move the texture binding to a push descriptor

with a descriptor update template, even

yay

this also moves us to a minimum Vulkan version of 1.4, which we understand to be widely deployed. in theory, push descriptors and update templates were available via extensions in earlier versions, but it doesn't seem worth doing the work to switch out whether we use the extensions based on the version, so we don't.

Force-Push: yes
Change-Id: I26db8771abf5626d9614630c66e019ea99babcac

1 files changed, 5 insertions, 2 deletions

diff --git a/shaders/shader.frag b/shaders/shader.frag
index a2561d1..90d6ab0 100644
--- a/shaders/shader.frag
+++ b/shaders/shader.frag
@@ -1,7 +1,10 @@
 #version 460
 
-layout(binding = 1) uniform sampler textureSampler;
-layout(binding = 2) uniform texture2D textureImage;
+//   Set 0 is the default, so we could omit it, but we prefer to be explicit.
+// It specifies which the descriptor set layout the binding index pertains to;
+// see init_pipeline() in render.rs.
+layout(set = 0, binding = 1) uniform sampler textureSampler;
+layout(set = 1, binding = 0) uniform texture2D textureImage;
 
 layout(location = 0) in vec3 fragmentColor;
 layout(location = 1) in vec2 fragmentTextureCoordinate;