Emit std430 layout qualifiers for storage buffers (#1435)

* Remove unused petgraph dependency from glsl-out

* Emit std430 layout qualifiers for storage buffers

Cargo.toml

@@ -35,7 +35,7 @@ default = []
 dot-out = []
 glsl-in = ["pp-rs"]
 glsl-validate = []
-glsl-out = ["petgraph"]
+glsl-out = []
 msl-out = []
 serialize = ["serde", "indexmap/serde-1"]
 deserialize = ["serde", "indexmap/serde-1"]

src/back/glsl/mod.rs

@@ -129,6 +129,10 @@ impl Version {
     fn supports_early_depth_test(&self) -> bool {
         *self >= Version::Desktop(130) || *self >= Version::Embedded(310)
     }
+
+    fn supports_std430_layout(&self) -> bool {
+        *self >= Version::Desktop(430) || *self >= Version::Embedded(310)
+    }
 }
 
 impl PartialOrd for Version {
@@ -816,8 +820,28 @@ impl<'a, W: Write> Writer<'a, W> {
         if self.options.version.supports_explicit_locations() {
             if let Some(ref br) = global.binding {
                 match self.options.binding_map.get(br) {
-                    Some(binding) => write!(self.out, "layout(binding = {}) ", binding)?,
-                    None => log::debug!("unassigned binding for {:?}", global.name),
+                    Some(binding) => {
+                        let layout = match global.class {
+                            crate::StorageClass::Storage { .. } => {
+                                if self.options.version.supports_std430_layout() {
+                                    "std430, "
+                                } else {
+                                    "std140, "
+                                }
+                            }
+                            crate::StorageClass::Uniform => "std140, ",
+                            _ => "",
+                        };
+                        write!(self.out, "layout({}binding = {}) ", layout, binding)?
+                    }
+                    None => {
+                        log::debug!("unassigned binding for {:?}", global.name);
+                        if let crate::StorageClass::Storage { .. } = global.class {
+                            if self.options.version.supports_std430_layout() {
+                                write!(self.out, "layout(std430) ")?
+                            }
+                        }
+                    }
                 }
             }
         }

tests/out/glsl/access.atomics.Compute.glsl

@@ -5,7 +5,7 @@ precision highp int;
 
 layout(local_size_x = 1, local_size_y = 1, local_size_z = 1) in;
 
-buffer Bar_block_0Cs {
+layout(std430) buffer Bar_block_0Cs {
     mat4x4 matrix;
     int atom;
     uvec2 arr[2];

tests/out/glsl/access.foo.Vertex.glsl

@@ -3,7 +3,7 @@
 precision highp float;
 precision highp int;
 
-buffer Bar_block_0Vs {
+layout(std430) buffer Bar_block_0Vs {
     mat4x4 matrix;
     int atom;
     uvec2 arr[2];

tests/out/glsl/boids.main.Compute.glsl

@@ -20,11 +20,11 @@ uniform SimParams_block_0Cs {
     float rule3Scale;
 } _group_0_binding_0;
 
-readonly buffer Particles_block_1Cs {
+layout(std430) readonly buffer Particles_block_1Cs {
     Particle particles[];
 } _group_0_binding_1;
 
-buffer Particles_block_2Cs {
+layout(std430) buffer Particles_block_2Cs {
     Particle particles[];
 } _group_0_binding_2;
 

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

@@ -13,7 +13,7 @@ uniform Globals_block_0Fs {
     uvec4 num_lights;
 } _group_0_binding_0;
 
-readonly buffer Lights_block_1Fs {
+layout(std430) readonly buffer Lights_block_1Fs {
     Light data[];
 } _group_0_binding_1;
 

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

@@ -8,7 +8,7 @@ struct VertexOutput {
     vec3 uv;
 };
 
-layout(binding = 0) uniform Data_block_0Vs {
+layout(std140, binding = 0) uniform Data_block_0Vs {
     mat4x4 proj_inv;
     mat4x4 view;
 } _group_0_binding_0;