From 68d5a47121eaad42a390fe8d7b85cbff551cf90e Mon Sep 17 00:00:00 2001
From: Vojtech Bubnik <bubnikv@gmail.com>
Date: Mon, 6 Dec 2021 11:45:02 +0100
Subject: [PATCH] Caching of shader program attribute and uniform IDs from
 strings.

---
 src/slic3r/GUI/GLShader.cpp | 30 ++++++++++++++++++++++++++++--
 src/slic3r/GUI/GLShader.hpp |  2 ++
 2 files changed, 30 insertions(+), 2 deletions(-)

diff --git a/src/slic3r/GUI/GLShader.cpp b/src/slic3r/GUI/GLShader.cpp
index 0473e5344..9c1e93652 100644
--- a/src/slic3r/GUI/GLShader.cpp
+++ b/src/slic3r/GUI/GLShader.cpp
@@ -358,12 +358,38 @@ bool GLShaderProgram::set_uniform(const char* name, const Vec3d& value) const
 
 int GLShaderProgram::get_attrib_location(const char* name) const
 {
-    return (m_id > 0) ? ::glGetAttribLocation(m_id, name) : -1;
+    assert(m_id > 0);
+
+    if (m_id <= 0)
+        // Shader program not loaded. This should not happen.
+        return -1;
+
+    auto it = std::find_if(m_attrib_location_cache.begin(), m_attrib_location_cache.end(), [name](const auto& p) { return p.first == name; });
+    if (it != m_attrib_location_cache.end())
+        // Attrib ID cached.
+        return it->second;
+
+    int id = ::glGetAttribLocation(m_id, name);
+    const_cast<GLShaderProgram*>(this)->m_attrib_location_cache.push_back({ name, id });
+    return id;
 }
 
 int GLShaderProgram::get_uniform_location(const char* name) const
 {
-    return (m_id > 0) ? ::glGetUniformLocation(m_id, name) : -1;
+    assert(m_id > 0);
+
+    if (m_id <= 0)
+        // Shader program not loaded. This should not happen.
+        return -1;
+
+    auto it = std::find_if(m_uniform_location_cache.begin(), m_uniform_location_cache.end(), [name](const auto &p) { return p.first == name; });
+    if (it != m_uniform_location_cache.end())
+        // Uniform ID cached.
+        return it->second;
+
+    int id = ::glGetUniformLocation(m_id, name);
+    const_cast<GLShaderProgram*>(this)->m_uniform_location_cache.push_back({ name, id });
+    return id;
 }
 
 } // namespace Slic3r
diff --git a/src/slic3r/GUI/GLShader.hpp b/src/slic3r/GUI/GLShader.hpp
index c92ea274a..d7b92000d 100644
--- a/src/slic3r/GUI/GLShader.hpp
+++ b/src/slic3r/GUI/GLShader.hpp
@@ -29,6 +29,8 @@ public:
 private:
     std::string m_name;
     unsigned int m_id{ 0 };
+    std::vector<std::pair<std::string, int>> m_attrib_location_cache;
+    std::vector<std::pair<std::string, int>> m_uniform_location_cache;
 
 public:
     ~GLShaderProgram();