Added shaders on GLSL 1.2 (#187)

* Added shaders on GLSL 1.2

- Used `glium::program` to create shaders
- Moved shaders code to its own sources and include it as str
- Added shaders implementation on GLSL which allows run egui on old hardware
  (Raspberry Pi 1/zero in game again)

* Moved webgl shaders code to sources in `shader` subdir

* Added GLSL ES shaders to glium backend to support OpenGL ES

* Described changes related to GLSL versions support

egui_glium/CHANGELOG.md

@@ -7,6 +7,9 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 ## Unreleased
 
+* Added GLSL 1.2 shaders (now `egui` works well on old hardware which supports OpenGL 2.1 only like Raspberry Pi 1 and Zero)
+* Added GLSL ES 1.0 and 3.0 shaders (by reusing from webgl backend)
+
 
 ## 0.9.0 - 2021-02-07
 

egui_glium/src/painter.rs

@@ -8,6 +8,7 @@ use {
     glium::{
         implement_vertex,
         index::PrimitiveType,
+        program,
         texture::{self, srgb_texture2d::SrgbTexture2d},
         uniform,
         uniforms::{MagnifySamplerFilter, SamplerWrapFunction},
@@ -15,53 +16,6 @@ use {
     },
 };
 
-const VERTEX_SHADER_SOURCE: &str = r#"
-    #version 140
-    uniform vec2 u_screen_size;
-    in vec2 a_pos;
-    in vec4 a_srgba; // 0-255 sRGB
-    in vec2 a_tc;
-    out vec4 v_rgba;
-    out vec2 v_tc;
-
-    // 0-1 linear  from  0-255 sRGB
-    vec3 linear_from_srgb(vec3 srgb) {
-        bvec3 cutoff = lessThan(srgb, vec3(10.31475));
-        vec3 lower = srgb / vec3(3294.6);
-        vec3 higher = pow((srgb + vec3(14.025)) / vec3(269.025), vec3(2.4));
-        return mix(higher, lower, cutoff);
-    }
-
-    vec4 linear_from_srgba(vec4 srgba) {
-        return vec4(linear_from_srgb(srgba.rgb), srgba.a / 255.0);
-    }
-
-    void main() {
-        gl_Position = vec4(
-            2.0 * a_pos.x / u_screen_size.x - 1.0,
-            1.0 - 2.0 * a_pos.y / u_screen_size.y,
-            0.0,
-            1.0);
-        // egui encodes vertex colors in gamma spaces, so we must decode the colors here:
-        v_rgba = linear_from_srgba(a_srgba);
-        v_tc = a_tc;
-    }
-"#;
-
-const FRAGMENT_SHADER_SOURCE: &str = r#"
-    #version 140
-    uniform sampler2D u_sampler;
-    in vec4 v_rgba;
-    in vec2 v_tc;
-    out vec4 f_color;
-
-    void main() {
-        // The texture sampler is sRGB aware, and glium already expects linear rgba output
-        // so no need for any sRGB conversions here:
-        f_color = v_rgba * texture(u_sampler, v_tc);
-    }
-"#;
-
 pub struct Painter {
     program: glium::Program,
     egui_texture: Option<SrgbTexture2d>,
@@ -83,9 +37,26 @@ struct UserTexture {
 
 impl Painter {
     pub fn new(facade: &dyn glium::backend::Facade) -> Painter {
-        let program =
-            glium::Program::from_source(facade, VERTEX_SHADER_SOURCE, FRAGMENT_SHADER_SOURCE, None)
-                .expect("Failed to compile shader");
+        let program = program! {
+            facade,
+            120 => {
+                vertex: include_str!("shader/vertex_120.glsl"),
+                fragment: include_str!("shader/fragment_120.glsl"),
+            },
+            140 => {
+                vertex: include_str!("shader/vertex_140.glsl"),
+                fragment: include_str!("shader/fragment_140.glsl"),
+            },
+            100 es => {
+                vertex: include_str!("shader/vertex_100es.glsl"),
+                fragment: include_str!("shader/fragment_100es.glsl"),
+            },
+            300 es => {
+                vertex: include_str!("shader/vertex_300es.glsl"),
+                fragment: include_str!("shader/fragment_300es.glsl"),
+            },
+        }
+        .expect("Failed to compile shader");
 
         Painter {
             program,

egui_glium/src/shader/fragment_100es.glsl

@@ -0,0 +1,45 @@
+#version 100 es
+
+precision mediump float;
+uniform sampler2D u_sampler;
+varying vec4 v_rgba;
+varying vec2 v_tc;
+
+// 0-255 sRGB  from  0-1 linear
+vec3 srgb_from_linear(vec3 rgb) {
+  bvec3 cutoff = lessThan(rgb, vec3(0.0031308));
+  vec3 lower = rgb * vec3(3294.6);
+  vec3 higher = vec3(269.025) * pow(rgb, vec3(1.0 / 2.4)) - vec3(14.025);
+  return mix(higher, lower, vec3(cutoff));
+}
+
+vec4 srgba_from_linear(vec4 rgba) {
+  return vec4(srgb_from_linear(rgba.rgb), 255.0 * rgba.a);
+}
+
+// 0-1 linear  from  0-255 sRGB
+vec3 linear_from_srgb(vec3 srgb) {
+  bvec3 cutoff = lessThan(srgb, vec3(10.31475));
+  vec3 lower = srgb / vec3(3294.6);
+  vec3 higher = pow((srgb + vec3(14.025)) / vec3(269.025), vec3(2.4));
+  return mix(higher, lower, vec3(cutoff));
+}
+
+vec4 linear_from_srgba(vec4 srgba) {
+  return vec4(linear_from_srgb(srgba.rgb), srgba.a / 255.0);
+}
+
+void main() {
+  // We must decode the colors, since WebGL doesn't come with sRGBA textures:
+  vec4 texture_rgba = linear_from_srgba(texture2D(u_sampler, v_tc) * 255.0);
+
+  /// Multiply vertex color with texture color (in linear space).
+  gl_FragColor = v_rgba * texture_rgba;
+
+  // We must gamma-encode again since WebGL doesn't support linear blending in the framebuffer.
+  gl_FragColor = srgba_from_linear(v_rgba * texture_rgba) / 255.0;
+
+  // WebGL doesn't support linear blending in the framebuffer,
+  // so we apply this hack to at least get a bit closer to the desired blending:
+  gl_FragColor.a = pow(gl_FragColor.a, 1.6); // Empiric nonsense
+}

egui_glium/src/shader/fragment_120.glsl

@@ -0,0 +1,11 @@
+#version 120
+
+uniform sampler2D u_sampler;
+varying vec4 v_rgba;
+varying vec2 v_tc;
+
+void main() {
+  // The texture sampler is sRGB aware, and glium already expects linear rgba output
+  // so no need for any sRGB conversions here:
+  gl_FragColor = v_rgba * texture2D(u_sampler, v_tc);
+}

egui_glium/src/shader/fragment_140.glsl

@@ -0,0 +1,12 @@
+#version 140
+
+uniform sampler2D u_sampler;
+in vec4 v_rgba;
+in vec2 v_tc;
+out vec4 f_color;
+
+void main() {
+  // The texture sampler is sRGB aware, and glium already expects linear rgba output
+  // so no need for any sRGB conversions here:
+  f_color = v_rgba * texture(u_sampler, v_tc);
+}

egui_glium/src/shader/fragment_300es.glsl

@@ -0,0 +1,33 @@
+#version 300 es
+
+precision mediump float;
+uniform sampler2D u_sampler;
+varying vec4 v_rgba;
+varying vec2 v_tc;
+
+// 0-255 sRGB  from  0-1 linear
+vec3 srgb_from_linear(vec3 rgb) {
+  bvec3 cutoff = lessThan(rgb, vec3(0.0031308));
+  vec3 lower = rgb * vec3(3294.6);
+  vec3 higher = vec3(269.025) * pow(rgb, vec3(1.0 / 2.4)) - vec3(14.025);
+  return mix(higher, lower, vec3(cutoff));
+}
+
+vec4 srgba_from_linear(vec4 rgba) {
+  return vec4(srgb_from_linear(rgba.rgb), 255.0 * rgba.a);
+}
+
+void main() {
+  // The texture is set up with `SRGB8_ALPHA8`, so no need to decode here!
+  vec4 texture_rgba = texture2D(u_sampler, v_tc);
+
+  /// Multiply vertex color with texture color (in linear space).
+  gl_FragColor = v_rgba * texture_rgba;
+
+  // We must gamma-encode again since WebGL doesn't support linear blending in the framebuffer.
+  gl_FragColor = srgba_from_linear(v_rgba * texture_rgba) / 255.0;
+
+  // WebGL doesn't support linear blending in the framebuffer,
+  // so we apply this hack to at least get a bit closer to the desired blending:
+  gl_FragColor.a = pow(gl_FragColor.a, 1.6); // Empiric nonsense
+}

egui_glium/src/shader/vertex_100es.glsl

@@ -0,0 +1,32 @@
+#version 100 es
+
+precision mediump float;
+uniform vec2 u_screen_size;
+attribute vec2 a_pos;
+attribute vec2 a_tc;
+attribute vec4 a_srgba;
+varying vec4 v_rgba;
+varying vec2 v_tc;
+
+// 0-1 linear  from  0-255 sRGB
+vec3 linear_from_srgb(vec3 srgb) {
+  bvec3 cutoff = lessThan(srgb, vec3(10.31475));
+  vec3 lower = srgb / vec3(3294.6);
+  vec3 higher = pow((srgb + vec3(14.025)) / vec3(269.025), vec3(2.4));
+  return mix(higher, lower, vec3(cutoff));
+}
+
+vec4 linear_from_srgba(vec4 srgba) {
+  return vec4(linear_from_srgb(srgba.rgb), srgba.a / 255.0);
+}
+
+void main() {
+  gl_Position = vec4(
+                     2.0 * a_pos.x / u_screen_size.x - 1.0,
+                     1.0 - 2.0 * a_pos.y / u_screen_size.y,
+                     0.0,
+                     1.0);
+  // egui encodes vertex colors in gamma spaces, so we must decode the colors here:
+  v_rgba = linear_from_srgba(a_srgba);
+  v_tc = a_tc;
+}

egui_glium/src/shader/vertex_120.glsl

@@ -0,0 +1,31 @@
+#version 120
+
+uniform vec2 u_screen_size;
+attribute vec2 a_pos;
+attribute vec4 a_srgba; // 0-255 sRGB
+attribute vec2 a_tc;
+varying vec4 v_rgba;
+varying vec2 v_tc;
+
+// 0-1 linear  from  0-255 sRGB
+vec3 linear_from_srgb(vec3 srgb) {
+  bvec3 cutoff = lessThan(srgb, vec3(10.31475));
+  vec3 lower = srgb / vec3(3294.6);
+  vec3 higher = pow((srgb + vec3(14.025)) / vec3(269.025), vec3(2.4));
+  return mix(higher, lower, vec3(cutoff));
+}
+
+vec4 linear_from_srgba(vec4 srgba) {
+  return vec4(linear_from_srgb(srgba.rgb), srgba.a / 255.0);
+}
+
+void main() {
+  gl_Position = vec4(
+                     2.0 * a_pos.x / u_screen_size.x - 1.0,
+                     1.0 - 2.0 * a_pos.y / u_screen_size.y,
+                     0.0,
+                     1.0);
+  // egui encodes vertex colors in gamma spaces, so we must decode the colors here:
+  v_rgba = linear_from_srgba(a_srgba);
+  v_tc = a_tc;
+}

egui_glium/src/shader/vertex_140.glsl

@@ -0,0 +1,31 @@
+#version 140
+
+uniform vec2 u_screen_size;
+in vec2 a_pos;
+in vec4 a_srgba; // 0-255 sRGB
+in vec2 a_tc;
+out vec4 v_rgba;
+out vec2 v_tc;
+
+// 0-1 linear  from  0-255 sRGB
+vec3 linear_from_srgb(vec3 srgb) {
+  bvec3 cutoff = lessThan(srgb, vec3(10.31475));
+  vec3 lower = srgb / vec3(3294.6);
+  vec3 higher = pow((srgb + vec3(14.025)) / vec3(269.025), vec3(2.4));
+  return mix(higher, lower, cutoff);
+}
+
+vec4 linear_from_srgba(vec4 srgba) {
+  return vec4(linear_from_srgb(srgba.rgb), srgba.a / 255.0);
+}
+
+void main() {
+  gl_Position = vec4(
+                     2.0 * a_pos.x / u_screen_size.x - 1.0,
+                     1.0 - 2.0 * a_pos.y / u_screen_size.y,
+                     0.0,
+                     1.0);
+  // egui encodes vertex colors in gamma spaces, so we must decode the colors here:
+  v_rgba = linear_from_srgba(a_srgba);
+  v_tc = a_tc;
+}

egui_glium/src/shader/vertex_300es.glsl

@@ -0,0 +1,32 @@
+#version 300 es
+
+precision mediump float;
+uniform vec2 u_screen_size;
+attribute vec2 a_pos;
+attribute vec2 a_tc;
+attribute vec4 a_srgba;
+varying vec4 v_rgba;
+varying vec2 v_tc;
+
+// 0-1 linear  from  0-255 sRGB
+vec3 linear_from_srgb(vec3 srgb) {
+  bvec3 cutoff = lessThan(srgb, vec3(10.31475));
+  vec3 lower = srgb / vec3(3294.6);
+  vec3 higher = pow((srgb + vec3(14.025)) / vec3(269.025), vec3(2.4));
+  return mix(higher, lower, vec3(cutoff));
+}
+
+vec4 linear_from_srgba(vec4 srgba) {
+  return vec4(linear_from_srgb(srgba.rgb), srgba.a / 255.0);
+}
+
+void main() {
+  gl_Position = vec4(
+                     2.0 * a_pos.x / u_screen_size.x - 1.0,
+                     1.0 - 2.0 * a_pos.y / u_screen_size.y,
+                     0.0,
+                     1.0);
+  // egui encodes vertex colors in gamma spaces, so we must decode the colors here:
+  v_rgba = linear_from_srgba(a_srgba);
+  v_tc = a_tc;
+}

egui_web/src/shader/fragment_100es.glsl

@@ -0,0 +1,45 @@
+#version 100 es
+
+precision mediump float;
+uniform sampler2D u_sampler;
+varying vec4 v_rgba;
+varying vec2 v_tc;
+
+// 0-255 sRGB  from  0-1 linear
+vec3 srgb_from_linear(vec3 rgb) {
+  bvec3 cutoff = lessThan(rgb, vec3(0.0031308));
+  vec3 lower = rgb * vec3(3294.6);
+  vec3 higher = vec3(269.025) * pow(rgb, vec3(1.0 / 2.4)) - vec3(14.025);
+  return mix(higher, lower, vec3(cutoff));
+}
+
+vec4 srgba_from_linear(vec4 rgba) {
+  return vec4(srgb_from_linear(rgba.rgb), 255.0 * rgba.a);
+}
+
+// 0-1 linear  from  0-255 sRGB
+vec3 linear_from_srgb(vec3 srgb) {
+  bvec3 cutoff = lessThan(srgb, vec3(10.31475));
+  vec3 lower = srgb / vec3(3294.6);
+  vec3 higher = pow((srgb + vec3(14.025)) / vec3(269.025), vec3(2.4));
+  return mix(higher, lower, vec3(cutoff));
+}
+
+vec4 linear_from_srgba(vec4 srgba) {
+  return vec4(linear_from_srgb(srgba.rgb), srgba.a / 255.0);
+}
+
+void main() {
+  // We must decode the colors, since WebGL doesn't come with sRGBA textures:
+  vec4 texture_rgba = linear_from_srgba(texture2D(u_sampler, v_tc) * 255.0);
+
+  /// Multiply vertex color with texture color (in linear space).
+  gl_FragColor = v_rgba * texture_rgba;
+
+  // We must gamma-encode again since WebGL doesn't support linear blending in the framebuffer.
+  gl_FragColor = srgba_from_linear(v_rgba * texture_rgba) / 255.0;
+
+  // WebGL doesn't support linear blending in the framebuffer,
+  // so we apply this hack to at least get a bit closer to the desired blending:
+  gl_FragColor.a = pow(gl_FragColor.a, 1.6); // Empiric nonsense
+}

egui_web/src/shader/fragment_300es.glsl

@@ -0,0 +1,33 @@
+#version 300 es
+
+precision mediump float;
+uniform sampler2D u_sampler;
+varying vec4 v_rgba;
+varying vec2 v_tc;
+
+// 0-255 sRGB  from  0-1 linear
+vec3 srgb_from_linear(vec3 rgb) {
+  bvec3 cutoff = lessThan(rgb, vec3(0.0031308));
+  vec3 lower = rgb * vec3(3294.6);
+  vec3 higher = vec3(269.025) * pow(rgb, vec3(1.0 / 2.4)) - vec3(14.025);
+  return mix(higher, lower, vec3(cutoff));
+}
+
+vec4 srgba_from_linear(vec4 rgba) {
+  return vec4(srgb_from_linear(rgba.rgb), 255.0 * rgba.a);
+}
+
+void main() {
+  // The texture is set up with `SRGB8_ALPHA8`, so no need to decode here!
+  vec4 texture_rgba = texture2D(u_sampler, v_tc);
+
+  /// Multiply vertex color with texture color (in linear space).
+  gl_FragColor = v_rgba * texture_rgba;
+
+  // We must gamma-encode again since WebGL doesn't support linear blending in the framebuffer.
+  gl_FragColor = srgba_from_linear(v_rgba * texture_rgba) / 255.0;
+
+  // WebGL doesn't support linear blending in the framebuffer,
+  // so we apply this hack to at least get a bit closer to the desired blending:
+  gl_FragColor.a = pow(gl_FragColor.a, 1.6); // Empiric nonsense
+}

egui_web/src/shader/vertex_100es.glsl

@@ -0,0 +1,32 @@
+#version 100 es
+
+precision mediump float;
+uniform vec2 u_screen_size;
+attribute vec2 a_pos;
+attribute vec2 a_tc;
+attribute vec4 a_srgba;
+varying vec4 v_rgba;
+varying vec2 v_tc;
+
+// 0-1 linear  from  0-255 sRGB
+vec3 linear_from_srgb(vec3 srgb) {
+  bvec3 cutoff = lessThan(srgb, vec3(10.31475));
+  vec3 lower = srgb / vec3(3294.6);
+  vec3 higher = pow((srgb + vec3(14.025)) / vec3(269.025), vec3(2.4));
+  return mix(higher, lower, vec3(cutoff));
+}
+
+vec4 linear_from_srgba(vec4 srgba) {
+  return vec4(linear_from_srgb(srgba.rgb), srgba.a / 255.0);
+}
+
+void main() {
+  gl_Position = vec4(
+                     2.0 * a_pos.x / u_screen_size.x - 1.0,
+                     1.0 - 2.0 * a_pos.y / u_screen_size.y,
+                     0.0,
+                     1.0);
+  // egui encodes vertex colors in gamma spaces, so we must decode the colors here:
+  v_rgba = linear_from_srgba(a_srgba);
+  v_tc = a_tc;
+}

egui_web/src/shader/vertex_300es.glsl

@@ -0,0 +1,32 @@
+#version 300 es
+
+precision mediump float;
+uniform vec2 u_screen_size;
+attribute vec2 a_pos;
+attribute vec2 a_tc;
+attribute vec4 a_srgba;
+varying vec4 v_rgba;
+varying vec2 v_tc;
+
+// 0-1 linear  from  0-255 sRGB
+vec3 linear_from_srgb(vec3 srgb) {
+  bvec3 cutoff = lessThan(srgb, vec3(10.31475));
+  vec3 lower = srgb / vec3(3294.6);
+  vec3 higher = pow((srgb + vec3(14.025)) / vec3(269.025), vec3(2.4));
+  return mix(higher, lower, vec3(cutoff));
+}
+
+vec4 linear_from_srgba(vec4 srgba) {
+  return vec4(linear_from_srgb(srgba.rgb), srgba.a / 255.0);
+}
+
+void main() {
+  gl_Position = vec4(
+                     2.0 * a_pos.x / u_screen_size.x - 1.0,
+                     1.0 - 2.0 * a_pos.y / u_screen_size.y,
+                     0.0,
+                     1.0);
+  // egui encodes vertex colors in gamma spaces, so we must decode the colors here:
+  v_rgba = linear_from_srgba(a_srgba);
+  v_tc = a_tc;
+}

egui_web/src/webgl1.rs

@@ -11,85 +11,6 @@ use egui::{
 
 type Gl = WebGlRenderingContext;
 
-const VERTEX_SHADER_SOURCE: &str = r#"
-    precision mediump float;
-    uniform vec2 u_screen_size;
-    attribute vec2 a_pos;
-    attribute vec2 a_tc;
-    attribute vec4 a_srgba;
-    varying vec4 v_rgba;
-    varying vec2 v_tc;
-
-    // 0-1 linear  from  0-255 sRGB
-    vec3 linear_from_srgb(vec3 srgb) {
-        bvec3 cutoff = lessThan(srgb, vec3(10.31475));
-        vec3 lower = srgb / vec3(3294.6);
-        vec3 higher = pow((srgb + vec3(14.025)) / vec3(269.025), vec3(2.4));
-        return mix(higher, lower, vec3(cutoff));
-    }
-
-    vec4 linear_from_srgba(vec4 srgba) {
-        return vec4(linear_from_srgb(srgba.rgb), srgba.a / 255.0);
-    }
-
-    void main() {
-        gl_Position = vec4(
-            2.0 * a_pos.x / u_screen_size.x - 1.0,
-            1.0 - 2.0 * a_pos.y / u_screen_size.y,
-            0.0,
-            1.0);
-        // egui encodes vertex colors in gamma spaces, so we must decode the colors here:
-        v_rgba = linear_from_srgba(a_srgba);
-        v_tc = a_tc;
-    }
-"#;
-
-const FRAGMENT_SHADER_SOURCE: &str = r#"
-    precision mediump float;
-    uniform sampler2D u_sampler;
-    varying vec4 v_rgba;
-    varying vec2 v_tc;
-
-    // 0-255 sRGB  from  0-1 linear
-    vec3 srgb_from_linear(vec3 rgb) {
-        bvec3 cutoff = lessThan(rgb, vec3(0.0031308));
-        vec3 lower = rgb * vec3(3294.6);
-        vec3 higher = vec3(269.025) * pow(rgb, vec3(1.0 / 2.4)) - vec3(14.025);
-        return mix(higher, lower, vec3(cutoff));
-    }
-
-    vec4 srgba_from_linear(vec4 rgba) {
-        return vec4(srgb_from_linear(rgba.rgb), 255.0 * rgba.a);
-    }
-
-    // 0-1 linear  from  0-255 sRGB
-    vec3 linear_from_srgb(vec3 srgb) {
-        bvec3 cutoff = lessThan(srgb, vec3(10.31475));
-        vec3 lower = srgb / vec3(3294.6);
-        vec3 higher = pow((srgb + vec3(14.025)) / vec3(269.025), vec3(2.4));
-        return mix(higher, lower, vec3(cutoff));
-    }
-
-    vec4 linear_from_srgba(vec4 srgba) {
-        return vec4(linear_from_srgb(srgba.rgb), srgba.a / 255.0);
-    }
-
-    void main() {
-        // We must decode the colors, since WebGL doesn't come with sRGBA textures:
-        vec4 texture_rgba = linear_from_srgba(texture2D(u_sampler, v_tc) * 255.0);
-
-        /// Multiply vertex color with texture color (in linear space).
-        gl_FragColor = v_rgba * texture_rgba;
-
-        // We must gamma-encode again since WebGL doesn't support linear blending in the framebuffer.
-        gl_FragColor = srgba_from_linear(v_rgba * texture_rgba) / 255.0;
-
-        // WebGL doesn't support linear blending in the framebuffer,
-        // so we apply this hack to at least get a bit closer to the desired blending:
-        gl_FragColor.a = pow(gl_FragColor.a, 1.6); // Empiric nonsense
-    }
-"#;
-
 pub struct WebGlPainter {
     canvas_id: String,
     canvas: web_sys::HtmlCanvasElement,
@@ -136,8 +57,16 @@ impl WebGlPainter {
         gl.tex_parameteri(Gl::TEXTURE_2D, Gl::TEXTURE_MIN_FILTER, Gl::LINEAR as i32);
         gl.tex_parameteri(Gl::TEXTURE_2D, Gl::TEXTURE_MAG_FILTER, Gl::LINEAR as i32);
 
-        let vert_shader = compile_shader(&gl, Gl::VERTEX_SHADER, VERTEX_SHADER_SOURCE)?;
-        let frag_shader = compile_shader(&gl, Gl::FRAGMENT_SHADER, FRAGMENT_SHADER_SOURCE)?;
+        let vert_shader = compile_shader(
+            &gl,
+            Gl::VERTEX_SHADER,
+            include_str!("shader/vertex_100es.glsl"),
+        )?;
+        let frag_shader = compile_shader(
+            &gl,
+            Gl::FRAGMENT_SHADER,
+            include_str!("shader/fragment_100es.glsl"),
+        )?;
 
         let program = link_program(&gl, [vert_shader, frag_shader].iter())?;
         let index_buffer = gl.create_buffer().ok_or("failed to create index_buffer")?;

egui_web/src/webgl2.rs

@@ -13,73 +13,6 @@ use egui::{
 
 type Gl = WebGl2RenderingContext;
 
-const VERTEX_SHADER_SOURCE: &str = r#"
-    precision mediump float;
-    uniform vec2 u_screen_size;
-    attribute vec2 a_pos;
-    attribute vec2 a_tc;
-    attribute vec4 a_srgba;
-    varying vec4 v_rgba;
-    varying vec2 v_tc;
-
-    // 0-1 linear  from  0-255 sRGB
-    vec3 linear_from_srgb(vec3 srgb) {
-        bvec3 cutoff = lessThan(srgb, vec3(10.31475));
-        vec3 lower = srgb / vec3(3294.6);
-        vec3 higher = pow((srgb + vec3(14.025)) / vec3(269.025), vec3(2.4));
-        return mix(higher, lower, vec3(cutoff));
-    }
-
-    vec4 linear_from_srgba(vec4 srgba) {
-        return vec4(linear_from_srgb(srgba.rgb), srgba.a / 255.0);
-    }
-
-    void main() {
-        gl_Position = vec4(
-            2.0 * a_pos.x / u_screen_size.x - 1.0,
-            1.0 - 2.0 * a_pos.y / u_screen_size.y,
-            0.0,
-            1.0);
-        // egui encodes vertex colors in gamma spaces, so we must decode the colors here:
-        v_rgba = linear_from_srgba(a_srgba);
-        v_tc = a_tc;
-    }
-"#;
-
-const FRAGMENT_SHADER_SOURCE: &str = r#"
-    precision mediump float;
-    uniform sampler2D u_sampler;
-    varying vec4 v_rgba;
-    varying vec2 v_tc;
-
-    // 0-255 sRGB  from  0-1 linear
-    vec3 srgb_from_linear(vec3 rgb) {
-        bvec3 cutoff = lessThan(rgb, vec3(0.0031308));
-        vec3 lower = rgb * vec3(3294.6);
-        vec3 higher = vec3(269.025) * pow(rgb, vec3(1.0 / 2.4)) - vec3(14.025);
-        return mix(higher, lower, vec3(cutoff));
-    }
-
-    vec4 srgba_from_linear(vec4 rgba) {
-        return vec4(srgb_from_linear(rgba.rgb), 255.0 * rgba.a);
-    }
-
-    void main() {
-        // The texture is set up with `SRGB8_ALPHA8`, so no need to decode here!
-        vec4 texture_rgba = texture2D(u_sampler, v_tc);
-
-        /// Multiply vertex color with texture color (in linear space).
-        gl_FragColor = v_rgba * texture_rgba;
-
-        // We must gamma-encode again since WebGL doesn't support linear blending in the framebuffer.
-        gl_FragColor = srgba_from_linear(v_rgba * texture_rgba) / 255.0;
-
-        // WebGL doesn't support linear blending in the framebuffer,
-        // so we apply this hack to at least get a bit closer to the desired blending:
-        gl_FragColor.a = pow(gl_FragColor.a, 1.6); // Empiric nonsense
-    }
-"#;
-
 pub struct WebGl2Painter {
     canvas_id: String,
     canvas: web_sys::HtmlCanvasElement,
@@ -126,8 +59,16 @@ impl WebGl2Painter {
         gl.tex_parameteri(Gl::TEXTURE_2D, Gl::TEXTURE_MIN_FILTER, Gl::LINEAR as i32);
         gl.tex_parameteri(Gl::TEXTURE_2D, Gl::TEXTURE_MAG_FILTER, Gl::LINEAR as i32);
 
-        let vert_shader = compile_shader(&gl, Gl::VERTEX_SHADER, VERTEX_SHADER_SOURCE)?;
-        let frag_shader = compile_shader(&gl, Gl::FRAGMENT_SHADER, FRAGMENT_SHADER_SOURCE)?;
+        let vert_shader = compile_shader(
+            &gl,
+            Gl::VERTEX_SHADER,
+            include_str!("shader/vertex_300es.glsl"),
+        )?;
+        let frag_shader = compile_shader(
+            &gl,
+            Gl::FRAGMENT_SHADER,
+            include_str!("shader/fragment_300es.glsl"),
+        )?;
 
         let program = link_program(&gl, [vert_shader, frag_shader].iter())?;
         let index_buffer = gl.create_buffer().ok_or("failed to create index_buffer")?;