Added ceilings and pos_z to sprites (they can now be on the ceiling)

1 files changed, 17 insertions, 8 deletions

diff --git a/src/raycast.zig b/src/raycast.zig
index 2a9b0a1..2b377de 100644
--- a/src/raycast.zig
+++ b/src/raycast.zig
@@ -160,16 +160,16 @@ pub fn Player(PlaneWidth: f32, PlaneHeight: f32) type {
                 if (left + width < 0 or left >= PlaneWidth) continue;
 
                 const height = PlaneDist * obj.height / scaled_perp_distance;
-                const top = PlaneHeight / 2 + PlaneDist * (obj.height - self.height) / scaled_perp_distance;
+                const top = PlaneHeight / 2 + PlaneDist * (obj.height - self.height + obj.pos_z) / scaled_perp_distance;
 
                 // TODO: likewise?
                 if (top < 0 or top - height >= PlaneHeight) continue;
 
                 // Something is on the screen, let's draw it!
                 const start = std.math.max(0, left);
-                const end = @floatToInt(i32, std.math.min(left + width, PlaneWidth));
+                const end = @floatToInt(i32, std.math.min(left + width, PlaneWidth - 1));
 
-                var tex_frac: f32 = (start - left) / width;
+                var tex_frac: f32 = std.math.clamp((start - left) / width, 0, 1);
                 var col: i32 = @floatToInt(i32, start);
                 const tex_frac_step = 1 / width;
                 while (col < end) : ({
@@ -316,8 +316,13 @@ pub fn Player(PlaneWidth: f32, PlaneHeight: f32) type {
             }
         }
 
-        pub fn renderFloorsToTexture(self: @This(), floors_image: Image, rendered_floors_texture: Texture, map: level.Map) !void {
-            var pixels = [_]Colour{Colour.Black} ** (PlaneWidth * PlaneHeight / 2);
+        pub fn renderFloorsToTexture(
+            self: @This(),
+            floors_image: Image,
+            rendered_floors_texture: Texture,
+            map: level.Map,
+        ) !void {
+            var pixels = [_]Colour{Colour.Black} ** (PlaneWidth * PlaneHeight);
 
             // Again, another TERRIBLE hack: we do the same nasty linear
             // interpolation trick and for whatever reason the floors look fine.
@@ -327,8 +332,11 @@ pub fn Player(PlaneWidth: f32, PlaneHeight: f32) type {
             const sin_last = std.math.sin(self.ang - 0.5 * FOV);
 
             var row: usize = 0;
-            while (row < PlaneHeight / 2) : (row += 1) {
-                const row_dist = self.height * PlaneDist / @intToFloat(f32, row + 1);
+            while (row < PlaneHeight) : (row += 1) {
+                if (row == PlaneHeight / 2) continue;
+                const frow = std.math.fabs(PlaneHeight / 2 - @intToFloat(f32, row));
+                const scale = if (row < PlaneHeight / 2) constants.MAX_HEIGHT - self.height else self.height;
+                const row_dist = scale * PlaneDist / frow;
 
                 const dx_step = row_dist * (cos_last - cos_first) / PlaneWidth;
                 const dy_step = row_dist * (sin_last - sin_first) / PlaneWidth;
@@ -352,7 +360,8 @@ pub fn Player(PlaneWidth: f32, PlaneHeight: f32) type {
                     const iy = @floatToInt(i32, sy.ipart);
 
                     if (map.inBounds(ix, iy)) {
-                        const tex = @as(c_uint, map.lookup(ix, iy).floor_texture);
+                        const cell = map.lookup(ix, iy);
+                        const tex = @as(c_uint, if (row > PlaneHeight / 2) cell.floor_texture else cell.ceiling_texture);
                         const toff = tex * @floatToInt(c_uint, constants.TextureDim);
                         const px = @floatToInt(c_uint, constants.TextureDim * std.math.fabs(sx.fpart));
                         const py = @floatToInt(c_uint, constants.TextureDim * std.math.fabs(sy.fpart));