From 0025f13adc3bf6cd164737b10fe990111baea864 Mon Sep 17 00:00:00 2001
From: Victor Brekenfeld <github@drakulix.de>
Date: Sun, 16 May 2021 23:05:44 +0200
Subject: [PATCH] gles2: Make proper use of formats to avoid unnecessary
 shaders

---
 src/backend/renderer/gles2/mod.rs     | 14 ++++-----
 src/backend/renderer/gles2/shaders.rs | 44 ++-------------------------
 2 files changed, 9 insertions(+), 49 deletions(-)

diff --git a/src/backend/renderer/gles2/mod.rs b/src/backend/renderer/gles2/mod.rs
index 2cb6486..5e1750e 100644
--- a/src/backend/renderer/gles2/mod.rs
+++ b/src/backend/renderer/gles2/mod.rs
@@ -373,8 +373,6 @@ impl Gles2Renderer {
         let programs = [
             texture_program(&gl, shaders::FRAGMENT_SHADER_ABGR)?,
             texture_program(&gl, shaders::FRAGMENT_SHADER_XBGR)?,
-            texture_program(&gl, shaders::FRAGMENT_SHADER_BGRA)?,
-            texture_program(&gl, shaders::FRAGMENT_SHADER_BGRX)?,
             texture_program(&gl, shaders::FRAGMENT_SHADER_EXTERNAL)?,
         ];
 
@@ -459,8 +457,8 @@ impl Gles2Renderer {
             let (gl_format, shader_idx) = match data.format {
                 wl_shm::Format::Abgr8888 => (ffi::RGBA, 0),
                 wl_shm::Format::Xbgr8888 => (ffi::RGBA, 1),
-                wl_shm::Format::Argb8888 => (ffi::BGRA_EXT, 2),
-                wl_shm::Format::Xrgb8888 => (ffi::BGRA_EXT, 3),
+                wl_shm::Format::Argb8888 => (ffi::BGRA_EXT, 0),
+                wl_shm::Format::Xrgb8888 => (ffi::BGRA_EXT, 1),
                 format => return Err(Gles2Error::UnsupportedPixelFormat(format)),
             };
 
@@ -493,7 +491,7 @@ impl Gles2Renderer {
                     width,
                     height,
                     0,
-                    ffi::RGBA,
+                    gl_format,
                     ffi::UNSIGNED_BYTE as u32,
                     slice.as_ptr() as *const _,
                 );
@@ -551,9 +549,9 @@ impl Gles2Renderer {
             Gles2Texture(Rc::new(Gles2TextureInternal {
                 texture: tex,
                 texture_kind: match new_buffer.format {
-                    EGLFormat::RGB => 3,
-                    EGLFormat::RGBA => 2,
-                    EGLFormat::External => 4,
+                    EGLFormat::RGB => 1,
+                    EGLFormat::RGBA => 0,
+                    EGLFormat::External => 2,
                     _ => unreachable!("EGLBuffer currenly does not expose multi-planar buffers to us"),
                 },
                 is_external: new_buffer.format == EGLFormat::External,
diff --git a/src/backend/renderer/gles2/shaders.rs b/src/backend/renderer/gles2/shaders.rs
index c23f56c..f17ef6c 100644
--- a/src/backend/renderer/gles2/shaders.rs
+++ b/src/backend/renderer/gles2/shaders.rs
@@ -17,7 +17,7 @@ void main() {
     }
 }"#;
 
-pub const FRAGMENT_COUNT: usize = 5;
+pub const FRAGMENT_COUNT: usize = 3;
 
 pub const FRAGMENT_SHADER_ABGR: &str = r#"
 #version 100
@@ -26,11 +26,7 @@ uniform sampler2D tex;
 uniform float alpha;
 varying vec2 v_tex_coords;
 void main() {
-    vec4 color = texture2D(tex, v_tex_coords);
-    gl_FragColor.r = color.w;
-    gl_FragColor.g = color.z;
-    gl_FragColor.b = color.y;
-    gl_FragColor.a = color.x * alpha;
+    gl_FragColor = texture2D(tex, v_tex_coords) * alpha;
 }
 "#;
 
@@ -41,41 +37,7 @@ uniform sampler2D tex;
 uniform float alpha;
 varying vec2 v_tex_coords;
 void main() {
-    vec4 color = texture2D(tex, v_tex_coords);
-    gl_FragColor.r = color.w;
-    gl_FragColor.g = color.z;
-    gl_FragColor.b = color.y;
-    gl_FragColor.a = alpha;
-}
-"#;
-
-pub const FRAGMENT_SHADER_BGRA: &str = r#"
-#version 100
-precision mediump float;
-uniform sampler2D tex;
-uniform float alpha;
-varying vec2 v_tex_coords;
-void main() {
-    vec4 color = texture2D(tex, v_tex_coords);
-    gl_FragColor.r = color.z;
-    gl_FragColor.g = color.y;
-    gl_FragColor.b = color.x;
-    gl_FragColor.a = color.w * alpha;
-}
-"#;
-
-pub const FRAGMENT_SHADER_BGRX: &str = r#"
-#version 100
-precision mediump float;
-uniform sampler2D tex;
-uniform float alpha;
-varying vec2 v_tex_coords;
-void main() {
-    vec4 color = texture2D(tex, v_tex_coords);
-    gl_FragColor.r = color.z;
-    gl_FragColor.g = color.y;
-    gl_FragColor.b = color.x;
-    gl_FragColor.a = alpha;
+    gl_FragColor = vec4(texture2D(tex, v_tex_coords).rgb, 1.0) * alpha;
 }
 "#;