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OpenGLUniformLocationMap.ixx File

Maps shader uniform semantics to OpenGL uniform locations. More...

Included Headers​

#include <array> #include <optional> #include <cassert> #include <format> #include <utility> #include <helios.util.log.Logger> #include <helios.util.log.LogManager> #include <helios.rendering.shader.UniformSemantics>

Namespaces Index​

namespacehelios
namespaceext

Platform-specific extensions and backend implementations. More...

namespaceopengl

OpenGL-specific implementations. More...

namespacerendering

OpenGL rendering implementations. More...

namespaceshader

OpenGL shader implementations. More...

Classes Index​

classOpenGLUniformLocationMap

Manages the mapping between OpenGL uniform semantics and their locations in an underlying OpenGL shader. More...

Macro Definitions Index​

#defineHELIOS_LOG_SCOPE   "helios::ext::opengl::rendering::shader::OpenGLUniformLocationMap"

Description​

Maps shader uniform semantics to OpenGL uniform locations.

Macro Definitions​

HELIOS_LOG_SCOPE​

#define HELIOS_LOG_SCOPE   "helios::ext::opengl::rendering::shader::OpenGLUniformLocationMap"

Definition at line 20 of file OpenGLUniformLocationMap.ixx.

20#define HELIOS_LOG_SCOPE "helios::ext::opengl::rendering::shader::OpenGLUniformLocationMap"

File Listing​

The file content with the documentation metadata removed is:

1/**
2 * @file OpenGLUniformLocationMap.ixx
3 * @brief Maps shader uniform semantics to OpenGL uniform locations.
4 */
5module;
6
7
8#include <array>
9#include <optional>
10#include <cassert>
11#include <format>
12#include <utility>
13
14export module helios.ext.opengl.rendering.shader.OpenGLUniformLocationMap;
15
16import helios.rendering.shader.UniformSemantics;
17import helios.util.log.LogManager;
18import helios.util.log.Logger;
19
20#define HELIOS_LOG_SCOPE "helios::ext::opengl::rendering::shader::OpenGLUniformLocationMap"
21export namespace helios::ext::opengl::rendering::shader {
22
23
24 /**
25 * @brief Manages the mapping between OpenGL uniform semantics and their locations
26 * in an underlying OpenGL shader.
27 *
28 * This class should be used to store and retrieve the uniform locations, e.g.
29 * for a OpenGL render backend for easy access.
30 */
31 class OpenGLUniformLocationMap final {
32
33 private:
34 /**
35 * @brief Bit mask serving as sentinel to keep track of set indices.
36 * Since position 0 is allowed for uniform locations, this bitmask keeps
37 * track of set indices in `map_`.
38 */
39 unsigned int sentinel_ = 0;
40
41 /**
42 * @brief The internal map used for mapping uniform semantics to positions.
43 */
44 std::array<int, std::to_underlying(helios::rendering::shader::UniformSemantics::size_)> map_ = {};
45
46 /**
47 * @brief Shared logger instance for all OpenGLUniformLocationMap objects.
48 */
49 inline static const helios::util::log::Logger& logger_ = helios::util::log::LogManager::loggerForScope(
50 HELIOS_LOG_SCOPE
51 );
52
53 public:
54 ~OpenGLUniformLocationMap() = default;
55
56 /**
57 * Make sure the sentinel has enough bits to keep track of the entries
58 * of the UniformSemantics enum.
59 */
60 static_assert(
61 static_cast<size_t>(helios::rendering::shader::UniformSemantics::size_)
62 <= (sizeof(sentinel_) * 8) && "sentinel type is too narrow");
63
64 /**
65 * @brief Default constructor for a OpenGLUniformLocationMap.
66 */
67 OpenGLUniformLocationMap() = default;
68
69 /**
70 * @brief Sets or updates the OpenGLUniform.
71 * If the semantics already exists in the map, it is updated with `position`.
72 *
73 * @param uniformSemantics The uniformSemantics to register with `position`
74 * @param position A positive integer value as the location of the uniform represented by
75 * uniformSemantics.
76 *
77 * @return true if the position for the specified uniformSemantics was registered with this
78 * map, otherwise false (e.g. if position was < 0)
79 */
80 bool set(
81 helios::rendering::shader::UniformSemantics uniformSemantics,
82 int position
83 ) noexcept {
84 assert(position >= 0 && "position must not be less than 0");
85
86 const decltype(sentinel_) index = std::to_underlying(uniformSemantics);
87
88 sentinel_ = (sentinel_ | (decltype(sentinel_){1} << index));
89 map_[std::to_underlying(uniformSemantics)] = position;
90 return true;
91 }
92
93 /**
94 * @brief Returns the index of the uniform variable for the specified UniformSemantics
95 * as configured with this location map.
96 * This method returns -1 if the specified semantics is not configured with this map.
97 *
98 * @param uniformSemantics The UniformSemantics for which the location index
99 * should be returned.
100 *
101 * @return The index as previously set for the specified uniformSemantics, or -1
102 * if not found.
103 *
104 * @see glGetUniformLocation
105 * @see [KSS17, 47]
106 */
107 [[nodiscard]] int get(helios::rendering::shader::UniformSemantics uniformSemantics) const noexcept {
108 const decltype(sentinel_) index = std::to_underlying(uniformSemantics);
109
110 if (!(sentinel_ & (decltype(sentinel_){1} << index))) {
111 return -1;
112 }
113
114 return map_[index];
115 }
116 };
117
118
119}

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