Extract OpenGL shader attribute bindings

src/renderer_gl/shader_bindings.cpp

@@ -0,0 +1,43 @@
+#include "renderer_gl/shader_bindings.h"
+
+#include <array>
+#include <cstring>
+
+namespace pp::renderer::gl {
+
+std::span<const OpenGlAttributeBinding> panopainter_shader_attribute_bindings() noexcept
+{
+    static constexpr std::array<OpenGlAttributeBinding, 5> bindings {
+        OpenGlAttributeBinding { .name = "pos", .location = 0 },
+        OpenGlAttributeBinding { .name = "uvs", .location = 1 },
+        OpenGlAttributeBinding { .name = "uvs2", .location = 2 },
+        OpenGlAttributeBinding { .name = "col", .location = 3 },
+        OpenGlAttributeBinding { .name = "nor", .location = 3 },
+    };
+
+    return bindings;
+}
+
+pp::foundation::Status validate_shader_attribute_bindings(
+    std::span<const OpenGlAttributeBinding> bindings) noexcept
+{
+    if (bindings.empty()) {
+        return pp::foundation::Status::invalid_argument("shader attribute binding catalog is empty");
+    }
+
+    for (std::size_t i = 0; i < bindings.size(); ++i) {
+        if (bindings[i].name == nullptr || bindings[i].name[0] == '\0') {
+            return pp::foundation::Status::invalid_argument("shader attribute binding has no name");
+        }
+
+        for (std::size_t j = i + 1; j < bindings.size(); ++j) {
+            if (bindings[j].name != nullptr && std::strcmp(bindings[i].name, bindings[j].name) == 0) {
+                return pp::foundation::Status::invalid_argument("shader attribute binding name is duplicated");
+            }
+        }
+    }
+
+    return pp::foundation::Status::success();
+}
+
+}

src/renderer_gl/shader_bindings.h

@@ -0,0 +1,19 @@
+#pragma once
+
+#include "foundation/result.h"
+
+#include <cstdint>
+#include <span>
+
+namespace pp::renderer::gl {
+
+struct OpenGlAttributeBinding {
+    const char* name = "";
+    std::uint32_t location = 0;
+};
+
+[[nodiscard]] std::span<const OpenGlAttributeBinding> panopainter_shader_attribute_bindings() noexcept;
+[[nodiscard]] pp::foundation::Status validate_shader_attribute_bindings(
+    std::span<const OpenGlAttributeBinding> bindings) noexcept;
+
+}

src/shader.cpp

@@ -3,6 +3,7 @@
 #include "shader.h"
 #include "asset.h"
 #include "app.h"
+#include "renderer_gl/shader_bindings.h"
 
 std::map<kShader, Shader> ShaderManager::m_shaders;
 Shader* ShaderManager::m_current;
@@ -230,20 +231,11 @@ bool Shader::create(const std::string& vertex, const std::string& fragment)
         glDeleteShader(fs);
 
         glLinkProgram(ps);
-        if (glGetAttribLocation(ps, "pos") != -1)
-            glBindAttribLocation(ps, 0, "pos");
-
-        if (glGetAttribLocation(ps, "uvs") != -1)
-            glBindAttribLocation(ps, 1, "uvs");
-
-        if (glGetAttribLocation(ps, "uvs2") != -1)
-            glBindAttribLocation(ps, 2, "uvs2");
-
-        if (glGetAttribLocation(ps, "col") != -1)
-            glBindAttribLocation(ps, 3, "col");
-
-        if (glGetAttribLocation(ps, "nor") != -1)
-            glBindAttribLocation(ps, 3, "nor");
+        for (const auto& binding : pp::renderer::gl::panopainter_shader_attribute_bindings())
+        {
+            if (glGetAttribLocation(ps, binding.name) != -1)
+                glBindAttribLocation(ps, static_cast<GLuint>(binding.location), binding.name);
+        }
 
         glLinkProgram(ps);
         glGetProgramiv(ps, GL_LINK_STATUS, &status);