361 lines
12 KiB
Rust
361 lines
12 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 emigui::{Frame, Texture};
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type Gl = WebGlRenderingContext;
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pub struct Painter {
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canvas: web_sys::HtmlCanvasElement,
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gl: WebGlRenderingContext,
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texture: WebGlTexture,
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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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tex_size: (u16, u16),
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current_texture_id: Option<u64>,
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}
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impl Painter {
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pub 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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pub fn new(canvas_id: &str) -> Result<Painter, JsValue> {
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let document = web_sys::window().unwrap().document().unwrap();
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let canvas = document.get_element_by_id(canvas_id).unwrap();
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let canvas: web_sys::HtmlCanvasElement = canvas.dyn_into::<web_sys::HtmlCanvasElement>()?;
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let gl = canvas
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.get_context("webgl")?
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.unwrap()
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.dyn_into::<WebGlRenderingContext>()?;
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// --------------------------------------------------------------------
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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::NEAREST as i32);
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gl.tex_parameteri(Gl::TEXTURE_2D, Gl::TEXTURE_MAG_FILTER, Gl::NEAREST as i32);
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// --------------------------------------------------------------------
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let vert_shader = compile_shader(
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&gl,
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Gl::VERTEX_SHADER,
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r#"
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uniform vec2 u_screen_size;
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uniform vec2 u_tex_size;
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attribute vec2 a_pos;
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attribute vec2 a_tc;
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attribute vec4 a_color;
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varying vec2 v_tc;
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varying vec4 v_color;
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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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v_tc = a_tc / u_tex_size;
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v_color = a_color;
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}
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"#,
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)?;
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let frag_shader = compile_shader(
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&gl,
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Gl::FRAGMENT_SHADER,
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r#"
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uniform sampler2D u_sampler;
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precision highp float;
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varying vec2 v_tc;
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varying vec4 v_color;
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void main() {
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gl_FragColor = v_color;
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gl_FragColor.a *= texture2D(u_sampler, v_tc).a;
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}
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"#,
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)?;
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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(Painter {
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canvas,
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gl,
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texture: gl_texture,
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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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tex_size: (0, 0),
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current_texture_id: None,
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})
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}
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fn upload_texture(&mut self, texture: &Texture) {
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if self.current_texture_id == Some(texture.id) {
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return; // No change
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}
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let gl = &self.gl;
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gl.bind_texture(Gl::TEXTURE_2D, Some(&self.texture));
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// TODO: remove once https://github.com/rustwasm/wasm-bindgen/issues/1005 is fixed.
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let mut pixels: Vec<_> = texture.pixels.iter().cloned().collect();
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let level = 0;
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let internal_format = Gl::ALPHA;
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let border = 0;
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let src_format = Gl::ALPHA;
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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(&mut pixels),
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)
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.unwrap();
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self.tex_size = (texture.width as u16, texture.height as u16);
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self.current_texture_id = Some(texture.id);
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}
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pub fn paint(&mut self, frame: &Frame, texture: &Texture) -> Result<(), JsValue> {
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self.upload_texture(texture);
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let gl = &self.gl;
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// --------------------------------------------------------------------
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gl.enable(Gl::BLEND);
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gl.blend_func(Gl::SRC_ALPHA, Gl::ONE_MINUS_SRC_ALPHA);
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gl.use_program(Some(&self.program));
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gl.active_texture(Gl::TEXTURE0);
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gl.bind_texture(Gl::TEXTURE_2D, Some(&self.texture));
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// --------------------------------------------------------------------
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let indices: Vec<u16> = frame.indices.iter().map(|idx| *idx as u16).collect();
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let mut positions: Vec<f32> = Vec::with_capacity(2 * frame.vertices.len());
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let mut tex_coords: Vec<u16> = Vec::with_capacity(2 * frame.vertices.len());
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for v in &frame.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.0);
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tex_coords.push(v.uv.1);
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}
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let mut colors: Vec<u8> = Vec::with_capacity(4 * frame.vertices.len());
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for v in &frame.vertices {
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colors.push(v.color.r);
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colors.push(v.color.g);
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colors.push(v.color.b);
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colors.push(v.color.a);
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}
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// --------------------------------------------------------------------
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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 / 2;
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let tc_array = js_sys::Uint16Array::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(
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a_tc_loc,
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2,
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Gl::UNSIGNED_SHORT,
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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_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_color_loc = gl.get_attrib_location(&self.program, "a_color");
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assert!(a_color_loc >= 0);
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let a_color_loc = a_color_loc as u32;
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let normalize = true;
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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_color_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_color_loc);
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// --------------------------------------------------------------------
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let u_screen_size_loc = gl
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.get_uniform_location(&self.program, "u_screen_size")
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.unwrap();
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gl.uniform2f(
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Some(&u_screen_size_loc),
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self.canvas.width() as f32,
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self.canvas.height() as f32,
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);
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let u_tex_size_loc = gl
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.get_uniform_location(&self.program, "u_tex_size")
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.unwrap();
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gl.uniform2f(
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Some(&u_tex_size_loc),
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self.tex_size.0 as f32,
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self.tex_size.1 as f32,
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);
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let u_sampler_loc = gl.get_uniform_location(&self.program, "u_sampler").unwrap();
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gl.uniform1i(Some(&u_sampler_loc), 0);
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gl.viewport(
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0,
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0,
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self.canvas.width() as i32,
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self.canvas.height() as i32,
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);
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gl.clear_color(0.05, 0.05, 0.05, 1.0);
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gl.clear(Gl::COLOR_BUFFER_BIT);
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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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fn compile_shader(
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gl: &WebGlRenderingContext,
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shader_type: u32,
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source: &str,
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) -> Result<WebGlShader, String> {
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let shader = gl
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.create_shader(shader_type)
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.ok_or_else(|| String::from("Unable to create shader object"))?;
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gl.shader_source(&shader, source);
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gl.compile_shader(&shader);
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if gl
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.get_shader_parameter(&shader, Gl::COMPILE_STATUS)
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.as_bool()
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.unwrap_or(false)
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{
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Ok(shader)
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} else {
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Err(gl
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.get_shader_info_log(&shader)
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.unwrap_or_else(|| "Unknown error creating shader".into()))
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}
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}
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fn link_program<'a, T: IntoIterator<Item = &'a WebGlShader>>(
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gl: &WebGlRenderingContext,
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shaders: T,
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) -> Result<WebGlProgram, String> {
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let program = gl
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.create_program()
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.ok_or_else(|| String::from("Unable to create shader object"))?;
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for shader in shaders {
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gl.attach_shader(&program, shader)
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}
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gl.link_program(&program);
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if gl
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.get_program_parameter(&program, Gl::LINK_STATUS)
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.as_bool()
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.unwrap_or(false)
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{
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Ok(program)
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} else {
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Err(gl
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.get_program_info_log(&program)
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.unwrap_or_else(|| "Unknown error creating program object".into()))
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}
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}
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