From 9e5ecc3acea611ffe0a009dc7f965bb7b7235422 Mon Sep 17 00:00:00 2001
From: frank <420@shampoo.ooo>
Date: Tue, 26 Oct 2021 12:48:02 -0400
Subject: [PATCH] bind and enable/disable attributes

---
 src/Attributes.cpp | 30 ++++++++++++++++++++++++++++++
 src/Attributes.hpp |  7 +++++--
 2 files changed, 35 insertions(+), 2 deletions(-)

diff --git a/src/Attributes.cpp b/src/Attributes.cpp
index 7901184..ac73b54 100644
--- a/src/Attributes.cpp
+++ b/src/Attributes.cpp
@@ -49,6 +49,18 @@ std::size_t sb::Attributes::count() const
     }, vertices);
 }
 
+/* Enable the attributes in the VAO. */
+void sb::Attributes::enable() const
+{
+    glEnableVertexAttribArray(*this);
+}
+
+/* Disable the attributes in the VAO. */
+void sb::Attributes::disable() const
+{
+    glDisableVertexAttribArray(*this);
+}
+
 /* Returns the size in bytes of the object's underlying vector of vertices. This can be passed to OpenGL
  * along with the memory pointer when copying vertices to the GPU. */
 std::size_t sb::Attributes::size() const
@@ -66,6 +78,22 @@ std::size_t sb::Attributes::size() const
     }, vertices);
 }
 
+/* Set the index to the location of attributes with given name in a shader program. The program
+ * must already be linked to get the location. */
+void sb::Attributes::bind(GLuint program, const std::string& name)
+{
+    index(glGetAttribLocation(program, name.c_str()));
+}
+
+/* Set the index and bind it to the given name in a shader program. This should be called before
+ * the shader program is linked, otherwise the name will already have been assigned a location
+ * index by GL. */
+void sb::Attributes::bind(std::uint32_t index, GLuint program, const std::string& name)
+{
+    glBindAttribLocation(program, index, name.c_str());
+    this->index(index);
+}
+
 /* Return the GLenum that corresponds to the type of scalar being held in the vertices. This
  * will return either GL_FLOAT, GL_INT, GL_UNSIGNED_INT, GL_UNSIGNED_BYTE, GL_BOOL, or
  * GL_INVALID_ENUM. A return value of GL_INVALID_ENUM indicates an error meaning there are no
@@ -224,11 +252,13 @@ void sb::Attributes::extend(const Attributes& other, std::size_t count)
  * prevent it being looked up with arguments other than attributes. */
 std::ostream& sb::operator<<(std::ostream& out, const Attributes& attributes)
 {
+    out << "<Attributes (#" << attributes.index() << ", " << attributes.size() << " bytes, ";
     std::visit([&] (const auto& vector) {
         if constexpr (!std::is_same_v<std::decay_t<decltype(vector)>, std::monostate>)
         {
             out << vector;
         }
     }, attributes.vertices);
+    out << ">";
     return out;
 }
diff --git a/src/Attributes.hpp b/src/Attributes.hpp
index 67c9812..453be76 100644
--- a/src/Attributes.hpp
+++ b/src/Attributes.hpp
@@ -120,8 +120,8 @@ namespace sb
          * Each variant alternative is a vector of vertex type, so only homogenous vectors can be used. Index 0 is the std::monostate
          * alternative, which is used here for default initialization to indicate Attributes are in an empty state where no variant
          * alternative is selected. 1D vertices are specified by vectors of scalars, rather than the 1D glm vertex types. 1D vertices
-         * also include an unsigned byte type. The std::vector<bool> alternative is not included because its specialization doesn't
-         * include a data member function. */
+         * also include an unsigned byte type. The std::vector<bool> alternative is not included because it is a special case of
+         * std::vector that doesn't have a data member function. */
         using Vertices = std::variant<
             std::monostate, std::vector<std::uint8_t>, std::vector<std::uint32_t>, std::vector<std::int32_t>, std::vector<float>,
             std::vector<glm::bvec2>, std::vector<glm::uvec2>, std::vector<glm::ivec2>, std::vector<glm::vec2>,
@@ -213,7 +213,10 @@ namespace sb
         void extend(const Attributes&, std::size_t = 1);
         void index(std::uint32_t);
         GLuint index() const;
+        void bind(GLuint, const std::string&);
+        void bind(std::uint32_t, GLuint, const std::string&);
         void enable() const;
+        void disable() const;
         std::size_t size() const;
         std::size_t count() const;
         GLenum type() const;