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//! Functions and types relating to textures. use std::cell::Cell; use std::path::Path; use std::rc::Rc; use crate::error::{Result, TetraError}; use crate::fs; use crate::graphics::{self, DrawParams, Drawable}; use crate::platform::{GraphicsDevice, RawTexture}; use crate::Context; #[derive(Debug)] pub(crate) struct TextureSharedData { pub(crate) handle: RawTexture, filter_mode: Cell<FilterMode>, } impl PartialEq for TextureSharedData { fn eq(&self, other: &TextureSharedData) -> bool { // filter_mode should always match what's set on the GPU, // so we can ignore it for equality checks. self.handle.eq(&other.handle) } } /// A texture, held in GPU memory. /// /// # Supported Formats /// /// Various file formats are supported, and can be enabled or disabled via Cargo features: /// /// | Format | Cargo feature | Enabled by default? | /// |-|-|-| /// | PNG | `texture_png` | Yes | /// | JPEG | `texture_jpeg` | Yes | /// | GIF | `texture_gif` | Yes | /// | BMP | `texture_bmp` | Yes | /// | TIFF | `texture_tiff` | No | /// | TGA | `texture_tga` | No | /// | WebP | `texture_webp` | No | /// | ICO | `texture_ico` | No | /// | PNM | `texture_pnm` | No | /// | DDS/DXT | `texture_dds` | No | /// /// # Performance /// /// Creating a `Texture` is a relatively expensive operation. If you can, store them in your /// [`State`](crate::State) struct rather than recreating them each frame. /// /// Cloning a `Texture` is a very cheap operation, as the underlying data is shared between the /// original instance and the clone via [reference-counting](https://doc.rust-lang.org/std/rc/struct.Rc.html). /// This does mean, however, that updating a `Texture` (for example, changing its filter mode) will also /// update any other clones of that `Texture`. /// /// # Examples /// /// The [`texture`](https://github.com/17cupsofcoffee/tetra/blob/main/examples/texture.rs) /// example demonstrates how to draw a simple texture. #[derive(Debug, Clone, PartialEq)] pub struct Texture { pub(crate) data: Rc<TextureSharedData>, } impl Texture { /// Creates a new texture from the given file. /// /// The format will be determined based on the file extension. /// /// # Errors /// /// * [`TetraError::PlatformError`] will be returned if the underlying graphics API encounters an error. /// * [`TetraError::FailedToLoadAsset`] will be returned if the file could not be loaded. /// * [`TetraError::InvalidTexture`] will be returned if the texture data was invalid. pub fn new<P>(ctx: &mut Context, path: P) -> Result<Texture> where P: AsRef<Path>, { let image = fs::read_to_image(path)?.to_rgba8(); let (width, height) = image.dimensions(); Texture::from_rgba( ctx, width as i32, height as i32, image.into_raw().as_slice(), ) } /// Creates a new texture from a slice of data, encoded in one of Tetra's supported /// file formats (except for TGA). /// /// This is useful in combination with [`include_bytes`](std::include_bytes), as it /// allows you to include your textures directly in the binary. /// /// The format will be determined based on the 'magic bytes' at the beginning of the /// data. This should be reasonably reliable, but a `from_data_with_format` function /// might have to be added later. Note that TGA files do not have recognizable magic /// bytes, so this function will not recognize them. /// /// # Errors /// /// * [`TetraError::PlatformError`] will be returned if the underlying graphics API encounters an error. /// * [`TetraError::InvalidTexture`] will be returned if the texture data was invalid. pub fn from_file_data(ctx: &mut Context, data: &[u8]) -> Result<Texture> { let image = image::load_from_memory(data) .map_err(TetraError::InvalidTexture)? .to_rgba8(); let (width, height) = image.dimensions(); Texture::from_rgba( ctx, width as i32, height as i32, image.into_raw().as_slice(), ) } /// Creates a new texture from a slice of RGBA pixel data. /// /// This is useful if you wish to create a texture at runtime. /// /// This method requires you to provide enough data to fill the texture. /// If you provide too little data, an error will be returned. /// If you provide too much data, it will be truncated. /// /// # Errors /// /// * [`TetraError::NotEnoughData`] will be returned if not enough data is provided to fill /// the texture. This is to prevent the graphics API from trying to read uninitialized memory. pub fn from_rgba(ctx: &mut Context, width: i32, height: i32, data: &[u8]) -> Result<Texture> { Texture::with_device( &mut ctx.device, width, height, data, ctx.graphics.default_filter_mode, ) } pub(crate) fn with_device( device: &mut GraphicsDevice, width: i32, height: i32, data: &[u8], filter_mode: FilterMode, ) -> Result<Texture> { let handle = device.new_texture(width, height)?; device.set_texture_data(&handle, &data, 0, 0, width, height)?; device.set_texture_filter_mode(&handle, filter_mode); Ok(Texture { data: Rc::new(TextureSharedData { handle, filter_mode: Cell::new(FilterMode::Linear), }), }) } pub(crate) fn with_device_empty( device: &mut GraphicsDevice, width: i32, height: i32, filter_mode: FilterMode, ) -> Result<Texture> { let handle = device.new_texture(width, height)?; device.set_texture_filter_mode(&handle, filter_mode); Ok(Texture { data: Rc::new(TextureSharedData { handle, filter_mode: Cell::new(filter_mode), }), }) } /// Returns the width of the texture. pub fn width(&self) -> i32 { self.data.handle.width() } /// Returns the height of the texture. pub fn height(&self) -> i32 { self.data.handle.height() } /// Returns the size of the canvas. pub fn size(&self) -> (i32, i32) { (self.data.handle.width(), self.data.handle.height()) } /// Returns the filter mode being used by the texture. pub fn filter_mode(&self) -> FilterMode { self.data.filter_mode.get() } /// Sets the filter mode that should be used by the texture. pub fn set_filter_mode(&mut self, ctx: &mut Context, filter_mode: FilterMode) { ctx.device .set_texture_filter_mode(&self.data.handle, filter_mode); self.data.filter_mode.set(filter_mode); } /// Writes RGBA pixel data to a specified region of the texture. /// /// This method requires you to provide enough data to fill the target rectangle. /// If you provide too little data, an error will be returned. /// If you provide too much data, it will be truncated. /// /// If you want to overwrite the entire texture, the [`replace_data`](Self::replace_data) /// method offers a more concise way of doing this. /// /// # Errors /// /// * [`TetraError::NotEnoughData`] will be returned if not enough data is provided to fill /// the target rectangle. This is to prevent the graphics API from trying to read /// uninitialized memory. /// /// # Panics /// /// Panics if any part of the target rectangle is outside the bounds of the texture. pub fn set_data( &self, ctx: &mut Context, x: i32, y: i32, width: i32, height: i32, data: &[u8], ) -> Result { ctx.device .set_texture_data(&self.data.handle, &data, x, y, width, height) } /// Overwrites the entire texture with new RGBA pixel data. /// /// This method requires you to provide enough data to fill the texture. /// If you provide too little data, an error will be returned. /// If you provide too much data, it will be truncated. /// /// If you only want to write to a subsection of the texture, use the [`set_data`](Self::set_data) /// method instead. /// /// # Errors /// /// * [`TetraError::NotEnoughData`] will be returned if not enough data is provided to fill /// the texture. This is to prevent the graphics API from trying to read uninitialized memory. pub fn replace_data(&self, ctx: &mut Context, data: &[u8]) -> Result { let (width, height) = self.size(); self.set_data(ctx, 0, 0, width, height, data) } } impl Drawable for Texture { fn draw<P>(&self, ctx: &mut Context, params: P) where P: Into<DrawParams>, { let params = params.into(); let texture_width = self.width() as f32; let texture_height = self.height() as f32; let (u, v, clip_width, clip_height) = match params.clip { Some(clip) => (clip.x, clip.y, clip.width, clip.height), None => (0.0, 0.0, texture_width, texture_height), }; let x1 = 0.0; let y1 = 0.0; let x2 = clip_width; let y2 = clip_height; let u1 = u / texture_width; let v1 = v / texture_height; let u2 = (u + clip_width) / texture_width; let v2 = (v + clip_height) / texture_height; graphics::set_texture(ctx, self); graphics::push_quad(ctx, x1, y1, x2, y2, u1, v1, u2, v2, ¶ms); } } /// Filtering algorithms that can be used when scaling an image. /// /// Tetra currently defaults to using `Nearest` for all newly created textures. #[derive(Debug, Clone, Copy)] pub enum FilterMode { /// Nearest-neighbor interpolation. This preserves hard edges and details, but may look pixelated. /// /// If you're using pixel art, this is probably the scaling mode you should use. Nearest, /// Linear interpolation. This smooths images when scaling them up or down. Linear, }