2 files changed, 19 insertions, 6 deletions

diff --git a/alacritty/src/renderer/mod.rs b/alacritty/src/renderer/mod.rs
index d8c6fb6d..fc6c357f 100644
--- a/alacritty/src/renderer/mod.rs
+++ b/alacritty/src/renderer/mod.rs
@@ -13,6 +13,7 @@ use alacritty_terminal::index::Point;
 use alacritty_terminal::term::cell::Flags;
 use alacritty_terminal::term::color::Rgb;
 
+use crate::config::debug::RendererPreference;
 use crate::display::content::RenderableCell;
 use crate::display::SizeInfo;
 use crate::gl;
@@ -87,7 +88,10 @@ impl Renderer {
     ///
     /// This will automatically pick between the GLES2 and GLSL3 renderer based on the GPU's
     /// supported OpenGL version.
-    pub fn new(context: &PossiblyCurrentContext) -> Result<Self, Error> {
+    pub fn new(
+        context: &PossiblyCurrentContext,
+        renderer_prefernce: Option<RendererPreference>,
+    ) -> Result<Self, Error> {
         // We need to load OpenGL functions once per instance, but only after we make our context
         // current due to WGL limitations.
         if !GL_FUNS_LOADED.swap(true, Ordering::Relaxed) {
@@ -106,12 +110,20 @@ impl Renderer {
 
         info!("Running on {}", renderer);
 
-        let (text_renderer, rect_renderer) = if version.as_ref() >= "3.3" {
+        // Use the config option to enforce a particular renderer configuration.
+        let (use_glsl3, allow_dsb) = match renderer_prefernce {
+            Some(RendererPreference::Glsl3) => (true, true),
+            Some(RendererPreference::Gles2) => (false, true),
+            Some(RendererPreference::Gles2Pure) => (false, false),
+            None => (version.as_ref() >= "3.3", true),
+        };
+
+        let (text_renderer, rect_renderer) = if use_glsl3 {
             let text_renderer = TextRendererProvider::Glsl3(Glsl3Renderer::new()?);
             let rect_renderer = RectRenderer::new(ShaderVersion::Glsl3)?;
             (text_renderer, rect_renderer)
         } else {
-            let text_renderer = TextRendererProvider::Gles2(Gles2Renderer::new()?);
+            let text_renderer = TextRendererProvider::Gles2(Gles2Renderer::new(allow_dsb)?);
             let rect_renderer = RectRenderer::new(ShaderVersion::Gles2)?;
             (text_renderer, rect_renderer)
         };
diff --git a/alacritty/src/renderer/text/gles2.rs b/alacritty/src/renderer/text/gles2.rs
index 29a80e98..2f537e5c 100644
--- a/alacritty/src/renderer/text/gles2.rs
+++ b/alacritty/src/renderer/text/gles2.rs
@@ -37,11 +37,12 @@ pub struct Gles2Renderer {
 }
 
 impl Gles2Renderer {
-    pub fn new() -> Result<Self, Error> {
+    pub fn new(allow_dsb: bool) -> Result<Self, Error> {
         info!("Using OpenGL ES 2.0 renderer");
 
-        let dual_source_blending = GlExtensions::contains("GL_EXT_blend_func_extended")
-            || GlExtensions::contains("GL_ARB_blend_func_extended");
+        let dual_source_blending = allow_dsb
+            && (GlExtensions::contains("GL_EXT_blend_func_extended")
+                || GlExtensions::contains("GL_ARB_blend_func_extended"));
 
         if dual_source_blending {
             info!("Using dual source blending");