roast2d_internal 0.4.0

//! Skinned mesh shader for skeletal animation rendering.

use std::borrow::Cow;

use glam::Mat4;

use crate::color::Color;
use crate::engine::Engine;
use crate::handle::Handle;
use crate::light3d::Material3D;
use crate::platform::types::TextureResource;
use crate::skeleton::{AnimationPlayer, MAX_BONES};

use super::shader_standard::{Mesh3DShader, ResolvedDraw3DSkinned};
use super::skinned::{SkinnedMesh3D, SkinnedMesh3DVertex};

/// Draw command for skinned meshes with skeletal animation.
pub struct Draw3DSkinned {
    pub mesh: SkinnedMesh3D,
    pub model: Mat4,
    pub texture: Option<Handle>,
    pub color: Color,
    pub material: Material3D,
    pub bone_matrices: Vec<Mat4>,
}

impl Draw3DSkinned {
    /// Create a new skinned draw command.
    pub fn new(mesh: SkinnedMesh3D, model: Mat4, player: &AnimationPlayer) -> Self {
        Self {
            mesh,
            model,
            texture: None,
            color: crate::color::WHITE,
            material: Material3D::default(),
            bone_matrices: player.bone_matrices().to_vec(),
        }
    }

    /// Set the texture.
    pub fn with_texture(mut self, texture: Handle) -> Self {
        self.texture = Some(texture);
        self
    }

    /// Set the color.
    pub fn with_color(mut self, color: Color) -> Self {
        self.color = color;
        self
    }

    /// Set the material.
    pub fn with_material(mut self, material: Material3D) -> Self {
        self.material = material;
        self
    }
}

/// Uniform data for skinned mesh rendering (same layout as Mesh3DUniform)
#[repr(C)]
#[derive(Clone, Copy, bytemuck::Pod, bytemuck::Zeroable, Debug)]
struct SkinnedMesh3DUniform {
    mvp: [[f32; 4]; 4],
    model: [[f32; 4]; 4],
    camera_pos: [f32; 4],
    diffuse: [f32; 4],
    specular: [f32; 4],
    emissive: [f32; 4],
    ambient: [f32; 4],
    light_dir: [f32; 4],
    light_color: [f32; 4],
    light_pos: [f32; 4],
    light_params: [f32; 4],
    shininess: f32,
    has_texture: f32,
    _padding: [f32; 2],
}

/// Shader for rendering skinned meshes with skeletal animation.
pub struct SkinnedMesh3DShader {
    pipeline: wgpu::RenderPipeline,
    uniform_buffer: wgpu::Buffer,
    bone_buffer: wgpu::Buffer,
    #[allow(dead_code)]
    bind_group_layout: wgpu::BindGroupLayout,
    bind_group: wgpu::BindGroup,
    texture_bind_group_layout: wgpu::BindGroupLayout,
    default_texture_bind_group: wgpu::BindGroup,
    texture_bind_group_cache: hashbrown::HashMap<usize, wgpu::BindGroup>,
}

impl SkinnedMesh3DShader {
    pub fn new(g: &Engine) -> Self {
        let state = g.backend_state();
        let device = &state.device;

        let shader = device.create_shader_module(wgpu::ShaderModuleDescriptor {
            label: Some("mesh3d_skinned.shader"),
            source: wgpu::ShaderSource::Wgsl(Cow::Borrowed(include_str!(
                "../../assets/shaders/mesh3d_skinned.wgsl"
            ))),
        });

        // Create uniform buffer
        let uniform_buffer = device.create_buffer(&wgpu::BufferDescriptor {
            label: Some("skinned_mesh3d.uniform"),
            size: std::mem::size_of::<SkinnedMesh3DUniform>() as u64,
            usage: wgpu::BufferUsages::UNIFORM | wgpu::BufferUsages::COPY_DST,
            mapped_at_creation: false,
        });

        // Create bone matrices storage buffer (128 bones * 64 bytes = 8KB)
        let bone_buffer = device.create_buffer(&wgpu::BufferDescriptor {
            label: Some("skinned_mesh3d.bones"),
            size: (MAX_BONES * std::mem::size_of::<[[f32; 4]; 4]>()) as u64,
            usage: wgpu::BufferUsages::STORAGE | wgpu::BufferUsages::COPY_DST,
            mapped_at_creation: false,
        });

        // Bind group layout for uniforms + bones
        let bind_group_layout = device.create_bind_group_layout(&wgpu::BindGroupLayoutDescriptor {
            label: Some("skinned_mesh3d.bgl"),
            entries: &[
                wgpu::BindGroupLayoutEntry {
                    binding: 0,
                    visibility: wgpu::ShaderStages::VERTEX | wgpu::ShaderStages::FRAGMENT,
                    ty: wgpu::BindingType::Buffer {
                        ty: wgpu::BufferBindingType::Uniform,
                        has_dynamic_offset: false,
                        min_binding_size: None,
                    },
                    count: None,
                },
                wgpu::BindGroupLayoutEntry {
                    binding: 1,
                    visibility: wgpu::ShaderStages::VERTEX,
                    ty: wgpu::BindingType::Buffer {
                        ty: wgpu::BufferBindingType::Storage { read_only: true },
                        has_dynamic_offset: false,
                        min_binding_size: None,
                    },
                    count: None,
                },
            ],
        });

        let bind_group = device.create_bind_group(&wgpu::BindGroupDescriptor {
            label: Some("skinned_mesh3d.bg"),
            layout: &bind_group_layout,
            entries: &[
                wgpu::BindGroupEntry {
                    binding: 0,
                    resource: uniform_buffer.as_entire_binding(),
                },
                wgpu::BindGroupEntry {
                    binding: 1,
                    resource: bone_buffer.as_entire_binding(),
                },
            ],
        });

        // Texture bind group layout (same as mesh3d)
        let texture_bind_group_layout =
            device.create_bind_group_layout(&wgpu::BindGroupLayoutDescriptor {
                label: Some("skinned_mesh3d.texture_bgl"),
                entries: &[
                    wgpu::BindGroupLayoutEntry {
                        binding: 0,
                        visibility: wgpu::ShaderStages::FRAGMENT,
                        ty: wgpu::BindingType::Texture {
                            sample_type: wgpu::TextureSampleType::Float { filterable: true },
                            view_dimension: wgpu::TextureViewDimension::D2,
                            multisampled: false,
                        },
                        count: None,
                    },
                    wgpu::BindGroupLayoutEntry {
                        binding: 1,
                        visibility: wgpu::ShaderStages::FRAGMENT,
                        ty: wgpu::BindingType::Sampler(wgpu::SamplerBindingType::Filtering),
                        count: None,
                    },
                ],
            });

        // Create default white texture
        let default_texture = Mesh3DShader::create_default_texture(device, &state.queue);
        let default_texture_bind_group = device.create_bind_group(&wgpu::BindGroupDescriptor {
            label: Some("skinned_mesh3d.default_texture_bg"),
            layout: &texture_bind_group_layout,
            entries: &[
                wgpu::BindGroupEntry {
                    binding: 0,
                    resource: wgpu::BindingResource::TextureView(&default_texture.view),
                },
                wgpu::BindGroupEntry {
                    binding: 1,
                    resource: wgpu::BindingResource::Sampler(&default_texture.sampler),
                },
            ],
        });

        // Pipeline layout
        let pipeline_layout = device.create_pipeline_layout(&wgpu::PipelineLayoutDescriptor {
            label: Some("skinned_mesh3d.pipeline_layout"),
            bind_group_layouts: &[&bind_group_layout, &texture_bind_group_layout],
            push_constant_ranges: &[],
        });

        // Vertex layout for SkinnedMesh3DVertex
        let vertex_layout = wgpu::VertexBufferLayout {
            array_stride: std::mem::size_of::<SkinnedMesh3DVertex>() as u64,
            step_mode: wgpu::VertexStepMode::Vertex,
            attributes: &[
                // position
                wgpu::VertexAttribute {
                    format: wgpu::VertexFormat::Float32x3,
                    offset: 0,
                    shader_location: 0,
                },
                // normal
                wgpu::VertexAttribute {
                    format: wgpu::VertexFormat::Float32x3,
                    offset: 12,
                    shader_location: 1,
                },
                // uv
                wgpu::VertexAttribute {
                    format: wgpu::VertexFormat::Float32x2,
                    offset: 24,
                    shader_location: 2,
                },
                // bone_indices
                wgpu::VertexAttribute {
                    format: wgpu::VertexFormat::Uint32x4,
                    offset: 32,
                    shader_location: 3,
                },
                // bone_weights
                wgpu::VertexAttribute {
                    format: wgpu::VertexFormat::Float32x4,
                    offset: 48,
                    shader_location: 4,
                },
            ],
        };

        // Create pipeline with reverse-Z depth
        let pipeline = device.create_render_pipeline(&wgpu::RenderPipelineDescriptor {
            label: Some("skinned_mesh3d.pipeline"),
            layout: Some(&pipeline_layout),
            vertex: wgpu::VertexState {
                module: &shader,
                entry_point: Some("vs_main"),
                buffers: &[vertex_layout],
                compilation_options: Default::default(),
            },
            fragment: Some(wgpu::FragmentState {
                module: &shader,
                entry_point: Some("fs_main"),
                targets: &[Some(wgpu::ColorTargetState {
                    format: state.surface_view_format,
                    blend: Some(wgpu::BlendState::ALPHA_BLENDING),
                    write_mask: wgpu::ColorWrites::ALL,
                })],
                compilation_options: Default::default(),
            }),
            primitive: wgpu::PrimitiveState {
                topology: wgpu::PrimitiveTopology::TriangleList,
                front_face: wgpu::FrontFace::Ccw,
                cull_mode: Some(wgpu::Face::Back),
                ..Default::default()
            },
            depth_stencil: Some(wgpu::DepthStencilState {
                format: wgpu::TextureFormat::Depth32Float,
                depth_write_enabled: true,
                depth_compare: wgpu::CompareFunction::Greater, // Reverse-Z
                stencil: wgpu::StencilState::default(),
                bias: wgpu::DepthBiasState::default(),
            }),
            multisample: wgpu::MultisampleState::default(),
            multiview: None,
            cache: None,
        });

        Self {
            pipeline,
            uniform_buffer,
            bone_buffer,
            bind_group_layout,
            bind_group,
            texture_bind_group_layout,
            default_texture_bind_group,
            texture_bind_group_cache: hashbrown::HashMap::new(),
        }
    }

    pub fn record(
        &mut self,
        g: &Engine,
        color_target: &wgpu::TextureView,
        depth_view: &wgpu::TextureView,
        draws: &[ResolvedDraw3DSkinned],
        encoder: &mut wgpu::CommandEncoder,
        should_clear: bool,
    ) {
        if draws.is_empty() {
            return;
        }

        let state = g.backend_state();
        let lighting = g.lighting();
        let camera = g.camera3d();
        let aspect = g.view_size().x / g.view_size().y;
        let view_proj = camera.view_proj(aspect);

        let load_op = if should_clear {
            wgpu::LoadOp::Clear(wgpu::Color::BLACK)
        } else {
            wgpu::LoadOp::Load
        };

        let depth_load_op = if should_clear {
            wgpu::LoadOp::Clear(0.0) // Reverse-Z: clear to 0
        } else {
            wgpu::LoadOp::Load
        };

        let mut pass = encoder.begin_render_pass(&wgpu::RenderPassDescriptor {
            label: Some("skinned_mesh3d.pass"),
            color_attachments: &[Some(wgpu::RenderPassColorAttachment {
                view: color_target,
                resolve_target: None,
                ops: wgpu::Operations {
                    load: load_op,
                    store: wgpu::StoreOp::Store,
                },
                depth_slice: None,
            })],
            depth_stencil_attachment: Some(wgpu::RenderPassDepthStencilAttachment {
                view: depth_view,
                depth_ops: Some(wgpu::Operations {
                    load: depth_load_op,
                    store: wgpu::StoreOp::Store,
                }),
                stencil_ops: None,
            }),
            ..Default::default()
        });

        pass.set_pipeline(&self.pipeline);

        for draw in draws {
            // Update uniform buffer
            let (light_dir, light_color, light_pos, light_params) =
                Self::get_light_params(lighting);

            let uniform = SkinnedMesh3DUniform {
                mvp: (view_proj * draw.model).to_cols_array_2d(),
                model: draw.model.to_cols_array_2d(),
                camera_pos: [camera.eye.x, camera.eye.y, camera.eye.z, 1.0],
                diffuse: [
                    draw.material.diffuse.r * draw.color.r,
                    draw.material.diffuse.g * draw.color.g,
                    draw.material.diffuse.b * draw.color.b,
                    draw.material.diffuse.a * draw.color.a,
                ],
                specular: [
                    draw.material.specular.r,
                    draw.material.specular.g,
                    draw.material.specular.b,
                    draw.material.specular.a,
                ],
                emissive: [
                    draw.material.emissive.r,
                    draw.material.emissive.g,
                    draw.material.emissive.b,
                    draw.material.emissive.a,
                ],
                ambient: [
                    lighting.ambient.r,
                    lighting.ambient.g,
                    lighting.ambient.b,
                    lighting.ambient.a,
                ],
                light_dir,
                light_color,
                light_pos,
                light_params,
                shininess: draw.material.shininess,
                has_texture: if draw.texture_bind_group.is_some() {
                    1.0
                } else {
                    0.0
                },
                _padding: [0.0, 0.0],
            };

            state
                .queue
                .write_buffer(&self.uniform_buffer, 0, bytemuck::bytes_of(&uniform));

            // Upload bone matrices
            let bone_data: Vec<[[f32; 4]; 4]> = draw
                .bone_matrices
                .iter()
                .map(|m| m.to_cols_array_2d())
                .collect();

            // Pad to MAX_BONES if needed
            let mut bone_buffer_data = vec![[[0.0f32; 4]; 4]; MAX_BONES];
            for (i, mat) in bone_data.iter().enumerate().take(MAX_BONES) {
                bone_buffer_data[i] = *mat;
            }
            state.queue.write_buffer(
                &self.bone_buffer,
                0,
                bytemuck::cast_slice(&bone_buffer_data),
            );

            pass.set_bind_group(0, &self.bind_group, &[]);

            // Set texture bind group
            if let Some(texture_bg) = &draw.texture_bind_group {
                pass.set_bind_group(1, texture_bg, &[]);
            } else {
                pass.set_bind_group(1, &self.default_texture_bind_group, &[]);
            }

            // Draw
            pass.set_vertex_buffer(0, draw.mesh.vertex.slice(..));
            pass.set_index_buffer(draw.mesh.index.slice(..), wgpu::IndexFormat::Uint16);
            pass.draw_indexed(0..draw.mesh.index_count, 0, 0..1);
        }
    }

    fn get_light_params(
        lighting: &crate::light3d::LightingState,
    ) -> ([f32; 4], [f32; 4], [f32; 4], [f32; 4]) {
        // Find first enabled light
        let light = lighting.lights.iter().find_map(|l| l.as_ref());

        if let Some(light) = light {
            use crate::light3d::LightKind;
            let (light_type, radius, inner_angle, outer_angle) = match light.kind {
                LightKind::Directional => (0.0, 0.0, 0.0, 0.0),
                LightKind::Point { radius } => (1.0, radius, 0.0, 0.0),
                LightKind::Spot {
                    radius,
                    inner_angle,
                    outer_angle,
                } => (2.0, radius, inner_angle, outer_angle),
            };

            (
                [light.direction.x, light.direction.y, light.direction.z, 0.0],
                [light.color.r, light.color.g, light.color.b, light.color.a],
                [
                    light.position.x,
                    light.position.y,
                    light.position.z,
                    light_type,
                ],
                [radius, inner_angle, outer_angle, light.intensity],
            )
        } else {
            // Default light
            (
                [-0.5, -1.0, -0.5, 0.0],
                [1.0, 1.0, 1.0, 1.0],
                [0.0, 0.0, 0.0, 0.0],
                [0.0, 0.0, 0.0, 1.0],
            )
        }
    }

    pub fn get_or_create_texture_bind_group(
        &mut self,
        g: &Engine,
        texture: &TextureResource,
    ) -> &wgpu::BindGroup {
        let key = std::ptr::from_ref(&texture.texture) as usize;
        if !self.texture_bind_group_cache.contains_key(&key) {
            let state = g.backend_state();
            let bind_group = state.device.create_bind_group(&wgpu::BindGroupDescriptor {
                label: Some("skinned_mesh3d.texture_bg"),
                layout: &self.texture_bind_group_layout,
                entries: &[
                    wgpu::BindGroupEntry {
                        binding: 0,
                        resource: wgpu::BindingResource::TextureView(&texture.view),
                    },
                    wgpu::BindGroupEntry {
                        binding: 1,
                        resource: wgpu::BindingResource::Sampler(&texture.sampler),
                    },
                ],
            });
            self.texture_bind_group_cache.insert(key, bind_group);
        }
        self.texture_bind_group_cache.get(&key).unwrap()
    }
}