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Diffstat (limited to 'yage/render/spritebatch.cpp')
| -rw-r--r-- | yage/render/spritebatch.cpp | 180 |
1 files changed, 180 insertions, 0 deletions
diff --git a/yage/render/spritebatch.cpp b/yage/render/spritebatch.cpp new file mode 100644 index 00000000..90958246 --- /dev/null +++ b/yage/render/spritebatch.cpp @@ -0,0 +1,180 @@ +/** --------------------------------------------------------------------------- + * @file: spritebatch.cpp + * + * Copyright (c) 2017 Yann Herklotz Grave <ymherklotz@gmail.com> + * MIT License, see LICENSE file for more details. + * ---------------------------------------------------------------------------- + */ + +#include "spritebatch.h" + +#include "../core/logger.h" +#include <algorithm> +#include <iostream> +#include <stdexcept> + +using std::cout; + +#include <GLFW/glfw3.h> + +namespace yage +{ + +const int SpriteBatch::NUM_VERTICES; + +SpriteBatch::SpriteBatch() : vao_(0), vbo_(0) +{ + glGenVertexArrays(1, &vao_); + if (vao_ == 0) { + throw std::runtime_error("failed to generate VAO"); + } + // bind vertex array object + glBindVertexArray(vao_); + + glGenBuffers(1, &vbo_); + if (vbo_ == 0) { + throw std::runtime_error("failed to generate VBO"); + } + // bind vertex buffer object + glBindBuffer(GL_ARRAY_BUFFER, vbo_); + + // 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, colour)); + glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex), + (void *)offsetof(Vertex, uv)); + + // enable vertex attribute arrays + glEnableVertexAttribArray(0); + glEnableVertexAttribArray(1); + glEnableVertexAttribArray(2); +} + +SpriteBatch::~SpriteBatch() +{ + if (vbo_ != 0) { + glDeleteBuffers(1, &vbo_); + } + if (vao_ != 0) { + glDeleteVertexArrays(1, &vao_); + } +} + +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 Colour &colour, float depth) +{ + Vertex top_left, top_right, bottom_right, bottom_left; + + top_left.colour = colour; + 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.colour = colour; + 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.colour = colour; + 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.colour = colour; + 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); +} + +void SpriteBatch::render() +{ + glBindVertexArray(vao_); + // sort and create render batches + sortGlyphs(); + createRenderBatches(); + glActiveTexture(GL_TEXTURE0); + for (auto &&batch : render_batches_) { + yLogDebug << "Drawing " << batch.num_vertices + << " vertices bound to texture: " << batch.texture; + glBindTexture(GL_TEXTURE_2D, batch.texture); + glDrawArrays(GL_TRIANGLES, batch.offset, batch.num_vertices); + } + + // clear and reset the vectors + glyphs_.clear(); + glyph_ptrs_.clear(); + render_batches_.clear(); +} + +void SpriteBatch::createRenderBatches() +{ + std::vector<Vertex> vertices; + if (glyph_ptrs_.empty()) { + return; + } + + vertices.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]->top_right); + vertices.push_back(glyph_ptrs_[i]->bottom_right); + vertices.push_back(glyph_ptrs_[i]->bottom_left); + } + + // orphan the buffer + glBufferData(GL_ARRAY_BUFFER, vertices.size() * sizeof(Vertex), nullptr, + GL_DYNAMIC_DRAW); + glBufferSubData(GL_ARRAY_BUFFER, 0, vertices.size() * sizeof(Vertex), + vertices.data()); +} + +void SpriteBatch::sortGlyphs() +{ + glyph_ptrs_.reserve(glyphs_.size()); + for (auto &glyph : glyphs_) { + glyph_ptrs_.push_back(&glyph); + } + + // sort using introsort or quicksort + std::sort(glyph_ptrs_.begin(), glyph_ptrs_.end(), + [](details::Glyph *a, details::Glyph *b) -> bool { + if (a->depth == b->depth) { + return a->texture < b->texture; + } + return a->depth < b->depth; + }); +} + +} // namespace yage |