src/tint/api/common/vertex_pulling_config.h

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#ifndef SRC_TINT_API_COMMON_VERTEX_PULLING_CONFIG_H_
#define SRC_TINT_API_COMMON_VERTEX_PULLING_CONFIG_H_

#include <cstdint>
#include <vector>

#include "src/tint/utils/reflection.h"

namespace tint {

/// Describes the format of data in a vertex buffer.
enum class VertexFormat : uint8_t {
    kUint8,            // uint8
    kUint8x2,          // uint8x2
    kUint8x4,          // uint8x4
    kSint8,            // sint8
    kSint8x2,          // sint8x2
    kSint8x4,          // sint8x4
    kUnorm8,           // unorm8
    kUnorm8x2,         // unorm8x2
    kUnorm8x4,         // unorm8x4
    kSnorm8,           // snorm8
    kSnorm8x2,         // snorm8x2
    kSnorm8x4,         // snorm8x4
    kUint16,           // uint16
    kUint16x2,         // uint16x2
    kUint16x4,         // uint16x4
    kSint16,           // sint16
    kSint16x2,         // sint16x2
    kSint16x4,         // sint16x4
    kUnorm16,          // unorm16
    kUnorm16x2,        // unorm16x2
    kUnorm16x4,        // unorm16x4
    kSnorm16,          // snorm16
    kSnorm16x2,        // snorm16x2
    kSnorm16x4,        // snorm16x4
    kFloat16,          // float16
    kFloat16x2,        // float16x2
    kFloat16x4,        // float16x4
    kFloat32,          // float32
    kFloat32x2,        // float32x2
    kFloat32x3,        // float32x3
    kFloat32x4,        // float32x4
    kUint32,           // uint32
    kUint32x2,         // uint32x2
    kUint32x3,         // uint32x3
    kUint32x4,         // uint32x4
    kSint32,           // sint32
    kSint32x2,         // sint32x2
    kSint32x3,         // sint32x3
    kSint32x4,         // sint32x4
    kUnorm10_10_10_2,  // unorm10-10-10-2
    kUnorm8x4BGRA,     // unorm8x4-bgra
};

/// Describes if a vertex attribute increments with vertex index or instance index.
enum class VertexStepMode : uint8_t { kVertex, kInstance };

/// Describes a vertex attribute within a buffer
struct VertexAttributeDescriptor {
    /// The format of the attribute.
    VertexFormat format;
    /// The byte offset of the attribute in the buffer.
    uint32_t offset;
    /// The shader location used for the attribute.
    uint32_t shader_location;

    /// Reflect the fields of this class so that it can be used by tint::ForeachField()
    TINT_REFLECT(VertexAttributeDescriptor, format, offset, shader_location);
};

/// Describes a buffer containing multiple vertex attributes
struct VertexBufferLayoutDescriptor {
    /// Constructor
    VertexBufferLayoutDescriptor();
    /// Constructor
    /// @param in_array_stride the array stride in bytes of the in buffer
    /// @param in_step_mode the step mode of the in buffer
    /// @param in_attributes the in attributes
    VertexBufferLayoutDescriptor(uint32_t in_array_stride,
                                 VertexStepMode in_step_mode,
                                 std::vector<VertexAttributeDescriptor> in_attributes);
    /// The array stride in bytes used in the in buffer.
    uint32_t array_stride = 0u;
    /// The input step mode used.
    VertexStepMode step_mode = VertexStepMode::kVertex;
    /// The vertex attributes.
    std::vector<VertexAttributeDescriptor> attributes;

    /// Reflect the fields of this class so that it can be used by tint::ForeachField()
    TINT_REFLECT(VertexBufferLayoutDescriptor, array_stride, step_mode, attributes);
};

/// Configuration options that control the vertex pulling transform.
struct VertexPullingConfig {
    /// The vertex state descriptor, containing info about attributes.
    std::vector<VertexBufferLayoutDescriptor> vertex_state;

    /// The "group" we will put all our vertex buffers into (as storage buffers).
    /// Default to 4 as it is past the limits of user-accessible groups.
    uint32_t pulling_group = 4u;

    /// Reflect the fields of this class so that it can be used by tint::ForeachField()
    TINT_REFLECT(VertexPullingConfig, vertex_state, pulling_group);
};

/// Reflection for VertexFormat.
TINT_REFLECT_ENUM_RANGE(tint::VertexFormat, kUint8x2, kUnorm8x4BGRA);

/// Reflection for VertexStepMode.
TINT_REFLECT_ENUM_RANGE(tint::VertexStepMode, kVertex, kInstance);

}  // namespace tint

#endif  // SRC_TINT_API_COMMON_VERTEX_PULLING_CONFIG_H_