rustial-renderer-wgpu 0.0.1

Pure WGPU renderer for the rustial 2.5D map engine
Documentation 
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//! Tile mesh generation for GPU rendering.

use crate::gpu::vertex::TileVertex;
use glam::DVec3;
use rustial_engine::{tile_bounds_world, TileId};

/// Generated mesh data for a single tile quad.
pub struct TileMesh {
    /// Four quad vertices in CCW order (bottom-left, bottom-right,
    /// top-right, top-left) in camera-relative world space.
    pub vertices: [TileVertex; 4],
    /// Triangle-list indices for the quad (`0,1,2` and `0,2,3`).
    pub indices: [u16; 6],
}

/// Build a tile quad mesh in world space, then offset relative to a camera origin
/// to avoid floating-point precision issues far from the origin.
pub fn build_tile_mesh(tile: &TileId, camera_origin: DVec3) -> TileMesh {
    let bounds = tile_bounds_world(tile);
    let min = bounds.min.position - camera_origin;
    let max = bounds.max.position - camera_origin;

    let vertices = [
        TileVertex {
            position: [min.x as f32, min.y as f32, 0.0],
            uv: [0.0, 1.0],
            opacity: 1.0,
        },
        TileVertex {
            position: [max.x as f32, min.y as f32, 0.0],
            uv: [1.0, 1.0],
            opacity: 1.0,
        },
        TileVertex {
            position: [max.x as f32, max.y as f32, 0.0],
            uv: [1.0, 0.0],
            opacity: 1.0,
        },
        TileVertex {
            position: [min.x as f32, max.y as f32, 0.0],
            uv: [0.0, 0.0],
            opacity: 1.0,
        },
    ];

    let indices = [0, 1, 2, 0, 2, 3];

    TileMesh { vertices, indices }
}