//
// Implementing Areal Lights with Linearly Transformed Cosines.
//
// Inspiration:
// https://advances.realtimerendering.com/s2016/s2016_ltc_rnd.pdf
// https://eheitzresearch.wordpress.com/415-2/
// GLAD, GLFW, STB-IMAGE
#include <glad/glad.h>
#include <GLFW/glfw3.h>
#include <stb_image.h>
// GLM
#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <glm/gtc/type_ptr.hpp>
// LEARNOPENGL
#include <learnopengl/shader.h>
#include <learnopengl/camera.h>
#include <learnopengl/model.h>
// STANDARD
#include <iostream>
#include <vector>
// CUSTOM
#include "../ltc_matrix.hpp"
#include "../colors.hpp" // LOOK FOR DIFFERENT COLORS!
// FUNCTION PROTOTYPES
void framebuffer_size_callback(GLFWwindow* window, int width, int height);
void key_callback(GLFWwindow* window, int key, int scancode, int action, int mode);
void mouse_callback(GLFWwindow* window, double xpos, double ypos);
void scroll_callback(GLFWwindow* window, double xoffset, double yoffset);
void do_movement(GLfloat deltaTime);
unsigned int loadTexture(const char *path, bool gammaCorrection);
void renderQuad();
void renderCube();
// SETTINGS AND GLOBALS
const unsigned int SCR_WIDTH = 800;
const unsigned int SCR_HEIGHT = 600;
const glm::vec3 LIGHT_COLOR = Color::BurlyWood; // CHANGE AREA LIGHT COLOR HERE!
bool keys[1024]; // activated keys
glm::vec3 areaLightTranslate;
Shader* ltcShaderPtr;
// camera
Camera camera(glm::vec3(0.0f, 1.0f, 0.5f), glm::vec3(0.0f, 1.0f, 0.0f), 180.0f, 0.0f);
float lastX = (float)SCR_WIDTH / 2.0;
float lastY = (float)SCR_HEIGHT / 2.0;
bool firstMouse = true;
// timing
float deltaTime = 0.0f;
float lastFrame = 0.0f;
//
// 2---3-5
// | / /|
// | / / |
// |/ / |
// 1-4---6
//
struct VertexAL {
glm::vec3 position;
glm::vec3 normal;
glm::vec2 texcoord;
};
const GLfloat psize = 10.0f;
VertexAL planeVertices[6] = {
{ {-psize, 0.0f, -psize}, {0.0f, 1.0f, 0.0f}, {0.0f, 0.0f} },
{ {-psize, 0.0f, psize}, {0.0f, 1.0f, 0.0f}, {0.0f, 1.0f} },
{ { psize, 0.0f, psize}, {0.0f, 1.0f, 0.0f}, {1.0f, 1.0f} },
{ {-psize, 0.0f, -psize}, {0.0f, 1.0f, 0.0f}, {0.0f, 0.0f} },
{ { psize, 0.0f, psize}, {0.0f, 1.0f, 0.0f}, {1.0f, 1.0f} },
{ { psize, 0.0f, -psize}, {0.0f, 1.0f, 0.0f}, {1.0f, 0.0f} }
};
VertexAL areaLightVertices[6] = {
{ {-8.0f, 2.4f, -1.0f}, {1.0f, 0.0f, 0.0f}, {0.0f, 0.0f} }, // 0 1 5 4
{ {-8.0f, 2.4f, 1.0f}, {1.0f, 0.0f, 0.0f}, {0.0f, 1.0f} },
{ {-8.0f, 0.4f, 1.0f}, {1.0f, 0.0f, 0.0f}, {1.0f, 1.0f} },
{ {-8.0f, 2.4f, -1.0f}, {1.0f, 0.0f, 0.0f}, {0.0f, 0.0f} },
{ {-8.0f, 0.4f, 1.0f}, {1.0f, 0.0f, 0.0f}, {1.0f, 1.0f} },
{ {-8.0f, 0.4f, -1.0f}, {1.0f, 0.0f, 0.0f}, {1.0f, 0.0f} }
};
GLuint planeVBO, planeVAO;
GLuint areaLightVBO, areaLightVAO;
void configureMockupData()
{
// PLANE
glGenVertexArrays(1, &planeVAO);
glGenBuffers(1, &planeVBO);
glBindVertexArray(planeVAO);
glBindBuffer(GL_ARRAY_BUFFER, planeVBO);
glBufferData(GL_ARRAY_BUFFER, sizeof(planeVertices), planeVertices, GL_STATIC_DRAW);
// position
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat),
(GLvoid*)0);
glEnableVertexAttribArray(0);
// normal
glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat),
(GLvoid*)(3 * sizeof(GLfloat)));
glEnableVertexAttribArray(1);
// texcoord
glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat),
(GLvoid*)(6 * sizeof(GLfloat)));
glEnableVertexAttribArray(2);
glBindVertexArray(0);
// AREA LIGHT
glGenVertexArrays(1, &areaLightVAO);
glBindVertexArray(areaLightVAO);
glGenBuffers(1, &areaLightVBO);
glBindBuffer(GL_ARRAY_BUFFER, areaLightVBO);
glBufferData(GL_ARRAY_BUFFER, sizeof(areaLightVertices), areaLightVertices, GL_STATIC_DRAW);
// position
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat),
(GLvoid*)0);
glEnableVertexAttribArray(0);
// normal
glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat),
(GLvoid*)(3 * sizeof(GLfloat)));
glEnableVertexAttribArray(1);
// texcoord
glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat),
(GLvoid*)(6 * sizeof(GLfloat)));
glEnableVertexAttribArray(2);
glBindVertexArray(0);
glBindVertexArray(0);
}
void renderPlane()
{
glBindVertexArray(planeVAO);
glDrawArrays(GL_TRIANGLES, 0, 6);
glBindVertexArray(0);
}
void renderAreaLight()
{
glBindVertexArray(areaLightVAO);
glDrawArrays(GL_TRIANGLES, 0, 6);
glBindVertexArray(0);
}
struct LTC_matrices {
GLuint mat1;
GLuint mat2;
};
GLuint loadMTexture()
{
GLuint texture = 0;
glGenTextures(1, &texture);
glBindTexture(GL_TEXTURE_2D, texture);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 64, 64,
0, GL_RGBA, GL_FLOAT, LTC1);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glBindTexture(GL_TEXTURE_2D, 0);
return texture;
}
GLuint loadLUTTexture()
{
GLuint texture = 0;
glGenTextures(1, &texture);
glBindTexture(GL_TEXTURE_2D, texture);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 64, 64,
0, GL_RGBA, GL_FLOAT, LTC2);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glBindTexture(GL_TEXTURE_2D, 0);
return texture;
}
void incrementRoughness(float step)
{
static glm::vec3 color = Color::SlateGray;
static float roughness = 0.5f;
roughness += step;
roughness = glm::clamp(roughness, 0.0f, 1.0f);
//std::cout << "roughness: " << roughness << '\n';
ltcShaderPtr->use();
ltcShaderPtr->setVec4("material.albedoRoughness", glm::vec4(color, roughness));
glUseProgram(0);
}
void incrementLightIntensity(float step)
{
static float intensity = 4.0f;
intensity += step;
intensity = glm::clamp(intensity, 0.0f, 10.0f);
//std::cout << "intensity: " << intensity << '\n';
ltcShaderPtr->use();
ltcShaderPtr->setFloat("areaLight.intensity", intensity);
glUseProgram(0);
}
void switchTwoSided(bool doSwitch)
{
static bool twoSided = true;
if (doSwitch) twoSided = !twoSided;
//std::cout << "twoSided: " << std::boolalpha << twoSided << '\n';
ltcShaderPtr->use();
ltcShaderPtr->setFloat("areaLight.twoSided", twoSided);
glUseProgram(0);
}
int main()
{
// glfw: initialize and configure
// ------------------------------
glfwInit();
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
#ifdef __APPLE__
glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
#endif
// glfw window creation
// --------------------
GLFWwindow* window = glfwCreateWindow(
SCR_WIDTH, SCR_HEIGHT, "LearnOpenGL: Area Lights", NULL, NULL);
if (window == NULL)
{
std::cout << "Failed to create GLFW window" << std::endl;
glfwTerminate();
return -1;
}
glfwMakeContextCurrent(window);
glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
glfwSetCursorPosCallback(window, mouse_callback);
glfwSetScrollCallback(window, scroll_callback);
glfwSetKeyCallback(window, key_callback);
// tell GLFW to capture our mouse
glfwSetInputMode(window, GLFW_CURSOR, GLFW_CURSOR_DISABLED);
// glad: load all OpenGL function pointers
// ---------------------------------------
if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
{
std::cout << "Failed to initialize GLAD" << std::endl;
return -1;
}
// configure global opengl state
// -----------------------------
glEnable(GL_DEPTH_TEST);
// LUT textures
LTC_matrices mLTC;
mLTC.mat1 = loadMTexture();
mLTC.mat2 = loadLUTTexture();
// SHADERS
Shader shaderLTC("7.area_light.vs", "7.area_light.fs");
ltcShaderPtr = &shaderLTC;
Shader shaderLightPlane("7.light_plane.vs", "7.light_plane.fs");
// TEXTURES
unsigned int concreteTexture = loadTexture(
FileSystem::getPath("resources/textures/concreteTexture.png").c_str(), true);
// SHADER CONFIGURATION
shaderLTC.use();
shaderLTC.setVec3("areaLight.points[0]", areaLightVertices[0].position);
shaderLTC.setVec3("areaLight.points[1]", areaLightVertices[1].position);
shaderLTC.setVec3("areaLight.points[2]", areaLightVertices[4].position);
shaderLTC.setVec3("areaLight.points[3]", areaLightVertices[5].position);
shaderLTC.setVec3("areaLight.color", LIGHT_COLOR);
shaderLTC.setInt("LTC1", 0);
shaderLTC.setInt("LTC2", 1);
shaderLTC.setInt("material.diffuse", 2);
incrementRoughness(0.0f);
incrementLightIntensity(0.0f);
switchTwoSided(false);
glUseProgram(0);
shaderLightPlane.use();
{
glm::mat4 model(1.0f);
shaderLightPlane.setMat4("model", model);
}
shaderLightPlane.setVec3("lightColor", LIGHT_COLOR);
glUseProgram(0);
// 3D OBJECTS
configureMockupData();
areaLightTranslate = glm::vec3(0.0f, 0.0f, 0.0f);
// RENDER LOOP
while (!glfwWindowShouldClose(window))
{
float currentFrame = static_cast<float>(glfwGetTime());
deltaTime = currentFrame - lastFrame;
lastFrame = currentFrame;
glfwPollEvents();
do_movement(deltaTime);
glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
shaderLTC.use();
glm::mat4 model(1.0f);
glm::mat3 normalMatrix = glm::mat3(model);
shaderLTC.setMat4("model", model);
shaderLTC.setMat3("normalMatrix", normalMatrix);
glm::mat4 view = camera.GetViewMatrix();
shaderLTC.setMat4("view", view);
glm::mat4 projection = glm::perspective(
glm::radians(camera.Zoom), (float)SCR_WIDTH / (float)SCR_HEIGHT, 0.1f, 100.0f);
shaderLTC.setMat4("projection", projection);
shaderLTC.setVec3("viewPosition", camera.Position);
shaderLTC.setVec3("areaLightTranslate", areaLightTranslate);
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, mLTC.mat1);
glActiveTexture(GL_TEXTURE1);
glBindTexture(GL_TEXTURE_2D, mLTC.mat2);
glActiveTexture(GL_TEXTURE2);
glBindTexture(GL_TEXTURE_2D, concreteTexture);
renderPlane();
glUseProgram(0);
shaderLightPlane.use();
model = glm::translate(model, areaLightTranslate);
shaderLightPlane.setMat4("model", model);
shaderLightPlane.setMat4("view", view);
shaderLightPlane.setMat4("projection", projection);
renderAreaLight();
glUseProgram(0);
glfwSwapBuffers(window);
}
glDeleteVertexArrays(1, &planeVAO);
glDeleteBuffers(1, &planeVBO);
glDeleteVertexArrays(1, &areaLightVAO);
glDeleteBuffers(1, &areaLightVBO);
glfwTerminate();
return 0;
}
// process all input: query GLFW whether relevant keys are pressed/released this frame and react accordingly
// ---------------------------------------------------------------------------------------------------------
void do_movement(GLfloat deltaTime)
{
float cameraSpeed = deltaTime * 3.0f;
if(keys[GLFW_KEY_W]) {
camera.ProcessKeyboard(FORWARD, cameraSpeed);
}
else if(keys[GLFW_KEY_S]) {
camera.ProcessKeyboard(BACKWARD, cameraSpeed);
}
if(keys[GLFW_KEY_A]) {
camera.ProcessKeyboard(LEFT, cameraSpeed);
}
else if(keys[GLFW_KEY_D]) {
camera.ProcessKeyboard(RIGHT, cameraSpeed);
}
if (keys[GLFW_KEY_R]) {
if (keys[GLFW_KEY_LEFT_SHIFT]) incrementRoughness(0.01f);
else incrementRoughness(-0.01f);
}
if (keys[GLFW_KEY_I]) {
if (keys[GLFW_KEY_LEFT_SHIFT]) incrementLightIntensity(0.025f);
else incrementLightIntensity(-0.025f);
}
if (keys[GLFW_KEY_LEFT]) {
areaLightTranslate.z += 0.01f;
}
if (keys[GLFW_KEY_RIGHT]) {
areaLightTranslate.z -= 0.01f;
}
if (keys[GLFW_KEY_UP]) {
areaLightTranslate.y += 0.01f;
}
if (keys[GLFW_KEY_DOWN]) {
areaLightTranslate.y -= 0.01f;
}
}
void key_callback(GLFWwindow* window, int key, int scancode, int action, int mode)
{
static unsigned short wireframe = 0;
if(action == GLFW_PRESS)
{
switch(key)
{
case GLFW_KEY_ESCAPE:
glfwSetWindowShouldClose(window, GL_TRUE);
return;
case GLFW_KEY_B:
switchTwoSided(true);
break;
default:
keys[key] = true;
break;
}
}
if(action == GLFW_RELEASE)
{
if(key == GLFW_KEY_SPACE) {
switch(wireframe)
{
case 0:
glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
wireframe = 1;
break;
default:
glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
wireframe = 0;
break;
}
}
else {
keys[key] = false;
}
}
}
// glfw: whenever the window size changed (by OS or user resize) this callback function executes
// ---------------------------------------------------------------------------------------------
void framebuffer_size_callback(GLFWwindow* window, int width, int height)
{
// make sure the viewport matches the new window dimensions; note that width and
// height will be significantly larger than specified on retina displays.
glViewport(0, 0, width, height);
}
// glfw: whenever the mouse moves, this callback is called
// -------------------------------------------------------
void mouse_callback(GLFWwindow* window, double xposIn, double yposIn)
{
float xpos = static_cast<float>(xposIn);
float ypos = static_cast<float>(yposIn);
if (firstMouse)
{
lastX = xpos;
lastY = ypos;
firstMouse = false;
}
float xoffset = xpos - lastX;
float yoffset = lastY - ypos; // reversed since y-coordinates go from bottom to top
lastX = xpos;
lastY = ypos;
camera.ProcessMouseMovement(xoffset, yoffset);
}
// glfw: whenever the mouse scroll wheel scrolls, this callback is called
// ----------------------------------------------------------------------
void scroll_callback(GLFWwindow* window, double xoffset, double yoffset)
{
camera.ProcessMouseScroll(static_cast<float>(yoffset));
}
// utility function for loading a 2D texture from file
// ---------------------------------------------------
unsigned int loadTexture(char const * path, bool gammaCorrection)
{
unsigned int textureID;
glGenTextures(1, &textureID);
int width, height, nrComponents;
unsigned char *data = stbi_load(path, &width, &height, &nrComponents, 0);
if (data)
{
GLenum internalFormat;
GLenum dataFormat;
if (nrComponents == 1)
{
internalFormat = dataFormat = GL_RED;
}
else if (nrComponents == 3)
{
internalFormat = gammaCorrection ? GL_SRGB : GL_RGB;
dataFormat = GL_RGB;
}
else if (nrComponents == 4)
{
internalFormat = gammaCorrection ? GL_SRGB_ALPHA : GL_RGBA;
dataFormat = GL_RGBA;
}
glBindTexture(GL_TEXTURE_2D, textureID);
glTexImage2D(GL_TEXTURE_2D, 0, internalFormat, width, height, 0, dataFormat, GL_UNSIGNED_BYTE, data);
glGenerateMipmap(GL_TEXTURE_2D);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
stbi_image_free(data);
}
else
{
std::cout << "Texture failed to load at path: " << path << std::endl;
stbi_image_free(data);
}
return textureID;
}
HI