Move cube face target mapping to renderer gl

src/renderer_gl/opengl_capabilities.cpp

@@ -1,5 +1,7 @@
 #include "renderer_gl/opengl_capabilities.h"
 
+#include <array>
+
 namespace pp::renderer::gl {
 
 namespace {
@@ -30,6 +32,12 @@ constexpr std::uint32_t gl_framebuffer_incomplete_read_buffer = 0x8CDCU;
 constexpr std::uint32_t gl_framebuffer_unsupported = 0x8CDDU;
 constexpr std::uint32_t gl_framebuffer_undefined = 0x8219U;
 constexpr std::uint32_t gl_framebuffer_incomplete_multisample = 0x8D56U;
+constexpr std::uint32_t gl_texture_cube_map_positive_x = 0x8515U;
+constexpr std::uint32_t gl_texture_cube_map_negative_x = 0x8516U;
+constexpr std::uint32_t gl_texture_cube_map_positive_y = 0x8517U;
+constexpr std::uint32_t gl_texture_cube_map_negative_y = 0x8518U;
+constexpr std::uint32_t gl_texture_cube_map_positive_z = 0x8519U;
+constexpr std::uint32_t gl_texture_cube_map_negative_z = 0x851AU;
 
 [[nodiscard]] bool contains(std::string_view text, std::string_view needle) noexcept
 {
@@ -163,4 +171,28 @@ std::uint32_t primitive_mode_for_stroke_count(std::uint32_t vertex_or_index_coun
     return gl_lines;
 }
 
+std::span<const std::uint32_t> panopainter_cube_face_texture_targets() noexcept
+{
+    static constexpr std::array<std::uint32_t, 6> targets {
+        gl_texture_cube_map_negative_z, // front
+        gl_texture_cube_map_negative_x, // right
+        gl_texture_cube_map_positive_z, // back
+        gl_texture_cube_map_positive_x, // left
+        gl_texture_cube_map_negative_y, // top
+        gl_texture_cube_map_positive_y, // bottom
+    };
+
+    return targets;
+}
+
+std::uint32_t cube_face_texture_target(std::uint32_t face_index) noexcept
+{
+    const auto targets = panopainter_cube_face_texture_targets();
+    if (face_index >= targets.size()) {
+        return 0U;
+    }
+
+    return targets[face_index];
+}
+
 }