glsl-out: fix emission of location/binding attributes (#1100)

src/back/glsl/mod.rs

@@ -101,9 +101,14 @@ impl Version {
         }
     }
 
-    /// Checks if the version supports explicit `layout(location=)` qualifiers.
+    /// Checks if the version supports all of the explicit layouts:
+    /// - `location=` qualifiers for bindings
+    /// - `binding=` qualifiers for resources
+    ///
+    /// Note: `location=` for vertex inputs and fragment outputs is supported
+    /// unconditionally for GLES 300.
     fn supports_explicit_locations(&self) -> bool {
-        *self >= Version::Embedded(300) || *self >= Version::Desktop(410)
+        *self >= Version::Embedded(310) || *self >= Version::Desktop(410)
     }
 }
 
@@ -865,19 +870,21 @@ impl<'a, W: Write> Writer<'a, W> {
                     ShaderStage::Fragment => !output,
                     _ => false,
                 };
+
+                // Write the I/O locations, if allowed
+                if self.options.version.supports_explicit_locations()
+                    || !emit_interpolation_and_auxiliary
+                {
+                    write!(self.out, "layout(location = {}) ", location)?;
+                }
+
+                // Write the interpolation qualifier.
                 if let Some(interp) = interpolation {
                     if emit_interpolation_and_auxiliary {
                         write!(self.out, "{} ", glsl_interpolation(interp))?;
                     }
                 }
 
-                // Write the storage class
-                if !emit_interpolation_and_auxiliary
-                    && self.options.version.supports_explicit_locations()
-                {
-                    write!(self.out, "layout(location = {}) ", location)?;
-                }
-
                 // Write the sampling auxiliary qualifier.
                 //
                 // Before GLSL 4.2, the `centroid` and `sample` qualifiers were required to appear

tests/in/quad.param.ron

@@ -2,4 +2,9 @@
 	spv_version: (1, 0),
 	spv_debug: true,
 	spv_adjust_coordinate_space: true,
+	glsl: (
+		version: Embedded(300),
+		writer_flags: (bits: 0),
+		binding_map: {},
+	),
 )

tests/out/glsl/quad-vert.main.Vertex.glsl

@@ -25,7 +25,7 @@ vec2 a_pos1 = vec2(0, 0);
 
 layout(location = 1) in vec2 _p2vs_location1;
 layout(location = 0) in vec2 _p2vs_location0;
-smooth out vec2 _vs2fs_location0;
+layout(location = 0) smooth out vec2 _vs2fs_location0;
 
 void main2() {
     vec2 _expr12 = a_uv1;

tests/out/glsl/quad.fs_extra.Fragment.glsl

@@ -1,4 +1,4 @@
-#version 310 es
+#version 300 es
 
 precision highp float;
 

tests/out/glsl/quad.main.Fragment.glsl

@@ -1,4 +1,4 @@
-#version 310 es
+#version 300 es
 
 precision highp float;
 

tests/out/glsl/quad.main.Vertex.glsl

@@ -1,4 +1,4 @@
-#version 310 es
+#version 300 es
 
 precision highp float;
 
@@ -17,7 +17,6 @@ void main() {
     VertexOutput _tmp_return = VertexOutput(uv, vec4((1.2 * pos), 0.0, 1.0));
     _vs2fs_location0 = _tmp_return.uv;
     gl_Position = _tmp_return.position;
-    gl_Position.yz = vec2(-gl_Position.y, gl_Position.z * 2.0 - gl_Position.w);
     return;
 }
 

tests/out/glsl/shadow.fs_main.Fragment.glsl

@@ -18,8 +18,8 @@ readonly buffer Lights_block_1 {
 
 uniform highp sampler2DArrayShadow _group_0_binding_2;
 
-smooth in vec3 _vs2fs_location0;
-smooth in vec4 _vs2fs_location1;
+layout(location = 0) smooth in vec3 _vs2fs_location0;
+layout(location = 1) smooth in vec4 _vs2fs_location1;
 layout(location = 0) out vec4 _fs2p_location0;
 
 float fetch_shadow(uint light_id, vec4 homogeneous_coords) {

tests/out/glsl/skybox.fs_main.Fragment.glsl

@@ -9,7 +9,7 @@ struct VertexOutput {
 
 layout(binding = 0) uniform highp samplerCube _group_0_binding_1;
 
-smooth in vec3 _vs2fs_location0;
+layout(location = 0) smooth in vec3 _vs2fs_location0;
 layout(location = 0) out vec4 _fs2p_location0;
 
 void main() {

tests/out/glsl/skybox.vs_main.Vertex.glsl

@@ -12,7 +12,7 @@ layout(binding = 0) uniform Data_block_0 {
     mat4x4 view;
 } _group_0_binding_0;
 
-smooth out vec3 _vs2fs_location0;
+layout(location = 0) smooth out vec3 _vs2fs_location0;
 
 void main() {
     uint vertex_index = uint(gl_VertexID);