RenderTarget.h

/*
 * Gamedev Framework (gf)
 * Copyright (C) 2016-2021 Julien Bernard
 *
 * This software is provided 'as-is', without any express or implied
 * warranty.  In no event will the authors be held liable for any damages
 * arising from the use of this software.
 *
 * Permission is granted to anyone to use this software for any purpose,
 * including commercial applications, and to alter it and redistribute it
 * freely, subject to the following restrictions:
 *
 * 1. The origin of this software must not be misrepresented; you must not
 *    claim that you wrote the original software. If you use this software
 *    in a product, an acknowledgment in the product documentation would be
 *    appreciated but is not required.
 * 2. Altered source versions must be plainly marked as such, and must not be
 *    misrepresented as being the original software.
 * 3. This notice may not be removed or altered from any source distribution.
 *
 * Part of this file comes from SFML, with the same license:
 * Copyright (C) 2007-2015 Laurent Gomila (laurent@sfml-dev.org)
 */
#ifndef GF_RENDER_TARGET_H
#define GF_RENDER_TARGET_H

#include <cstdint>

#include "GraphicsApi.h"
#include "GraphicsHandle.h"
#include "Image.h"
#include "Matrix.h"
#include "PrimitiveType.h"
#include "Range.h"
#include "Region.h"
#include "RenderStates.h"
#include "Shader.h"
#include "Span.h"
#include "View.h"

namespace gf {
#ifndef DOXYGEN_SHOULD_SKIP_THIS
inline namespace v1 {
#endif

  class Drawable;
  class VertexBuffer;
  struct Vertex;

  enum class RenderAttributeType {
    Byte    = 0x1400,
    UByte   = 0x1401,
    Short   = 0x1402,
    UShort  = 0x1403,
    Float   = 0x1406,
  };

  struct GF_GRAPHICS_API RenderAttributeInfo {
    const char *name; 
    int size; 
    RenderAttributeType type; 
    bool normalized; 
    std::size_t offset; 
  };

  template<>
  struct GF_GRAPHICS_API GraphicsTrait<GraphicsTag::Framebuffer> {
    static void gen(int n, unsigned* resources);
    static void del(int n, const unsigned* resources);
  };

  class GF_GRAPHICS_API RenderTarget {
  public:

    RenderTarget(Vector2i size);

    virtual ~RenderTarget();

    RenderTarget(const RenderTarget&) = delete;

    RenderTarget& operator=(const RenderTarget&) = delete;

    virtual Vector2i getSize() const = 0;

    Region getCanonicalScissorBox();

    void setCanonicalScissorBox(const Region& box);

    RectI getScissorBox();

    void setScissorBox(const RectI& box);

    void clear(const Color4f& color);

    void clear();

    RangeF getAliasedLineWidthRange() const;

    float getLineWidth() const;

    void draw(const Vertex *vertices, std::size_t count, PrimitiveType type, const RenderStates& states = RenderStates());

    void draw(const Vertex *vertices, const uint16_t *indices, std::size_t count, PrimitiveType type, const RenderStates& states = RenderStates());

    void draw(const VertexBuffer& buffer, const RenderStates& states = RenderStates());

    void draw(Drawable& drawable, const RenderStates& states = RenderStates());

    void customDraw(const void *vertices, std::size_t size, std::size_t count, PrimitiveType type, Span<const RenderAttributeInfo> attributes, const RenderStates& states = RenderStates());

    void customDraw(const void *vertices, std::size_t size, const uint16_t *indices, std::size_t count, PrimitiveType type, Span<const RenderAttributeInfo> attributes, const RenderStates& states = RenderStates());

    void customDraw(const VertexBuffer& buffer, Span<const RenderAttributeInfo> attributes, const RenderStates& states = RenderStates());

    void setView(const View& view);

    const View& getView() const {
      return m_view;
    }

    Region getCanonicalViewport(const View& view) const;

    RectI getViewport(const View& view) const;

    Vector2f mapPixelToCoords(Vector2i point, const View& view) const;

    Vector2f mapPixelToCoords(Vector2i point) const;

    Vector2i mapCoordsToPixel(Vector2f point, const View& view) const;

    Vector2i mapCoordsToPixel(Vector2f point) const;

  protected:
    Image captureFramebuffer(unsigned name) const;

  private:
    struct Locations {
      static constexpr std::size_t CountMax = 5;
      int data[CountMax];
      std::size_t count = 0;
    };

    void drawStart(const RenderStates& states, Locations& locations, std::size_t size, Span<const RenderAttributeInfo> attributes);
    void drawFinish(const Locations& locations);

  private:
    View m_view;
    Shader m_defaultShader;
    Shader m_defaultAlphaShader;
    Texture m_defaultTexture;
  };

#ifndef DOXYGEN_SHOULD_SKIP_THIS
}
#endif
}

#endif // GF_RENDER_TARGET_H