src/text.c

/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 * Copyright 2023 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
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include "ascension/text.h"

#include "ascension/error.h"
#include "ascension/context.h"
#include "ascension/shader.h"
#include "ascension/constants.h"

#include <assert.h>
#include <cx/printf.h>

typedef struct asc_text_shader_s {
    AscShaderProgram program;
    asc_uniform_loc tex;
} AscTextShader;

AscShaderProgram *asc_text_shader_create(cx_attr_unused int unused) {
    AscShaderCodes codes;
    // TODO: with more advanced feature we want to create specific text shaders
    if (asc_shader_load_code_files((AscShaderCodeInfo){
        .files.vtx = "sprite_vtx.glsl",
        .files.frag = "sprite_frag.glsl",
        .defines.frag = "#define USE_RECT",
    }, &codes)) {
        asc_error("Loading text shader failed.");
        return NULL;
    }
    AscShaderProgram *shader = asc_shader_create(codes, sizeof(*shader));
    if (asc_shader_invalid(shader)) {
        asc_shader_free_codes(codes);
        return shader;
    }
    asc_ptr_cast(AscTextShader, text_shader, shader);
    text_shader->tex = asc_shader_get_uniform_loc(shader, "tex");
    asc_shader_free_codes(codes);

    asc_error_catch_all_gl();

    return shader;
}

static void asc_text_update(AscSceneNode *node) {
    asc_ptr_cast(AscText, text, node);

    // Render text onto a surface
    TTF_Font *font = asc_font_load(text->font);
    if (font == NULL) {
        // cannot load font - hide the text node to avoid errors when trying to draw
        asc_set_flag(node->flags, ASC_SCENE_NODE_HIDDEN);
        return;
    }
    static int alignments[] = {
            TTF_WRAPPED_ALIGN_LEFT,
            TTF_WRAPPED_ALIGN_CENTER,
            TTF_WRAPPED_ALIGN_RIGHT
    };
    TTF_SetFontWrappedAlign(
            font, alignments[text->base.flags & ASC_TEXT_ALIGNMENT_MASK]);
    SDL_Surface *surface = TTF_RenderUTF8_Blended_Wrapped(
            font, text->text.ptr, asc_col_sdl(text->color), text->max_width
    );
    if (surface == NULL) {
        asc_error("Rendering TTF surface failed: %s", SDL_GetError());
        return;
    }
    if (asc_test_flag(text->base.flags, ASC_TEXT_CENTERED_FLAG)) {
        asc_scene_node_set_origin(node, ASC_VEC3F(surface->w / 2, 0, 0));
    }

    // Transfer Image Data
    asc_texture_from_surface(text->texture, surface);

    // If dimensions changed, update the mesh
    if (text->dimension.width != (unsigned)surface->w || text->dimension.height != (unsigned)surface->h) {
        text->dimension.width = surface->w;
        text->dimension.height = surface->h;
        const asc_vec2f uv_scale = asc_texture_calculate_uv_scale(text->texture, text->dimension, ASC_VEC2F_1);
        asc_mesh_plane_2d(&text->mesh,
            .size = ASC_VEC2F(surface->w, surface->h),
            .uv_scale = uv_scale
        );
    }

    // Free the surface
    SDL_FreeSurface(surface);

    // Schedule for transform update
    asc_scene_node_update_transform(node);
}

static void asc_text_draw(const AscCamera *camera, const AscSceneNode *node) {
    asc_cptr_cast(AscText, text, node);

    // early exit when the text has no width
    if (text->dimension.width == 0) return;

    // Activate shader
    // TODO: scene should know which shader we are going to activate s.t. it can pre-sort nodes
    const AscShaderProgram *shader = asc_shader_lookup_or_create(
            ASC_SHADER_TEXT, asc_text_shader_create, 0);
    if (asc_shader_use(shader, camera)) return;
    asc_cptr_cast(AscTextShader, text_shader, shader);

    // Upload model matrix
    asc_shader_upload_model_matrix(shader, node);

    // Bind texture
    asc_texture_bind(text->texture, text_shader->tex, 0);

    // Draw mesh
    asc_mesh_draw_triangle_strip(&text->mesh);
}

static void asc_text_destroy(AscSceneNode *node) {
    asc_ptr_cast(AscText, text, node);
    asc_mesh_destroy(&text->mesh);
    asc_texture_destroy(text->texture, 1);
    assert(text->texture->refcount == 0);
    cxFreeDefault(text->texture);
    cx_strfree(&text->text);
}

AscSceneNode *asc_text_create(struct asc_text_create_args args) {
    AscText *text = cxZallocDefault(sizeof(AscText));
    asc_ptr_cast(AscSceneNode, node, text);

    // text properties
    node->flags = args.alignment; // use flags variable to save some space
    text->max_width = args.max_width;
    text->font = asc_active_font;
    text->color = asc_context.ink;
    if (args.text == NULL) {
        text->text = cx_mutstr(strdup(" "));
    } else {
        text->text = cx_mutstr(strdup(args.text));
    }
    if (args.centered) {
        asc_set_flag(node->flags, ASC_TEXT_CENTERED_FLAG);
    }

    // initialize texture
    // mesh will be created in the update func
    text->texture = cxMallocDefault(sizeof(AscTexture));
    asc_texture_init_rectangle(text->texture, 1);

    // basic node properties
    asc_scene_node_init(node,
        ASC_SCENE_NODE_FUNCS(asc_text),
        .name = args.name,
        .render_group = ASC_RENDER_GROUP_2D_BLEND,
        .pos2d = ASC_VEC2I(args.x, args.y)
    );

    return node;
}

void asc_text_alignment(
        AscText *node,
        enum asc_text_alignment alignment
) {
    asc_ptr_cast(AscSceneNode, snode, node);
    asc_set_flag_masked(snode->flags, ASC_TEXT_ALIGNMENT_MASK, alignment);
    asc_scene_node_update(snode);
}

void asc_text_centered(AscText *node, bool centered) {
    asc_ptr_cast(AscSceneNode, snode, node);
    if (centered) {
        asc_clear_flag(snode->flags, ASC_TEXT_ALIGN_CENTERED);
    } else {
        asc_set_flag(snode->flags, ASC_TEXT_ALIGN_CENTERED);
    }
    asc_scene_node_update(snode);
}

void asc_text_max_width(AscText *node, unsigned max_width) {
    node->max_width = max_width;
    asc_scene_node_update((AscSceneNode*)node);
}

void asc_text_printf(
        AscText *node,
        const char *format,
        ...
) {
    va_list ap;
    va_start(ap, format);
    cx_vsprintf(
            &node->text.ptr,
            &node->text.length,
            format,
            ap
    );
    va_end(ap);
    asc_scene_node_update((AscSceneNode*)node);
}