From 788626357a94cb44680052f22e88fe972eef5e03 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?H=C3=A9ctor=20Ram=C3=B3n=20Jim=C3=A9nez?=
 <hector0193@gmail.com>
Date: Fri, 22 May 2020 01:57:42 +0200
Subject: [PATCH] Target GLSL 3.30

---
 examples/clipping.rs     |  2 +-
 examples/hello.rs        |  2 +-
 src/pipeline.rs          | 34 ++++++++++++++++++++++++++++++++--
 src/shader/fragment.frag |  4 ++--
 src/shader/vertex.vert   |  4 ++--
 5 files changed, 38 insertions(+), 8 deletions(-)

diff --git a/examples/clipping.rs b/examples/clipping.rs
index 1afee93..f3e51e6 100644
--- a/examples/clipping.rs
+++ b/examples/clipping.rs
@@ -11,7 +11,7 @@ fn main() -> Result<(), String> {
         glutin::window::WindowBuilder::new().with_resizable(false);
 
     let context = glutin::ContextBuilder::new()
-        .with_srgb(true)
+        .with_vsync(true)
         .build_windowed(window_builder, &event_loop)
         .expect("Open window");
 
diff --git a/examples/hello.rs b/examples/hello.rs
index 45d2446..68f8840 100644
--- a/examples/hello.rs
+++ b/examples/hello.rs
@@ -11,7 +11,7 @@ fn main() -> Result<(), String> {
         glutin::window::WindowBuilder::new().with_resizable(false);
 
     let context = glutin::ContextBuilder::new()
-        .with_srgb(true)
+        .with_vsync(true)
         .build_windowed(window_builder, &event_loop)
         .expect("Open window");
 
diff --git a/src/pipeline.rs b/src/pipeline.rs
index 2130bf5..397d05e 100644
--- a/src/pipeline.rs
+++ b/src/pipeline.rs
@@ -10,6 +10,8 @@ pub struct Pipeline {
     program: <glow::Context as HasContext>::Program,
     vertex_array: <glow::Context as HasContext>::VertexArray,
     instances: <glow::Context as HasContext>::Buffer,
+    transform: <glow::Context as HasContext>::UniformLocation,
+    sampler: <glow::Context as HasContext>::UniformLocation,
     cache: Cache,
     current_instances: usize,
     supported_instances: usize,
@@ -40,11 +42,35 @@ impl Pipeline {
         let (vertex_array, instances) =
             unsafe { create_instance_buffer(gl, Instance::INITIAL_AMOUNT) };
 
+        let transform = unsafe {
+            gl.get_uniform_location(program, "transform")
+                .expect("Get transform location")
+        };
+
+        let sampler = unsafe {
+            gl.get_uniform_location(program, "font_sampler")
+                .expect("Get sampler location")
+        };
+
+        unsafe {
+            gl.use_program(Some(program));
+
+            gl.uniform_matrix_4_f32_slice(
+                Some(&transform),
+                false,
+                &IDENTITY_MATRIX,
+            );
+
+            gl.use_program(None);
+        }
+
         Pipeline {
             program,
             cache,
             vertex_array,
             instances,
+            transform,
+            sampler,
             current_instances: 0,
             supported_instances: Instance::INITIAL_AMOUNT,
             current_transform: IDENTITY_MATRIX,
@@ -63,7 +89,11 @@ impl Pipeline {
 
         if self.current_transform != transform {
             unsafe {
-                gl.uniform_matrix_4_f32_slice(Some(&0), false, &transform);
+                gl.uniform_matrix_4_f32_slice(
+                    Some(&self.transform),
+                    false,
+                    &transform,
+                );
             }
 
             self.current_transform = transform;
@@ -82,7 +112,7 @@ impl Pipeline {
 
             gl.active_texture(glow::TEXTURE0);
             gl.bind_texture(glow::TEXTURE_2D, Some(self.cache.texture));
-            gl.uniform_1_i32(Some(&1), 0);
+            gl.uniform_1_i32(Some(&self.sampler), 0);
 
             gl.bind_vertex_array(Some(self.vertex_array));
 
diff --git a/src/shader/fragment.frag b/src/shader/fragment.frag
index 4a335b1..5464b3f 100644
--- a/src/shader/fragment.frag
+++ b/src/shader/fragment.frag
@@ -1,6 +1,6 @@
-#version 450
+#version 330
 
-layout(location = 1) uniform sampler2D font_sampler;
+uniform sampler2D font_sampler;
 
 in vec2 f_tex_pos;
 in vec4 f_color;
diff --git a/src/shader/vertex.vert b/src/shader/vertex.vert
index ddfb139..023ce31 100644
--- a/src/shader/vertex.vert
+++ b/src/shader/vertex.vert
@@ -1,6 +1,6 @@
-#version 450
+#version 330
 
-layout(location = 0) uniform mat4 transform;
+uniform mat4 transform;
 
 layout(location = 0) in vec3 left_top;
 layout(location = 1) in vec2 right_bottom;