PointCloud.cpp

#include "PointCloud.h"


PointCloud::PointCloud(std::string objFilename, GLfloat pointSize) 
	: pointSize(pointSize)
{
	/* 
	 * TODO: Section 2: Currently, all the points are hard coded below. 
	 * Modify this to read points from an obj file.
	 */
	
	points = {
		glm::vec3(-2.5, 2.5, 2.5),
		glm::vec3(-2.5, -2.5, 2.5),
		glm::vec3(2.5, -2.5, 2.5),
		glm::vec3(2.5, 2.5, 2.5),
		glm::vec3(-2.5, 2.5, -2.5),
		glm::vec3(-2.5, -2.5, -2.5),
		glm::vec3(2.5, -2.5, -2.5),
		glm::vec3(2.5, 2.5, -2.5)
	};

	/*
	 * TODO: Section 4, you will need to normalize the object to fit in the
	 * screen. 
	 */

	// Set the model matrix to an identity matrix. 
	model = glm::mat4(1);

	// Set the color. 
	color = glm::vec3(1, 0, 0);

	// Generate a Vertex Array (VAO) and Vertex Buffer Object (VBO)
	glGenVertexArrays(1, &VAO);
	glGenBuffers(1, &VBO);

	// Bind VAO
	glBindVertexArray(VAO);

	// Bind VBO to the bound VAO, and store the point data
	glBindBuffer(GL_ARRAY_BUFFER, VBO);
	glBufferData(GL_ARRAY_BUFFER, sizeof(glm::vec3) * points.size(), points.data(), GL_STATIC_DRAW);
	// Enable Vertex Attribute 0 to pass point data through to the shader
	glEnableVertexAttribArray(0);
	glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(GLfloat), 0);

	// Unbind the VBO/VAO
	glBindBuffer(GL_ARRAY_BUFFER, 0);
	glBindVertexArray(0);
}

PointCloud::~PointCloud() 
{
	// Delete the VBO and the VAO.
	glDeleteBuffers(1, &VBO);
	glDeleteVertexArrays(1, &VAO);
}

void PointCloud::draw(const glm::mat4& view, const glm::mat4& projection, GLuint shader)
{
	// Actiavte the shader program 
	glUseProgram(shader);

	// Get the shader variable locations and send the uniform data to the shader 
	glUniformMatrix4fv(glGetUniformLocation(shader, "view"), 1, false, glm::value_ptr(view));
	glUniformMatrix4fv(glGetUniformLocation(shader, "projection"), 1, false, glm::value_ptr(projection));
	glUniformMatrix4fv(glGetUniformLocation(shader, "model"), 1, GL_FALSE, glm::value_ptr(model));
	glUniform3fv(glGetUniformLocation(shader, "color"), 1, glm::value_ptr(color));

	// Bind the VAO
	glBindVertexArray(VAO);

	// Set point size
	glPointSize(pointSize);

	// Draw the points 
	glDrawArrays(GL_POINTS, 0, points.size());

	// Unbind the VAO and shader program
	glBindVertexArray(0);
	glUseProgram(0);
}

void PointCloud::update()
{
	// Spin the cube by 1 degree
	spin(0.1f);
}

void PointCloud::updatePointSize(GLfloat size) 
{
	/*
	 * TODO: Section 3: Implement this function to adjust the point size.
	 */
}

void PointCloud::spin(float deg)
{
	// Update the model matrix by multiplying a rotation matrix
	model = model * glm::rotate(glm::radians(deg), glm::vec3(0.0f, 1.0f, 0.0f));
}