diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/render.zig | 70 |
1 files changed, 37 insertions, 33 deletions
diff --git a/src/render.zig b/src/render.zig index 8d2faca..e2aa401 100644 --- a/src/render.zig +++ b/src/render.zig @@ -70,8 +70,8 @@ fn fasterColourBlend(onto: Colour, from: Colour) Colour { } const LocalCoordHit = struct { - local_dist : f32, - frac : f32, + local_dist: f32, + frac: f32, }; // The primary observation is: if a line segment AB disconnects the unit square, @@ -81,16 +81,18 @@ const LocalCoordHit = struct { // TODO: handle hitting vertices fn hitDistLocalCoords( - ray0: [2]f32, - ray1: [2]f32, + ray0_x: f32, + ray0_y: f32, + ray1_x: f32, + ray1_y: f32, vertices: []const [2]f32, ) ?LocalCoordHit { - const rdy = ray1[1] - ray0[1]; - const rdx = ray1[0] - ray0[0]; + const rdy = ray1_y - ray0_y; + const rdx = ray1_x - ray0_x; const rdist = std.math.sqrt(rdx * rdx + rdy * rdy); var vp = vertices[0]; - var crossp: f32 = rdy * (vp[0] - ray0[0]) - rdx * (vp[1] - ray0[1]); + var crossp: f32 = rdy * (vp[0] - ray0_x) - rdx * (vp[1] - ray0_y); // if (crossp == 0) { // // hit a vertex exactly @@ -100,7 +102,7 @@ fn hitDistLocalCoords( // } var ret_val: ?LocalCoordHit = null; - var v : [2]f32 = undefined; + var v: [2]f32 = undefined; var cross: f32 = 0; var i: usize = 1; while (i < vertices.len) : ({ @@ -109,7 +111,7 @@ fn hitDistLocalCoords( i += 1; }) { v = vertices[i]; - cross = rdy * (v[0] - ray0[0]) - rdx * (v[1] - ray0[1]); + cross = rdy * (v[0] - ray0_x) - rdx * (v[1] - ray0_y); // if (cross == 0) { // const dx = v[0] - ray0[0]; // const dy = v[1] - ray0[1]; @@ -120,7 +122,7 @@ fn hitDistLocalCoords( // return_val = new_distance; // } // } else - { + { if (crossp * cross < 0) { const vdx = v[0] - vp[0]; const vdy = v[1] - vp[1]; @@ -129,12 +131,12 @@ fn hitDistLocalCoords( // so along ray0->ray1 which we use for fast distance, and frac // indexes it along vp->v which we use for texture mapping. const denom = (rdx * vdy - vdx * rdy); - const t = (vdx * (ray0[1] - vp[1]) - vdy * (ray0[0] - vp[0])) / denom; + const t = (vdx * (ray0_y - vp[1]) - vdy * (ray0_x - vp[0])) / denom; const frac = crossp / denom; const new_distance = rdist * t; if (ret_val == null or (new_distance < ret_val.?.local_dist)) { - ret_val = LocalCoordHit{.local_dist = new_distance, .frac = frac}; + ret_val = LocalCoordHit{ .local_dist = new_distance, .frac = frac }; } } } @@ -403,29 +405,31 @@ pub fn Renderer(PlaneWidth: f32, PlaneHeight: f32) type { // Are we drawing vertical surfaces? if (cell.floor_height > 0 or cell.draw_down) { - const ray0: [2]f32 = if (hit_horizontal) - [2]f32{ - std.math.modf(distance * cosra + ppos_x).fpart, - (if (step_y > 0) 0 else 1), - } - else - [2]f32{ - (if (step_x > 0) 0 else 1), - std.math.modf(distance * sinra + ppos_y).fpart, - }; + var ray0_x: f32 = undefined; + var ray0_y: f32 = undefined; + var ray1_x: f32 = undefined; + var ray1_y: f32 = undefined; - const ray1: [2]f32 = if (next_hit_horizontal) - [2]f32{ - std.math.modf(next_distance * cosra + ppos_x).fpart, - (if (step_y > 0) 1 else 0), - } - else - [2]f32{ - (if (step_x > 0) 1 else 0), - std.math.modf(next_distance * sinra + ppos_y).fpart, - }; + const ray_enter_y: f32 = if (step_y > 0) 0 else 1; + const ray_enter_x: f32 = if (step_x > 0) 0 else 1; + + if (hit_horizontal) { + ray0_x = std.math.modf(distance * cosra + ppos_x).fpart; + ray0_y = ray_enter_y; + } else { + ray0_x = ray_enter_x; + ray0_y = std.math.modf(distance * sinra + ppos_y).fpart; + } + + if (next_hit_horizontal) { + ray1_x = std.math.modf(next_distance * cosra + ppos_x).fpart; + ray1_y = 1 - ray_enter_y; + } else { + ray1_x = 1 - ray_enter_x; + ray1_y = std.math.modf(next_distance * sinra + ppos_y).fpart; + } - if (hitDistLocalCoords(ray0, ray1, cell.vertices)) |dist_frac| { + if (hitDistLocalCoords(ray0_x, ray0_y, ray1_x, ray1_y, cell.vertices)) |dist_frac| { // TODO: Correct for fisheye? const adj_distance = distance + dist_frac.local_dist; |