libretro.h

/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

#ifndef BACKENDS_GRAPHICS_OPENGL_PIPELINES_LIBRETRO_H
#define BACKENDS_GRAPHICS_OPENGL_PIPELINES_LIBRETRO_H

#include "graphics/opengl/system_headers.h"

#if !USE_FORCED_GLES
#include "backends/graphics/opengl/pipelines/shader.h"

#include "common/array.h"
#include "common/fs.h"

namespace Graphics {
struct Surface;
}

namespace OpenGL {

namespace LibRetro {
struct ShaderPreset;
struct ShaderPass;
} // End of namespace LibRetro

class TextureTarget;
class LibRetroTextureTarget;

class LibRetroPipeline : public Pipeline {
public:
    LibRetroPipeline();
    ~LibRetroPipeline() override;

    void setColor(GLfloat r, GLfloat g, GLfloat b, GLfloat a) override;
    void setProjectionMatrix(const Math::Matrix4 &projectionMatrix) override;

    bool open(const Common::Path &shaderPath, Common::SearchSet &archSet);
    void close();

    /* Called by OpenGLGraphicsManager */
    void enableLinearFiltering(bool enabled) { _linearFiltering = enabled; }
    /* Called by OpenGLGraphicsManager to setup the internal objects sizes */
    void setDisplaySizes(uint inputWidth, uint inputHeight, const Common::Rect &outputRect);
    /* Called by OpenGLGraphicsManager to indicate that next draws need to be scaled. */
    void beginScaling();
    /* Called by OpenGLGraphicsManager to indicate that next draws don't need to be scaled.
     * This must be called to execute scaling. */
    void finishScaling();
    bool isAnimated() const { return _isAnimated; }

    static bool isSupportedByContext() {
        return OpenGLContext.shadersSupported
            && OpenGLContext.multitextureSupported
            && OpenGLContext.framebufferObjectSupported;
    }
private:
    void activateInternal() override;
    void deactivateInternal() override;
    void drawTextureInternal(const Texture &texture, const GLfloat *coordinates, const GLfloat *texcoords) override;

    bool loadTextures(Common::SearchSet &archSet);
    bool loadPasses(Common::SearchSet &archSet);

    void setPipelineState();
    bool setupFBOs();
    void setupPassUniforms(const uint id);
    void setShaderTexUniforms(const Common::String &prefix, Shader *shader, const Texture &texture);

    /* Pipelines used to draw all layers
     * First before the scaler then after it to draw on screen
     */
    ShaderPipeline _inputPipeline;
    ShaderPipeline _outputPipeline;
    bool _needsScaling;

    const LibRetro::ShaderPreset *_shaderPreset;

    uint _inputWidth;
    uint _inputHeight;
    Common::Rect _outputRect;

    bool _linearFiltering;

    /* Determines if preset depends on frameCount or from previous frames */
    bool _isAnimated;
    uint _frameCount;

    Common::Array<LibRetroTextureTarget> _inputTargets;
    uint _currentTarget;

    struct LibRetroTexture {
        LibRetroTexture() : textureData(nullptr), glTexture(nullptr) {}
        LibRetroTexture(Graphics::Surface *tD, Texture *glTex) : textureData(tD), glTexture(glTex) {}

        Common::String id;
        Graphics::Surface *textureData;
        Texture *glTexture;
    };
    LibRetroTexture loadTexture(const Common::Path &fileName, Common::Archive *container, Common::SearchSet &archSet);

    typedef Common::Array<LibRetroTexture> TextureArray;
    TextureArray _textures;

    struct Pass {
        Pass()
            : shaderPass(nullptr), shader(nullptr), target(nullptr), texCoords(), texSamplers(),
            inputTexture(nullptr), vertexCoord(), hasFrameCount(false), prevCount(0) {}
        Pass(const LibRetro::ShaderPass *sP, Shader *s, TextureTarget *t)
            : shaderPass(sP), shader(s), target(t), texCoords(), texSamplers(),
            inputTexture(nullptr), vertexCoord(), hasFrameCount(false), prevCount(0) {}

        const LibRetro::ShaderPass *shaderPass;
        Shader *shader;
        TextureTarget *target;

        struct TexCoordAttribute {
            Common::String name;

            enum Type {
                kTypeTexture,

                kTypePass,

                kTypePrev
            };

            Type type;

            uint index;

            TexCoordAttribute() : name(), type(), index() {}
            TexCoordAttribute(const Common::String &n, Type t, uint i) : name(n), type(t), index(i) {}
        };

        typedef Common::Array<TexCoordAttribute> TexCoordAttributeArray;
        TexCoordAttributeArray texCoords;

        void buildTexCoords(const uint id, const Common::StringArray &aliases);

        void addTexCoord(const Common::String &prefix, const TexCoordAttribute::Type type, const uint index);

        struct TextureSampler {
            uint unit;

            enum Type {
                kTypeTexture,

                kTypePass,

                kTypePrev
            };

            Type type;

            uint index;

            TextureSampler() : unit(), type(), index() {}
            TextureSampler(uint u, Type t, uint i) : unit(u), type(t), index(i) {}
        };

        typedef Common::Array<TextureSampler> TextureSamplerArray;
        TextureSamplerArray texSamplers;

        void buildTexSamplers(const uint id, const TextureArray &textures, const Common::StringArray &aliases);

        bool addTexSampler(const Common::String &name, uint *unit, const TextureSampler::Type type, const uint index, const bool prefixIsId = false);

        const Texture *inputTexture;

        GLfloat vertexCoord[2*4];

        bool hasFrameCount;

        uint prevCount;
    };

    typedef Common::Array<Pass> PassArray;
    PassArray _passes;

    void renderPass(const Pass &pass);
    void renderPassSetupCoordinates(const Pass &pass);
    void renderPassSetupTextures(const Pass &pass);
};

} // End of namespace OpenGL
#endif // !USE_FORCED_GLES

#endif