Extract OpenGL shader uniform catalog

src/renderer_gl/shader_bindings.cpp

@@ -2,9 +2,23 @@
 
 #include <array>
 #include <cstring>
+#include <string_view>
 
 namespace pp::renderer::gl {
 
+namespace {
+
+constexpr std::uint16_t djb2_hash(std::string_view text) noexcept
+{
+    std::uint16_t value = 5381U;
+    for (std::size_t i = text.size(); i > 0U; --i) {
+        value = static_cast<std::uint16_t>(text[i - 1U]) + static_cast<std::uint16_t>(33U * value);
+    }
+    return value;
+}
+
+}
+
 std::span<const OpenGlAttributeBinding> panopainter_shader_attribute_bindings() noexcept
 {
     static constexpr std::array<OpenGlAttributeBinding, 5> bindings {
@@ -40,4 +54,90 @@ pp::foundation::Status validate_shader_attribute_bindings(
     return pp::foundation::Status::success();
 }
 
+std::span<const OpenGlUniformName> panopainter_shader_uniform_names() noexcept
+{
+    static constexpr std::array<OpenGlUniformName, 43> uniforms {
+        OpenGlUniformName { .name = "mvp", .id = djb2_hash("mvp") },
+        OpenGlUniformName { .name = "tex", .id = djb2_hash("tex") },
+        OpenGlUniformName { .name = "tex_alpha", .id = djb2_hash("tex_alpha") },
+        OpenGlUniformName { .name = "tex_fg", .id = djb2_hash("tex_fg") },
+        OpenGlUniformName { .name = "tex_bg", .id = djb2_hash("tex_bg") },
+        OpenGlUniformName { .name = "tex_mix", .id = djb2_hash("tex_mix") },
+        OpenGlUniformName { .name = "tex_mix_alpha", .id = djb2_hash("tex_mix_alpha") },
+        OpenGlUniformName { .name = "tex_mask", .id = djb2_hash("tex_mask") },
+        OpenGlUniformName { .name = "tex_dual", .id = djb2_hash("tex_dual") },
+        OpenGlUniformName { .name = "tex_stroke", .id = djb2_hash("tex_stroke") },
+        OpenGlUniformName { .name = "tex_pattern", .id = djb2_hash("tex_pattern") },
+        OpenGlUniformName { .name = "pattern_offset", .id = djb2_hash("pattern_offset") },
+        OpenGlUniformName { .name = "pattern_alpha", .id = djb2_hash("pattern_alpha") },
+        OpenGlUniformName { .name = "mix_alpha", .id = djb2_hash("mix_alpha") },
+        OpenGlUniformName { .name = "opacity", .id = djb2_hash("opacity") },
+        OpenGlUniformName { .name = "wet", .id = djb2_hash("wet") },
+        OpenGlUniformName { .name = "lock", .id = djb2_hash("lock") },
+        OpenGlUniformName { .name = "col", .id = djb2_hash("col") },
+        OpenGlUniformName { .name = "tof", .id = djb2_hash("tof") },
+        OpenGlUniformName { .name = "tsz", .id = djb2_hash("tsz") },
+        OpenGlUniformName { .name = "alpha", .id = djb2_hash("alpha") },
+        OpenGlUniformName { .name = "mask", .id = djb2_hash("mask") },
+        OpenGlUniformName { .name = "resolution", .id = djb2_hash("resolution") },
+        OpenGlUniformName { .name = "highlight", .id = djb2_hash("highlight") },
+        OpenGlUniformName { .name = "blend_mode", .id = djb2_hash("blend_mode") },
+        OpenGlUniformName { .name = "dual_blend_mode", .id = djb2_hash("dual_blend_mode") },
+        OpenGlUniformName { .name = "noise", .id = djb2_hash("noise") },
+        OpenGlUniformName { .name = "dir", .id = djb2_hash("dir") },
+        OpenGlUniformName { .name = "use_dual", .id = djb2_hash("use_dual") },
+        OpenGlUniformName { .name = "use_pattern", .id = djb2_hash("use_pattern") },
+        OpenGlUniformName { .name = "light_dir", .id = djb2_hash("light_dir") },
+        OpenGlUniformName { .name = "mode", .id = djb2_hash("mode") },
+        OpenGlUniformName { .name = "ambient", .id = djb2_hash("ambient") },
+        OpenGlUniformName { .name = "pattern_invert", .id = djb2_hash("pattern_invert") },
+        OpenGlUniformName { .name = "pattern_scale", .id = djb2_hash("pattern_scale") },
+        OpenGlUniformName { .name = "pattern_bright", .id = djb2_hash("pattern_bright") },
+        OpenGlUniformName { .name = "pattern_contr", .id = djb2_hash("pattern_contr") },
+        OpenGlUniformName { .name = "pattern_depth", .id = djb2_hash("pattern_depth") },
+        OpenGlUniformName { .name = "patt_blend_mode", .id = djb2_hash("patt_blend_mode") },
+        OpenGlUniformName { .name = "colorize", .id = djb2_hash("colorize") },
+        OpenGlUniformName { .name = "dual_alpha", .id = djb2_hash("dual_alpha") },
+        OpenGlUniformName { .name = "use_fragcoord", .id = djb2_hash("use_fragcoord") },
+        OpenGlUniformName { .name = "draw_outline", .id = djb2_hash("draw_outline") },
+    };
+
+    return uniforms;
+}
+
+std::uint16_t shader_uniform_id(std::string_view name) noexcept
+{
+    return djb2_hash(name);
+}
+
+pp::foundation::Status validate_shader_uniform_names(
+    std::span<const OpenGlUniformName> uniforms) noexcept
+{
+    if (uniforms.empty()) {
+        return pp::foundation::Status::invalid_argument("shader uniform catalog is empty");
+    }
+
+    for (std::size_t i = 0; i < uniforms.size(); ++i) {
+        if (uniforms[i].name == nullptr || uniforms[i].name[0] == '\0') {
+            return pp::foundation::Status::invalid_argument("shader uniform has no name");
+        }
+
+        if (uniforms[i].id != shader_uniform_id(uniforms[i].name)) {
+            return pp::foundation::Status::invalid_argument("shader uniform hash does not match its name");
+        }
+
+        for (std::size_t j = i + 1; j < uniforms.size(); ++j) {
+            if (uniforms[j].name != nullptr && std::strcmp(uniforms[i].name, uniforms[j].name) == 0) {
+                return pp::foundation::Status::invalid_argument("shader uniform name is duplicated");
+            }
+
+            if (uniforms[i].id == uniforms[j].id) {
+                return pp::foundation::Status::invalid_argument("shader uniform hash is duplicated");
+            }
+        }
+    }
+
+    return pp::foundation::Status::success();
+}
+
 }

src/renderer_gl/shader_bindings.h

@@ -4,6 +4,7 @@
 
 #include <cstdint>
 #include <span>
+#include <string_view>
 
 namespace pp::renderer::gl {
 
@@ -12,8 +13,17 @@ struct OpenGlAttributeBinding {
     std::uint32_t location = 0;
 };
 
+struct OpenGlUniformName {
+    const char* name = "";
+    std::uint16_t id = 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;
+[[nodiscard]] std::span<const OpenGlUniformName> panopainter_shader_uniform_names() noexcept;
+[[nodiscard]] std::uint16_t shader_uniform_id(std::string_view name) noexcept;
+[[nodiscard]] pp::foundation::Status validate_shader_uniform_names(
+    std::span<const OpenGlUniformName> uniforms) noexcept;
 
 }