shader.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 GRAPHICS_OPENGL_SHADER_H
#define GRAPHICS_OPENGL_SHADER_H

#include "common/file.h"
#include "common/array.h"
#include "common/ptr.h"

#include "math/matrix3.h"
#include "math/matrix4.h"
#include "math/vector2d.h"
#include "math/vector3d.h"
#include "math/vector4d.h"

#include "graphics/opengl/debug.h"
#include "graphics/opengl/system_headers.h"

namespace OpenGL {

struct VertexAttrib {
    VertexAttrib(uint32 idx, const char *name) :
        _enabled(false), _idx(idx), _name(name), _vbo(0), _size(0),
        _type(GL_FLOAT), _normalized(false), _stride(0), _pointer(0) {}
    bool _enabled;
    uint32 _idx;
    Common::String _name;
    GLuint _vbo;
    GLint _size;
    GLenum _type;
    bool _normalized;
    GLsizei _stride;
    uintptr _pointer;
    float _const[4];
};

class Shader {
    typedef Common::HashMap<Common::String, GLint> UniformsMap;

public:
    Shader();
    ~Shader();
    Shader *clone() {
        return new Shader(*this);
    }

    void use(bool forceReload = false);

    bool setUniform(const Common::String &uniform, const Math::Matrix4 &m) {
        GLint pos = getUniformLocation(uniform);
        if (pos != -1) {
            use();
            GL_CALL(glUniformMatrix4fv(pos, 1, GL_FALSE, m.getData()));
            return true;
        } else {
            return false;
        }
    }

    bool setUniform(const Common::String &uniform, const Math::Matrix3 &m) {
        GLint pos = getUniformLocation(uniform);
        if (pos != -1) {
            use();
            GL_CALL(glUniformMatrix3fv(pos, 1, GL_FALSE, m.getData()));
            return true;
        } else {
            return false;
        }
    }

    bool setUniform(const Common::String &uniform, const Math::Vector4d &v) {
        GLint pos = getUniformLocation(uniform);
        if (pos != -1) {
            use();
            GL_CALL(glUniform4fv(pos, 1, v.getData()));
            return true;
        } else {
            return false;
        }
    }

    bool setUniform(const Common::String &uniform, const Math::Vector3d &v) {
        GLint pos = getUniformLocation(uniform);
        if (pos != -1) {
            use();
            GL_CALL(glUniform3fv(pos, 1, v.getData()));
            return true;
        } else {
            return false;
        }
    }

    bool setUniform(const Common::String &uniform, const Math::Vector2d &v) {
        GLint pos = getUniformLocation(uniform);
        if (pos != -1) {
            use();
            GL_CALL(glUniform2fv(pos, 1, v.getData()));
            return true;
        } else {
            return false;
        }
    }

    bool setUniform(const Common::String &uniform, unsigned int x) {
        GLint pos = getUniformLocation(uniform);
        if (pos != -1) {
            use();
            GL_CALL(glUniform1i(pos, x));
            return true;
        } else {
            return false;
        }
    }

    bool setUniform(const Common::String &uniform, const int size, const int *array) {
        GLint pos = getUniformLocation(uniform);
        if (pos != -1) {
            use();
            GL_CALL(glUniform1iv(pos, size, array));
            return true;
        } else {
            return false;
        }
    }

    // Different name to avoid overload ambiguity
    bool setUniform1f(const Common::String &uniform, float f) {
        GLint pos = getUniformLocation(uniform);
        if (pos != -1) {
            use();
            GL_CALL(glUniform1f(pos, f));
            return true;
        } else {
            return false;
        }
    }

    GLint getUniformLocation(const Common::String &uniform) const {
        UniformsMap::iterator kv = _uniforms->find(uniform);
        if (kv == _uniforms->end()) {
            GLint ret;
            GL_ASSIGN(ret, glGetUniformLocation(*_shaderNo, uniform.c_str()));
            _uniforms->setVal(uniform, ret);
            return ret;
        } else {
            return kv->_value;
        }
    }

    void enableVertexAttribute(const char *attrib, GLint size, GLenum type, GLboolean normalized, GLsizei stride, const void *pointer);
    void enableVertexAttribute(const char *attrib, GLuint vbo, GLint size, GLenum type, GLboolean normalized, GLsizei stride, uint32 offset);
    void disableVertexAttribute(const char *attrib, int size, const float *data);
    template <int r>
    void disableVertexAttribute(const char *attrib, const Math::Matrix<r,1> &m) {
        disableVertexAttribute(attrib, r, m.getData());
    }
    bool addAttribute(const char *attrib);
    VertexAttrib & getAttributeAt(uint32 idx);
    VertexAttrib & getAttribute(const char *attrib);

    static GLuint createBuffer(GLenum target, GLsizeiptr size, const GLvoid* data, GLenum usage = GL_STATIC_DRAW);
    static void freeBuffer(GLuint vbo);

    static Shader *fromFiles(const char *vertex, const char *fragment, const char *const *attributes, int compatGLSLVersion = 120);
    static Shader *fromFiles(const char *shared, const char *const *attributes, int compatGLSLVersion = 120) {
        return fromFiles(shared, shared, attributes, compatGLSLVersion);
    }

    static Shader *fromStrings(const Common::String &name, const char *vertex, const char *fragment, const char *const *attributes, int compatGLSLVersion = 0);

    bool loadFromFiles(const char *vertex, const char *fragment, const char *const *attributes, int compatGLSLVersion = 120);
    bool loadFromStrings(const Common::String &name, const char *vertex, const char *fragment, const char *const *attributes, int compatGLSLVersion = 0);

    bool loadFromStringsArray(const Common::String &name,
            size_t vertexCount, const char *const *vertex,
            size_t fragmentCount, const char *const *fragment,
            const char *const *attributes);

    void unbind();

    Common::String &getError() { return _error; }
    bool hasError() { return !_error.empty(); }

private:
    bool loadShader(const Common::String &name, GLuint vertexShader, GLuint fragmentShader, const char *const *attributes);

    GLuint createCompatShader(const char *shaderSource, GLenum shaderType, const Common::String &name, int compatGLSLVersion);
    GLuint createDirectShader(size_t shaderSourcesCount, const char *const *shaderSources, GLenum shaderType, const Common::String &name);
    GLuint loadShaderFromFile(const char *base, const char *extension, GLenum shaderType, int compatGLSLVersion);

    // Since this class is cloned using the implicit copy constructor,
    // a reference counting pointer is used to ensure deletion of the OpenGL
    // program upon destruction of the last clone.
    Common::SharedPtr<GLuint> _shaderNo;

    Common::String _name;

    Common::Array<VertexAttrib> _attributes;
    Common::SharedPtr<UniformsMap> _uniforms;

    static Shader *_previousShader;
    static uint32 previousNumAttributes;

    Common::String _error;
};

} // End of namespace OpenGL

#endif