magnum/src/Shader.h

#ifndef Magnum_Shader_h
#define Magnum_Shader_h
/*
    This file is part of Magnum.

    Copyright © 2010, 2011, 2012, 2013 Vladimír Vondruš <mosra@centrum.cz>

    Permission is hereby granted, free of charge, to any person obtaining a
    copy of this software and associated documentation files (the "Software"),
    to deal in the Software without restriction, including without limitation
    the rights to use, copy, modify, merge, publish, distribute, sublicense,
    and/or sell copies of the Software, and to permit persons to whom the
    Software is furnished to do so, subject to the following conditions:

    The above copyright notice and this permission notice shall be included
    in all copies or substantial portions of the Software.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
    THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
    FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
    DEALINGS IN THE SOFTWARE.
*/

/** @file
 * @brief Class Magnum::Shader
 */

#include <vector>
#include <string>

#include "Magnum.h"
#include "Context.h"

#include "magnumVisibility.h"

namespace Magnum {

/**
@brief %Shader

See AbstractShaderProgram for more information.
 */
class MAGNUM_EXPORT Shader {
    Shader(const Shader&) = delete;
    Shader& operator=(const Shader&) = delete;

    public:
        /**
         * @brief %Shader type
         *
         * @see @ref Shader(Version, Type),
         *      @ref maxAtomicCounterBuffers(),
         *      @ref maxAtomicCounters(),
         *      @ref maxImageUniforms()
         *      @ref maxShaderStorageBlocks(),
         *      @ref maxTextureImageUnits(),
         *      @ref maxUniformBlocks(),
         *      @ref maxUniformComponents(),
         *      @ref maxCombinedUniformComponents()
         */
        enum class Type: GLenum {
            Vertex = GL_VERTEX_SHADER,      /**< Vertex shader */

            #ifndef MAGNUM_TARGET_GLES
            /**
             * Tessellation control shader
             * @requires_gl40 %Extension @extension{ARB,tessellation_shader}
             * @requires_gl Tessellation shaders are not available in OpenGL ES.
             */
            TessellationControl = GL_TESS_CONTROL_SHADER,

            /**
             * Tessellation evaluation shader
             * @requires_gl40 %Extension @extension{ARB,tessellation_shader}
             * @requires_gl Tessellation shaders are not available in OpenGL ES.
             */
            TessellationEvaluation = GL_TESS_EVALUATION_SHADER,

            /**
             * Geometry shader
             * @requires_gl32 %Extension @extension{ARB,geometry_shader4}
             * @requires_gl Geometry shaders are not available in OpenGL ES.
             */
            Geometry = GL_GEOMETRY_SHADER,

            /**
             * Compute shader
             * @requires_gl43 %Extension @extension{ARB,compute_shader}
             * @requires_gl Compute shaders are not available in OpenGL ES.
             */
            Compute = GL_COMPUTE_SHADER,
            #endif

            Fragment = GL_FRAGMENT_SHADER   /**< Fragment shader */
        };

        /**
         * @brief Max supported component count on vertex shader output
         *
         * The result is cached, repeated queries don't result in repeated
         * OpenGL calls. In OpenGL ES 2.0 the four-component vector count is
         * queried and multiplied with 4.
         * @see @fn_gl{Get} with @def_gl{MAX_VERTEX_OUTPUT_COMPONENTS},
         *      @def_gl{MAX_VARYING_COMPONENTS} in OpenGL <3.2 or
         *      @def_gl{MAX_VARYING_VECTORS} in OpenGL ES 2.0
         */
        static Int maxVertexOutputComponents();

        /** @todo `GL_MAX_PATCH_VERTICES`, `GL_MAX_TESS_GEN_LEVEL`, `GL_MAX_TESS_PATCH_COMPONENTS` when @extension{ARB,tessellation_shader} is done */

        #ifndef MAGNUM_TARGET_GLES
        /**
         * @brief Max supported component count of tessellation control shader input vertex
         *
         * The result is cached, repeated queries don't result in repeated
         * OpenGL calls. If extension @extension{ARB,tessellation_shader}
         * is not available, returns `0`.
         * @requires_gl Tessellation shaders are not available in OpenGL ES.
         * @see @fn_gl{Get} with @def_gl{MAX_TESS_CONTROL_INPUT_COMPONENTS}
         */
        static Int maxTessellationControlInputComponents();

        /**
         * @brief Max supported component count of tessellation control shader output vertex
         *
         * The result is cached, repeated queries don't result in repeated
         * OpenGL calls. If extension @extension{ARB,tessellation_shader}
         * is not available, returns `0`.
         * @requires_gl Tessellation shaders are not available in OpenGL ES.
         * @see @fn_gl{Get} with @def_gl{MAX_TESS_CONTROL_OUTPUT_COMPONENTS}
         */
        static Int maxTessellationControlOutputComponents();

        /**
         * @brief Max supported component count of all tessellation control shader output vertices combined
         *
         * The result is cached, repeated queries don't result in repeated
         * OpenGL calls. If extension @extension{ARB,tessellation_shader}
         * is not available, returns `0`.
         * @requires_gl Tessellation shaders are not available in OpenGL ES.
         * @see @fn_gl{Get} with @def_gl{MAX_TESS_CONTROL_TOTAL_OUTPUT_COMPONENTS}
         */
        static Int maxTessellationControlTotalOutputComponents();

        /**
         * @brief Max supported component count of tessellation evaluation shader input vertex
         *
         * The result is cached, repeated queries don't result in repeated
         * OpenGL calls. If extension @extension{ARB,tessellation_shader}
         * is not available, returns `0`.
         * @requires_gl Tessellation shaders are not available in OpenGL ES.
         * @see @fn_gl{Get} with @def_gl{MAX_TESS_EVALUATION_INPUT_COMPONENTS}
         */
        static Int maxTessellationEvaluationInputComponents();

        /**
         * @brief Max supported component count of tessellation evaluation shader output vertex
         *
         * The result is cached, repeated queries don't result in repeated
         * OpenGL calls. If extension @extension{ARB,tessellation_shader}
         * is not available, returns `0`.
         * @requires_gl Tessellation shaders are not available in OpenGL ES.
         * @see @fn_gl{Get} with @def_gl{MAX_TESS_EVALUATION_OUTPUT_COMPONENTS}
         */
        static Int maxTessellationEvaluationOutputComponents();

        /**
         * @brief Max supported component count of geometry shader input vertex
         *
         * The result is cached, repeated queries don't result in repeated
         * OpenGL calls. If extension @extension{ARB,geometry_shader4}
         * is not available, returns `0`.
         * @requires_gl Geometry shaders are not available in OpenGL ES.
         * @see @fn_gl{Get} with @def_gl{MAX_GEOMETRY_INPUT_COMPONENTS}
         */
        static Int maxGeometryInputComponents();

        /**
         * @brief Max supported component count of geometry shader output vertex
         *
         * The result is cached, repeated queries don't result in repeated
         * OpenGL calls. If extension @extension{ARB,geometry_shader4}
         * is not available, returns `0`.
         * @requires_gl Geometry shaders are not available in OpenGL ES.
         * @see @fn_gl{Get} with @def_gl{MAX_GEOMETRY_OUTPUT_COMPONENTS}
         */
        static Int maxGeometryOutputComponents();

        /**
         * @brief Max supported component count of all geometry shader output vertices combined
         *
         * The result is cached, repeated queries don't result in repeated
         * OpenGL calls. If extension @extension{ARB,geometry_shader4}
         * is not available, returns `0`.
         * @requires_gl Geometry shaders are not available in OpenGL ES.
         * @see @fn_gl{Get} with @def_gl{MAX_GEOMETRY_TOTAL_OUTPUT_COMPONENTS}
         */
        static Int maxGeometryTotalOutputComponents();
        #endif

        /**
         * @brief Max supported component count on fragment shader input
         *
         * The result is cached, repeated queries don't result in repeated
         * OpenGL calls. In OpenGL ES 2.0 the four-component vector count is
         * queried and multiplied with 4.
         * @see @fn_gl{Get} with @def_gl{MAX_FRAGMENT_INPUT_COMPONENTS},
         *      @def_gl{MAX_VARYING_COMPONENTS} in OpenGL <3.2 or
         *      @def_gl{MAX_VARYING_VECTORS} in OpenGL ES 2.0
         */
        static Int maxFragmentInputComponents();

        /**
         * @brief Max supported uniform component count in default block
         *
         * The result is cached, repeated queries don't result in repeated
         * OpenGL calls. If particular shader stage is not available, returns
         * `0`. In OpenGL ES 2.0 the four-component vector count is queried and
         * multiplied with 4.
         * @see @ref maxCombinedUniformComponents(),
         *      @fn_gl{Get} with @def_gl{MAX_VERTEX_UNIFORM_COMPONENTS},
         *      @def_gl{MAX_TESS_CONTROL_UNIFORM_COMPOENTS},
         *      @def_gl{MAX_TESS_EVALUATION_UNIFORM_COMPONENTS},
         *      @def_gl{MAX_GEOMETRY_UNIFORM_COMPONENTS},
         *      @def_gl{MAX_COMPUTE_UNIFORM_COMPONENTS},
         *      @def_gl{MAX_FRAGMENT_UNIFORM_COMPONENTS} or
         *      @def_gl{MAX_VERTEX_UNIFORM_VECTORS},
         *      @def_gl{MAX_FRAGMENT_UNIFORM_VECTORS} in OpenGL ES 2.0
         */
        static Int maxUniformComponents(Type type);

        #ifndef MAGNUM_TARGET_GLES
        /**
         * @brief Max supported atomic counter buffer count
         *
         * The result is cached, repeated queries don't result in repeated
         * OpenGL calls. If extension @extension{ARB,shader_atomic_counters} or
         * particular shader stage is not available, returns `0`.
         * @requires_gl Atomic counters are not available in OpenGL ES.
         * @see @ref maxCombinedAtomicCounterBuffers(), @ref maxAtomicCounters(),
         *      @fn_gl{Get} with @def_gl{MAX_VERTEX_ATOMIC_COUNTER_BUFFERS},
         *      @def_gl{MAX_TESS_CONTROL_ATOMIC_COUNTER_BUFFERS},
         *      @def_gl{MAX_TESS_EVALUATION_ATOMIC_COUNTER_BUFFERS},
         *      @def_gl{MAX_GEOMETRY_ATOMIC_COUNTER_BUFFERS},
         *      @def_gl{MAX_COMPUTE_ATOMIC_COUNTER_BUFFERS} or
         *      @def_gl{MAX_FRAGMENT_ATOMIC_COUNTER_BUFFERS}
         */
        static Int maxAtomicCounterBuffers(Type type);

        /**
         * @brief Max supported atomic counter buffer count for all stages combined
         *
         * The result is cached, repeated queries don't result in repeated
         * OpenGL calls. If extension @extension{ARB,shader_atomic_counters} is
         * not available, returns `0`.
         * @requires_gl Atomic counters are not available in OpenGL ES.
         * @see @ref maxAtomicCounterBuffers(), @ref maxCombinedAtomicCounters(),
         *      @fn_gl{Get} with @def_gl{MAX_COMBINED_ATOMIC_COUNTER_BUFFERS}
         */
        static Int maxCombinedAtomicCounterBuffers();

        /**
         * @brief Max supported atomic counter count
         *
         * The result is cached, repeated queries don't result in repeated
         * OpenGL calls. If extension @extension{ARB,shader_atomic_counters} or
         * particular shader stage is not available, returns `0`.
         * @requires_gl Atomic counters are not available in OpenGL ES.
         * @see @ref maxCombinedAtomicCounters(), @ref maxAtomicCounterBuffers(),
         *      @fn_gl{Get} with @def_gl{MAX_VERTEX_ATOMIC_COUNTERS},
         *      @def_gl{MAX_TESS_CONTROL_ATOMIC_COUNTERS},
         *      @def_gl{MAX_TESS_EVALUATION_ATOMIC_COUNTERS},
         *      @def_gl{MAX_GEOMETRY_ATOMIC_COUNTERS},
         *      @def_gl{MAX_COMPUTE_ATOMIC_COUNTERS} or
         *      @def_gl{MAX_FRAGMENT_ATOMIC_COUNTERS}
         */
        static Int maxAtomicCounters(Type type);

        /**
         * @brief Max supported atomic counter count for all stages combined
         *
         * The result is cached, repeated queries don't result in repeated
         * OpenGL calls. If extension @extension{ARB,shader_atomic_counters} is
         * not available, returns `0`.
         * @requires_gl Atomic counters are not available in OpenGL ES.
         * @see @ref maxAtomicCounters(), @ref maxCombinedAtomicCounterBuffers(),
         *      @fn_gl{Get} with @def_gl{MAX_COMBINED_ATOMIC_COUNTERS}
         */
        static Int maxCombinedAtomicCounters();

        /**
         * @brief Max supported image uniform count
         *
         * The result is cached, repeated queries don't result in repeated
         * OpenGL calls. If extension @extension{ARB,shader_image_load_store}
         * or particular shader stage is not available, returns `0`.
         * @requires_gl Image load/store is not available in OpenGL ES.
         * @see @ref maxCombinedImageUniforms(),
         *      @fn_gl{Get} with @def_gl{MAX_VERTEX_IMAGE_UNIFORMS},
         *      @def_gl{MAX_TESS_CONTROL_IMAGE_UNIFORMS},
         *      @def_gl{MAX_TESS_EVALUATION_IMAGE_UNIFORMS},
         *      @def_gl{MAX_GEOMETRY_IMAGE_UNIFORMS},
         *      @def_gl{MAX_COMPUTE_IMAGE_UNIFORMS} or
         *      @def_gl{MAX_FRAGMENT_IMAGE_UNIFORMS}
         */
        static Int maxImageUniforms(Type type);

        /**
         * @brief Max supported image uniform count for all stages combined
         *
         * The result is cached, repeated queries don't result in repeated
         * OpenGL calls. If extension @extension{ARB,shader_image_load_store}
         * is not available, returns `0`.
         * @requires_gl Image load/store is not available in OpenGL ES.
         * @see @ref maxImageUniforms(),
         *      @fn_gl{Get} with @def_gl{MAX_COMBINED_IMAGE_UNIFORMS}
         */
        static Int maxCombinedImageUniforms();

        /**
         * @brief Max supported shader storage block count
         *
         * The result is cached, repeated queries don't result in repeated
         * OpenGL calls. If extension @extension{ARB,shader_storage_buffer_object}
         * or particular shader stage is not available, returns `0`.
         * @requires_gl Shader storage is not available in OpenGL ES.
         * @see @ref maxCombinedShaderStorageBlocks(),
         *      @fn_gl{Get} with @def_gl{MAX_VERTEX_SHADER_STORAGE_BLOCKS},
         *      @def_gl{MAX_TESS_CONTROL_SHADER_STORAGE_BLOCKS},
         *      @def_gl{MAX_TESS_EVALUATION_SHADER_STORAGE_BLOCKS},
         *      @def_gl{MAX_GEOMETRY_SHADER_STORAGE_BLOCKS},
         *      @def_gl{MAX_COMPUTE_SHADER_STORAGE_BLOCKS} or
         *      @def_gl{MAX_FRAGMENT_SHADER_STORAGE_BLOCKS}
         */
        static Int maxShaderStorageBlocks(Type type);

        /**
         * @brief Max supported shader storage block count for all stages combined
         *
         * The result is cached, repeated queries don't result in repeated
         * OpenGL calls. If extension @extension{ARB,shader_storage_buffer_object}
         * is not available, returns `0`.
         * @requires_gl Shader storage is not available in OpenGL ES.
         * @see @ref maxShaderStorageBlocks(),
         *      @fn_gl{Get} with @def_gl{MAX_COMBINED_SHADER_STORAGE_BLOCKS}
         */
        static Int maxCombinedShaderStorageBlocks();
        #endif

        /**
         * @brief Max supported texture image unit count
         *
         * The result is cached, repeated queries don't result in repeated
         * OpenGL calls. If particular shader stage is not available, returns
         * `0`.
         * @see @ref maxCombinedTextureImageUnits(),
         *      @fn_gl{Get} with @def_gl{MAX_VERTEX_TEXTURE_IMAGE_UNITS},
         *      @fn_gl{MAX_TESS_CONTROL_TEXTURE_IMAGE_UNITS},
         *      @fn_gl{MAX_TESS_EVALUATION_TEXTURE_IMAGE_UNITS},
         *      @fn_gl{MAX_GEOMETRY_TEXTURE_IMAGE_UNITS},
         *      @fn_gl{MAX_COMPUTE_TEXTURE_IMAGE_UNITS},
         *      @fn_gl{MAX_TEXTURE_IMAGE_UNITS}
         */
        static Int maxTextureImageUnits(Type type);

        /**
         * @brief Max supported texture image unit count for all stages combined
         *
         * The result is cached, repeated queries don't result in repeated
         * OpenGL calls.
         * @see @ref AbstractTexture::maxLayers(), @ref maxTextureImageUnits(),
         *      @fn_gl{Get} with @def_gl{MAX_COMBINED_TEXTURE_IMAGE_UNITS}
         */
        static Int maxCombinedTextureImageUnits();

        #ifndef MAGNUM_TARGET_GLES2
        /**
         * @brief Max supported uniform block count
         *
         * The result is cached, repeated queries don't result in repeated
         * OpenGL calls. If extension @extension{ARB,uniform_buffer_objects} or
         * particular shader stage is not available, returns `0`.
         * @requires_gles30 Uniform blocks are not available in OpenGL ES 2.0.
         * @see @ref maxCombinedUniformBlocks(), @ref maxUniformComponents(),
         *      @ref maxCombinedUniformComponents(),
         *      @fn_gl{Get} with @def_gl{MAX_VERTEX_UNIFORM_BLOCKS},
         *      @def_gl{MAX_TESS_CONTROL_UNIFORM_BLOCKS},
         *      @def_gl{MAX_TESS_EVALUATION_UNIFORM_BLOCKS},
         *      @def_gl{MAX_GEOMETRY_UNIFORM_BLOCKS},
         *      @def_gl{MAX_COMPUTE_UNIFORM_BLOCKS} or
         *      @def_gl{MAX_FRAGMENT_UNIFORM_BLOCKS}
         */
        static Int maxUniformBlocks(Type type);

        /**
         * @brief Max supported uniform block count for all stages combined
         *
         * The result is cached, repeated queries don't result in repeated
         * OpenGL calls. If extension @extension{ARB,uniform_buffer_objects} is
         * not available, returns `0`.
         * @requires_gles30 Uniform blocks are not available in OpenGL ES 2.0.
         * @see @ref maxUniformBlocks(), @ref maxUniformComponents(),
         *      @ref maxCombinedUniformComponents(),
         *      @fn_gl{Get} with @def_gl{MAX_COMBINED_UNIFORM_BLOCKS}
         */
        static Int maxCombinedUniformBlocks();
        #endif

        #ifndef MAGNUM_TARGET_GLES2
        /**
         * @brief Max supported uniform component count in all blocks combined
         *
         * The result is cached, repeated queries don't result in repeated
         * OpenGL calls. If extension @extension{ARB,uniform_buffer_objects}
         * or particular shader stage is not available, returns `0`.
         * @requires_gles30 Uniform blocks are not available in OpenGL ES 2.0.
         * @see @ref maxUniformComponents(), @ref maxUniformBlocks(),
         *      @fn_gl{Get} with @def_gl{MAX_COMBINED_VERTEX_UNIFORM_COMPONENTS},
         *      @def_gl{MAX_COMBINED_TESS_CONTROL_UNIFORM_COMPONENTS},
         *      @def_gl{MAX_COMBINED_TESS_EVALUATION_UNIFORM_COMPONENTS},
         *      @def_gl{MAX_COMBINED_GEOMETRY_UNIFORM_COMPONENTS},
         *      @def_gl{MAX_COMBINED_COMPUTE_UNIFORM_COMPONENTS} or
         *      @def_gl{MAX_COMBINED_FRAGMENT_UNIFORM_COMPONENTS}
         */
        static Int maxCombinedUniformComponents(Type type);
        #endif

        /**
         * @brief Constructor
         * @param version   Target version
         * @param type      %Shader type
         *
         * Creates empty OpenGL shader and adds @c \#version directive at the
         * beginning. Sources can be added with addSource() or addFile().
         * @see @fn_gl{CreateShader}
         */
        explicit Shader(Version version, Type type);

        /**
         * @brief Destructor
         *
         * Deletes associated OpenGL shader.
         * @see @fn_gl{DeleteShader}
         */
        ~Shader();

        /** @brief Move constructor */
        Shader(Shader&& other);

        /** @brief Move assignment operator */
        Shader& operator=(Shader&& other);

        /** @brief OpenGL shader ID */
        GLuint id() const { return _id; }

        /**
         * @brief Add shader source
         * @param source    String with shader source
         * @return Reference to self (for method chaining)
         *
         * Adds given source to source list, preceeded with @c \#line directive
         * marking first line of the source as `n(1)` where n is number of
         * added source. If passed string is empty, the function does nothing.
         * @see addFile()
         */
        Shader& addSource(std::string source);

        /**
         * @brief Add source file
         * @param filename  Name of source file to read from
         * @return Reference to self (for method chaining)
         *
         * The file must exist and must be readable. Calls addSource() with
         * the contents.
         */
        Shader& addFile(const std::string& filename);

        /**
         * @brief Compile shader
         *
         * Returns `false` if compilation failed, `true` otherwise. Compiler
         * message (if any) is printed to error output.
         * @see @fn_gl{ShaderSource}, @fn_gl{CompileShader}, @fn_gl{GetShader}
         *      with @def_gl{COMPILE_STATUS} and @def_gl{INFO_LOG_LENGTH},
         *      @fn_gl{GetShaderInfoLog}
         */
        bool compile();

    private:
        Type _type;
        GLuint _id;

        std::vector<std::string> sources;
};

}

#endif