Map renderer viewport and scissor to OpenGL

docs/modernization/build-inventory.md

@@ -224,11 +224,12 @@ Known local toolchain state:
   names directly. It also owns the PanoPainter shader uniform catalog and legacy hash
   mapping used by `Shader` active-uniform discovery and the uniform uniqueness
   check. App OpenGL initialization debug severity, debug output, GL info string,
-  default depth/program-point/line-smooth state, blend factor/equation, and UI
+  renderer API viewport/scissor rect conversion, default depth/program-point/
-  render-target RGBA8 format tokens are cataloged and tested here too, including
+  line-smooth state, blend factor/equation, and UI render-target RGBA8 format
-  the legacy convert command and resize path. App clear color-buffer masks,
+  tokens are cataloged and tested here too, including the legacy convert command
-  default framebuffer binding, scissor state, and sampler filter/wrap tokens
+  and resize path. App clear color-buffer masks, default framebuffer binding,
-  also consume the backend mapping. OpenGL extension enumeration query tokens
+  scissor state, and sampler filter/wrap tokens also consume the backend mapping.
+  OpenGL extension enumeration query tokens
   used before runtime capability detection are cataloged here. Legacy font
   atlas texture formats, text mesh buffer targets, attribute component and
   normalization tokens, draw primitive/index type, upload usage, and active

docs/modernization/roadmap.md

@@ -481,8 +481,9 @@ depth-state to OpenGL enable/write/compare mapping also live in
 validation, active-uniform mapping, and the legacy uniform uniqueness check now
 delegate to `pp_renderer_gl` as well. `Shader` no longer spells GL enum names
 directly. App OpenGL initialization debug severity, debug output, GL info
-string, default depth/program-point/line-smooth state, blend factor/equation,
+string, renderer API viewport/scissor rect conversion, default
-and UI render-target RGBA8 format tokens are now also cataloged and tested in
+depth/program-point/line-smooth state, blend factor/equation, and UI
+render-target RGBA8 format tokens are now also cataloged and tested in
 `pp_renderer_gl`; the legacy convert command and resize path consume the same
 backend-owned mapping. App clear color-buffer masks, default framebuffer
 binding, scissor state, and sampler filter/wrap tokens now share that backend

src/renderer_gl/opengl_capabilities.cpp

@@ -669,6 +669,18 @@ std::uint32_t viewport_query() noexcept
     return gl_viewport;
 }
 
+OpenGlViewportRect viewport_for_renderer_viewport(pp::renderer::Viewport viewport) noexcept
+{
+    return OpenGlViewportRect {
+        .x = viewport.x,
+        .y = viewport.y,
+        .width = static_cast<std::int32_t>(viewport.width),
+        .height = static_cast<std::int32_t>(viewport.height),
+        .min_depth = viewport.min_depth,
+        .max_depth = viewport.max_depth,
+    };
+}
+
 std::uint32_t color_clear_value_query() noexcept
 {
     return gl_color_clear_value;
@@ -749,6 +761,17 @@ std::uint32_t scissor_test_state() noexcept
     return gl_scissor_test;
 }
 
+OpenGlScissorRect scissor_rect_for_renderer_scissor(pp::renderer::ScissorRect scissor) noexcept
+{
+    return OpenGlScissorRect {
+        .enabled = scissor.enabled ? gl_boolean_true : gl_boolean_false,
+        .x = scissor.x,
+        .y = scissor.y,
+        .width = static_cast<std::int32_t>(scissor.width),
+        .height = static_cast<std::int32_t>(scissor.height),
+    };
+}
+
 std::uint32_t program_point_size_state() noexcept
 {
     return gl_program_point_size;

src/renderer_gl/opengl_capabilities.h

@@ -34,6 +34,23 @@ struct OpenGlTextureParameter {
     std::uint32_t value = 0;
 };
 
+struct OpenGlViewportRect {
+    std::int32_t x = 0;
+    std::int32_t y = 0;
+    std::int32_t width = 0;
+    std::int32_t height = 0;
+    float min_depth = 0.0F;
+    float max_depth = 1.0F;
+};
+
+struct OpenGlScissorRect {
+    std::uint8_t enabled = 0;
+    std::int32_t x = 0;
+    std::int32_t y = 0;
+    std::int32_t width = 0;
+    std::int32_t height = 0;
+};
+
 struct OpenGlEnumMapping {
     std::uint32_t value = 0;
     bool supported = false;
@@ -158,6 +175,8 @@ struct OpenGlWindowsWglContextConfig {
 [[nodiscard]] std::uint32_t renderer_string_name() noexcept;
 [[nodiscard]] std::uint32_t shading_language_version_string_name() noexcept;
 [[nodiscard]] std::uint32_t viewport_query() noexcept;
+[[nodiscard]] OpenGlViewportRect viewport_for_renderer_viewport(
+    pp::renderer::Viewport viewport) noexcept;
 [[nodiscard]] std::uint32_t color_clear_value_query() noexcept;
 [[nodiscard]] std::uint32_t current_program_query() noexcept;
 [[nodiscard]] std::uint32_t active_texture_query() noexcept;
@@ -171,6 +190,8 @@ struct OpenGlWindowsWglContextConfig {
 [[nodiscard]] OpenGlDepthState depth_state_for_renderer_depth_state(
     pp::renderer::DepthState state) noexcept;
 [[nodiscard]] std::uint32_t scissor_test_state() noexcept;
+[[nodiscard]] OpenGlScissorRect scissor_rect_for_renderer_scissor(
+    pp::renderer::ScissorRect scissor) noexcept;
 [[nodiscard]] std::uint32_t program_point_size_state() noexcept;
 [[nodiscard]] std::uint32_t line_smooth_state() noexcept;
 [[nodiscard]] std::uint32_t source_alpha_blend_factor() noexcept;

tests/renderer_gl/capabilities_tests.cpp

@@ -529,6 +529,44 @@ void maps_app_initialization_parameters(pp::tests::Harness& h)
     PP_EXPECT(h, pp::renderer::gl::active_texture_unit(4U) == 0x84C4U);
 }
 
+void maps_renderer_viewports_and_scissors(pp::tests::Harness& h)
+{
+    const auto viewport = pp::renderer::gl::viewport_for_renderer_viewport(
+        pp::renderer::Viewport {
+            .x = 4,
+            .y = 8,
+            .width = 640U,
+            .height = 320U,
+            .min_depth = 0.25F,
+            .max_depth = 0.75F,
+        });
+    const auto disabled_scissor = pp::renderer::gl::scissor_rect_for_renderer_scissor(
+        pp::renderer::ScissorRect {});
+    const auto enabled_scissor = pp::renderer::gl::scissor_rect_for_renderer_scissor(
+        pp::renderer::ScissorRect {
+            .enabled = true,
+            .x = 12,
+            .y = 16,
+            .width = 128U,
+            .height = 64U,
+        });
+
+    PP_EXPECT(h, viewport.x == 4);
+    PP_EXPECT(h, viewport.y == 8);
+    PP_EXPECT(h, viewport.width == 640);
+    PP_EXPECT(h, viewport.height == 320);
+    PP_EXPECT(h, viewport.min_depth == 0.25F);
+    PP_EXPECT(h, viewport.max_depth == 0.75F);
+    PP_EXPECT(h, disabled_scissor.enabled == 0U);
+    PP_EXPECT(h, disabled_scissor.width == 0);
+    PP_EXPECT(h, disabled_scissor.height == 0);
+    PP_EXPECT(h, enabled_scissor.enabled == 1U);
+    PP_EXPECT(h, enabled_scissor.x == 12);
+    PP_EXPECT(h, enabled_scissor.y == 16);
+    PP_EXPECT(h, enabled_scissor.width == 128);
+    PP_EXPECT(h, enabled_scissor.height == 64);
+}
+
 void maps_renderer_blend_state_tokens(pp::tests::Harness& h)
 {
     const auto zero = pp::renderer::gl::blend_factor_for_renderer_factor(pp::renderer::BlendFactor::zero);
@@ -863,6 +901,7 @@ int main()
     harness.run("maps_renderer_sampler_tokens", maps_renderer_sampler_tokens);
     harness.run("exposes_shader_attribute_binding_catalog", exposes_shader_attribute_binding_catalog);
     harness.run("maps_app_initialization_parameters", maps_app_initialization_parameters);
+    harness.run("maps_renderer_viewports_and_scissors", maps_renderer_viewports_and_scissors);
     harness.run("maps_renderer_blend_state_tokens", maps_renderer_blend_state_tokens);
     harness.run("maps_renderer_color_write_masks", maps_renderer_color_write_masks);
     harness.run("maps_renderer_blend_states", maps_renderer_blend_states);