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/* ----------------------------------------------------------------------------
* spritebatch.cpp
*
* Copyright (c) 2017 Yann Herklotz Grave <ymherklotz@gmail.com> -- MIT License
* See file LICENSE for more details
* ----------------------------------------------------------------------------
*/
#include <yage/base/spritebatch.h>
#include <algorithm>
#include <stdexcept>
namespace yage
{
const int SpriteBatch::NUM_VERTICES;
Glyph::Glyph(GLuint texture, float depth, const Vertex &top_left,
const Vertex &top_right, const Vertex &bottom_right,
const Vertex &bottom_left)
: texture_(texture), depth_(depth), top_left_(top_left),
top_right_(top_right), bottom_right_(bottom_right),
bottom_left_(bottom_left)
{
}
RenderBatch::RenderBatch(GLint offset, GLsizei num_vertices, GLuint texture)
: num_vertices_(num_vertices), offset_(offset), texture_(texture)
{
}
SpriteBatch::SpriteBatch() = default;
SpriteBatch::~SpriteBatch()
{
if (vao_ != 0) {
glDeleteVertexArrays(1, &vao_);
}
if (vbo_ != 0) {
glDeleteVertexArrays(1, &vbo_);
}
}
void SpriteBatch::init()
{
createVertexArray();
}
void SpriteBatch::begin()
{
glyphs_.clear();
glyph_ptrs_.clear();
render_batches_.clear();
}
void SpriteBatch::end()
{
sortGlyphs();
createRenderBatches();
}
void SpriteBatch::draw(const glm::vec4 &destination_rect,
const glm::vec4 &uv_rect, GLuint texture,
const Color &color, float depth)
{
Vertex top_left, top_right, bottom_right, bottom_left;
top_left.color = color;
top_left.setPosition(destination_rect.x,
destination_rect.y + destination_rect.w);
top_left.setUv(uv_rect.x, uv_rect.y + uv_rect.w);
top_right.color = color;
top_right.setPosition(destination_rect.x + destination_rect.z,
destination_rect.y + destination_rect.w);
top_right.setUv(uv_rect.x + uv_rect.z, uv_rect.y + uv_rect.w);
bottom_right.color = color;
bottom_right.setPosition(destination_rect.x + destination_rect.z,
destination_rect.y);
bottom_right.setUv(uv_rect.x + uv_rect.z, uv_rect.y);
bottom_left.color = color;
bottom_left.setPosition(destination_rect.x, destination_rect.y);
bottom_left.setUv(uv_rect.x, uv_rect.y);
// deal with fragmenting by creating vector of pointers
glyphs_.emplace_back(texture, depth, top_left, top_right, bottom_right,
bottom_left);
glyph_ptrs_.push_back(&glyphs_.back());
}
void SpriteBatch::render()
{
glBindVertexArray(vao_);
for (auto &&batch : render_batches_) {
glBindTexture(GL_TEXTURE_2D, batch.texture());
glDrawArrays(GL_TRIANGLES, batch.offset(), batch.num_vertices());
}
glBindVertexArray(0);
}
void SpriteBatch::createVertexArray()
{
if (vao_ == 0) {
glGenVertexArrays(1, &vao_);
if (vao_ == 0) {
throw std::runtime_error("glGenVertexArrays failed");
}
}
// bind vertex array object
glBindVertexArray(vao_);
if (vbo_ == 0) {
glGenBuffers(1, &vbo_);
if (vbo_ == 0) {
throw std::runtime_error("glGenBuffers failed");
}
}
// bind vertex buffer object
glBindBuffer(GL_ARRAY_BUFFER, vbo_);
// enable vertex attribute arrays
glEnableVertexAttribArray(0);
glEnableVertexAttribArray(1);
glEnableVertexAttribArray(2);
// set the vertex attribute pointers
glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex),
(void *)offsetof(Vertex, position));
glVertexAttribPointer(1, 4, GL_UNSIGNED_BYTE, GL_TRUE, sizeof(Vertex),
(void *)offsetof(Vertex, color));
glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex),
(void *)offsetof(Vertex, uv));
glDrawArrays(GL_TRIANGLES, 0, 6);
// unbind vertex array object
glBindVertexArray(0);
}
void SpriteBatch::createRenderBatches()
{
std::vector<Vertex> vertices;
if (glyph_ptrs_.empty()) {
return;
}
render_batches_.reserve(glyph_ptrs_.size() * NUM_VERTICES);
for (int i = 0; i < (int)glyph_ptrs_.size(); ++i) {
if (i == 0 || (i > 0 && (glyph_ptrs_[i]->texture() !=
glyph_ptrs_[i - 1]->texture()))) {
render_batches_.emplace_back(i * NUM_VERTICES, NUM_VERTICES,
glyph_ptrs_[i]->texture());
} else {
render_batches_.back().num_vertices_ += NUM_VERTICES;
}
vertices.push_back(glyph_ptrs_[i]->bottom_left());
vertices.push_back(glyph_ptrs_[i]->top_left());
vertices.push_back(glyph_ptrs_[i]->top_right());
vertices.push_back(glyph_ptrs_[i]->bottom_left());
vertices.push_back(glyph_ptrs_[i]->bottom_right());
vertices.push_back(glyph_ptrs_[i]->top_right());
// bind vbo
glBindBuffer(GL_ARRAY_BUFFER, vbo_);
// orphan the buffer
glBufferData(GL_ARRAY_BUFFER, vertices.size() * sizeof(Vertex), nullptr,
GL_DYNAMIC_DRAW);
// upload the data
glBufferSubData(GL_ARRAY_BUFFER, 0, vertices.size() * sizeof(Vertex),
vertices.data());
// unbind buffer
glBindBuffer(GL_ARRAY_BUFFER, 0);
}
}
void SpriteBatch::sortGlyphs()
{
// sort using introsort or quicksort
std::sort(glyph_ptrs_.begin(), glyph_ptrs_.end(),
[](Glyph *a, Glyph *b) -> bool {
if (a->depth() == b->depth()) {
return a->texture() < b->texture();
}
return a->depth() < b->depth();
});
}
} // namespace yage
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