16bit Z buffer and lores/hires switch

examples/3d-demo/3d-demo.cpp

diff --git a/examples/3d-demo/3d-demo.cpp b/examples/3d-demo/3d-demo.cpp
index 1037a68..6797468 100644
--- a/examples/3d-demo/3d-demo.cpp
+++ b/examples/3d-demo/3d-demo.cpp
@@ -27,7 +27,7 @@
 bool draw_lines = false;
 bool draw_vertices = false;
 
-float* zbuffer;
+int16_t* zbuffer;
 
 Object *link_object;
 Camera cam(
@@ -41,10 +41,12 @@
 constexpr uint32_t fixed_shift = 0;
 constexpr uint32_t fixed_mul = 1 << fixed_shift;
 
-void init() {
-  set_screen_mode(lores);
+ScreenMode screen_mode = hires;
 
-  zbuffer = new float[screen.bounds.w * screen.bounds.h];
+void init() {
+  set_screen_mode(hires);
+
+  zbuffer = new int16_t[screen.bounds.w * screen.bounds.h];
 
   link_object = Object::load_obj((char*)link_obj);
   main_texture = Surface::load(main_texture_packed);
@@ -114,8 +116,8 @@
   return;
 }
 
-float near = 1.0f;
-float far = 50.0f;
+int16_t near = 1;
+int16_t far = 50;
 
 void render(uint32_t time_ms) {
   // clear the screen buffer
@@ -124,7 +126,7 @@
 
   // reset the zbuffer
   for (uint32_t i = 0; i < screen.bounds.w * screen.bounds.h; i++) {
-    zbuffer[i] = -1.0f;
+    zbuffer[i] = -1;
   }
 
   uint32_t ms_start = now();
@@ -270,5 +272,10 @@
   if(buttons.pressed & Button::Y) {
     draw_vertices = !draw_vertices;
   }
+
+  if(buttons.pressed & Button::MENU) {
+    screen_mode = screen_mode == hires ? lores : hires;
+    set_screen_mode(screen_mode);
+  }
 }
 

examples/3d-demo/renderer.cpp

diff --git a/examples/3d-demo/renderer.cpp b/examples/3d-demo/renderer.cpp
index 1a25c6d..ab118d9 100644
--- a/examples/3d-demo/renderer.cpp
+++ b/examples/3d-demo/renderer.cpp
@@ -18,7 +18,7 @@
 

 uint32_t pixels_drawn = 0;

 

-void draw_face(Vec3* vertices, Vec3* normals, Vec2* texture_coordinates, Surface* texture, Vec3 light, Pen *color, float* zbuffer, float near, float far) {

+void draw_face(Vec3* vertices, Vec3* normals, Vec2* texture_coordinates, Surface* texture, Vec3 light, Pen *color, int16_t* zbuffer, int16_t near, int16_t far) {

   // convert vertices into Q8 integer points

   Point p0(vertices[0].x, vertices[0].y);

   Point p1(vertices[1].x, vertices[1].y);

@@ -81,9 +81,9 @@
         float  beta = w1 * invarea;

         float gamma = 1.0f - alpha - beta; // ensures sum == 1.0f

 

-        float z = vertices[0].z * alpha + vertices[1].z * beta + vertices[2].z * gamma;

+        int16_t z = (vertices[0].z * alpha + vertices[1].z * beta + vertices[2].z * gamma) * 16384;

 

-        if (z > zbuffer[p.x + (p.y * screen.bounds.w)] && z > -1.0f) {

+        if (z > zbuffer[p.x + (p.y * screen.bounds.w)] && z > -1) {

           zbuffer[p.x + (p.y * screen.bounds.w)] = z;

 

           pixels_drawn++;

examples/3d-demo/renderer.hpp

diff --git a/examples/3d-demo/renderer.hpp b/examples/3d-demo/renderer.hpp
index c5efc61..c82338b 100644
--- a/examples/3d-demo/renderer.hpp
+++ b/examples/3d-demo/renderer.hpp
@@ -6,4 +6,4 @@
 

 extern uint32_t pixels_drawn;

 

-void draw_face(Vec3* vertices, Vec3* normals, Vec2* texture_coordinates, Surface* texture, Vec3 light, Pen* color, float *zbuffer, float near, float far);
\ No newline at end of file
+void draw_face(Vec3* vertices, Vec3* normals, Vec2* texture_coordinates, Surface* texture, Vec3 light, Pen* color, int16_t *zbuffer, int16_t near, int16_t far);
\ No newline at end of file