Move cube face target mapping to renderer gl

docs/modernization/build-inventory.md

@@ -132,10 +132,11 @@ Known local toolchain state:
   invalid channel counts rejected by `Texture2D::create(Image)`, and
   framebuffer status naming used by `RTT` diagnostics. It also validates
   Shape index-type and fill/stroke primitive-mode mapping used by the legacy
-  mesh draw path, plus the PanoPainter shader attribute binding catalog used
-  by legacy `Shader` creation. It also owns the PanoPainter shader uniform
-  catalog and legacy hash mapping used by `Shader` active-uniform discovery and
-  the uniform uniqueness check.
+  mesh draw path, plus the PanoPainter cube-face to OpenGL texture-target
+  mapping used by `TextureCube`. The PanoPainter shader attribute binding
+  catalog used by legacy `Shader` creation also lives here. It also owns the
+  PanoPainter shader uniform catalog and legacy hash mapping used by `Shader`
+  active-uniform discovery and the uniform uniqueness check.
 - `windows-msvc-vcpkg-headless` validates manifest install/configure/build/test
   for the current headless component matrix; see DEBT-0007 for remaining app
   and platform triplet migration.

docs/modernization/roadmap.md

@@ -391,9 +391,10 @@ float texture support. It also owns the OpenGL texture upload-type mapping used
 by legacy `Texture2D` and `RTT` creation, plus image channel-count to texture
 format mapping for `Texture2D` image uploads and framebuffer status naming for
 `RTT` diagnostics. Mesh index-type and primitive-mode decisions used by legacy
-`Shape` drawing also live in `pp_renderer_gl`. The legacy app delegates
-extension, upload-format, framebuffer diagnostic, and mesh draw-mode
-interpretation to that backend library. The PanoPainter shader attribute
+`Shape` drawing and the PanoPainter cube-face to OpenGL texture-target mapping
+used by `TextureCube` also live in `pp_renderer_gl`. The legacy app delegates
+extension, upload-format, framebuffer diagnostic, mesh draw-mode, and cube-face
+texture-target interpretation to that backend library. The PanoPainter shader attribute
 binding catalog also lives in `pp_renderer_gl` and is consumed by legacy
 `Shader` creation. Shader uniform hashing, catalog validation, active-uniform
 mapping, and the legacy uniform uniqueness check now delegate to
@@ -640,10 +641,11 @@ Results:
   WebGL exclusion behavior, upload types for RGBA8/RGBA16F/RGBA32F internal
   formats, image channel-count format mapping including invalid counts, and
   framebuffer status names, plus Shape index-type and fill/stroke primitive
-  mode mapping. Shader attribute binding catalog validation covers the current
-  `pos`, `uvs`, `uvs2`, `col`, and `nor` bindings and rejects empty, unnamed,
-  null-name, and duplicate-name catalogs while preserving legacy shared
-  locations. Shader uniform catalog validation covers the 43 legacy uniform
+  mode mapping and PanoPainter cube-face texture-target order. Shader attribute
+  binding catalog validation covers the current `pos`, `uvs`, `uvs2`, `col`,
+  and `nor` bindings and rejects empty, unnamed, null-name, and duplicate-name
+  catalogs while preserving legacy shared locations. Shader uniform catalog
+  validation covers the 43 legacy uniform
   names used by `Shader`, preserves the legacy hash ids, and rejects empty,
   unnamed, null-name, mismatched-hash, and duplicate-name catalogs.
 - PowerShell analyze automation returns JSON summaries and includes the shader

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];
+}
+
 }

src/renderer_gl/opengl_capabilities.h

@@ -36,5 +36,7 @@ struct OpenGlPixelFormat {
 [[nodiscard]] std::uint32_t index_type_for_index_size(std::uint32_t index_size_bytes) noexcept;
 [[nodiscard]] std::uint32_t primitive_mode_for_fill_count(std::uint32_t vertex_or_index_count) noexcept;
 [[nodiscard]] std::uint32_t primitive_mode_for_stroke_count(std::uint32_t vertex_or_index_count) noexcept;
+[[nodiscard]] std::span<const std::uint32_t> panopainter_cube_face_texture_targets() noexcept;
+[[nodiscard]] std::uint32_t cube_face_texture_target(std::uint32_t face_index) noexcept;
 
 }

src/texture.cpp

@@ -9,12 +9,12 @@
 
 std::map<uint16_t, Texture2D> TextureManager::m_textures;
 std::array<int, 6> TextureCube::m_faces_map {
-    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
+    static_cast<int>(pp::renderer::gl::cube_face_texture_target(0U)),
+    static_cast<int>(pp::renderer::gl::cube_face_texture_target(1U)),
+    static_cast<int>(pp::renderer::gl::cube_face_texture_target(2U)),
+    static_cast<int>(pp::renderer::gl::cube_face_texture_target(3U)),
+    static_cast<int>(pp::renderer::gl::cube_face_texture_target(4U)),
+    static_cast<int>(pp::renderer::gl::cube_face_texture_target(5U)),
 };
 
 TextureCube::TextureCube(TextureCube&& other) noexcept

tests/renderer_gl/capabilities_tests.cpp

@@ -158,6 +158,22 @@ void maps_shape_index_and_primitive_modes(pp::tests::Harness& h)
     PP_EXPECT(h, pp::renderer::gl::primitive_mode_for_stroke_count(99U) == gl_lines);
 }
 
+void maps_panopainter_cube_faces_to_texture_targets(pp::tests::Harness& h)
+{
+    const auto targets = pp::renderer::gl::panopainter_cube_face_texture_targets();
+
+    PP_EXPECT(h, targets.size() == 6U);
+    PP_EXPECT(h, targets[0] == 0x851AU);
+    PP_EXPECT(h, targets[1] == 0x8516U);
+    PP_EXPECT(h, targets[2] == 0x8519U);
+    PP_EXPECT(h, targets[3] == 0x8515U);
+    PP_EXPECT(h, targets[4] == 0x8518U);
+    PP_EXPECT(h, targets[5] == 0x8517U);
+    PP_EXPECT(h, pp::renderer::gl::cube_face_texture_target(0U) == 0x851AU);
+    PP_EXPECT(h, pp::renderer::gl::cube_face_texture_target(5U) == 0x8517U);
+    PP_EXPECT(h, pp::renderer::gl::cube_face_texture_target(6U) == 0U);
+}
+
 void exposes_shader_attribute_binding_catalog(pp::tests::Harness& h)
 {
     const auto bindings = pp::renderer::gl::panopainter_shader_attribute_bindings();
@@ -260,6 +276,7 @@ int main()
     harness.run("maps_image_channel_count_to_texture_format", maps_image_channel_count_to_texture_format);
     harness.run("names_framebuffer_status_codes", names_framebuffer_status_codes);
     harness.run("maps_shape_index_and_primitive_modes", maps_shape_index_and_primitive_modes);
+    harness.run("maps_panopainter_cube_faces_to_texture_targets", maps_panopainter_cube_faces_to_texture_targets);
     harness.run("exposes_shader_attribute_binding_catalog", exposes_shader_attribute_binding_catalog);
     harness.run("rejects_invalid_shader_attribute_binding_catalogs", rejects_invalid_shader_attribute_binding_catalogs);
     harness.run("exposes_shader_uniform_catalog", exposes_shader_uniform_catalog);