src/ascension/texture.h

/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 * Copyright 2024 Mike Becker. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *   1. Redistributions of source code must retain the above copyright
 *      notice, this list of conditions and the following disclaimer.
 *
 *   2. Redistributions in binary form must reproduce the above copyright
 *      notice, this list of conditions and the following disclaimer in the
 *      documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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 */

#ifndef ASCENSION_TEXTURE_H
#define ASCENSION_TEXTURE_H

#include "datatypes.h"

#include <SDL2/SDL_surface.h>

typedef struct asc_texture_s {
    /**
     * OpenGL texture target.
     * Not to be confused with asc_texture_target!
     */
    unsigned target;
    unsigned tex_id;
    unsigned width;
    unsigned height;
    unsigned refcount;
    // TODO: add support for texture atlas - idea: rects are defined in AscTexture and can be indexed
} AscTexture;

enum asc_texture_target {
    ASC_TEXTURE_RECTANGLE,
    ASC_TEXTURE_2D
};

enum asc_texture_min_filter {
    ASC_TEXTURE_MIN_FILTER_NEAREST,
    ASC_TEXTURE_MIN_FILTER_LINEAR,
    ASC_TEXTURE_MIN_FILTER_NEAREST_MIPMAP_NEAREST,
    ASC_TEXTURE_MIN_FILTER_LINEAR_MIPMAP_NEAREST,
    ASC_TEXTURE_MIN_FILTER_NEAREST_MIPMAP_LINEAR,
    ASC_TEXTURE_MIN_FILTER_LINEAR_MIPMAP_LINEAR
};

enum asc_texture_mag_filter {
    ASC_TEXTURE_MAG_FILTER_NEAREST,
    ASC_TEXTURE_MAG_FILTER_LINEAR
};

enum asc_texture_scale_mode {
    ASC_TEXTURE_SCALE_FIT,
    ASC_TEXTURE_SCALE_REPEAT
};

void asc_texture_init(
        AscTexture *tex,
        unsigned count,
        enum asc_texture_target target,
        enum asc_texture_min_filter min_filter,
        enum asc_texture_mag_filter mag_filter
);

void asc_texture_destroy(AscTexture *tex, unsigned count);

#define asc_texture_init_rectangle(tex, count) \
    asc_texture_init(tex, count, ASC_TEXTURE_RECTANGLE, \
        ASC_TEXTURE_MIN_FILTER_NEAREST, ASC_TEXTURE_MAG_FILTER_NEAREST)

#define asc_texture_init_2d(tex, count) \
    asc_texture_init(tex, count, ASC_TEXTURE_2D, \
        ASC_TEXTURE_MIN_FILTER_LINEAR, ASC_TEXTURE_MAG_FILTER_LINEAR)

void asc_texture_bind(AscTexture const *tex, int uniform_location, int unit);

void asc_texture_from_surface(AscTexture *tex, SDL_Surface const *surface);

void asc_texture_from_file(AscTexture *tex, const char *name);


/**
 * Calculates UV scaling factors depending on texture and surface dimensions.
 *
 * @param tex the texture
 * @param surface_dimension the dimensions of the surface the texture is applied to
 * @param factors additional scaling factors
 * @return the calculated UV scaling factors
 */
asc_vec2f asc_texture_calculate_uv_scale(const AscTexture *tex, asc_vec2u surface_dimension, asc_vec2f factors);

#endif //ASCENSION_TEXTURE_H