/*

 * Copyright 2021 Google LLC

 *

 * Use of this source code is governed by a BSD-style license that can be

 * found in the LICENSE file.

 */

#ifndef skgpu_graphite_Uniform_DEFINED

#define skgpu_graphite_Uniform_DEFINED

#include "src/core/SkSLTypeShared.h"

namespace skgpu::graphite {

// TODO: can SkRuntimeEffect::Uniform be absorbed into this class!?

/**

 * Describes a uniform. Uniforms consist of:

 *  name:       The constant string name to use in the generated SkSL (with mangling)

 *  type:       The type of the uniform

 *  count:      Number of elements of 'type' in the array or kNonArray if not an array.

 */

class Uniform {

public:

    static constexpr int kNonArray = 0;

    constexpr Uniform(const char* name, SkSLType type, int count = kNonArray)

            : Uniform(name, type, count, /*isPaintColor=*/false) {}

    /*

     * The paint color uniform is treated special and will only be added to the uniform block

     * once. Its name will not be mangled.

     */

    static constexpr Uniform PaintColor() {

        return Uniform("paintColor", SkSLType::kFloat4,

                       Uniform::kNonArray, /*isPaintColor=*/true);

    }

    constexpr Uniform(const Uniform&) = default;

    Uniform& operator=(const Uniform&) = default;

    constexpr const char* name()  const { return fName; }

    constexpr SkSLType    type()  const { return static_cast<SkSLType>(fType);  }

    constexpr int         count() const { return static_cast<int>(fCount); }

    constexpr bool isPaintColor() const { return static_cast<bool>(fIsPaintColor); }

private:

    constexpr Uniform(const char* name, SkSLType type, int count, bool isPaintColor)

            : fName(name)

            , fType(static_cast<unsigned>(type))

            , fIsPaintColor(static_cast<unsigned>(isPaintColor))

            , fCount(static_cast<unsigned>(count)) {

        SkASSERT(SkSLTypeCanBeUniformValue(type));

        SkASSERT(count >= 0);

    }

Unexecuted instantiation: skgpu::graphite::Uniform::Uniform(char const*, SkSLType, int, bool)

Unexecuted instantiation: skgpu::graphite::Uniform::Uniform(char const*, SkSLType, int, bool)

    const char* fName;

    // Uniform definitions for all encountered SkRuntimeEffects are stored permanently in the

    // ShaderCodeDictionary as part of the stable ShaderSnippet and code ID assigned to the

    // effect, including de-duplicating equivalent or re-created SkRuntimeEffects with the same

    // SkSL. To help keep this memory overhead as low as possible, we pack the Uniform fields

    // as tightly as possible.

    uint32_t    fType         : 6;

    uint32_t    fIsPaintColor : 1;

    uint32_t    fCount        : 25;

    static_assert(kSkSLTypeCount <= (1 << 6));

};

} // namespace skgpu::graphite

#endif // skgpu_graphite_Uniform_DEFINED