src/graphics/SimpleVAO.hpp

   1 #ifndef BLOBS_GRAPHICS_VAO_HPP_
   2 #define BLOBS_GRAPHICS_VAO_HPP_
   3
   4 #include "buffer.hpp"
   5 #include "gl_traits.hpp"
   6
   7 #include <GL/glew.h>
   8
   9
  10 namespace blobs {
  11 namespace graphics {
  12
  13 /// Simple vertex array object based on indexed draw calls with attributes
  14 /// interleaved in a single buffer.
  15 template<class Attributes, class Element>
  16 class SimpleVAO {
  17
  18 public:
  19         SimpleVAO()
  20         : vao(0)
  21         , buffers{0} {
  22                 glGenVertexArrays(1, &vao);
  23                 glGenBuffers(2, buffers);
  24         }
  25         ~SimpleVAO() noexcept {
  26                 glDeleteBuffers(2, buffers);
  27                 glDeleteVertexArrays(1, &vao);
  28         }
  29
  30         SimpleVAO(const SimpleVAO &) = delete;
  31         SimpleVAO &operator =(const SimpleVAO &) = delete;
  32
  33 public:
  34         void Bind() const noexcept {
  35                 glBindVertexArray(vao);
  36         }
  37         void Unbind() const noexcept {
  38                 glBindVertexArray(0);
  39         }
  40         void BindAttributes() const noexcept {
  41                 glBindBuffer(GL_ARRAY_BUFFER, buffers[0]);
  42         }
  43         void BindElements() const noexcept {
  44                 glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, buffers[1]);
  45         }
  46         void EnableAttribute(GLuint index) noexcept {
  47                 glEnableVertexAttribArray(index);
  48         }
  49         void DisableAttribute(GLuint index) noexcept {
  50                 glDisableVertexAttribArray(index);
  51         }
  52         template<class Attribute>
  53         void AttributePointer(GLuint index, bool normalized, std::size_t offset) noexcept {
  54                 glVertexAttribPointer(
  55                         index,
  56                         gl_traits<Attribute>::size,
  57                         gl_traits<Attribute>::type,
  58                         normalized,
  59                         sizeof(Attributes),
  60                         reinterpret_cast<const void *>(offset)
  61                 );
  62         }
  63         void ReserveAttributes(std::size_t size, GLenum usage) noexcept {
  64                 glBufferData(GL_ARRAY_BUFFER, size * sizeof(Attributes), nullptr, usage);
  65         }
  66         MappedBuffer<Attributes> MapAttributes(GLenum access) {
  67                 return MappedBuffer<Attributes>(GL_ARRAY_BUFFER, access);
  68         }
  69         void ReserveElements(std::size_t size, GLenum usage) noexcept {
  70                 glBufferData(GL_ELEMENT_ARRAY_BUFFER, size * sizeof(Element), nullptr, usage);
  71         }
  72         MappedBuffer<Element> MapElements(GLenum access) {
  73                 return MappedBuffer<Element>(GL_ELEMENT_ARRAY_BUFFER, access);
  74         }
  75         void DrawTriangles(std::size_t size, std::size_t offset = 0) const noexcept {
  76                 glDrawElements(GL_TRIANGLES, size, gl_traits<Element>::type, ((Element *) nullptr) + offset);
  77         }
  78
  79 private:
  80         GLuint vao;
  81         GLuint buffers[2];
  82
  83 };
  84
  85 }
  86 }
  87
  88 #endif