Vertex and attribute compression to reduce the size of the vertex format.

This allows Godot to automatically compress meshes to save a lot of bandwidth.

In general, this requires no interaction from the user and should result in
no noticable quality loss.

This scheme is not backwards compatible, so we have provided an upgrade
mechanism, and a mesh versioning mechanism.

Existing meshes can still be used as a result, but users can get a
performance boost by reimporting assets.

gles3_builders.py

@@ -364,6 +364,13 @@ def build_gles3_header(
             + str(defspec)
             + ") { _FU GLfloat vec3[3]={float(p_vec3.x),float(p_vec3.y),float(p_vec3.z)}; glUniform3fv(version_get_uniform(p_uniform,p_version,p_variant,p_specialization),1,vec3); }\n\n"
         )
+        fd.write(
+            "\t_FORCE_INLINE_ void version_set_uniform(Uniforms p_uniform, const Vector4& p_vec4,RID p_version,ShaderVariant p_variant"
+            + defvariant
+            + ",uint64_t p_specialization="
+            + str(defspec)
+            + ") { _FU GLfloat vec4[4]={float(p_vec4.x),float(p_vec4.y),float(p_vec4.z),float(p_vec4.w)}; glUniform4fv(version_get_uniform(p_uniform,p_version,p_variant,p_specialization),1,vec4); }\n\n"
+        )
         fd.write(
             "\t_FORCE_INLINE_ void version_set_uniform(Uniforms p_uniform, float p_a, float p_b,RID p_version,ShaderVariant p_variant"
             + defvariant