142 lines
3.9 KiB
C++
142 lines
3.9 KiB
C++
#include <glm/glm.hpp>
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#include <map>
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#include <glad/glad.h>
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#include "text.h"
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#include "shader.h"
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FT_Library ft;
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FT_Face face;
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const char *textcolorC = "textColor";
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unsigned int textVAO, textVBO;
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struct character_t {
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unsigned int texture_id;
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glm::ivec2 size;
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glm::ivec2 bearing;
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unsigned int advance;
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};
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std::map<char, character_t> glyph_to_character;
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int init_text(int *shader) {
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if (FT_Init_FreeType(&ft)) {
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printf("Could not init freetype library.\n");
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return -1;
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}
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if (FT_New_Face(ft, "fonts/LiberationSerif-Regular.ttf", 0, &face)) {
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printf("Could not font face.\n");
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return -1;
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}
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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 < 128; c++) {
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if (FT_Load_Char(face, c, FT_LOAD_RENDER)) {
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printf("Failed to load glyph: %c\n", c);
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return -1;
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}
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unsigned int texture;
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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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);
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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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character_t character = {
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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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glyph_to_character.insert(std::pair<char, character_t>(c, character));
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}
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glBindTexture(GL_TEXTURE_2D, 0);
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FT_Done_Face(face);
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FT_Done_FreeType(ft);
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// configure textVAO/textVBO for texture quads
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// -----------------------------------
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glGenVertexArrays(1, &textVAO);
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glGenBuffers(1, &textVBO);
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glBindVertexArray(textVAO);
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glBindBuffer(GL_ARRAY_BUFFER, textVBO);
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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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glBindBuffer(GL_ARRAY_BUFFER, 0);
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glBindVertexArray(0);
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*shader = create_shader_program("textshader.glsl", "textfragshader.glsl");
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if (*shader < 0) {
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printf("Got error compiling text shader!\n");
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return -1;
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}
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return 0;
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}
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void render_text(int shader, std::string text, float x, float y, float scale, glm::vec3 color) {
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set_uniform(shader, textcolorC, color);
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glActiveTexture(GL_TEXTURE0);
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glBindVertexArray(textVAO);
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std::string::const_iterator c;
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for (c = text.begin(); c != text.end(); c++) {
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character_t ch = glyph_to_character[*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[24] = {
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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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glBindTexture(GL_TEXTURE_2D, ch.texture_id);
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glBindBuffer(GL_ARRAY_BUFFER, textVBO);
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glBufferSubData(GL_ARRAY_BUFFER, 0, sizeof(float) * (2 + 2) * 6, vertices);
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glBindBuffer(GL_ARRAY_BUFFER, 0);
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glDrawArrays(GL_TRIANGLES, 0, (2 + 2) * 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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