Files
LearnOpenGL/src/4.advanced_opengl/10.2.instancing_asteroids/instancing_asteroids.cpp
2017-04-17 20:40:26 +02:00

248 lines
8.9 KiB
C++

// GLEW
#define GLEW_STATIC
#include <GL/glew.h>
// GLFW
#include <GLFW/glfw3.h>
// GL includes
#include <learnopengl/shader.h>
#include <learnopengl/camera.h>
#include <learnopengl/model.h>
// GLM Mathemtics
#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <glm/gtc/type_ptr.hpp>
#include <learnopengl/filesystem.h>
// Properties
GLuint screenWidth = 800, screenHeight = 600;
// Function prototypes
void key_callback(GLFWwindow* window, int key, int scancode, int action, int mode);
void mouse_callback(GLFWwindow* window, double xpos, double ypos);
void Do_Movement();
// Camera
Camera camera(glm::vec3(0.0f, 0.0f, 155.0f));
bool keys[1024];
GLfloat lastX = 400, lastY = 300;
bool firstMouse = true;
GLfloat deltaTime = 0.0f;
GLfloat lastFrame = 0.0f;
// The MAIN function, from here we start our application and run our Game loop
int main()
{
// Init GLFW
glfwInit();
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
glfwWindowHint(GLFW_RESIZABLE, GL_FALSE);
GLFWwindow* window = glfwCreateWindow(screenWidth, screenHeight, "LearnOpenGL", nullptr, nullptr); // Windowed
glfwMakeContextCurrent(window);
// Set the required callback functions
glfwSetKeyCallback(window, key_callback);
glfwSetCursorPosCallback(window, mouse_callback);
// Options
glfwSetInputMode(window, GLFW_CURSOR, GLFW_CURSOR_DISABLED);
// Initialize GLEW to setup the OpenGL Function pointers
glewExperimental = GL_TRUE;
glewInit();
// Define the viewport dimensions
glViewport(0, 0, screenWidth, screenHeight);
// Setup OpenGL options
glEnable(GL_DEPTH_TEST);
// Setup and compile our shaders
Shader planetShader("planet.vs", "planet.frag");
Shader instanceShader("instanced_asteroids.vs", "instanced_asteroids.frag");
// Load models
Model rock(FileSystem::getPath("resources/objects/rock/rock.obj").c_str());
Model planet(FileSystem::getPath("resources/objects/planet/planet.obj").c_str());
// Set projection matrix
glm::mat4 projection = glm::perspective(45.0f, (GLfloat)screenWidth/(GLfloat)screenHeight, 1.0f, 10000.0f);
planetShader.Use();
glUniformMatrix4fv(glGetUniformLocation(planetShader.Program, "projection"), 1, GL_FALSE, glm::value_ptr(projection));
// Also of instance shader
instanceShader.Use();
glUniformMatrix4fv(glGetUniformLocation(instanceShader.Program, "projection"), 1, GL_FALSE, glm::value_ptr(projection));
// Generate a large list of semi-random model transformation matrices
GLuint amount = 100000;
glm::mat4* modelMatrices;
modelMatrices = new glm::mat4[amount];
srand(glfwGetTime()); // initialize random seed
GLfloat radius = 150.0f;
GLfloat offset = 25.0f;
for(GLuint i = 0; i < amount; i++)
{
glm::mat4 model;
// 1. Translation: Randomly displace along circle with radius 'radius' in range [-offset, offset]
GLfloat angle = (GLfloat)i / (GLfloat)amount * 360.0f;
GLfloat displacement = (rand() % (GLint)(2 * offset * 100)) / 100.0f - offset;
GLfloat x = sin(angle) * radius + displacement;
displacement = (rand() % (GLint)(2 * offset * 100)) / 100.0f - offset;
GLfloat y = -2.5f + displacement * 0.4f; // Keep height of asteroid field smaller compared to width of x and z
displacement = (rand() % (GLint)(2 * offset * 100)) / 100.0f - offset;
GLfloat z = cos(angle) * radius + displacement;
model = glm::translate(model, glm::vec3(x, y, z));
// 2. Scale: Scale between 0.05 and 0.25f
GLfloat scale = (rand() % 20) / 100.0f + 0.05;
model = glm::scale(model, glm::vec3(scale));
// 3. Rotation: add random rotation around a (semi)randomly picked rotation axis vector
GLfloat rotAngle = (rand() % 360);
model = glm::rotate(model, rotAngle, glm::vec3(0.4f, 0.6f, 0.8f));
// 4. Now add to list of matrices
modelMatrices[i] = model;
}
// forward declare the buffer
GLuint buffer;
glGenBuffers(1, &buffer);
glBindBuffer(GL_ARRAY_BUFFER, buffer);
glBufferData(GL_ARRAY_BUFFER, amount * sizeof(glm::mat4), &modelMatrices[0], GL_STATIC_DRAW);
// Set transformation matrices as an instance vertex attribute (with divisor 1)
// NOTE: We're cheating a little by taking the, now publicly declared, VAO of the model's mesh(es) and adding new vertexAttribPointers
// Normally you'd want to do this in a more organized fashion, but for learning purposes this will do.
for(GLuint i = 0; i < rock.meshes.size(); i++)
{
GLuint VAO = rock.meshes[i].VAO;
glBindVertexArray(VAO);
// Set attribute pointers for matrix (4 times vec4)
glEnableVertexAttribArray(3);
glVertexAttribPointer(3, 4, GL_FLOAT, GL_FALSE, sizeof(glm::mat4), (GLvoid*)0);
glEnableVertexAttribArray(4);
glVertexAttribPointer(4, 4, GL_FLOAT, GL_FALSE, sizeof(glm::mat4), (GLvoid*)(sizeof(glm::vec4)));
glEnableVertexAttribArray(5);
glVertexAttribPointer(5, 4, GL_FLOAT, GL_FALSE, sizeof(glm::mat4), (GLvoid*)(2 * sizeof(glm::vec4)));
glEnableVertexAttribArray(6);
glVertexAttribPointer(6, 4, GL_FLOAT, GL_FALSE, sizeof(glm::mat4), (GLvoid*)(3 * sizeof(glm::vec4)));
glVertexAttribDivisor(3, 1);
glVertexAttribDivisor(4, 1);
glVertexAttribDivisor(5, 1);
glVertexAttribDivisor(6, 1);
glBindVertexArray(0);
}
// Game loop
while(!glfwWindowShouldClose(window))
{
// Set frame time
GLfloat currentFrame = glfwGetTime();
deltaTime = currentFrame - lastFrame;
lastFrame = currentFrame;
// Check and call events
glfwPollEvents();
Do_Movement();
// Clear buffers
glClearColor(0.03f, 0.03f, 0.03f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
// Add transformation matrices
planetShader.Use();
glUniformMatrix4fv(glGetUniformLocation(planetShader.Program, "view"), 1, GL_FALSE, glm::value_ptr(camera.GetViewMatrix()));
instanceShader.Use();
glUniformMatrix4fv(glGetUniformLocation(instanceShader.Program, "view"), 1, GL_FALSE, glm::value_ptr(camera.GetViewMatrix()));
// Draw Planet
planetShader.Use();
glm::mat4 model;
model = glm::translate(model, glm::vec3(0.0f, -5.0f, 0.0f));
model = glm::scale(model, glm::vec3(4.0f, 4.0f, 4.0f));
glUniformMatrix4fv(glGetUniformLocation(planetShader.Program, "model"), 1, GL_FALSE, glm::value_ptr(model));
planet.Draw(planetShader);
// Draw meteorites
instanceShader.Use();
// NB: This could all be implemented as a method within the Model class, perhaps "DrawInstanced(const GLuint amount)"
glActiveTexture(GL_TEXTURE0); // Activate proper texture unit before binding
glUniform1i(glGetUniformLocation(instanceShader.Program, "texture_diffuse1"), 0); // Now set the sampler to the correct texture unit
glBindTexture(GL_TEXTURE_2D, rock.textures_loaded[0].id); // Note we also made the textures_loaded vector public (instead of private) from the model class.
for(GLuint i = 0; i < rock.meshes.size(); i++)
{
glBindVertexArray(rock.meshes[i].VAO);
glDrawElementsInstanced(GL_TRIANGLES, rock.meshes[i].indices.size(), GL_UNSIGNED_INT, 0, amount);
glBindVertexArray(0);
}
// reset our texture binding
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, 0);
// Swap the buffers
glfwSwapBuffers(window);
}
delete[] modelMatrices;
glfwTerminate();
return 0;
}
#pragma region "User input"
// Moves/alters the camera positions based on user input
void Do_Movement()
{
// Camera controls
if(keys[GLFW_KEY_W])
camera.ProcessKeyboard(FORWARD, deltaTime);
if(keys[GLFW_KEY_S])
camera.ProcessKeyboard(BACKWARD, deltaTime);
if(keys[GLFW_KEY_A])
camera.ProcessKeyboard(LEFT, deltaTime);
if(keys[GLFW_KEY_D])
camera.ProcessKeyboard(RIGHT, deltaTime);
}
// Is called whenever a key is pressed/released via GLFW
void key_callback(GLFWwindow* window, int key, int scancode, int action, int mode)
{
if(key == GLFW_KEY_ESCAPE && action == GLFW_PRESS)
glfwSetWindowShouldClose(window, GL_TRUE);
if(action == GLFW_PRESS)
keys[key] = true;
else if(action == GLFW_RELEASE)
keys[key] = false;
}
void mouse_callback(GLFWwindow* window, double xpos, double ypos)
{
if(firstMouse)
{
lastX = xpos;
lastY = ypos;
firstMouse = false;
}
GLfloat xoffset = xpos - lastX;
GLfloat yoffset = lastY - ypos;
lastX = xpos;
lastY = ypos;
camera.ProcessMouseMovement(xoffset, yoffset);
}
#pragma endregion