charcoal/OpenGLEngine/MyBatch.cpp

#include "MyBatch.h"

void MyBatch::setup_element_buffers()
{
	glBindBuffer(GL_ARRAY_BUFFER, m_element_buffers[COLOR_VBO_INDEX]);
	glBufferData(GL_ARRAY_BUFFER, m_color_elements.size() * sizeof(MyBatchTestShaderProgram::Color), NULL, GL_STREAM_DRAW);

	glBindBuffer(GL_ARRAY_BUFFER, m_element_buffers[OFFSET_VBO_INDEX]);
	glBufferData(GL_ARRAY_BUFFER, m_offset_elements.size() * sizeof(MyBatchTestShaderProgram::Offset), NULL, GL_STREAM_DRAW);
}

void MyBatch::setup_vao()
{
	glBindBuffer(GL_ARRAY_BUFFER, m_vertex_vbo);
	glEnableVertexAttribArray(0);
	glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, NULL);
	glBindBuffer(GL_ARRAY_BUFFER, m_element_buffers[COLOR_VBO_INDEX]);
	glEnableVertexAttribArray(1);
	glVertexAttribPointer(1, 4, GL_FLOAT, GL_FALSE, 0, NULL);
	glBindBuffer(GL_ARRAY_BUFFER, m_element_buffers[OFFSET_VBO_INDEX]);
	glEnableVertexAttribArray(2);
	glVertexAttribPointer(2, 3, GL_FLOAT, GL_FALSE, 0, NULL);

	glVertexAttribDivisor(0, 0); // Only need to send the mesh data once (This should probably be done every time)
	glVertexAttribDivisor(1, 1); // Send the color data for each instance drawn
	glVertexAttribDivisor(2, 1); // Send the offset data for each instance drawn
}

void MyBatch::update_element_buffers()
{
	// TODO: There are probably better ways to do this. Should check with the old engine to see what I did there.
	glBindBuffer(GL_ARRAY_BUFFER, m_element_buffers[COLOR_VBO_INDEX]);
	glBufferData(GL_ARRAY_BUFFER, m_color_elements.size() * sizeof(MyBatchTestShaderProgram::Color), NULL, GL_STREAM_DRAW);
	glBufferSubData(GL_ARRAY_BUFFER, 0, m_color_elements.size() * sizeof(MyBatchTestShaderProgram::Color), m_color_elements.data());
	
	glBindBuffer(GL_ARRAY_BUFFER, m_element_buffers[OFFSET_VBO_INDEX]);
	glBufferData(GL_ARRAY_BUFFER, m_offset_elements.size() * sizeof(MyBatchTestShaderProgram::Offset), NULL, GL_STREAM_DRAW);
	glBufferSubData(GL_ARRAY_BUFFER, 0, m_offset_elements.size() * sizeof(MyBatchTestShaderProgram::Offset), m_offset_elements.data());
}