.9, 20.0, 0.0, 0.0, 192, 192, 192]
+[-10.0, 1.0, -10.0, 5.0, 6.0, 5.0, 0.0, 0.0, 92, 92, 92]
+[5.0, 1.0, 5.0, 5.0, 6.0, 5.0, 0.0, 0.0, 92, 92, 93]
+
+Teleporters :
+[-10.0, 1.0, -5.0, 1.0, 2.0, 10.0, 0.0, 0.0, 255, 0, 0; 0, -1]
+[-5.0, 1.0, -10.0, 10.0, 2.0, 1.0, 0.0, 0.0, 255, 255, 0; -1, 0]
+[9.0, 1.0, -5.0, 1.0, 2.0, 10.0, 0.0, 0.0, 0, 255, 0; 0, 1]
+[-5.0, 1.0, 9.0, 10.0, 2.0, 1.0, 0.0, 0.0, 0, 0, 255; 1, 0]
+
+Weight :
+50
+
+$
\ No newline at end of file