1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67

use crate::core::*;
use crate::renderer::*;

///
/// A material that renders the isosurface defined by the voxel data in the [IsourfaceMaterial::voxels] and the [IsourfaceMaterial::threshold].
/// The surface is defined by all the points in the volume where the red channel of the voxel data is equal to the threshold.
/// This material should be applied to a cube with center in origo, for example [CpuMesh::cube].
///
#[derive(Clone)]
pub struct IsourfaceMaterial {
    /// The voxel data that defines the isosurface.
    pub voxels: std::rc::Rc<Texture3D>,
    /// Threshold (in the range [0..1]) that defines the surface in the voxel data.
    pub threshold: f32,
    /// Base surface color. Assumed to be in linear color space.
    pub color: Color,
    /// A value in the range `[0..1]` specifying how metallic the surface is.
    pub metallic: f32,
    /// A value in the range `[0..1]` specifying how rough the surface is.
    pub roughness: f32,
    /// The size of the cube that is used to render the voxel data. The texture is scaled to fill the entire cube.
    pub size: Vec3,
    /// The lighting model used when rendering this material
    pub lighting_model: LightingModel,
}

impl Material for IsourfaceMaterial {
    fn fragment_shader_source(&self, _use_vertex_colors: bool, lights: &[&dyn Light]) -> String {
        let mut output = lights_fragment_shader_source(lights, self.lighting_model);
        output.push_str(include_str!("shaders/isosurface_material.frag"));
        output
    }
    fn use_uniforms(
        &self,
        program: &Program,
        camera: &Camera,
        lights: &[&dyn Light],
    ) -> ThreeDResult<()> {
        for (i, light) in lights.iter().enumerate() {
            light.use_uniforms(program, i as u32)?;
        }
        program.use_uniform("camera_position", camera.position())?;
        program.use_uniform("surface_color", self.color)?;
        program.use_uniform("metallic", self.metallic)?;
        program.use_uniform_if_required("roughness", self.roughness)?;
        program.use_uniform("size", self.size)?;
        program.use_uniform("threshold", self.threshold)?;
        program.use_uniform(
            "h",
            vec3(
                1.0 / self.voxels.width() as f32,
                1.0 / self.voxels.height() as f32,
                1.0 / self.voxels.depth() as f32,
            ),
        )?;
        program.use_texture_3d("tex", &self.voxels)
    }
    fn render_states(&self) -> RenderStates {
        RenderStates {
            blend: Blend::TRANSPARENCY,
            ..Default::default()
        }
    }
    fn is_transparent(&self) -> bool {
        true
    }
}