/*
    This file is part of Magnum.

    Copyright © 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019,
                2020, 2021, 2022, 2023 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.
*/

#if defined(SHADER_STORAGE_BUFFERS) && !defined(GL_ES)
#extension GL_ARB_shader_storage_buffer_object: require
#endif

#ifdef MULTI_DRAW
#ifndef GL_ES
#extension GL_ARB_shader_draw_parameters: require
#else /* covers WebGL as well */
#extension GL_ANGLE_multi_draw: require
#endif
#endif

#ifndef NEW_GLSL
#define in attribute
#define out varying
#endif

#ifndef RUNTIME_CONST
#define const
#endif

/* Uniforms */

#ifndef UNIFORM_BUFFERS
#ifdef EXPLICIT_UNIFORM_LOCATION
layout(location = 0)
#endif
#ifdef TWO_DIMENSIONS
uniform highp mat3 transformationProjectionMatrix
    #ifndef GL_ES
    = mat3(1.0)
    #endif
    ;
#elif defined(THREE_DIMENSIONS)
uniform highp mat4 transformationProjectionMatrix
    #ifndef GL_ES
    = mat4(1.0)
    #endif
    ;
#else
#error
#endif

#ifdef TEXTURE_TRANSFORMATION
#ifdef EXPLICIT_UNIFORM_LOCATION
layout(location = 1)
#endif
uniform mediump mat3 textureMatrix
    #ifndef GL_ES
    = mat3(1.0)
    #endif
    ;
#endif

/* Uniform / shader storage buffers */

#else
/* For SSBOs, the per-draw arrays are unbounded */
#ifdef SHADER_STORAGE_BUFFERS
#define DRAW_COUNT
#define BUFFER_OR_UNIFORM buffer
#define BUFFER_READONLY readonly
#else
#define BUFFER_OR_UNIFORM uniform
#define BUFFER_READONLY
#endif

/* With SSBOs DRAW_COUNT is defined to be empty, +0 makes the condition not
   cause a compile error */
#if defined(SHADER_STORAGE_BUFFERS) || DRAW_COUNT+0 > 1
#ifdef EXPLICIT_UNIFORM_LOCATION
layout(location = 0)
#endif
uniform highp uint drawOffset
    #ifndef GL_ES
    = 0u
    #endif
    ;
#else
#define drawOffset 0u
#endif

layout(std140
    #if defined(EXPLICIT_BINDING) || defined(SHADER_STORAGE_BUFFERS)
    , binding = 1
    #endif
) BUFFER_OR_UNIFORM TransformationProjection {
    BUFFER_READONLY highp
        #ifdef TWO_DIMENSIONS
        /* Can't be a mat3 because of ANGLE, see DrawUniform in Phong.vert for
           details */
        mat3x4
        #elif defined(THREE_DIMENSIONS)
        mat4
        #else
        #error
        #endif
    transformationProjectionMatrices[DRAW_COUNT];
};

#ifdef TEXTURE_TRANSFORMATION
struct TextureTransformationUniform {
    highp vec4 rotationScaling;
    highp vec4 offsetReservedReserved;
    #define textureTransformation_offset offsetReservedReserved.xy
};

layout(std140
    #if defined(EXPLICIT_BINDING) || defined(SHADER_STORAGE_BUFFERS)
    , binding = 3
    #endif
) BUFFER_OR_UNIFORM TextureTransformation {
    BUFFER_READONLY TextureTransformationUniform textureTransformations[DRAW_COUNT];
};
#endif
#endif

/* Inputs */

#ifdef EXPLICIT_ATTRIB_LOCATION
layout(location = POSITION_ATTRIBUTE_LOCATION)
#endif
#ifdef TWO_DIMENSIONS
in highp vec2 position;
#elif defined(THREE_DIMENSIONS)
in highp vec4 position;
#else
#error
#endif

#ifdef EXPLICIT_ATTRIB_LOCATION
layout(location = TEXTURECOORDINATES_ATTRIBUTE_LOCATION)
#endif
in mediump vec2 textureCoordinates;

/* Outputs */

out mediump vec2 interpolatedTextureCoordinates;

#ifdef MULTI_DRAW
flat out highp uint drawId;
#endif

void main() {
    #ifdef UNIFORM_BUFFERS
    #ifdef MULTI_DRAW
    drawId = drawOffset + uint(
        #ifndef GL_ES
        gl_DrawIDARB /* Using GL_ARB_shader_draw_parameters, not GLSL 4.6 */
        #else
        gl_DrawID
        #endif
        );
    #else
    #define drawId drawOffset
    #endif

    #ifdef TWO_DIMENSIONS
    highp const mat3 transformationProjectionMatrix = mat3(transformationProjectionMatrices[drawId]);
    #elif defined(THREE_DIMENSIONS)
    highp const mat4 transformationProjectionMatrix = transformationProjectionMatrices[drawId];
    #else
    #error
    #endif
    #ifdef TEXTURE_TRANSFORMATION
    mediump const mat3 textureMatrix = mat3(textureTransformations[drawId].rotationScaling.xy, 0.0, textureTransformations[drawId].rotationScaling.zw, 0.0, textureTransformations[drawId].textureTransformation_offset, 1.0);
    #endif
    #endif

    #ifdef TWO_DIMENSIONS
    gl_Position.xywz = vec4(transformationProjectionMatrix*vec3(position, 1.0), 0.0);
    #elif defined(THREE_DIMENSIONS)
    gl_Position = transformationProjectionMatrix*position;
    #else
    #error
    #endif

    interpolatedTextureCoordinates =
        #ifdef TEXTURE_TRANSFORMATION
        (textureMatrix*vec3(textureCoordinates, 1.0)).xy
        #else
        textureCoordinates
        #endif
        ;
}