experimenting with z buffering

src/display.c

@@ -20,6 +20,8 @@
 #include "generation.h"
 #include "display.h"
 
+int flashlight = 20 ;
+
 int* drawOrder;
 
 double draw_constant ;
@@ -474,9 +476,9 @@ void renderTriangleNoProject(
 ) {
 
     const SDL_Vertex vtxs[3] = {
-        construct_vertex(px0, py0, red, green, blue, 255),
+        construct_vertex(px0, py0, max(red - (int)(flashlight*pz0), 0), max(green - (int)(flashlight*pz0), 0), max(blue - (int)(flashlight*pz0), 0), 255),
-        construct_vertex(px1, py1, red, green, blue, 255),
+        construct_vertex(px1, py1, max(red - (int)(flashlight*pz1), 0), max(green - (int)(flashlight*pz1), 0), max(blue - (int)(flashlight*pz1), 0), 255),
-        construct_vertex(px2, py2, red, green, blue, 255),
+        construct_vertex(px2, py2, max(red - (int)(flashlight*pz2), 0), max(green - (int)(flashlight*pz2), 0), max(blue - (int)(flashlight*pz2), 0), 255),
     };
     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);
@@ -484,6 +486,14 @@ void renderTriangleNoProject(
     SDL_RenderGeometry(renderer, NULL, vtxs, 3, NULL, 0);
 }
 
+double near = -1.0 ;
+double far = 1.0 ;
+double getZbuffer(double z) {
+    //return z;
+    return (2.0*(z - near)/(far - near) -1.0);
+    //return ((far + near)/(far - near) + (1.0/z)*((-2.0*far*near)/(far - near)));
+}
+
 pt_2d to_pt_2d(double x0, double y0, double z0) {
     pt_2d res;
     res.x = x0;
@@ -509,9 +519,9 @@ void addTriangle(
     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) {
-        triangles_to_render[triangles_i][0] = to_pt_2d(1500.0 * (1.0 + (px0 / (1.5 * pz0 * tan_fov))) / 2.0, 1000.0 * (1.0 + (py0 / (pz0 * tan_fov))) / 2.0, pz0);
+        triangles_to_render[triangles_i][0] = to_pt_2d(1500.0 * (1.0 + (px0 / (1.5 * pz0 * tan_fov))) / 2.0, 1000.0 * (1.0 + (py0 / (pz0 * tan_fov))) / 2.0, getZbuffer(pz0));
-        triangles_to_render[triangles_i][1] = to_pt_2d(1500.0 * (1.0 + (px1 / (1.5 * pz1 * tan_fov))) / 2.0, 1000.0 * (1.0 + (py1 / (pz1 * tan_fov))) / 2.0, pz1);
+        triangles_to_render[triangles_i][1] = to_pt_2d(1500.0 * (1.0 + (px1 / (1.5 * pz1 * tan_fov))) / 2.0, 1000.0 * (1.0 + (py1 / (pz1 * tan_fov))) / 2.0, getZbuffer(pz1));
-        triangles_to_render[triangles_i][2] = to_pt_2d(1500.0 * (1.0 + (px2 / (1.5 * pz2 * tan_fov))) / 2.0, 1000.0 * (1.0 + (py2 / (pz2 * tan_fov))) / 2.0, pz2);
+        triangles_to_render[triangles_i][2] = to_pt_2d(1500.0 * (1.0 + (px2 / (1.5 * pz2 * tan_fov))) / 2.0, 1000.0 * (1.0 + (py2 / (pz2 * tan_fov))) / 2.0, getZbuffer(pz2));
         reds[triangles_i] = red ;
         greens[triangles_i] = green ;
         blues[triangles_i] = blue ;
@@ -570,12 +580,12 @@ void addTriangle(
             &mpx1, &mpy1, &mpz1) ;
         }
 
-        triangles_to_render[triangles_i][0] = to_pt_2d(1500.0 * (1.0 + (fpx0 / (1.5 * fpz0 * tan_fov))) / 2.0, 1000.0 * (1.0 + (fpy0 / (fpz0 * tan_fov))) / 2.0, fpz0);
+        triangles_to_render[triangles_i][0] = to_pt_2d(1500.0 * (1.0 + (fpx0 / (1.5 * fpz0 * tan_fov))) / 2.0, 1000.0 * (1.0 + (fpy0 / (fpz0 * tan_fov))) / 2.0, getZbuffer(fpz0));
-        triangles_to_render[triangles_i][1] = to_pt_2d(1500.0 * (1.0 + (mpx0 / (1.5 * mpz0 * tan_fov))) / 2.0, 1000.0 * (1.0 + (mpy0 / (mpz0 * tan_fov))) / 2.0, mpz0);
+        triangles_to_render[triangles_i][1] = to_pt_2d(1500.0 * (1.0 + (mpx0 / (1.5 * mpz0 * tan_fov))) / 2.0, 1000.0 * (1.0 + (mpy0 / (mpz0 * tan_fov))) / 2.0, getZbuffer(mpz0));
-        triangles_to_render[triangles_i][2] = to_pt_2d(1500.0 * (1.0 + (fpx1 / (1.5 * fpz1 * tan_fov))) / 2.0, 1000.0 * (1.0 + (fpy1 / (fpz1 * tan_fov))) / 2.0, fpz1);
+        triangles_to_render[triangles_i][2] = to_pt_2d(1500.0 * (1.0 + (fpx1 / (1.5 * fpz1 * tan_fov))) / 2.0, 1000.0 * (1.0 + (fpy1 / (fpz1 * tan_fov))) / 2.0, getZbuffer(fpz1));
-        triangles_to_render[triangles_i+1][0] = to_pt_2d(1500.0 * (1.0 + (mpx0 / (1.5 * mpz0 * tan_fov))) / 2.0, 1000.0 * (1.0 + (mpy0 / (mpz0 * tan_fov))) / 2.0, mpz0);
+        triangles_to_render[triangles_i+1][0] = to_pt_2d(1500.0 * (1.0 + (mpx0 / (1.5 * mpz0 * tan_fov))) / 2.0, 1000.0 * (1.0 + (mpy0 / (mpz0 * tan_fov))) / 2.0, getZbuffer(mpz0));
-        triangles_to_render[triangles_i+1][1] = to_pt_2d(1500.0 * (1.0 + (mpx1 / (1.5 * mpz1 * tan_fov))) / 2.0, 1000.0 * (1.0 + (mpy1 / (mpz1 * tan_fov))) / 2.0, mpz1);
+        triangles_to_render[triangles_i+1][1] = to_pt_2d(1500.0 * (1.0 + (mpx1 / (1.5 * mpz1 * tan_fov))) / 2.0, 1000.0 * (1.0 + (mpy1 / (mpz1 * tan_fov))) / 2.0, getZbuffer(mpz1));
-        triangles_to_render[triangles_i+1][2] = to_pt_2d(1500.0 * (1.0 + (fpx1 / (1.5 * fpz1 * tan_fov))) / 2.0, 1000.0 * (1.0 + (fpy1 / (fpz1 * tan_fov))) / 2.0, fpz1);
+        triangles_to_render[triangles_i+1][2] = to_pt_2d(1500.0 * (1.0 + (fpx1 / (1.5 * fpz1 * tan_fov))) / 2.0, 1000.0 * (1.0 + (fpy1 / (fpz1 * tan_fov))) / 2.0, getZbuffer(fpz1));
         reds[triangles_i] = red ;
         greens[triangles_i] = green ;
         blues[triangles_i] = blue ;
@@ -619,9 +629,9 @@ void addTriangle(
             &px1, &py1, &pz1);
         }
 
-        triangles_to_render[triangles_i][0] = to_pt_2d(1500.0 * (1.0 + (px0 / (1.5 * pz0 * tan_fov))) / 2.0, 1000.0 * (1.0 + (py0 / (pz0 * tan_fov))) / 2.0, pz0);
+        triangles_to_render[triangles_i][0] = to_pt_2d(1500.0 * (1.0 + (px0 / (1.5 * pz0 * tan_fov))) / 2.0, 1000.0 * (1.0 + (py0 / (pz0 * tan_fov))) / 2.0, getZbuffer(pz0));
-        triangles_to_render[triangles_i][1] = to_pt_2d(1500.0 * (1.0 + (px1 / (1.5 * pz1 * tan_fov))) / 2.0, 1000.0 * (1.0 + (py1 / (pz1 * tan_fov))) / 2.0, pz1);
+        triangles_to_render[triangles_i][1] = to_pt_2d(1500.0 * (1.0 + (px1 / (1.5 * pz1 * tan_fov))) / 2.0, 1000.0 * (1.0 + (py1 / (pz1 * tan_fov))) / 2.0, getZbuffer(pz1));
-        triangles_to_render[triangles_i][2] = to_pt_2d(1500.0 * (1.0 + (px2 / (1.5 * pz2 * tan_fov))) / 2.0, 1000.0 * (1.0 + (py2 / (pz2 * tan_fov))) / 2.0, pz2);
+        triangles_to_render[triangles_i][2] = to_pt_2d(1500.0 * (1.0 + (px2 / (1.5 * pz2 * tan_fov))) / 2.0, 1000.0 * (1.0 + (py2 / (pz2 * tan_fov))) / 2.0, getZbuffer(pz2));
         reds[triangles_i] = red ;
         greens[triangles_i] = green ;
         blues[triangles_i] = blue ;
@@ -757,6 +767,14 @@ void drawCurrentRoom(SDL_Renderer* renderer) {
     for(int k = 0; k < triangles_i; k++) {
         renderTriangleFull(renderer, triangles_order[k]);
     }
+    /*for(int k = 0; k < triangles_i; k++) {
+        drawNumberToRenderer(renderer, digits, 
+            (int)(0.33*(triangles_to_render[k][0].z+triangles_to_render[k][1].z+triangles_to_render[k][2].z)),
+            (int)(0.33*(triangles_to_render[k][0].x+triangles_to_render[k][1].x+triangles_to_render[k][2].x)),
+            (int)(0.33*(triangles_to_render[k][0].y+triangles_to_render[k][1].y+triangles_to_render[k][2].y)),
+            75/4, 105/4, 0
+        );
+    }*/
 }
 
 // -------------------------------------------------------------------------------------------------------------------------------- //

src/triangles.c

@@ -475,6 +475,21 @@ 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);
 }
 
+double triangle_dist(pt_2d* tri) {
+    return (tri[0].z + tri[1].z + tri[2].z);
+}
+
+bool delta_get2(pt_2d* tri1, pt_2d* tri2, double* ret) {
+    if(triangleIntersection(tri1, tri2)) {
+        if(ret != NULL) {
+            *ret = triangle_dist(tri2) - triangle_dist(tri1);
+        }
+        return true;
+    } else {
+        return false ;
+    }
+}
+
 bool delta_get(pt_2d* tri1, pt_2d* tri2, double* ret) {
     double th1 = 0.0;
     double th2 = 0.0;
@@ -497,7 +512,7 @@ bool delta_get(pt_2d* tri1, pt_2d* tri2, double* ret) {
                 //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
+                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);}
                 return true;
             }
         }