src/graphics/vao.hpp

   1 #ifndef TACOS_GRAPHICS_VAO_HPP_
   2 #define TACOS_GRAPHICS_VAO_HPP_
   3
   4 #include "buffer.hpp"
   5 #include "gl_traits.hpp"
   6
   7 #include <GL/glew.h>
   8
   9
  10 namespace tacos {
  11
  12 /// Simple vertex array object based on indexed draw calls with attributes
  13 /// interleaved in a single buffer.
  14 template<class Attributes, class Element>
  15 class SimpleVAO {
  16
  17 public:
  18         SimpleVAO()
  19         : vao(0)
  20         , buffers{0} {
  21                 glGenVertexArrays(1, &vao);
  22                 glGenBuffers(2, buffers);
  23         }
  24         ~SimpleVAO() noexcept {
  25                 glDeleteBuffers(2, buffers);
  26                 glDeleteVertexArrays(1, &vao);
  27         }
  28
  29         SimpleVAO(const SimpleVAO &) = delete;
  30         SimpleVAO &operator =(const SimpleVAO &) = delete;
  31
  32 public:
  33         void Bind() const noexcept {
  34                 glBindVertexArray(vao);
  35         }
  36         void Unbind() const noexcept {
  37                 glBindVertexArray(0);
  38         }
  39         void BindAttributes() const noexcept {
  40                 glBindBuffer(GL_ARRAY_BUFFER, buffers[0]);
  41         }
  42         void BindElements() const noexcept {
  43                 glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, buffers[1]);
  44         }
  45         void EnableAttribute(GLuint index) noexcept {
  46                 glEnableVertexAttribArray(index);
  47         }
  48         void DisableAttribute(GLuint index) noexcept {
  49                 glDisableVertexAttribArray(index);
  50         }
  51         template<class Attribute>
  52         void AttributePointer(GLuint index, bool normalized, std::size_t offset) noexcept {
  53                 glVertexAttribPointer(
  54                         index,
  55                         gl_traits<Attribute>::size,
  56                         gl_traits<Attribute>::type,
  57                         normalized,
  58                         sizeof(Attributes),
  59                         reinterpret_cast<const void *>(offset)
  60                 );
  61         }
  62         void ReserveAttributes(std::size_t size, GLenum usage) noexcept {
  63                 glBufferData(GL_ARRAY_BUFFER, size * sizeof(Attributes), nullptr, usage);
  64         }
  65         MappedBuffer<Attributes> MapAttributes(GLenum access) {
  66                 return MappedBuffer<Attributes>(GL_ARRAY_BUFFER, access);
  67         }
  68         void ReserveElements(std::size_t size, GLenum usage) noexcept {
  69                 glBufferData(GL_ELEMENT_ARRAY_BUFFER, size * sizeof(Element), nullptr, usage);
  70         }
  71         MappedBuffer<Element> MapElements(GLenum access) {
  72                 return MappedBuffer<Element>(GL_ELEMENT_ARRAY_BUFFER, access);
  73         }
  74         void DrawTriangles(std::size_t size, std::size_t offset = 0) const noexcept {
  75                 glDrawElements(GL_TRIANGLES, size, gl_traits<Element>::type, ((Element *) nullptr) + offset);
  76         }
  77
  78 private:
  79         GLuint vao;
  80         GLuint buffers[2];
  81
  82 };
  83
  84 }
  85
  86 #endif