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Merged
btipling merged 7 commits into from
Aug 19, 2024
Merged

Reduce vertices #11

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bbaf525
this doesn't work
btipling Aug 18, 2024
e47e4bc
ok
btipling Aug 18, 2024
964368c
ok more
btipling Aug 18, 2024
7612c79
okish
btipling Aug 18, 2024
b38ea40
clear up hole
btipling Aug 18, 2024
66e3774
I give up for now. I need to do that math on paper
btipling Aug 19, 2024
8155126
I give up
btipling Aug 19, 2024
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135 changes: 73 additions & 62 deletions src/foundations/object/object_sphere/ObjectSphere.zig
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Original file line number Diff line number Diff line change
@@ -1,8 +1,11 @@
mesh: rhi.mesh,

const Sphere = @This();
const num_quads = 10000;
const num_vertices: usize = num_quads * 4;
const angle_delta: f32 = std.math.pi * 0.02;
const grid_dimension: usize = @intFromFloat((2.0 * std.math.pi) / angle_delta);
const num_vertices: usize = grid_dimension * grid_dimension;
const quad_dimensions = grid_dimension - 1;
const num_quads = quad_dimensions * quad_dimensions;
const num_indices: usize = num_quads * 6;
const sphere_scale: f32 = 0.75;

Expand All @@ -21,6 +24,9 @@ pub fn init(
.vao = vao_buf.vao,
.buffer = vao_buf.buffer,
.wire_mesh = wireframe,
// TODO: this code has a degenerate triangle, cull face bug at when i % grid_dimension == 0
// I have to do the math on paper to figure this out.
.cull = false,
.instance_type = .{
.instanced = .{
.index_count = num_indices,
Expand All @@ -39,73 +45,78 @@ fn data() struct { attribute_data: [num_vertices]rhi.attributeData, indices: [nu
var indices: [num_indices]u32 = undefined;
var x_axis_angle: f32 = 0;

var pi: usize = 0;
var ii: usize = 0;
const x_angle_delta: f32 = angle_delta;

const x_angle_delta: f32 = std.math.pi * 0.02;
var positions: [num_vertices]math.vector.vec3 = undefined;
{
var pi: usize = 0;
while (x_axis_angle < 2 * std.math.pi) : (x_axis_angle += x_angle_delta) {
const y_angle_delta: f32 = x_angle_delta;
var y_axis_angle: f32 = 0;
while (y_axis_angle < 2 * std.math.pi) : (y_axis_angle += y_angle_delta) {
positions[pi] = math.rotation.sphericalCoordinatesToCartesian3D(math.vector.vec3, .{
1.0,
y_axis_angle,
x_axis_angle,
});
pi += 1;
}
}
}

{
var ii: usize = 0;
var last: usize = 0;
var fl: usize = 0;
var sl: usize = 0;
for (0..quad_dimensions) |_| {
for (0..quad_dimensions) |_| {
const i = fl + sl;
const tr = i + 1;
const br = i + grid_dimension + 1;
const tl = i;
var bl = i + grid_dimension;
bl += 0;

while (x_axis_angle < 2 * std.math.pi) : (x_axis_angle += x_angle_delta) {
var y_axis_angle: f32 = 0;
const y_angle_delta: f32 = x_angle_delta;
while (y_axis_angle <= 2 * std.math.pi) : (y_axis_angle += y_angle_delta) {
const tr_coordinates: math.vector.vec3 = math.rotation.sphericalCoordinatesToCartesian3D(math.vector.vec3, .{
1.0,
y_axis_angle,
x_axis_angle,
});
const br_coordinates: math.vector.vec3 = math.rotation.sphericalCoordinatesToCartesian3D(math.vector.vec3, .{
1.0,
y_axis_angle,
x_axis_angle + x_angle_delta,
});
const tl_coordinates: math.vector.vec3 = math.rotation.sphericalCoordinatesToCartesian3D(math.vector.vec3, .{
1.0,
y_axis_angle + y_angle_delta,
x_axis_angle,
});
const bl_coordinates: math.vector.vec3 = math.rotation.sphericalCoordinatesToCartesian3D(math.vector.vec3, .{
1.0,
y_axis_angle + y_angle_delta,
x_axis_angle + x_angle_delta,
});
const tr = pi;
const br = pi + 1;
const tl = pi + 2;
const bl = pi + 3;
attribute_data[tr] = .{ .position = tr_coordinates, .normals = math.vector.normalize(tr_coordinates) };
attribute_data[br] = .{ .position = br_coordinates, .normals = math.vector.normalize(br_coordinates) };
attribute_data[tl] = .{ .position = tl_coordinates, .normals = math.vector.normalize(tl_coordinates) };
attribute_data[bl] = .{ .position = bl_coordinates, .normals = math.vector.normalize(bl_coordinates) };
// Triangle 1
indices[ii] = @intCast(tl);
indices[ii + 1] = @intCast(bl);
indices[ii + 2] = @intCast(br);
// Triangle 2
indices[ii + 3] = @intCast(tr);
indices[ii + 4] = @intCast(tl);
indices[ii + 5] = @intCast(br);
pi += 4;
ii += 6;
addVertexData(positions, indices[0..], attribute_data[0..], tr, br, tl, bl, ii);

ii += 6;
last = br;
fl += 1;
}
sl += 1;
}
}

return .{ .attribute_data = attribute_data, .indices = indices };
}

fn addVertexData(attribute_data: *[num_vertices]rhi.attributeData, new_coordinates: [3]f32, i: usize) void {
{
const p = math.vector.mul(
sphere_scale,
@as(math.vector.vec3, .{
new_coordinates[2],
new_coordinates[1],
new_coordinates[0],
}),
);
attribute_data[i] = .{
.position = p,
.normals = math.vector.normalize(p),
};
}
fn addVertexData(
positions: [num_vertices]math.vector.vec3,
indices: []u32,
attribute_data: []rhi.attributeData,
tr: usize,
br: usize,
tl: usize,
bl: usize,
ii: usize,
) void {
const tr_coordinates = positions[tr];
const br_coordinates = positions[br];
const tl_coordinates = positions[tl];
const bl_coordinates = positions[bl];
attribute_data[tr] = .{ .position = tr_coordinates, .normals = math.vector.normalize(tr_coordinates) };
attribute_data[br] = .{ .position = br_coordinates, .normals = math.vector.normalize(br_coordinates) };
attribute_data[tl] = .{ .position = tl_coordinates, .normals = math.vector.normalize(tl_coordinates) };
attribute_data[bl] = .{ .position = bl_coordinates, .normals = math.vector.normalize(bl_coordinates) };
// Triangle 1
indices[ii] = @intCast(tl);
indices[ii + 1] = @intCast(br);
indices[ii + 2] = @intCast(tr);
// Triangle 2
indices[ii + 3] = @intCast(tl);
indices[ii + 4] = @intCast(bl);
indices[ii + 5] = @intCast(br);
}

const std = @import("std");
Expand Down