src/tint/lang/glsl/writer/raise/offset_first_index.h

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#ifndef SRC_TINT_LANG_GLSL_WRITER_RAISE_OFFSET_FIRST_INDEX_H_
#define SRC_TINT_LANG_GLSL_WRITER_RAISE_OFFSET_FIRST_INDEX_H_

#include "src/tint/lang/core/ir/transform/prepare_push_constants.h"
#include "src/tint/utils/result/result.h"

// Forward declarations.
namespace tint::core::ir {
class Module;
}  // namespace tint::core::ir

namespace tint::glsl::writer::raise {

/// OffsetFirstIndexConfig describes the configuration options for the OffsetFirstIndex transform.
struct OffsetFirstIndexConfig {
    /// Push constant layout information.
    const core::ir::transform::PushConstantLayout& push_constant_layout;

    /// Offset of the firstVertex push constant.
    std::optional<uint32_t> first_vertex_offset{};

    /// Offset of the firstInstance push constant.
    std::optional<uint32_t> first_instance_offset{};
};

/// OffsetFirstIndex is a transform that adds an offset to the `vertex_index` and `instance_index`
/// builtin values.
///
/// @param module the module to transform
/// @returns success or failure
Result<SuccessType> OffsetFirstIndex(core::ir::Module& module,
                                     const OffsetFirstIndexConfig& config);

}  // namespace tint::glsl::writer::raise

#endif  // SRC_TINT_LANG_GLSL_WRITER_RAISE_OFFSET_FIRST_INDEX_H_