114 lines
3.4 KiB
C++
114 lines
3.4 KiB
C++
#include "text.hpp"
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#include <glm/glm.hpp>
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#include <glm/gtc/matrix_transform.hpp>
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#include <glm/gtc/type_ptr.hpp>
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#include <glad/glad.h>
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#include <GLFW/glfw3.h>
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#include "config.hpp"
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#include <ft2build.h>
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#include FT_FREETYPE_H
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void Text::render(const std::string& text, float x, float y, float scale, glm::vec3 color) {
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text_shader.use();
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glm::mat4 projection = glm::ortho(0.0f, static_cast<float>(SCR_WIDTH), 0.0f, static_cast<float>(SCR_HEIGHT));
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text_shader.setMat4("projection", projection);
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glUniform3f(glGetUniformLocation(text_shader.ID, "textColor"), color.x, color.y, color.z);
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glActiveTexture(GL_TEXTURE0);
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glBindVertexArray(text_vao);
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for(auto c : text) {
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auto& ch = characters.at(c);
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float xpos = x + ch.bearing.x * scale;
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float ypos = y - (ch.size.y - ch.bearing.y) * scale;
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float w = ch.size.x * scale;
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float h = ch.size.y * scale;
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float vertices[6][4] = {
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{ xpos, ypos + h, 0.0f, 0.0f },
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{ xpos, ypos, 0.0f, 1.0f },
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{ xpos + w, ypos, 1.0f, 1.0f },
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{ xpos, ypos + h, 0.0f, 0.0f },
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{ xpos + w, ypos, 1.0f, 1.0f },
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{ xpos + w, ypos + h, 1.0f, 0.0f }
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};
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// rander glyph texture over quad
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glBindTexture(GL_TEXTURE_2D, ch.texture_id);
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// update content of VBO memory
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glBindBuffer(GL_ARRAY_BUFFER, text_vbo);
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glBufferSubData(GL_ARRAY_BUFFER, 0, sizeof(vertices), vertices);
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glBindBuffer(GL_ARRAY_BUFFER, 0);
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// render quad
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glDrawArrays(GL_TRIANGLES, 0, 6);
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x += (ch.advance >> 6) * scale;
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}
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glBindVertexArray(0);
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glBindTexture(GL_TEXTURE_2D, 0);
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}
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void Text::load_font() {
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FT_Library ft;
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int fail = FT_Init_FreeType(&ft);
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dbc::check(fail == 0, "FreeType failed.");
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FT_Face face;
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fail = FT_New_Face(ft, font.c_str(), 0, &face);
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dbc::check(fail == 0, "Failed to load font.");
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// load the font bitmaps
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FT_Set_Pixel_Sizes(face, 0, 48);
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glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
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for(unsigned char c = 0; c < 255; c++) {
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fail = FT_Load_Char(face, c, FT_LOAD_RENDER);
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dbc::check(fail == 0, $F("Failed to load char {}", int(c)));
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unsigned int texture = UINT_MAX;
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glGenTextures(1, &texture);
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glBindTexture(GL_TEXTURE_2D, texture);
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glTexImage2D(
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GL_TEXTURE_2D,
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0,
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GL_RED,
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face->glyph->bitmap.width,
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face->glyph->bitmap.rows,
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0,
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GL_RED,
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GL_UNSIGNED_BYTE,
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face->glyph->bitmap.buffer);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
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characters.try_emplace(c,
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texture,
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glm::ivec2(face->glyph->bitmap.width, face->glyph->bitmap.rows),
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glm::ivec2(face->glyph->bitmap_left, face->glyph->bitmap_top),
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static_cast<unsigned int>(face->glyph->advance.x));
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}
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// unbind
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glBindTexture(GL_TEXTURE_2D, 0);
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// cleanup
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FT_Done_Face(face);
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FT_Done_FreeType(ft);
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// create teh vao/vbo
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glGenVertexArrays(1, &text_vao);
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glGenBuffers(1, &text_vbo);
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glBindVertexArray(text_vao);
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glBindBuffer(GL_ARRAY_BUFFER, text_vbo);
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glBufferData(GL_ARRAY_BUFFER, sizeof(float) * 6 * 4, NULL, GL_DYNAMIC_DRAW);
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glEnableVertexAttribArray(0);
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glVertexAttribPointer(0, 4, GL_FLOAT, GL_FALSE, 4 * sizeof(float), 0);
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glBindVertexArray(0);
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}
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