Move OpenGL texture upload mapping

docs/modernization/build-inventory.md

@@ -126,7 +126,8 @@ Known local toolchain state:
 - `pp_renderer_gl` owns headless OpenGL runtime capability detection consumed
   by the legacy app initialization path; `pp_renderer_gl_capabilities_tests`
   validates framebuffer fetch, map-buffer alignment, desktop GL float support,
-  GLES float/half-float extensions, and WebGL exclusion behavior.
+  GLES float/half-float extensions, WebGL exclusion behavior, and the
+  upload-type mapping used by legacy `Texture2D` and `RTT` creation.
 - `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

@@ -387,9 +387,10 @@ readback, trace interface validation, and the canonical PanoPainter shader
 catalog now consumed by the legacy OpenGL app initialization path.
 `pp_renderer_gl` now exists as the first OpenGL backend library and owns pure
 OpenGL capability detection for framebuffer fetch, map-buffer alignment, and
-float texture support. The legacy app delegates extension interpretation to
-that backend library, but the existing renderer classes are not yet fully
-behind the renderer interfaces.
+float texture support. It also owns the OpenGL texture upload-type mapping used
+by legacy `Texture2D` and `RTT` creation. The legacy app delegates extension
+and upload-format interpretation to that backend library, but the existing
+renderer classes are not yet fully behind the renderer interfaces.
 
 Implementation tasks:
 
@@ -628,7 +629,8 @@ Results:
 - `pp_renderer_gl_capabilities_tests` passed on default MSVC, vcpkg-headless,
   and Android arm64 configure/build, covering framebuffer fetch, map-buffer
   alignment, desktop GL core float support, GLES float/half-float extensions,
-  and WebGL exclusion behavior.
+  WebGL exclusion behavior, and upload types for RGBA8/RGBA16F/RGBA32F
+  internal formats.
 - PowerShell analyze automation returns JSON summaries and includes the shader
   validation target.
 - `windows-msvc-vcpkg-headless` configured through the Visual Studio bundled

src/renderer_gl/opengl_capabilities.cpp

@@ -4,6 +4,12 @@ namespace pp::renderer::gl {
 
 namespace {
 
+constexpr std::uint32_t gl_unsigned_byte = 0x1401U;
+constexpr std::uint32_t gl_float = 0x1406U;
+constexpr std::uint32_t gl_half_float = 0x140BU;
+constexpr std::uint32_t gl_rgba32f = 0x8814U;
+constexpr std::uint32_t gl_rgba16f = 0x881AU;
+
 [[nodiscard]] bool contains(std::string_view text, std::string_view needle) noexcept
 {
     return text.find(needle) != std::string_view::npos;
@@ -50,4 +56,16 @@ OpenGlCapabilities detect_opengl_capabilities(
     return capabilities;
 }
 
+std::uint32_t texture_upload_type_for_internal_format(std::uint32_t internal_format) noexcept
+{
+    switch (internal_format) {
+    case gl_rgba32f:
+        return gl_float;
+    case gl_rgba16f:
+        return gl_half_float;
+    default:
+        return gl_unsigned_byte;
+    }
+}
+
 }

src/renderer_gl/opengl_capabilities.h

@@ -1,5 +1,6 @@
 #pragma once
 
+#include <cstdint>
 #include <span>
 #include <string_view>
 
@@ -23,4 +24,6 @@ struct OpenGlCapabilities {
     std::span<const std::string_view> extensions,
     OpenGlRuntime runtime) noexcept;
 
+[[nodiscard]] std::uint32_t texture_upload_type_for_internal_format(std::uint32_t internal_format) noexcept;
+
 }

src/rtt.cpp

@@ -3,6 +3,9 @@
 #include "rtt.h"
 #include "util.h"
 #include "app.h"
+#include "renderer_gl/opengl_capabilities.h"
+
+#include <cstdint>
 
 RTT& RTT::operator=(RTT&& other)
 {
@@ -204,9 +207,8 @@ bool RTT::create(int width, int height, int tex/* = -1*/, GLint internal_format,
             texID = tex;
         }
 
-        auto ifmt = GL_UNSIGNED_BYTE;
-        if (internal_format == GL_RGBA32F) ifmt = GL_FLOAT;
-        if (internal_format == GL_RGBA16F) ifmt = GL_HALF_FLOAT;
+        const auto ifmt = static_cast<GLenum>(
+            pp::renderer::gl::texture_upload_type_for_internal_format(static_cast<std::uint32_t>(internal_format)));
 
         glBindTexture(GL_TEXTURE_2D, texID);
         if (tex == -1)

src/texture.cpp

@@ -3,6 +3,9 @@
 #include "texture.h"
 #include "util.h"
 #include "app.h"
+#include "renderer_gl/opengl_capabilities.h"
+
+#include <cstdint>
 
 std::map<uint16_t, Texture2D> TextureManager::m_textures;
 std::array<int, 6> TextureCube::m_faces_map {
@@ -176,9 +179,8 @@ bool Texture2D::create(int width, int height, GLint internal_format, GLint forma
         glGenTextures(1, &m_tex);
         //LOG("TEX create %d", m_tex);
         bind();
-        auto ifmt = GL_UNSIGNED_BYTE;
-        if (internal_format == GL_RGBA32F) ifmt = GL_FLOAT;
-        if (internal_format == GL_RGBA16F) ifmt = GL_HALF_FLOAT;
+        const auto ifmt = static_cast<GLenum>(
+            pp::renderer::gl::texture_upload_type_for_internal_format(static_cast<std::uint32_t>(internal_format)));
         glTexImage2D(GL_TEXTURE_2D, 0, internal_format, width, height, 0, format, ifmt, data);
         unbind();
     });

tests/renderer_gl/capabilities_tests.cpp

@@ -2,6 +2,7 @@
 #include "test_harness.h"
 
 #include <array>
+#include <cstdint>
 #include <string_view>
 
 namespace {
@@ -68,6 +69,21 @@ void ignores_gles_texture_extensions_for_webgl_runtime(pp::tests::Harness& h)
     PP_EXPECT(h, !capabilities.float16_textures);
 }
 
+void selects_texture_upload_type_from_internal_format(pp::tests::Harness& h)
+{
+    constexpr std::uint32_t gl_unsigned_byte = 0x1401U;
+    constexpr std::uint32_t gl_float = 0x1406U;
+    constexpr std::uint32_t gl_half_float = 0x140BU;
+    constexpr std::uint32_t gl_rgba8 = 0x8058U;
+    constexpr std::uint32_t gl_rgba32f = 0x8814U;
+    constexpr std::uint32_t gl_rgba16f = 0x881AU;
+
+    PP_EXPECT(h, pp::renderer::gl::texture_upload_type_for_internal_format(gl_rgba8) == gl_unsigned_byte);
+    PP_EXPECT(h, pp::renderer::gl::texture_upload_type_for_internal_format(gl_rgba32f) == gl_float);
+    PP_EXPECT(h, pp::renderer::gl::texture_upload_type_for_internal_format(gl_rgba16f) == gl_half_float);
+    PP_EXPECT(h, pp::renderer::gl::texture_upload_type_for_internal_format(0U) == gl_unsigned_byte);
+}
+
 }
 
 int main()
@@ -77,5 +93,6 @@ int main()
     harness.run("treats_desktop_gl_float_rendering_as_core", treats_desktop_gl_float_rendering_as_core);
     harness.run("detects_gles_texture_float_extensions", detects_gles_texture_float_extensions);
     harness.run("ignores_gles_texture_extensions_for_webgl_runtime", ignores_gles_texture_extensions_for_webgl_runtime);
+    harness.run("selects_texture_upload_type_from_internal_format", selects_texture_upload_type_from_internal_format);
     return harness.finish();
 }