pigine/rendering/FontRenderer.cpp

#include "rendering/FontRenderer.h"
#include "utils/Buffer.h"
#include "utils/Color.h"

FontRenderer::FontRenderer() : activeTex(0), scale(1) {
}

void FontRenderer::init() {
    tex[0].load("resources/font8x8.png", 0);
    tex[1].load("resources/font16x16.png", 0);
    tex[2].load("resources/font24x24.png", 0);
    vertexBuffer.init(
        VertexBuffer::Attributes().addFloat(2).addFloat(2).addColor4());
    vertexBuffer.setData(256 * 4 * sizeof(float) * 8, nullptr, GL::STREAM_DRAW);
}

float FontRenderer::drawString(float x, float y, const char* text) {
    const int maxIndex = 256;

    Buffer buffer(sizeof(float) * maxIndex * 4 * 8);

    int index = 0;
    Color4 color(0xFF, 0xFF, 0xFF, 0xFF);

    float addX = 6.0f * scale;
    float addY = 8.0f * scale;

    while(text[index] != '\0' && index < maxIndex) {
        char32_t c = text[index];
        if(c > 128 && index + 1 < maxIndex && text[index + 1] != '\0') {
            index++;
            c = (text[index] & 0x3F) | ((c & 0x1F) << 6);
        }
        if(c == '&') {
            if(text[index + 1] == '\0' || text[index + 2] == '\0' ||
               text[index + 3] == '\0') {
                break;
            }
            color[0] = ((text[index + 1] - '0') * 255) / 9;
            color[1] = ((text[index + 2] - '0') * 255) / 9;
            color[2] = ((text[index + 3] - '0') * 255) / 9;
            index += 4;
            continue;
        }

        float minX = (c & 0xF) * (1.0f / 16.0f) + 1.0f / 128.0f;
        float minY = (c >> 4) * (1.0f / 16.0f);
        float maxX = minX + (1.0f / 16.0f) - 2.0f / 128.0f;
        float maxY = minY + (1.0f / 16.0f);

        buffer.add(x).add(y).add(minX).add(minY).add(color);
        buffer.add(x).add(y + addY).add(minX).add(maxY).add(color);
        buffer.add(x + addX).add(y).add(maxX).add(minY).add(color);
        buffer.add(x + addX).add(y + addY).add(maxX).add(maxY).add(color);

        x += addX;
        index++;
    }

    tex[activeTex].bindTo(0);
    vertexBuffer.updateData(0, buffer.getLength(), buffer);
    vertexBuffer.drawStrip(buffer.getLength() /
                           (4 * sizeof(float) + sizeof(Color4)));
    return y + addY;
}

void FontRenderer::setSize(int size) {
    if(size == 1 || size == 2) {
        activeTex = size;
        scale = size + 1;
    } else {
        activeTex = 0;
        scale = 1;
    }
}