#include <glad/glad.h>
#include <GLFW/glfw3.h>
#define STB_IMAGE_IMPLEMENTATION
#include "stb_image.h"
#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <learnopengl/shader_t.h>
#include <learnopengl/camera.h>
#include <iostream>
#include <vector>
void framebuffer_size_callback(GLFWwindow* window, int width, int height);
void key_callback(GLFWwindow* window, int key, int scancode, int action, int modifiers);
void mouse_callback(GLFWwindow* window, double xpos, double ypos);
void scroll_callback(GLFWwindow* window, double xoffset, double yoffset);
void processInput(GLFWwindow *window);
// settings
const unsigned int SCR_WIDTH = 800;
const unsigned int SCR_HEIGHT = 600;
const unsigned int NUM_PATCH_PTS = 4;
// camera - give pretty starting point
Camera camera(glm::vec3(67.0f, 627.5f, 169.9f),
glm::vec3(0.0f, 1.0f, 0.0f),
-128.1f, -42.4f);
float lastX = SCR_WIDTH / 2.0f;
float lastY = SCR_HEIGHT / 2.0f;
bool firstMouse = true;
// timing
float deltaTime = 0.0f;
float lastFrame = 0.0f;
int main()
{
// glfw: initialize and configure
// ------------------------------
glfwInit();
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 4);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 1);
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: Terrain GPU", NULL, NULL);
if (window == NULL)
{
std::cout << "Failed to create GLFW window" << std::endl;
glfwTerminate();
return -1;
}
glfwMakeContextCurrent(window);
glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
glfwSetKeyCallback(window, key_callback);
glfwSetCursorPosCallback(window, mouse_callback);
glfwSetScrollCallback(window, scroll_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;
}
GLint maxTessLevel;
glGetIntegerv(GL_MAX_TESS_GEN_LEVEL, &maxTessLevel);
std::cout << "Max available tess level: " << maxTessLevel << std::endl;
// configure global opengl state
// -----------------------------
glEnable(GL_DEPTH_TEST);
// build and compile our shader program
// ------------------------------------
Shader tessHeightMapShader("8.3.gpuheight.vs","8.3.gpuheight.fs", nullptr, // if wishing to render as is
"8.3.gpuheight.tcs", "8.3.gpuheight.tes");
// load and create a texture
// -------------------------
unsigned int texture;
glGenTextures(1, &texture);
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, texture); // all upcoming GL_TEXTURE_2D operations now have effect on this texture object
// set the texture wrapping parameters
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT); // set texture wrapping to GL_REPEAT (default wrapping method)
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
// set texture filtering parameters
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
// load image, create texture and generate mipmaps
int width, height, nrChannels;
// The FileSystem::getPath(...) is part of the GitHub repository so we can find files on any IDE/platform; replace it with your own image path.
unsigned char *data = stbi_load("heightmaps/iceland_heightmap.png", &width, &height, &nrChannels, 0);
if (data)
{
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, data);
glGenerateMipmap(GL_TEXTURE_2D);
tessHeightMapShader.setInt("heightMap", 0);
std::cout << "Loaded heightmap of size " << height << " x " << width << std::endl;
}
else
{
std::cout << "Failed to load texture" << std::endl;
}
stbi_image_free(data);
// set up vertex data (and buffer(s)) and configure vertex attributes
// ------------------------------------------------------------------
std::vector<float> vertices;
unsigned rez = 20;
for(unsigned i = 0; i <= rez-1; i++)
{
for(unsigned j = 0; j <= rez-1; j++)
{
vertices.push_back(-width/2.0f + width*i/(float)rez); // v.x
vertices.push_back(0.0f); // v.y
vertices.push_back(-height/2.0f + height*j/(float)rez); // v.z
vertices.push_back(i / (float)rez); // u
vertices.push_back(j / (float)rez); // v
vertices.push_back(-width/2.0f + width*(i+1)/(float)rez); // v.x
vertices.push_back(0.0f); // v.y
vertices.push_back(-height/2.0f + height*j/(float)rez); // v.z
vertices.push_back((i+1) / (float)rez); // u
vertices.push_back(j / (float)rez); // v
vertices.push_back(-width/2.0f + width*i/(float)rez); // v.x
vertices.push_back(0.0f); // v.y
vertices.push_back(-height/2.0f + height*(j+1)/(float)rez); // v.z
vertices.push_back(i / (float)rez); // u
vertices.push_back((j+1) / (float)rez); // v
vertices.push_back(-width/2.0f + width*(i+1)/(float)rez); // v.x
vertices.push_back(0.0f); // v.y
vertices.push_back(-height/2.0f + height*(j+1)/(float)rez); // v.z
vertices.push_back((i+1) / (float)rez); // u
vertices.push_back((j+1) / (float)rez); // v
}
}
std::cout << "Loaded " << rez*rez << " patches of 4 control points each" << std::endl;
std::cout << "Processing " << rez*rez*4 << " vertices in vertex shader" << std::endl;
// first, configure the cube's VAO (and terrainVBO)
unsigned int terrainVAO, terrainVBO;
glGenVertexArrays(1, &terrainVAO);
glBindVertexArray(terrainVAO);
glGenBuffers(1, &terrainVBO);
glBindBuffer(GL_ARRAY_BUFFER, terrainVBO);
glBufferData(GL_ARRAY_BUFFER, sizeof(float) * vertices.size(), &vertices[0], GL_STATIC_DRAW);
// position attribute
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void*)0);
glEnableVertexAttribArray(0);
// texCoord attribute
glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void*)(sizeof(float) * 3));
glEnableVertexAttribArray(1);
glPatchParameteri(GL_PATCH_VERTICES, NUM_PATCH_PTS);
// render loop
// -----------
while (!glfwWindowShouldClose(window))
{
// per-frame time logic
// --------------------
float currentFrame = glfwGetTime();
deltaTime = currentFrame - lastFrame;
lastFrame = currentFrame;
// input
// -----
processInput(window);
// render
// ------
glClearColor(0.1f, 0.1f, 0.1f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
// be sure to activate shader when setting uniforms/drawing objects
tessHeightMapShader.use();
// view/projection transformations
glm::mat4 projection = glm::perspective(glm::radians(camera.Zoom), (float)SCR_WIDTH / (float)SCR_HEIGHT, 0.1f, 100000.0f);
glm::mat4 view = camera.GetViewMatrix();
tessHeightMapShader.setMat4("projection", projection);
tessHeightMapShader.setMat4("view", view);
// world transformation
glm::mat4 model = glm::mat4(1.0f);
tessHeightMapShader.setMat4("model", model);
// render the terrain
glBindVertexArray(terrainVAO);
glDrawArrays(GL_PATCHES, 0, NUM_PATCH_PTS*rez*rez);
// glfw: swap buffers and poll IO events (keys pressed/released, mouse moved etc.)
// -------------------------------------------------------------------------------
glfwSwapBuffers(window);
glfwPollEvents();
}
// optional: de-allocate all resources once they've outlived their purpose:
// ------------------------------------------------------------------------
glDeleteVertexArrays(1, &terrainVAO);
glDeleteBuffers(1, &terrainVBO);
// glfw: terminate, clearing all previously allocated GLFW resources.
// ------------------------------------------------------------------
glfwTerminate();
return 0;
}
// process all input: query GLFW whether relevant keys are pressed/released this frame and react accordingly
// ---------------------------------------------------------------------------------------------------------
void processInput(GLFWwindow *window)
{
if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
glfwSetWindowShouldClose(window, true);
if (glfwGetKey(window, GLFW_KEY_W) == GLFW_PRESS)
camera.ProcessKeyboard(FORWARD, deltaTime);
if (glfwGetKey(window, GLFW_KEY_S) == GLFW_PRESS)
camera.ProcessKeyboard(BACKWARD, deltaTime);
if (glfwGetKey(window, GLFW_KEY_A) == GLFW_PRESS)
camera.ProcessKeyboard(LEFT, deltaTime);
if (glfwGetKey(window, GLFW_KEY_D) == GLFW_PRESS)
camera.ProcessKeyboard(RIGHT, deltaTime);
}
// 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 a key event occurs, this callback is called
// ---------------------------------------------------------------------------------------------
void key_callback(GLFWwindow* window, int key, int scancode, int action, int modifiers)
{
if(action == GLFW_PRESS)
{
switch(key)
{
default:
break;
}
}
}
// glfw: whenever the mouse moves, this callback is called
// -------------------------------------------------------
void mouse_callback(GLFWwindow* window, double xpos, double ypos)
{
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(yoffset);
}
HI