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Merged
btipling merged 4 commits into from
Aug 26, 2024
Merged

frustum extraction enhancement #20

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866f041
improve this
btipling Aug 26, 2024
6d86b32
use a function for these
btipling Aug 26, 2024
893af33
FIx stuff
btipling Aug 26, 2024
6de96c4
remove unused incorrect extraction function
btipling Aug 26, 2024
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35 changes: 34 additions & 1 deletion src/foundations/math/matrix.zig
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Original file line number Diff line number Diff line change
Expand Up @@ -78,6 +78,37 @@ pub inline fn perspectiveProjection(field_of_view_y_angle: f32, aspect_ratio_s:
return perspectiveProjectionCamera(perspective_plane_distance_g, aspect_ratio_s, near, far);
}

test perspectiveProjection {
const fovy: f32 = rotation.degreesToRadians(70);
const width: f32 = 3840;
const height: f32 = 2400;
const s = width / height;
const near: f32 = 0.1;
const far: f32 = 500;
const g: f32 = 1.0 / @tan(fovy * 0.5);
const p = perspectiveProjectionCamera(g, s, near, far);
const plane_extracted_left = vector.normalize(vector.add(p.columns[3], p.columns[0]));
const clip_space_left: vector.vec4 = .{ 1, 0, 0, 1 };
const perspective_transformed_left = vector.normalize(transformVector(p, clip_space_left));

var cam = identity();
cam = transformMatrix(cam, translate(10, -3, 9));
cam = transformMatrix(cam, rotationX(std.math.pi * 0.2));
const nl: vector.vec4 = vector.normalize(vector.add(
vector.mul(g, cam.columns[0]),
vector.mul(s, cam.columns[2]),
));
const dl = vector.dotProduct(vector.negate(nl), cam.columns[3]);
const left_plane = geometry.Plane.init(vector.vec4ToVec3(nl), dl);

const camera_space_left: vector.vec4 = .{ g, 0, s, 0 };
const f_camera = vector.mul(1.0 / @sqrt(g * g + s * s), camera_space_left);
const f_world = transformVector(transpose(inverse(cam)), f_camera);

try std.testing.expect(float.equal(plane_extracted_left[0], perspective_transformed_left[0], 0.000001));
try std.testing.expect(float.equal(left_plane.parameterized[0], f_world[0], 0.000001));
}

pub inline fn perspectiveProjectionCamera(perspective_plane_distance_g: f32, aspect_ratio_s: f32, near: f32, far: f32) matrix {
const depth_scale = far / (far - near);
// zig fmt: off
Expand Down Expand Up @@ -986,4 +1017,6 @@ test toReducedRowEchelonForm {
const std = @import("std");
const vector = @import("vector.zig");
const float = @import("float.zig");
const Quat = @import("rotation.zig").Quat;
const rotation = @import("rotation.zig");
const geometry = @import("geometry/geometry.zig");
const Quat = rotation.Quat;
40 changes: 13 additions & 27 deletions src/foundations/scenes/frustum_planes/FrustumPlanes.zig
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Expand Up @@ -116,37 +116,23 @@ fn pointVisible(
return true;
}

pub fn cameraPlaneExtraction(a: f32, b: f32, v1: math.vector.vec4, v2: math.vector.vec4, cam: math.matrix) math.geometry.Plane {
const n: math.vector.vec4 = math.vector.normalize(math.vector.add(
math.vector.mul(a, v1),
math.vector.mul(b, v2),
));
const d = math.vector.dotProduct(n, cam.columns[3]);
return math.geometry.Plane.init(math.vector.normalize(math.vector.vec4ToVec3(n)), d);
}

pub fn updateCamera(self: *FrustumPlanes) void {
const cam = self.view_camera_0;
const cm = cam.camera_matrix;

const nl: math.vector.vec3 = math.vector.add(
math.vector.mul(cam.aspect_ratio_s, math.vector.vec4ToVec3(cm.columns[1])),
math.vector.mul(cam.perspective_plane_distance_g, math.vector.vec4ToVec3(cm.columns[2])),
);
const dl = math.vector.dotProduct(nl, math.vector.vec4ToVec3(cm.columns[3]));
const left_plane = math.geometry.Plane.init(nl, dl);

const nr: math.vector.vec3 = math.vector.add(
math.vector.mul(cam.aspect_ratio_s, math.vector.vec4ToVec3(cm.columns[1])),
math.vector.mul(-cam.perspective_plane_distance_g, math.vector.vec4ToVec3(cm.columns[2])),
);
const dr = math.vector.dotProduct(nr, math.vector.vec4ToVec3(cm.columns[3]));
const right_plane = math.geometry.Plane.init(nr, dr);

const nb: math.vector.vec3 = math.vector.add(
math.vector.mul(-cam.perspective_plane_distance_g, math.vector.vec4ToVec3(cm.columns[0])),
math.vector.vec4ToVec3(cm.columns[1]),
);
const db = math.vector.dotProduct(nb, math.vector.vec4ToVec3(cm.columns[3]));
const bot_plane = math.geometry.Plane.init(nb, db);

const nt: math.vector.vec3 = math.vector.add(
math.vector.mul(cam.perspective_plane_distance_g, math.vector.vec4ToVec3(cm.columns[0])),
math.vector.vec4ToVec3(cm.columns[1]),
);
const dt = math.vector.dotProduct(nt, math.vector.vec4ToVec3(cm.columns[3]));
const top_plane = math.geometry.Plane.init(nt, dt);
const left_plane = cameraPlaneExtraction(cam.aspect_ratio_s, cam.perspective_plane_distance_g, cm.columns[1], cm.columns[2], cm);
const right_plane = cameraPlaneExtraction(cam.aspect_ratio_s, -cam.perspective_plane_distance_g, cm.columns[1], cm.columns[2], cm);
const bot_plane = cameraPlaneExtraction(-cam.perspective_plane_distance_g, 1.0, cm.columns[0], cm.columns[1], cm);
const top_plane = cameraPlaneExtraction(cam.perspective_plane_distance_g, 1.0, cm.columns[0], cm.columns[1], cm);

for (0..self.num_voxels) |i| {
const vox = self.voxel_map[i];
Expand Down