593 lines
20 KiB
Rust
593 lines
20 KiB
Rust
use {
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js_sys::WebAssembly,
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wasm_bindgen::{prelude::*, JsCast},
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web_sys::{WebGlBuffer, WebGlProgram, WebGlRenderingContext, WebGlShader, WebGlTexture},
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};
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use egui::{
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math::clamp,
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paint::{Color32, PaintJobs, Texture, Triangles},
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vec2,
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};
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type Gl = WebGlRenderingContext;
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const VERTEX_SHADER_SOURCE: &str = r#"
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precision mediump float;
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uniform vec2 u_screen_size;
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attribute vec2 a_pos;
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attribute vec2 a_tc;
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attribute vec4 a_srgba;
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varying vec4 v_rgba;
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varying vec2 v_tc;
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// 0-1 linear from 0-255 sRGB
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vec3 linear_from_srgb(vec3 srgb) {
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bvec3 cutoff = lessThan(srgb, vec3(10.31475));
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vec3 lower = srgb / vec3(3294.6);
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vec3 higher = pow((srgb + vec3(14.025)) / vec3(269.025), vec3(2.4));
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return mix(higher, lower, vec3(cutoff));
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}
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vec4 linear_from_srgba(vec4 srgba) {
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return vec4(linear_from_srgb(srgba.rgb), srgba.a / 255.0);
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}
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void main() {
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gl_Position = vec4(
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2.0 * a_pos.x / u_screen_size.x - 1.0,
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1.0 - 2.0 * a_pos.y / u_screen_size.y,
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0.0,
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1.0);
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// Egui encodes vertex colors in gamma spaces, so we must decode the colors here:
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v_rgba = linear_from_srgba(a_srgba);
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v_tc = a_tc;
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}
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"#;
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const FRAGMENT_SHADER_SOURCE: &str = r#"
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precision mediump float;
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uniform sampler2D u_sampler;
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varying vec4 v_rgba;
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varying vec2 v_tc;
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// 0-255 sRGB from 0-1 linear
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vec3 srgb_from_linear(vec3 rgb) {
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bvec3 cutoff = lessThan(rgb, vec3(0.0031308));
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vec3 lower = rgb * vec3(3294.6);
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vec3 higher = vec3(269.025) * pow(rgb, vec3(1.0 / 2.4)) - vec3(14.025);
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return mix(higher, lower, vec3(cutoff));
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}
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vec4 srgba_from_linear(vec4 rgba) {
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return vec4(srgb_from_linear(rgba.rgb), 255.0 * rgba.a);
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}
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// 0-1 linear from 0-255 sRGB
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vec3 linear_from_srgb(vec3 srgb) {
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bvec3 cutoff = lessThan(srgb, vec3(10.31475));
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vec3 lower = srgb / vec3(3294.6);
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vec3 higher = pow((srgb + vec3(14.025)) / vec3(269.025), vec3(2.4));
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return mix(higher, lower, vec3(cutoff));
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}
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vec4 linear_from_srgba(vec4 srgba) {
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return vec4(linear_from_srgb(srgba.rgb), srgba.a / 255.0);
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}
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void main() {
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// We must decode the colors, since WebGL doesn't come with sRGBA textures:
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vec4 texture_rgba = linear_from_srgba(texture2D(u_sampler, v_tc) * 255.0);
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/// Multiply vertex color with texture color (in linear space).
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gl_FragColor = v_rgba * texture_rgba;
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// We must gamma-encode again since WebGL doesn't support linear blending in the framebuffer.
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gl_FragColor = srgba_from_linear(v_rgba * texture_rgba) / 255.0;
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// WebGL doesn't support linear blending in the framebuffer,
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// so we apply this hack to at least get a bit closer to the desired blending:
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gl_FragColor.a = pow(gl_FragColor.a, 1.6); // Empiric nonsense
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}
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"#;
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pub struct WebGlPainter {
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canvas_id: String,
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canvas: web_sys::HtmlCanvasElement,
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gl: WebGlRenderingContext,
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program: WebGlProgram,
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index_buffer: WebGlBuffer,
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pos_buffer: WebGlBuffer,
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tc_buffer: WebGlBuffer,
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color_buffer: WebGlBuffer,
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egui_texture: WebGlTexture,
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egui_texture_version: Option<u64>,
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/// `None` means unallocated (freed) slot.
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user_textures: Vec<Option<UserTexture>>,
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}
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#[derive(Default)]
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struct UserTexture {
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size: (usize, usize),
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/// Pending upload (will be emptied later).
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pixels: Vec<u8>,
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/// Lazily uploaded
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gl_texture: Option<WebGlTexture>,
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}
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impl WebGlPainter {
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pub fn new(canvas_id: &str) -> Result<WebGlPainter, JsValue> {
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let canvas = crate::canvas_element_or_die(canvas_id);
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let gl = canvas
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.get_context("webgl")?
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.ok_or_else(|| JsValue::from("Failed to get WebGl context"))?
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.dyn_into::<WebGlRenderingContext>()?;
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// --------------------------------------------------------------------
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let egui_texture = gl.create_texture().unwrap();
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gl.bind_texture(Gl::TEXTURE_2D, Some(&egui_texture));
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gl.tex_parameteri(Gl::TEXTURE_2D, Gl::TEXTURE_WRAP_S, Gl::CLAMP_TO_EDGE as i32);
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gl.tex_parameteri(Gl::TEXTURE_2D, Gl::TEXTURE_WRAP_T, Gl::CLAMP_TO_EDGE as i32);
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gl.tex_parameteri(Gl::TEXTURE_2D, Gl::TEXTURE_MIN_FILTER, Gl::LINEAR as i32);
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gl.tex_parameteri(Gl::TEXTURE_2D, Gl::TEXTURE_MAG_FILTER, Gl::LINEAR as i32);
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let vert_shader = compile_shader(&gl, Gl::VERTEX_SHADER, VERTEX_SHADER_SOURCE)?;
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let frag_shader = compile_shader(&gl, Gl::FRAGMENT_SHADER, FRAGMENT_SHADER_SOURCE)?;
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let program = link_program(&gl, [vert_shader, frag_shader].iter())?;
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let index_buffer = gl.create_buffer().ok_or("failed to create index_buffer")?;
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let pos_buffer = gl.create_buffer().ok_or("failed to create pos_buffer")?;
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let tc_buffer = gl.create_buffer().ok_or("failed to create tc_buffer")?;
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let color_buffer = gl.create_buffer().ok_or("failed to create color_buffer")?;
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Ok(WebGlPainter {
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canvas_id: canvas_id.to_owned(),
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canvas,
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gl,
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program,
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index_buffer,
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pos_buffer,
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tc_buffer,
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color_buffer,
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egui_texture,
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egui_texture_version: None,
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user_textures: Default::default(),
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})
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}
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fn alloc_user_texture_index(&mut self) -> usize {
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for (index, tex) in self.user_textures.iter_mut().enumerate() {
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if tex.is_none() {
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*tex = Some(Default::default());
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return index;
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}
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}
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let index = self.user_textures.len();
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self.user_textures.push(Some(Default::default()));
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index
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}
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fn alloc_user_texture(
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&mut self,
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size: (usize, usize),
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srgba_pixels: &[Color32],
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) -> egui::TextureId {
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let index = self.alloc_user_texture_index();
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assert_eq!(size.0 * size.1, srgba_pixels.len());
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if let Some(user_texture) = self.user_textures.get_mut(index) {
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if let Some(user_texture) = user_texture {
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let mut pixels: Vec<u8> = Vec::with_capacity(srgba_pixels.len() * 4);
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for srgba in srgba_pixels {
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pixels.push(srgba.r());
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pixels.push(srgba.g());
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pixels.push(srgba.b());
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pixels.push(srgba.a());
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}
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*user_texture = UserTexture {
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size,
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pixels,
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gl_texture: None,
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};
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}
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}
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egui::TextureId::User(index as u64)
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}
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fn free_user_texture(&mut self, id: egui::TextureId) {
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if let egui::TextureId::User(id) = id {
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let index = id as usize;
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if index < self.user_textures.len() {
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self.user_textures[index] = None;
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}
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}
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}
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fn get_texture(&self, texture_id: egui::TextureId) -> Option<&WebGlTexture> {
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match texture_id {
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egui::TextureId::Egui => Some(&self.egui_texture),
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egui::TextureId::User(id) => self
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.user_textures
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.get(id as usize)?
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.as_ref()?
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.gl_texture
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.as_ref(),
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}
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}
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fn upload_user_textures(&mut self) {
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let gl = &self.gl;
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for user_texture in &mut self.user_textures {
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if let Some(user_texture) = user_texture {
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if user_texture.gl_texture.is_none() {
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let pixels = std::mem::take(&mut user_texture.pixels);
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let gl_texture = gl.create_texture().unwrap();
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gl.bind_texture(Gl::TEXTURE_2D, Some(&gl_texture));
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gl.tex_parameteri(Gl::TEXTURE_2D, Gl::TEXTURE_WRAP_S, Gl::CLAMP_TO_EDGE as i32);
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gl.tex_parameteri(Gl::TEXTURE_2D, Gl::TEXTURE_WRAP_T, Gl::CLAMP_TO_EDGE as i32);
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gl.tex_parameteri(Gl::TEXTURE_2D, Gl::TEXTURE_MIN_FILTER, Gl::LINEAR as i32);
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gl.tex_parameteri(Gl::TEXTURE_2D, Gl::TEXTURE_MAG_FILTER, Gl::LINEAR as i32);
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gl.bind_texture(Gl::TEXTURE_2D, Some(&gl_texture));
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// TODO: https://developer.mozilla.org/en-US/docs/Web/API/EXT_sRGB
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let level = 0;
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let internal_format = Gl::RGBA;
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let border = 0;
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let src_format = Gl::RGBA;
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let src_type = Gl::UNSIGNED_BYTE;
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gl.tex_image_2d_with_i32_and_i32_and_i32_and_format_and_type_and_opt_u8_array(
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Gl::TEXTURE_2D,
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level,
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internal_format as i32,
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user_texture.size.0 as i32,
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user_texture.size.1 as i32,
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border,
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src_format,
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src_type,
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Some(&pixels),
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)
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.unwrap();
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user_texture.gl_texture = Some(gl_texture);
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}
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}
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}
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}
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fn paint_triangles(&self, triangles: &Triangles) -> Result<(), JsValue> {
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debug_assert!(triangles.is_valid());
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let indices: Vec<u16> = triangles.indices.iter().map(|idx| *idx as u16).collect();
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let mut positions: Vec<f32> = Vec::with_capacity(2 * triangles.vertices.len());
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let mut tex_coords: Vec<f32> = Vec::with_capacity(2 * triangles.vertices.len());
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for v in &triangles.vertices {
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positions.push(v.pos.x);
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positions.push(v.pos.y);
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tex_coords.push(v.uv.x);
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tex_coords.push(v.uv.y);
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}
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let mut colors: Vec<u8> = Vec::with_capacity(4 * triangles.vertices.len());
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for v in &triangles.vertices {
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colors.push(v.color[0]);
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colors.push(v.color[1]);
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colors.push(v.color[2]);
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colors.push(v.color[3]);
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}
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// --------------------------------------------------------------------
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let gl = &self.gl;
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let indices_memory_buffer = wasm_bindgen::memory()
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.dyn_into::<WebAssembly::Memory>()?
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.buffer();
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let indices_ptr = indices.as_ptr() as u32 / 2;
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let indices_array = js_sys::Int16Array::new(&indices_memory_buffer)
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.subarray(indices_ptr, indices_ptr + indices.len() as u32);
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gl.bind_buffer(Gl::ELEMENT_ARRAY_BUFFER, Some(&self.index_buffer));
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gl.buffer_data_with_array_buffer_view(
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Gl::ELEMENT_ARRAY_BUFFER,
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&indices_array,
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Gl::STREAM_DRAW,
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);
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// --------------------------------------------------------------------
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let pos_memory_buffer = wasm_bindgen::memory()
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.dyn_into::<WebAssembly::Memory>()?
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.buffer();
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let pos_ptr = positions.as_ptr() as u32 / 4;
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let pos_array = js_sys::Float32Array::new(&pos_memory_buffer)
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.subarray(pos_ptr, pos_ptr + positions.len() as u32);
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gl.bind_buffer(Gl::ARRAY_BUFFER, Some(&self.pos_buffer));
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gl.buffer_data_with_array_buffer_view(Gl::ARRAY_BUFFER, &pos_array, Gl::STREAM_DRAW);
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let a_pos_loc = gl.get_attrib_location(&self.program, "a_pos");
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assert!(a_pos_loc >= 0);
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let a_pos_loc = a_pos_loc as u32;
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let normalize = false;
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let stride = 0;
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let offset = 0;
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gl.vertex_attrib_pointer_with_i32(a_pos_loc, 2, Gl::FLOAT, normalize, stride, offset);
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gl.enable_vertex_attrib_array(a_pos_loc);
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// --------------------------------------------------------------------
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let tc_memory_buffer = wasm_bindgen::memory()
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.dyn_into::<WebAssembly::Memory>()?
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.buffer();
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let tc_ptr = tex_coords.as_ptr() as u32 / 4;
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let tc_array = js_sys::Float32Array::new(&tc_memory_buffer)
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.subarray(tc_ptr, tc_ptr + tex_coords.len() as u32);
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gl.bind_buffer(Gl::ARRAY_BUFFER, Some(&self.tc_buffer));
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gl.buffer_data_with_array_buffer_view(Gl::ARRAY_BUFFER, &tc_array, Gl::STREAM_DRAW);
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let a_tc_loc = gl.get_attrib_location(&self.program, "a_tc");
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assert!(a_tc_loc >= 0);
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let a_tc_loc = a_tc_loc as u32;
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let normalize = false;
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let stride = 0;
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let offset = 0;
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gl.vertex_attrib_pointer_with_i32(a_tc_loc, 2, Gl::FLOAT, normalize, stride, offset);
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gl.enable_vertex_attrib_array(a_tc_loc);
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// --------------------------------------------------------------------
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let colors_memory_buffer = wasm_bindgen::memory()
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.dyn_into::<WebAssembly::Memory>()?
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.buffer();
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let colors_ptr = colors.as_ptr() as u32;
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let colors_array = js_sys::Uint8Array::new(&colors_memory_buffer)
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.subarray(colors_ptr, colors_ptr + colors.len() as u32);
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gl.bind_buffer(Gl::ARRAY_BUFFER, Some(&self.color_buffer));
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gl.buffer_data_with_array_buffer_view(Gl::ARRAY_BUFFER, &colors_array, Gl::STREAM_DRAW);
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let a_srgba_loc = gl.get_attrib_location(&self.program, "a_srgba");
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assert!(a_srgba_loc >= 0);
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let a_srgba_loc = a_srgba_loc as u32;
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let normalize = false;
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let stride = 0;
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let offset = 0;
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gl.vertex_attrib_pointer_with_i32(
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a_srgba_loc,
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4,
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Gl::UNSIGNED_BYTE,
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normalize,
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stride,
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offset,
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);
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gl.enable_vertex_attrib_array(a_srgba_loc);
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// --------------------------------------------------------------------
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gl.draw_elements_with_i32(Gl::TRIANGLES, indices.len() as i32, Gl::UNSIGNED_SHORT, 0);
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Ok(())
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}
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}
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impl epi::TextureAllocator for WebGlPainter {
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fn alloc_srgba_premultiplied(
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&mut self,
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size: (usize, usize),
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srgba_pixels: &[egui::Color32],
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) -> egui::TextureId {
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self.alloc_user_texture(size, srgba_pixels)
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}
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fn free(&mut self, id: egui::TextureId) {
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self.free_user_texture(id)
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}
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}
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impl crate::Painter for WebGlPainter {
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fn as_tex_allocator(&mut self) -> &mut dyn epi::TextureAllocator {
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self
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}
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fn debug_info(&self) -> String {
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format!(
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"Stored canvas size: {} x {}\n\
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gl context size: {} x {}",
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self.canvas.width(),
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self.canvas.height(),
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self.gl.drawing_buffer_width(),
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self.gl.drawing_buffer_height(),
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)
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}
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/// id of the canvas html element containing the rendering
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fn canvas_id(&self) -> &str {
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&self.canvas_id
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}
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fn upload_egui_texture(&mut self, texture: &Texture) {
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if self.egui_texture_version == Some(texture.version) {
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return; // No change
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}
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let mut pixels: Vec<u8> = Vec::with_capacity(texture.pixels.len() * 4);
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for srgba in texture.srgba_pixels() {
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pixels.push(srgba.r());
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pixels.push(srgba.g());
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pixels.push(srgba.b());
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pixels.push(srgba.a());
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}
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let gl = &self.gl;
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gl.bind_texture(Gl::TEXTURE_2D, Some(&self.egui_texture));
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// TODO: https://developer.mozilla.org/en-US/docs/Web/API/EXT_sRGB
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// https://www.khronos.org/registry/webgl/extensions/EXT_sRGB/
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let level = 0;
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let internal_format = Gl::RGBA;
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let border = 0;
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let src_format = Gl::RGBA;
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let src_type = Gl::UNSIGNED_BYTE;
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gl.tex_image_2d_with_i32_and_i32_and_i32_and_format_and_type_and_opt_u8_array(
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Gl::TEXTURE_2D,
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level,
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internal_format as i32,
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texture.width as i32,
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texture.height as i32,
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border,
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src_format,
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src_type,
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Some(&pixels),
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)
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.unwrap();
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self.egui_texture_version = Some(texture.version);
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}
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fn clear(&mut self, clear_color: egui::Rgba) {
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let gl = &self.gl;
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gl.disable(Gl::SCISSOR_TEST);
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let width = self.canvas.width() as i32;
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let height = self.canvas.height() as i32;
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gl.viewport(0, 0, width, height);
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let clear_color: Color32 = clear_color.into();
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gl.clear_color(
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clear_color[0] as f32 / 255.0,
|
|
clear_color[1] as f32 / 255.0,
|
|
clear_color[2] as f32 / 255.0,
|
|
clear_color[3] as f32 / 255.0,
|
|
);
|
|
gl.clear(Gl::COLOR_BUFFER_BIT);
|
|
}
|
|
|
|
fn paint_jobs(&mut self, jobs: PaintJobs, pixels_per_point: f32) -> Result<(), JsValue> {
|
|
self.upload_user_textures();
|
|
|
|
let gl = &self.gl;
|
|
|
|
gl.enable(Gl::SCISSOR_TEST);
|
|
gl.disable(Gl::CULL_FACE); // Egui is not strict about winding order.
|
|
gl.enable(Gl::BLEND);
|
|
gl.blend_func(Gl::ONE, Gl::ONE_MINUS_SRC_ALPHA); // premultiplied alpha
|
|
gl.use_program(Some(&self.program));
|
|
gl.active_texture(Gl::TEXTURE0);
|
|
|
|
let u_screen_size_loc = gl
|
|
.get_uniform_location(&self.program, "u_screen_size")
|
|
.unwrap();
|
|
let screen_size_pixels = vec2(self.canvas.width() as f32, self.canvas.height() as f32);
|
|
let screen_size_points = screen_size_pixels / pixels_per_point;
|
|
gl.uniform2f(
|
|
Some(&u_screen_size_loc),
|
|
screen_size_points.x,
|
|
screen_size_points.y,
|
|
);
|
|
|
|
let u_sampler_loc = gl.get_uniform_location(&self.program, "u_sampler").unwrap();
|
|
gl.uniform1i(Some(&u_sampler_loc), 0);
|
|
|
|
for (clip_rect, triangles) in jobs {
|
|
if let Some(gl_texture) = self.get_texture(triangles.texture_id) {
|
|
gl.bind_texture(Gl::TEXTURE_2D, Some(gl_texture));
|
|
|
|
let clip_min_x = pixels_per_point * clip_rect.min.x;
|
|
let clip_min_y = pixels_per_point * clip_rect.min.y;
|
|
let clip_max_x = pixels_per_point * clip_rect.max.x;
|
|
let clip_max_y = pixels_per_point * clip_rect.max.y;
|
|
let clip_min_x = clamp(clip_min_x, 0.0..=screen_size_pixels.x);
|
|
let clip_min_y = clamp(clip_min_y, 0.0..=screen_size_pixels.y);
|
|
let clip_max_x = clamp(clip_max_x, clip_min_x..=screen_size_pixels.x);
|
|
let clip_max_y = clamp(clip_max_y, clip_min_y..=screen_size_pixels.y);
|
|
let clip_min_x = clip_min_x.round() as i32;
|
|
let clip_min_y = clip_min_y.round() as i32;
|
|
let clip_max_x = clip_max_x.round() as i32;
|
|
let clip_max_y = clip_max_y.round() as i32;
|
|
|
|
// scissor Y coordinate is from the bottom
|
|
gl.scissor(
|
|
clip_min_x,
|
|
self.canvas.height() as i32 - clip_max_y,
|
|
clip_max_x - clip_min_x,
|
|
clip_max_y - clip_min_y,
|
|
);
|
|
|
|
for triangles in triangles.split_to_u16() {
|
|
self.paint_triangles(&triangles)?;
|
|
}
|
|
} else {
|
|
crate::console_warn(format!(
|
|
"WebGL: Failed to find texture {:?}",
|
|
triangles.texture_id
|
|
));
|
|
}
|
|
}
|
|
Ok(())
|
|
}
|
|
}
|
|
|
|
fn compile_shader(
|
|
gl: &WebGlRenderingContext,
|
|
shader_type: u32,
|
|
source: &str,
|
|
) -> Result<WebGlShader, String> {
|
|
let shader = gl
|
|
.create_shader(shader_type)
|
|
.ok_or_else(|| String::from("Unable to create shader object"))?;
|
|
gl.shader_source(&shader, source);
|
|
gl.compile_shader(&shader);
|
|
|
|
if gl
|
|
.get_shader_parameter(&shader, Gl::COMPILE_STATUS)
|
|
.as_bool()
|
|
.unwrap_or(false)
|
|
{
|
|
Ok(shader)
|
|
} else {
|
|
Err(gl
|
|
.get_shader_info_log(&shader)
|
|
.unwrap_or_else(|| "Unknown error creating shader".into()))
|
|
}
|
|
}
|
|
|
|
fn link_program<'a, T: IntoIterator<Item = &'a WebGlShader>>(
|
|
gl: &WebGlRenderingContext,
|
|
shaders: T,
|
|
) -> Result<WebGlProgram, String> {
|
|
let program = gl
|
|
.create_program()
|
|
.ok_or_else(|| String::from("Unable to create shader object"))?;
|
|
for shader in shaders {
|
|
gl.attach_shader(&program, shader)
|
|
}
|
|
gl.link_program(&program);
|
|
|
|
if gl
|
|
.get_program_parameter(&program, Gl::LINK_STATUS)
|
|
.as_bool()
|
|
.unwrap_or(false)
|
|
{
|
|
Ok(program)
|
|
} else {
|
|
Err(gl
|
|
.get_program_info_log(&program)
|
|
.unwrap_or_else(|| "Unknown error creating program object".into()))
|
|
}
|
|
}
|