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#include "TextureAtlas.hpp"
#define STB_RECT_PACK_IMPLEMENTATION
#include <stb_rect_pack.h>
#include <easylogging++.h>
#include "Utility.hpp"
TextureAtlas::TextureAtlas(std::vector<TextureData> &textures) {
LOG(INFO) << "Initializing texture atlas...";
LOG(INFO) << "Textures count: " << textures.size();
//Texture packing
const int textureSize = 1024;
const int padding = 1;
const int paddingLimit = 128;
std::vector<stbrp_rect> totalRects;
for (int i = 0; i < textures.size(); i++) {
stbrp_rect rect;
rect.id = i;
rect.x = 0;
rect.y = 0;
if (textures[i].width >= paddingLimit || textures[i].height >= paddingLimit) {
rect.w = textures[i].width;
rect.h = textures[i].height;
} else {
rect.w = textures[i].width + padding * 2;
rect.h = textures[i].height + padding * 2;
}
rect.was_packed = 0;
totalRects.push_back(rect);
}
textureCoords.resize(textures.size());
int layer = 0;
for (;;layer++) {
stbrp_context context;
std::vector<stbrp_node> nodes;
int nodesCount = textureSize * 2;
nodes.resize(nodesCount);
stbrp_init_target(&context, textureSize, textureSize, nodes.data(), nodesCount);
std::vector<stbrp_rect> rects;
for (const auto &it : totalRects) {
if (it.was_packed != 0)
continue;
rects.push_back(it);
}
stbrp_pack_rects(&context, rects.data(), rects.size());
int unpackedTextures = 0;
for (auto &it : rects) {
if (!it.was_packed) {
unpackedTextures++;
continue;
}
if (it.w >= paddingLimit || it.h >= paddingLimit) {
textureCoords[it.id].pixelX = it.x;
textureCoords[it.id].pixelY = it.y;
textureCoords[it.id].pixelW = it.w;
textureCoords[it.id].pixelH = it.h;
} else {
textureCoords[it.id].pixelX = it.x + padding;
textureCoords[it.id].pixelY = it.y + padding;
textureCoords[it.id].pixelW = it.w - padding * 2;
textureCoords[it.id].pixelH = it.h - padding * 2;
}
textureCoords[it.id].x = (double)textureCoords[it.id].pixelX / textureSize;
textureCoords[it.id].y = (double)textureCoords[it.id].pixelY / textureSize;
textureCoords[it.id].w = (double)textureCoords[it.id].pixelW / textureSize;
textureCoords[it.id].h = (double)textureCoords[it.id].pixelH / textureSize;
textureCoords[it.id].layer = layer;
totalRects[it.id].was_packed = 1;
}
if (unpackedTextures == 0)
break;
}
LOG(INFO) << "Texture atlas size is " << textureSize << "x" << textureSize << "x" << layer;
//OpenGL
int mipLevelCount = 1;
glGenTextures(1, &texture);
glBindTexture(GL_TEXTURE_2D_ARRAY, texture);
glTexStorage3D(GL_TEXTURE_2D_ARRAY, mipLevelCount, GL_RGBA8, textureSize, textureSize, layer+1);
glTexParameteri(GL_TEXTURE_2D_ARRAY, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D_ARRAY, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D_ARRAY, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D_ARRAY, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glCheckError();
//Uploading texture data
for (int i = 0; i < textureCoords.size(); i++) {
size_t bytesPerLine = textureCoords[i].pixelW * 4;
for (int y = 0; y < textureCoords[i].pixelH / 2; y++) {
int invY = textureCoords[i].pixelH - y - 1;
unsigned char *src = textures[i].data.data() + y * bytesPerLine;
unsigned char *dst = textures[i].data.data() + invY * bytesPerLine;
for (int j = 0; j < bytesPerLine; j++) {
std::swap(*(src + j), *(dst + j));
}
}
glTexSubImage3D(GL_TEXTURE_2D_ARRAY, 0, textureCoords[i].pixelX, textureSize - textureCoords[i].pixelY - textureCoords[i].pixelH, textureCoords[i].layer,
textureCoords[i].pixelW, textureCoords[i].pixelH, 1, GL_RGBA, GL_UNSIGNED_INT_8_8_8_8_REV, textures[i].data.data());
glCheckError();
}
LOG(INFO) << "Texture atlas initialized";
}
TextureAtlas::~TextureAtlas() {
glDeleteTextures(1, &texture);
}
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