Recently, I have been trying to add lighting to a simple OpenGL scene using the Blinn-Phong shading model as described in this website.
I tried to follow the tutorial as closely as possible. However, the lighting seems off, especially on the side faces of the cube as the light source begins to move across the front.
I believe it would have something to do with the positions of the Normals not being in the right place due to rotation on the model matrix or having done something wrong in the lighting shader, however, I am not sure whether either of those is really the cause.
Here is the source code, by the way:
#include <glad/glad.h>
#include <SFML/Graphics.hpp>
#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <glm/gtc/type_ptr.hpp>
#include <iostream>
#include <cstdlib>
#include <cmath>
// Vertex shader for the light source cube
const std::string source_vert_shader = R"(
#version 330 core
layout (location = 0) in vec3 vertPos;
uniform mat4 proj, view, model;
void main() {
gl_Position = proj * view * model * vec4(vertPos, 1);
}
)";
// Fragment shader for the light source cube
const std::string source_frag_shader = R"(
#version 330 core
out vec4 FragColor;
void main() {
FragColor = vec4(1);
}
)";
// Vertex shader for the cube
const std::string cube_vert_shader = R"(
#version 330 core
layout (location = 0) in vec3 vertPos;
layout (location = 1) in vec3 vertNorm;
uniform mat4 proj, view, model;
out vec3 fragPos;
out vec3 interNorm;
void main() {
fragPos = vec3(model * vec4(vertPos, 1));
gl_Position = proj * view * vec4(fragPos, 1);
interNorm = mat3(transpose(inverse(model))) * vertNorm;
}
)";
// Fragment shader for the cube
const std::string cube_frag_shader = R"(
#version 330 core
in vec3 fragPos;
in vec3 interNorm;
out vec4 FragColor;
uniform vec3 viewPos;
uniform vec3 lightPos;
uniform vec3 objectColor;
const float pi = 3.14159265;
const float shininess = 16;
void main() {
vec3 normal = normalize(interNorm);
vec3 lightDir = normalize(lightPos - fragPos);
float dist = length(lightPos - fragPos);
float attenuation = 1 / (dist * dist);
// Ambient light effect
const float ambientStrength = 0.05;
vec3 ambient = ambientStrength * objectColor;
// Diffuse light effect
float diff = max(dot(normal, lightDir), 0);
vec3 diffuse = attenuation * diff * objectColor;
// Specular light effect
vec3 specular = vec3(0);
if (diff != 0) {
const float energy_conservation = (8 + shininess) / (8 * pi);
vec3 viewDir = normalize(viewPos - fragPos);
vec3 halfwayDir = normalize(lightDir + viewDir);
float spec = energy_conservation * pow(max(dot(normal, halfwayDir), 0), shininess);
specular = attenuation * spec * vec3(0.3);
}
const float gamma = 2.2;
// Apply the different lighting techniques of the Phong shading model and finally apply gamma correction
FragColor = vec4(pow(ambient + diffuse + specular, vec3(1 / gamma)), 1);
}
)";
int main() {
// Initialize the window
sf::RenderWindow window(
sf::VideoMode(1365, 768), "Lighting", sf::Style::Default,
sf::ContextSettings(24, 8, 4, 3, 3, sf::ContextSettings::Core, true));
// Initialize OpenGL functions
gladLoadGLLoader(reinterpret_cast<GLADloadproc>(sf::Context::getFunction));
// Specify the viewport of the scene
glViewport(0, 0, window.getSize().x, window.getSize().y);
// Enable depth testing
glEnable(GL_DEPTH_TEST);
glDepthFunc(GL_LESS);
// Enable blending
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
// Load the shaders into the application
sf::Shader shader, source_shader;
(void)shader.loadFromMemory(cube_vert_shader, cube_frag_shader);
(void)source_shader.loadFromMemory(source_vert_shader, source_frag_shader);
// Define the vertices of the cube and the light source cube
float vertices[] = {
// Vertices Normals
-0.5f, -0.5f, -0.5f, 0.0f, 0.0f, -1.0f,
0.5f, -0.5f, -0.5f, 0.0f, 0.0f, -1.0f,
0.5f, 0.5f, -0.5f, 0.0f, 0.0f, -1.0f,
0.5f, 0.5f, -0.5f, 0.0f, 0.0f, -1.0f,
-0.5f, 0.5f, -0.5f, 0.0f, 0.0f, -1.0f,
-0.5f, -0.5f, -0.5f, 0.0f, 0.0f, -1.0f,
-0.5f, -0.5f, 0.5f, 0.0f, 0.0f, 1.0f,
0.5f, -0.5f, 0.5f, 0.0f, 0.0f, 1.0f,
0.5f, 0.5f, 0.5f, 0.0f, 0.0f, 1.0f,
0.5f, 0.5f, 0.5f, 0.0f, 0.0f, 1.0f,
-0.5f, 0.5f, 0.5f, 0.0f, 0.0f, 1.0f,
-0.5f, -0.5f, 0.5f, 0.0f, 0.0f, 1.0f,
-0.5f, 0.5f, 0.5f, -1.0f, 0.0f, 0.0f,
-0.5f, 0.5f, -0.5f, -1.0f, 0.0f, 0.0f,
-0.5f, -0.5f, -0.5f, -1.0f, 0.0f, 0.0f,
-0.5f, -0.5f, -0.5f, -1.0f, 0.0f, 0.0f,
-0.5f, -0.5f, 0.5f, -1.0f, 0.0f, 0.0f,
-0.5f, 0.5f, 0.5f, -1.0f, 0.0f, 0.0f,
0.5f, 0.5f, 0.5f, 1.0f, 0.0f, 0.0f,
0.5f, 0.5f, -0.5f, 1.0f, 0.0f, 0.0f,
0.5f, -0.5f, -0.5f, 1.0f, 0.0f, 0.0f,
0.5f, -0.5f, -0.5f, 1.0f, 0.0f, 0.0f,
0.5f, -0.5f, 0.5f, 1.0f, 0.0f, 0.0f,
0.5f, 0.5f, 0.5f, 1.0f, 0.0f, 0.0f,
-0.5f, -0.5f, -0.5f, 0.0f, -1.0f, 0.0f,
0.5f, -0.5f, -0.5f, 0.0f, -1.0f, 0.0f,
0.5f, -0.5f, 0.5f, 0.0f, -1.0f, 0.0f,
0.5f, -0.5f, 0.5f, 0.0f, -1.0f, 0.0f,
-0.5f, -0.5f, 0.5f, 0.0f, -1.0f, 0.0f,
-0.5f, -0.5f, -0.5f, 0.0f, -1.0f, 0.0f,
-0.5f, 0.5f, -0.5f, 0.0f, 1.0f, 0.0f,
0.5f, 0.5f, -0.5f, 0.0f, 1.0f, 0.0f,
0.5f, 0.5f, 0.5f, 0.0f, 1.0f, 0.0f,
0.5f, 0.5f, 0.5f, 0.0f, 1.0f, 0.0f,
-0.5f, 0.5f, 0.5f, 0.0f, 1.0f, 0.0f,
-0.5f, 0.5f, -0.5f, 0.0f, 1.0f, 0.0f
};
// Attach the vertices in the vertices array to the VAO and the VBO
GLuint vao, vbo;
glGenVertexArrays(1, &vao);
glGenBuffers(1, &vbo);
glBindVertexArray(vao);
glBindBuffer(GL_ARRAY_BUFFER, vbo);
glBufferData(GL_ARRAY_BUFFER, sizeof vertices, vertices, GL_STATIC_DRAW);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(GLfloat), nullptr);
glEnableVertexAttribArray(0);
glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(GLfloat), reinterpret_cast<void*>(3 * sizeof(GLfloat)));
glEnableVertexAttribArray(1);
// The same VBO can be used to render the light source cube
GLuint source_vao;
glGenVertexArrays(1, &source_vao);
glBindVertexArray(source_vao);
glBindBuffer(GL_ARRAY_BUFFER, vbo);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(GLfloat), nullptr);
glEnableVertexAttribArray(0);
// Projection matrix
auto proj = glm::perspective(glm::radians(45.0f), static_cast<GLfloat>(window.getSize().x) / window.getSize().y, 0.1f, 100.0f);
glm::vec3 view_pos(0.0f, 0.0f, -5.0f);
// View/camera matrix
glm::mat4 view(1.0f);
view = glm::translate(view, view_pos);
view = glm::rotate(view, glm::radians(45.0f), glm::vec3(1.0f, 1.0f, 1.0f));
// Model matrix
glm::mat4 model(1.0f);
//model = glm::rotate(model, glm::radians(45.0f), glm::vec3(1.0f, 1.0f, 0.0f));
// For the cube in the center
shader.setUniform("proj", sf::Glsl::Mat4(glm::value_ptr(proj)));
shader.setUniform("view", sf::Glsl::Mat4(glm::value_ptr(view)));
shader.setUniform("model", sf::Glsl::Mat4(glm::value_ptr(model)));
shader.setUniform("viewPos", sf::Glsl::Vec3(view_pos.x, view_pos.y, view_pos.z));
shader.setUniform("objectColor", sf::Glsl::Vec3(1.0f, 0.3f, 1.0f));
// For the light source cube
source_shader.setUniform("proj", sf::Glsl::Mat4(glm::value_ptr(proj)));
source_shader.setUniform("view", sf::Glsl::Mat4(glm::value_ptr(view)));
sf::Clock clock;
sf::Event evt{};
while (window.isOpen()) {
while (window.pollEvent(evt)) {
if (evt.type == sf::Event::Closed) {
// When window is closed, destroy the VAO and the VBO
glDeleteBuffers(1, &vbo);
glDeleteVertexArrays(1, &vao);
window.close();
}
if (evt.type == sf::Event::Resized)
// Update the viewport as the window is resized
glViewport(0, 0, evt.size.width, evt.size.height);
}
// Clear the screen with a color
glClearColor(0.8f, 0.2f, 0.6f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
// Calculate an angular factor based on the elapsed time
auto const angular_factor = glm::radians(45.0f) * clock.getElapsedTime().asSeconds();
sf::Shader::bind(&shader);
// Makes the light source move in circles around the cube in the center
glm::vec3 light_pos(
6.0f * std::sin(angular_factor),
0.0f,
6.0f * std::cos(angular_factor)
);
shader.setUniform("lightPos", sf::Glsl::Vec3(light_pos.x, light_pos.y, light_pos.z));
// Draw the cube
glBindVertexArray(vao);
glDrawArrays(GL_TRIANGLES, 0, 36);
sf::Shader::bind(&source_shader);
model = glm::identity<glm::mat4>();
model = glm::scale(model, glm::vec3(0.3f, 0.3f, 0.3f));
model = glm::translate(model, light_pos);
source_shader.setUniform("model", sf::Glsl::Mat4(glm::value_ptr(model)));
// Draw the light source cube
glBindVertexArray(source_vao);
glDrawArrays(GL_TRIANGLES, 0, 36);
sf::Shader::bind(nullptr);
// Swap the window's buffers
window.display();
}
}
I'm working on a project involving viewing a 3D from different viewpoints using mouse and keyboard input. When I submitted my first draft, I received the following feedback:
"Your object did not react to any of the buttons I pressed to change the camera view! The object of this project is to have the user control the camera by being able to change different views but your object didn't give me that ability!"
I currently have it coded to zoom in on the object when pressing the up key and out when pressing the down key. The camera view is supposed to move up and down when moving the mouse.
I've tried using some previous code that involved the cameraPosition variable, but it does not function properly when utilized in the pressSpecialKey function or in the rendering function.
/*Header Inclusions*/
#include <iostream>
#include <GL/glew.h>
#include <GL/freeglut.h>
//GLM Math Header Inclusions
#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <glm/gtc/type_ptr.hpp>
//SOIL image loader Inclusion
#include "SOIL2/SOIL2.h"
using namespace std; //Standard namespace
#define WINDOW_TITLE "Final Project: Spoon" //Window title Macro
/*Shader program Macro*/
#ifndef GLSL
#define GLSL(Version, Source) "#version " #Version "\n" #Source
#endif
//Global variable declarations
int view_state = 1;
/*Variable declarations for shader, window size initialization, buffer and array objects*/
GLint spoonShaderProgram, lampShaderProgram, WindowWidth = 800, WindowHeight = 600;
GLuint VBO, SpoonVAO, LightVAO, texture;
GLfloat cameraSpeed = 0.0005f; //Movement speed per frame
//TODO: Remove unnessary code
GLchar currentKey; //Will store key pressed
GLfloat lastMouseX = 400, lastMouseY = 300; //Locks mouse cursor at the center of the screen
GLfloat mouseXOffset, mouseYOffset, yaw = 0.0f, pitch = 0.0f; //mouse offset, yaw, and pitch variables
GLfloat sensitivity = 0.5f; //Used for mouse / camera rotation sensitivity
bool mouseDetected = true; //Initially true when mouse movement is detected
//Global vector declarations
glm::vec3 cameraPosition = glm::vec3(-2.0f, 1.0f, 2.0f); //Initial camera position.
glm::vec3 CameraUpY = glm::vec3(0.0f, 1.0f, 0.0f); //Temporary y unit vector
glm::vec3 CameraForwardZ = glm::vec3(0.0f, 0.0f, -1.0f); //Temporary z unit vector
glm::vec3 front; //Temporary z unit vector for mouse
//Subject position and scale
glm::vec3 spoonPosition(0.0f, 0.0f, 0.0f);
glm::vec3 spoonScale(2.0f);
//spoon and light color
glm::vec3 objectColor(1.0f, 1.0f, 1.0f);
glm::vec3 lightColor(1.0f, 1.0f, 1.0f);
//Light position and scale
glm::vec3 lightPosition(0.5f, 0.5f, 3.0f);
glm::vec3 lightScale(0.3f);
/*Function prototypes*/
void UResizeWindow(int, int);
void URenderGraphics(void);
void UCreateShader(void);
void UCreateBuffers(void);
void pressSpecialKey(int key, int xx, int yy);
void UMouseMove(int x, int y);
void UGenerateTexture(void);
/*Spoon Vertex Shader Course Code*/
const GLchar * spoonVertexShaderSource = GLSL(330,
layout (location = 0) in vec3 position; //Vertex data from Vertex Attrib Pointer 0
layout (location = 1) in vec3 normal; //VAP for normals from Vertex Attrib Pointer 1
layout (location = 2) in vec2 textureCoordinate; //Texture vertex data from Vertex Attrib Pointer 2
out vec3 FragmentPos; //For outgoing color / pixels to fragment shader
out vec3 Normal; //For outgoing normals to fragment shader
out vec2 mobileTextureCoordinate;
//Global variables for the transform matrices
uniform mat4 model;
uniform mat4 view;
uniform mat4 projection;
void main(){
gl_Position = projection * view * model * vec4(position, 1.0f); //transforms vertices to clip coordinates
FragmentPos = vec3(model * vec4(position, 1.0f)); //Gets fragment / pixel position in world space only (exclude view and projection)
Normal = mat3(transpose(inverse(model))) * normal; //get normal vectors in world space only and exclude normal translation properties
mobileTextureCoordinate = vec2(textureCoordinate.x, 1 - textureCoordinate.y); //flips the texture horizontal
}
);
/*Spoon Fragment Shader Source Code*/
const GLchar * spoonFragmentShaderSource = GLSL(330,
in vec3 FragmentPos; //For incoming fragment position
in vec3 Normal; //For incoming normals
in vec2 mobileTextureCoordinate;
out vec4 spoonColor; //For outgoing spoon color to the GPU
//Uniform / Global variables for object color, light color, light position, and camera/view position
uniform vec3 lightColor;
uniform vec3 lightPos;
uniform vec3 viewPosition;
uniform sampler2D uTexture; //Useful when working with multiple textures
void main(){
/*Phong lighting model calculations to generate ambient, diffuse, and specular components*/
//Calculate Ambient Lighting
float ambientStrength = 0.1f; //Set ambient or global lighting strength
vec3 ambient = ambientStrength * lightColor; //Generate ambient light color
//Calculate Diffuse Lighting
vec3 norm = normalize(Normal); //Normalize vectors to 1 unit
vec3 lightDirection = normalize(lightPos - FragmentPos); //Calculate distance (light direction) between light source and fragments/pixels on
float impact = max(dot(norm, lightDirection), 0.0); //Calculate diffuse impact by generating dot product of normal and light
vec3 diffuse = impact * lightColor; //Generate diffuse light color
//Calculate Specular lighting
float specularIntensity = 1.6f; //Set specular light strength
float highlightSize = 128.0f; //Set specular highlight size
vec3 viewDir = normalize(viewPosition - FragmentPos); //Calculate view direction
vec3 reflectDir = reflect(-lightDirection, norm); //Calculate reflection vector
//Calculate specular component
float specularComponent = pow(max(dot(viewDir, reflectDir), 0.0), highlightSize);
vec3 specular = specularIntensity * specularComponent * lightColor;
//Calculate phong result
vec3 objectColor = texture(uTexture, mobileTextureCoordinate).xyz;
vec3 phong = (ambient + diffuse) * objectColor + specular;
spoonColor = vec4(phong, 1.0f); //Send lighting results to GPU
}
);
/*Lamp Shader Source Code*/
const GLchar * lampVertexShaderSource = GLSL(330,
layout (location = 0) in vec3 position; //VAP position 0 for vertex position data
//Uniform / Global variables for the transform matrices
uniform mat4 model;
uniform mat4 view;
uniform mat4 projection;
void main()
{
gl_Position = projection * view *model * vec4(position, 1.0f); //Transforms vertices into clip coordinates
}
);
/*Lamp Fragment Shader Source Code*/
const GLchar * lampFragmentShaderSource = GLSL(330,
out vec4 color; //For outgoing lamp color (smaller spoon) to the GPU
void main()
{
color = vec4(1.0f); //Set color to white (1.0f, 1.0f, 1.0f) with alpha 1.0
}
);
/*Main Program*/
int main(int argc, char* argv[])
{
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_DEPTH | GLUT_DOUBLE | GLUT_RGBA);
glutInitWindowSize(WindowWidth, WindowHeight);
glutCreateWindow(WINDOW_TITLE);
glutReshapeFunc(UResizeWindow);
glewExperimental = GL_TRUE;
if (glewInit() != GLEW_OK)
{
std::cout << "Failed to initialize GLEW" << std::endl;
return -1;
}
UCreateShader();
UCreateBuffers();
UGenerateTexture();
glClearColor(0.8f, 0.8f, 0.8f, 1.0f); //Set background color
glutDisplayFunc(URenderGraphics);
glutSpecialFunc(pressSpecialKey); //Detects key press
glutPassiveMotionFunc(UMouseMove);
glutMainLoop();
//Destroys Buffer objects once used
glDeleteVertexArrays(1, &SpoonVAO);
glDeleteVertexArrays(1, &LightVAO);
glDeleteBuffers(1, &VBO);
return 0;
}
/*Resizes the window*/
void UResizeWindow(int w, int h)
{
WindowWidth = w;
WindowHeight = h;
glViewport(0, 0, WindowWidth, WindowHeight);
}
/*Renders graphics*/
void URenderGraphics(void)
{
glEnable(GL_DEPTH_TEST); //Enable z-depth
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); //Clears the screen
GLint uTextureLoc, lightColorLoc, lightPositionLoc, viewPositionLoc;
/*********Use the Spoon Shader to activate the Spoon Vertex Array Object for rendering and transforming*********/
glUseProgram(spoonShaderProgram);
glBindVertexArray(SpoonVAO);
CameraForwardZ = front; //Replaces camera forward vector with Radians normalized as a unit vector
//Transforms the object
glm::mat4 model;
model = glm::translate(model, glm::vec3(0.0f, 0.0f, 0.0f)); //Place the object at the center of the viewport
model = glm::rotate(model, 45.0f, glm:: vec3(0.0, 1.0f, 0.0f)); //Rotate the object 45 degrees on the X
model = glm::scale(model, glm::vec3(2.0f, 2.0f, 2.0f)); //Increase the object size by a scale of 2
//Transform the camera
glm::mat4 view;
view = glm::lookAt(cameraPosition - CameraForwardZ, cameraPosition, CameraUpY);
//Creates a perspective projection
glm::mat4 projection;
if(view_state == 1){
projection = glm::perspective(45.0f, (GLfloat)WindowWidth / (GLfloat)WindowHeight, 0.1f, 100.0f);
}else if(view_state == 0){
projection = glm::ortho(-5.0f, 5.0f, -5.0f, 5.0f, 0.1f, 100.0f);
}
//Reference matrix uniforms from the spoon Shader program
GLint modelLoc = glGetUniformLocation(spoonShaderProgram, "model");
GLint viewLoc = glGetUniformLocation(spoonShaderProgram, "view");
GLint projLoc = glGetUniformLocation(spoonShaderProgram, "projection");
//Pass matrix data to the spoon Shader program's matrix uniforms
glUniformMatrix4fv(modelLoc, 1, GL_FALSE, glm::value_ptr(model));
glUniformMatrix4fv(viewLoc, 1, GL_FALSE, glm::value_ptr(view));
glUniformMatrix4fv(projLoc, 1, GL_FALSE, glm::value_ptr(projection));
//Reference matrix uniforms from the spoon Shader program for the spoon color, light color, light position, and camera position
uTextureLoc = glGetUniformLocation(spoonShaderProgram, "uTexture");
lightColorLoc = glGetUniformLocation(spoonShaderProgram, "lightColor");
lightPositionLoc = glGetUniformLocation(spoonShaderProgram, "lightPos");
viewPositionLoc = glGetUniformLocation(spoonShaderProgram, "viewPosition");
//Pass color, light, and camera data to the spoon Shader programs corresponding uniforms
glUniform1i(uTextureLoc, 0); // texture unit 0
glUniform3f(lightColorLoc, lightColor.r, lightColor.g, lightColor.b);
glUniform3f(lightPositionLoc, lightPosition.x, lightPosition.y, lightPosition.z);
glUniform3f(viewPositionLoc, cameraPosition.x, cameraPosition.y, cameraPosition.z);
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, texture);
glDrawArrays(GL_TRIANGLES, 0, 126); //Draw the primitives / spoon
glBindVertexArray(0); //Deactivate the spoon Vertex Array Object
/***************Use the Lamp Shader and activate the Lamp Vertex Array Object for rendering and transforming ************/
glUseProgram(lampShaderProgram);
glBindVertexArray(LightVAO);
//Transform the smaller spoon used as a visual cue for the light source
model = glm::translate(model, lightPosition);
model = glm::scale(model, lightScale);
//Reference matrix uniforms from the Lamp Shader program
modelLoc = glGetUniformLocation(lampShaderProgram, "model");
viewLoc = glGetUniformLocation(lampShaderProgram, "view");
projLoc = glGetUniformLocation(lampShaderProgram, "projection");
//Pass matrix uniforms from the Lamp Shader Program
glUniformMatrix4fv(modelLoc, 1, GL_FALSE, glm::value_ptr(model));
glUniformMatrix4fv(viewLoc, 1, GL_FALSE, glm::value_ptr(view));
glUniformMatrix4fv(projLoc, 1, GL_FALSE, glm::value_ptr(projection));
//Draws the triangles
glDrawArrays(GL_TRIANGLES, 0, 126);
glBindVertexArray(0); //Deactivate the Vertex Array Object
glutPostRedisplay();
glutSwapBuffers(); //Flips the back buffer with the front buffer every frame. Similar to GL Flush
}
/*Creates the Shader program*/
void UCreateShader()
{
//Spoon Vertex shader
GLint spoonVertexShader = glCreateShader(GL_VERTEX_SHADER); //Create the Vertex shader
glShaderSource(spoonVertexShader, 1, &spoonVertexShaderSource, NULL); //Attaches the vertex shader to the source code
glCompileShader(spoonVertexShader); //Compiles the Vertex shader
//Spoon Fragment shader
GLint spoonFragmentShader = glCreateShader(GL_FRAGMENT_SHADER); //Create the Fragment shader
glShaderSource(spoonFragmentShader, 1, &spoonFragmentShaderSource, NULL); //Attaches the Fragment shader to the source code
glCompileShader(spoonFragmentShader); //Compiles the Fragment shader
//Spoon Shader program
spoonShaderProgram = glCreateProgram(); //Creates the Shader program and returns an id
glAttachShader(spoonShaderProgram, spoonVertexShader); //Attach Vertex shader to the Shader program
glAttachShader(spoonShaderProgram, spoonFragmentShader); //Attach Fragment shader to the Shader program
glLinkProgram(spoonShaderProgram); //Link Vertex and Fragment shaders to Shader program
//Delete the Vertex and Fragment shaders once linked
glDeleteShader(spoonVertexShader);
glDeleteShader(spoonFragmentShader);
//Lamp Vertex shader
GLint lampVertexShader = glCreateShader(GL_VERTEX_SHADER); //Creates the Vertex shader
glShaderSource(lampVertexShader, 1, &lampVertexShaderSource, NULL); //Attaches the Vertex shader to the source code
glCompileShader(lampVertexShader); //Compiles the Vertex shader
//Lamp Fragment shader
GLint lampFragmentShader = glCreateShader(GL_FRAGMENT_SHADER); //Creates the Fragment shader
glShaderSource(lampFragmentShader, 1, &lampFragmentShaderSource, NULL); //Attaches the Fragment shader to the source code
glCompileShader(lampFragmentShader); //Compiles the Fragment shader
//Lamp Shader Program
lampShaderProgram = glCreateProgram(); //Creates the Shader program and returns an id
glAttachShader(lampShaderProgram, lampVertexShader); //Attach Vertex shader to the Shader program
glAttachShader(lampShaderProgram, lampFragmentShader); //Attach Fragment shader to the Shader program
glLinkProgram(lampShaderProgram); //Link Vertex and Fragment shaders to the Shader program
//Delete the lamp shaders once linked
glDeleteShader(lampVertexShader);
glDeleteShader(lampFragmentShader);
}
void UCreateBuffers()
{
GLfloat vertices[] = {
//Position //Normals //Texture //Point Name
//Front of Scoop //Positive Z
-0.4f, 0.05f, 0.1f, 0.0f, 0.0f, 1.0f, 0.3f, 1.0f, //Q
-0.4f, -0.1f, 0.1f, 0.0f, 0.0f, 1.0f, 0.3f, 0.0f, //R
-0.6f, 0.1f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 1.0f, //U
-0.4f, 0.05f, 0.1f, 0.0f, 0.0f, 1.0f, 0.3f, 1.0f, //Q
-0.2f, 0.0f, 0.1f, 0.0f, 0.0f, 1.0f, 0.6f, 1.0f, //W
-0.4f, -0.1f, 0.1f, 0.0f, 0.0f, 1.0f, 0.3f, 0.0f, //R
-0.4f, -0.1f, 0.1f, 0.0f, 0.0f, 1.0f, 0.3f, 0.0f, //R
-0.2f, -0.1f, 0.1f, 0.0f, 0.0f, 1.0f, 1.0f, 1.0f, //A
-0.2f, 0.0f, 0.1f, 0.0f, 0.0f, 1.0f, 0.6f, 1.0f, //W
-0.2f, 0.0f, 0.1f, 0.0f, 0.0f, 1.0f, 0.6f, 1.0f, //W
-0.2f, -0.1f, 0.1f, 0.0f, 0.0f, 1.0f, 0.6f, 0.0f, //A_1
0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f, 1.0f, 1.0f, //A
0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f, 1.0f, 1.0f, //A
-0.2f, -0.1f, 0.1f, 0.0f, 0.0f, 1.0f, 0.6f, 1.0f, //A_1
0.0f, -0.05f, 0.0f, 0.0f, 0.0f, 1.0f, 1.0f, 0.0f, //B
//Bottom of Scoop Slant //Negative X
-0.6f, 0.1f, 0.0f, -1.0f, 0.0f, 0.0f, 0.0f, 0.6f, //U
-0.6f, 0.1f, -0.1f, -1.0f, 0.0f, 0.0f, 0.0f, 0.3f, //V
-0.4f, -0.1f, 0.1f, -1.0f, 0.0f, 0.0f, 0.3f, 1.0f, //R
-0.4f, -0.1f, 0.1f, -1.0f, 0.0f, 0.0f, 0.3f, 1.0f, //R
-0.4f, -0.1f, -0.2f, -1.0f, 0.0f, 0.0f, 0.3f, 0.0f, //T
-0.6f, 0.1f, -0.1f, -1.0f, 0.0f, 0.0f, 0.0f, 0.3f, //V
//Bottom of Scoop //Negative Y
-0.4f, -0.1f, -0.2f, 0.0f, -1.0f, 0.0f, 0.3f, 0.0f, //T
-0.4f, -0.1f, 0.1f, 0.0f, -1.0f, 0.0f, 0.3f, 1.0f, //R
-0.2f, -0.1f, -0.2f, 0.0f, -1.0f, 0.0f, 0.6f, 0.0f, //B_1
-0.2f, -0.1f, -0.2f, 0.0f, -1.0f, 0.0f, 0.6f, 0.0f, //B_1
-0.4f, -0.1f, 0.1f, 0.0f, -1.0f, 0.0f, 0.3f, 1.0f, //R
-0.2f, -0.1f, 0.1f, 0.0f, -1.0f, 0.0f, 0.6f, 1.0f, //A_1
-0.2f, -0.1f, 0.1f, 0.0f, -1.0f, 0.0f, 0.6f, 1.0f, //A_1
-0.2f, -0.1f, -0.2f, 0.0f, -1.0f, 0.0f, 0.3f, 0.0f, //B_1
0.0f, -0.05f, 0.0f, 0.0f, -1.0f, 0.0f, 1.0f, 0.6f, //B
-0.2f, -0.1f, -0.2f, 0.0f, -1.0f, 0.0f, 0.6f, 0.0f, //B_1
0.0f, -0.05f, 0.0f, 0.0f, -1.0f, 0.0f, 1.0f, 0.6f, //B
0.0f, -0.05f, -0.1f, 0.0f, -1.0f, 0.0f, 1.0f, 0.3f, //D
//Back of Scoop //Negative Z
-0.6f, 0.1f, -0.1f, 0.0f, 0.0f, -1.0f, 0.0f, 1.0f, //V
-0.4f, 0.05f, -0.2f, 0.0f, 0.0f, -1.0f, 0.3f, 1.0f, //S
-0.4f, -0.1f, -0.2f, 0.0f, 0.0f, -1.0f, 0.3f, 0.0f, //T
-0.4f, 0.05f, -0.2f, 0.0f, 0.0f, -1.0f, 0.3f, 1.0f, //S
-0.4f, -0.1f, -0.2f, 0.0f, 0.0f, -1.0f, 0.3f, 0.0f, //T
-0.2f, -0.1f, -0.2f, 0.0f, 0.0f, -1.0f, 0.6f, 0.0f, //B_1
-0.4f, 0.05f, -0.2f, 0.0f, 0.0f, -1.0f, 0.3f, 1.0f, //S
-0.2f, -0.1f, -0.2f, 0.0f, 0.0f, -1.0f, 0.6f, 0.0f, //B_1
-0.2f, 0.0f, -0.2f, 0.0f, 0.0f, -1.0f, 0.6f, 1.0f, //Z
-0.2f, 0.0f, -0.2f, 0.0f, 0.0f, -1.0f, 0.6f, 1.0f, //Z
-0.2f, -0.1f, -0.2f, 0.0f, 0.0f, -1.0f, 0.6f, 0.0f, //B_1
0.0f, 0.0f, -0.1f, 0.0f, 0.0f, -1.0f, 1.0f, 1.0f, //C
0.0f, 0.0f, -0.1f, 0.0f, 0.0f, -1.0f, 1.0f, 1.0f, //C
-0.2f, -0.1f, -0.2f, 0.0f, 0.0f, -1.0f, 0.6f, 0.0f, //B_1
0.0f, -0.05f, -0.1f, 0.0f, 0.0f, -1.0f, 1.0f, 0.0f, //D
//Top of Scoop //Positive Y
-0.6f, 0.1f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, 0.3f, //U
-0.6f, 0.1f, -0.1f, 0.0f, 1.0f, 0.0f, 0.0f, 0.6f, //V
-0.4f, 0.05f, -0.2f, 0.0f, 1.0f, 0.0f, 0.3f, 1.0f, //S
-0.6f, 0.1f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, 0.3f, //U
-0.4f, 0.05f, -0.2f, 0.0f, 1.0f, 0.0f, 0.3f, 1.0f, //S
-0.4f, 0.05f, 0.1f, 0.0f, 1.0f, 0.0f, 0.3f, 0.0f, //Q
-0.4f, 0.05f, -0.2f, 0.0f, 1.0f, 0.0f, 0.3f, 1.0f, //S
-0.4f, 0.05f, 0.1f, 0.0f, 1.0f, 0.0f, 0.3f, 0.0f, //Q
-0.2f, 0.0f, -0.2f, 0.0f, 1.0f, 0.0f, 0.6f, 1.0f, //Z
-0.4f, 0.05f, 0.1f, 0.0f, 1.0f, 0.0f, 0.3f, 0.0f, //Q
-0.2f, 0.0f, -0.2f, 0.0f, 1.0f, 0.0f, 0.6f, 1.0f, //Z
-0.2f, 0.0f, 0.1f, 0.0f, 1.0f, 0.0f, 0.6f, 0.0f, //W
-0.2f, 0.0f, 0.1f, 0.0f, 1.0f, 0.0f, 0.6f, 0.0f, //W
-0.2f, 0.0f, -0.2f, 0.0f, 1.0f, 0.0f, 0.6f, 1.0f, //Z
0.0f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 1.0f, 0.3f, //A
-0.2f, 0.0f, -0.2f, 0.0f, 1.0f, 0.0f, 0.6f, 1.0f, //Z
0.0f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 1.0f, 0.3f, //A
0.0f, 0.0f, -0.1f, 0.0f, 1.0f, 0.0f, 1.0f, 0.6f, //C
//Front of Handle //Positive Z
0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.1f, //A
0.0f, -0.05f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, //B
0.6f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f, 1.0f, 1.0f, //E
0.6f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f, 1.0f, 1.0f, //E
0.0f, -0.05f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, //B
0.6f, -0.1f, 0.0f, 0.0f, 0.0f, 1.0f, 1.0f, 0.0f, //F
//Bottom of Handle //Negative Y
0.0f, -0.05f, 0.0f, 0.0f, -1.0f, 0.0f, 0.0f, 1.0f, //B
0.0f, -0.05f, -0.1f, 0.0f, -1.0f, 0.0f, 0.0f, 0.0f, //D
0.6f, -0.1f, 0.0f, 0.0f, -1.0f, 0.0f, 1.0f, 1.0f, //F
0.0f, -0.05f, -0.1f, 0.0f, -1.0f, 0.0f, 0.0f, 0.0f, //D
0.6f, -0.1f, 0.0f, 0.0f, -1.0f, 0.0f, 1.0f, 1.0f, //F
0.6f, -0.1f, -0.1f, 0.0f, -1.0f, 0.0f, 1.0f, 0.0f, //H
//Back of Handle //Negative Z
0.0f, 0.0f, -0.1f, 0.0f, 0.0f, -1.0f, 0.0f, 1.0f, //C
0.0f, -0.05f, -0.1f, 0.0f, 0.0f, -1.0f, 0.0f, 0.0f, //D
0.6f, 0.0f, -0.1f, 0.0f, 0.0f, -1.0f, 1.0f, 1.0f, //G
0.0f, -0.05f, -0.1f, 0.0f, 0.0f, -1.0f, 0.0f, 0.0f, //D
0.6f, 0.0f, -0.1f, 0.0f, 0.0f, -1.0f, 1.0f, 1.0f, //G
0.6f, -0.1f, -0.1f, 0.0f, 0.0f, -1.0f, 1.0f, 0.0f, //H
//Top of Handle //Positive Y
0.0f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, 1.0f, //A
0.0f, 0.0f, -0.1f, 0.0f, 1.0f, 0.0f, 0.0f, 0.0f, //C
0.6f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 1.0f, 1.0f, //E
0.0f, 0.0f, -0.1f, 0.0f, 1.0f, 0.0f, 0.0f, 0.0f, //C
0.6f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 1.0f, 1.0f, //E
0.6f, 0.0f, -0.1f, 0.0f, 1.0f, 0.0f, 1.0f, 0.0f, //G
//Grip Connection //Negative X
0.6f, 0.0f, 0.1f, -1.0f, 0.0f, 0.0f, 1.0f, 1.0f, //I
0.6f, 0.0f, -0.2f, -1.0f, 0.0f, 0.0f, 0.0f, 1.0f, //J
0.6f, -0.1f, 0.1f, -1.0f, 0.0f, 0.0f, 1.0f, 0.0f, //K
0.6f, 0.0f, -0.2f, -1.0f, 0.0f, 0.0f, 0.0f, 1.0f, //J
0.6f, -0.1f, 0.1f, -1.0f, 0.0f, 0.0f, 1.0f, 0.0f, //K
0.6f, -0.1f, -0.2f, -1.0f, 0.0f, 0.0f, 0.0f, 0.0f, //L
//Front to Grip //Positive Z
0.6f, 0.0f, 0.1f, 0.0f, 0.0f, 1.0f, 0.0f, 1.0f, //I
1.0f, 0.0f, 0.05f, 0.0f, 0.0f, 1.0f, 1.0f, 0.0f, //M
0.6f, -0.1f, 0.1f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, //K
1.0f, 0.0f, 0.05f, 0.0f, 0.0f, 1.0f, 1.0f, 0.0f, //M
0.6f, -0.1f, 0.1f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, //K
1.0f, -0.1f, 0.05f, 0.0f, 0.0f, 1.0f, 1.0f, 1.0f, //N
//Bottom to Grip //Negative Y
0.6f, -0.1f, 0.1f, 0.0f, -1.0f, 0.0f, 0.0f, 0.0f, //K
1.0f, -0.1f, 0.05f, 0.0f, -1.0f, 0.0f, 1.0f, 0.0f, //N
0.6f, -0.1f, -0.2f, 0.0f, -1.0f, 0.0f, 0.0f, 1.0f, //L
1.0f, -0.1f, 0.05f, 0.0f, -1.0f, 0.0f, 1.0f, 0.0f, //N
0.6f, -0.1f, -0.2f, 0.0f, -1.0f, 0.0f, 0.0f, 1.0f, //L
1.0f, -0.1f, -0.15f, 0.0f, -1.0f, 0.0f, 1.0f, 1.0f, //P
//Back to Grip //Negative Z
0.6f, 0.0f, -0.2f, 0.0f, 0.0f, -1.0f, 0.0f, 1.0f, //J
0.6f, -0.1f, -0.2f, 0.0f, 0.0f, -1.0f, 0.0f, 0.0f, //L
1.0f, 0.0f, -0.15f, 0.0f, 0.0f, -1.0f, 1.0f, 1.0f, //O
0.6f, -0.1f, -0.2f, 0.0f, 0.0f, -1.0f, 0.0f, 0.0f, //L
1.0f, 0.0f, -0.15f, 0.0f, 0.0f, -1.0f, 1.0f, 1.0f, //O
1.0f, -0.1f, -0.15f, 0.0f, 0.0f, -1.0f, 1.0f, 0.0f, //P
//Top to Grip //Positive Y
1.0f, 0.0f, -0.15f, 0.0f, 1.0f, 0.0f, 1.0f, 0.0f, //O
1.0f, 0.0f, 0.05f, 0.0f, 1.0f, 0.0f, 1.0f, 1.0f, //M
0.6f, 0.0f, -0.2f, 0.0f, 1.0f, 0.0f, 0.0f, 0.0f, //J
1.0f, 0.0f, 0.05f, 0.0f, 1.0f, 0.0f, 1.0f, 1.0, //M
0.6f, 0.0f, -0.2f, 0.0f, 1.0f, 0.0f, 0.0f, 0.0f, //J
0.6f, 0.0f, 0.1f, 0.0f, 1.0f, 0.0f, 0.0f, 1.0f, //I
//Base of Grip //Positive X
1.0f, 0.0f, 0.05f, 1.0f, 0.0f, 0.0f, 0.0f, 1.0f, //M
1.0f, -0.1f, 0.05f, 1.0f, 0.0f, 0.0f, 0.0f, 0.0f, //N
1.0f, 0.0f, -0.15f, 1.0f, 0.0f, 0.0f, 1.0f, 1.0f, //O
1.0f, -0.1f, 0.05f, 1.0f, 0.0f, 0.0f, 0.0f, 0.0f, //N
1.0f, 0.0f, -0.15f, 1.0f, 0.0f, 0.0f, 1.0f, 1.0f, //O
1.0f, -0.1f, -0.15f, 1.0f, 0.0f, 0.0f, 1.0f, 0.0f //P
};
//Generate buffer ids
glGenVertexArrays(1, &SpoonVAO);
glGenBuffers(1, &VBO);
//Activate the Vertex Array Object before binding and setting any VBOs and Vertex Attribute Pointers.
glBindVertexArray(SpoonVAO);
//Activate the VBO
glBindBuffer(GL_ARRAY_BUFFER, VBO);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW); //Copy vertices to VBO
//Set attribute pointer 0 to hold position data
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (GLvoid*)0);
glEnableVertexAttribArray(0); //Enables vertex attribute
//Set attribute pointer 1 to hold Normal data
glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (GLvoid*)(3 * sizeof(GLfloat)));
glEnableVertexAttribArray(1); //Enables vertex attribute
//Set attribute pointer 2 to hold Texture coordinate data
glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (GLvoid*)(6 * sizeof(GLfloat)));
glEnableVertexAttribArray(2);
glBindVertexArray(0); //Deactivate the Spoon VAO which is good practice
}
void pressSpecialKey(int key, int xx, int yy)
{
switch(key){
//Zoom object in
case GLUT_KEY_UP:
front.x += 0.1f;
front.y += 0.1f;
front.z += 0.1f;
break;
//Zoom object out
case GLUT_KEY_DOWN:
front.x -= 0.1f;
front.y -= 0.1f;
front.z -= 0.1f;
break;
//Change view to orthogonal state
case GLUT_KEY_LEFT:
view_state = 0;
break;
//Change view to perspective state
case GLUT_KEY_RIGHT:
view_state = 1;
break;
}
}
/*Implements the UMouseMove function*/
void UMouseMove(int x, int y)
{
//Immediately replaces center locked coordinated with new mouse coordinates
if(mouseDetected)
{
lastMouseX = x;
lastMouseY = y;
mouseDetected = false;
}
//Gets the direction the mouse was moved in x and y
mouseXOffset = x - lastMouseX;
mouseYOffset = lastMouseY - y; //Inverted Y
//Updates with new mouse coordinates
lastMouseX = x;
lastMouseY = y;
//Applies sensitivity to mouse direction
mouseXOffset *= sensitivity;
mouseYOffset *= sensitivity;
//Accumulates the yaw and pitch variables
yaw += mouseXOffset;
pitch += mouseYOffset;
//Maintains a 90 degree pitch for gimbal lock
if(pitch > 89.0f)
pitch = 89.0f;
if(pitch < -89.0f)
pitch = -89.0f;
//Converts mouse coordinates / degrees into Radians, then to vectors
front.x = cos(glm::radians(pitch)) * cos(glm::radians(yaw));
front.y = sin(glm::radians(pitch));
front.z = cos(glm::radians(pitch)) * sin(glm::radians(yaw));
}
/*Generate and load the texture*/
void UGenerateTexture(){
glGenTextures(1, &texture);
glBindTexture(GL_TEXTURE_2D, texture);
int width, height;
unsigned char* image = SOIL_load_image("spoon.jpg", &width, &height, 0, SOIL_LOAD_RGB); //Loads texture file
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, image);
glGenerateMipmap(GL_TEXTURE_2D);
SOIL_free_image_data(image);
glBindTexture(GL_TEXTURE_2D, 0); //Unbind the texture
}
Expected: Spoon in center of the screen, mousemovement changes the camera view (horizontally and vertically), up arrow causes camera to zoom in, and down arrow causes camera to zoom out.
Actual: Spoon not in center. Mousemovement causes the object to move (horizontally and vertically). Arrows not detected (?).
Zooming at perspective projection can be achieved by shifting the the camera position along the line of sight:
void pressSpecialKey(int key, int xx, int yy)
{
switch(key){
case GLUT_KEY_UP: cameraPosition += front * 0.1f; break;
case GLUT_KEY_DOWN: cameraPosition -= front * 0.1f; break;
// [...]
}
or by changing the field of view angle:
float fov_angle = 45.0f;
projection = glm::perspective(glm::radians(fov_angle),
(GLfloat)WindowWidth / (GLfloat)WindowHeight, 0.1f, 100.0f);
void pressSpecialKey(int key, int xx, int yy)
{
switch(key){
case GLUT_KEY_UP: fov_angle -= 0.1f; break;
case GLUT_KEY_DOWN: fov_angle += 0.1f; break;
// [...]
}
If you want to keep the spoon in the center of the view ant to orbit around the spoon, then you've to change the camera position according to the viewing direction:
void UMouseMove(int x, int y)
{
// [...]
cameraPosition = - front * glm::length( cameraPosition );
}
The matrices of the OpenGL Mathematics (GLM) have to be initialized. An identity matrix can be initialized by the single parameter 1.0:
e.g.
glm::mat4 model(1.0f);
The angles which are passed to the OpenGL Mathematics (GLM) library functions have to be set in radians rather than degrees. (In glm version 0.9.4 or less this was different).
glm::perspective():
LM_FUNC_DECL tmat4x4<T, defaultp> glm::perspective(T fovy, T aspect, T near, T far)
Creates a matrix for a symetric perspective-view frustum based on the default handedness.
Parameters
fovy Specifies the field of view angle in the y direction. Expressed in radians.
glm::rotate()
GLM_FUNC_DECL mat<4, 4, T, Q> glm::rotate (mat< 4, 4, T, Q > const & m, T angle, vec<3, T, Q> const & axis)
Builds a rotation 4 * 4 matrix created from an axis vector and an angle.
Parameters
angle Rotation angle expressed in radians.
Initialize the matrices and use glm::radians() to convert from degree to radians:
//Transforms the object
glm::mat4 model(1.0f); // <--- init
model = glm::translate(model, glm::vec3(0.0f, 0.0f, 0.0f)); //Place the object at the center of the viewport
// model = glm::rotate(model, 45.0f, glm:: vec3(0.0, 1.0f, 0.0f));
model = glm::rotate(model, glm::radians(45.0f), glm:: vec3(0.0, 1.0f, 0.0f));
model = glm::scale(model, glm::vec3(2.0f, 2.0f, 2.0f)); //Increase the object size by a scale of 2
//Transform the camera
glm::mat4 view(1.0f); // <--- init
view = glm::lookAt(cameraPosition - CameraForwardZ, cameraPosition, CameraUpY);
//Creates a perspective projection
glm::mat4 projection(1.0f); // <--- init
if(view_state == 1){
// projection = glm::perspective(45.0f,
(GLfloat)WindowWidth / (GLfloat)WindowHeight, 0.1f, 100.0f);
projection = glm::perspective(glm::radians(45.0f),
(GLfloat)WindowWidth / (GLfloat)WindowHeight, 0.1f, 100.0f);
} else if(view_state == 0){
projection = glm::ortho(-5.0f, 5.0f, -5.0f, 5.0f, 0.1f, 100.0f);
}
I have a code that initially had one shader (ourShader), one VAO and one VBO. It would render a scene with a textured cube and its reflection on the ground using Stencil testing. Now, I wanted to add a framebuffer for post-processing so I needed a second shader. I added a second shader (screenShader) and a second VBO. I don't use them in my drawing yet, but the simple fact that I'm adding them makes my code render a black, red triangle instead of the usual scene.
My code looks like this :
Shader ourShader(string("core.vs"), string("core.frag")); // shader class creating a shader program from vertex shader and fragment shader source files.
Shader screenShader(string("core2.vs"), string("core2.frag"));
// Setting up attributes, VAO, VBO
GLuint VAO;
array<GLuint, 2> VBO;
glGenVertexArrays(1, &VAO);
glGenBuffers(2, &VBO[0]);
glBindVertexArray(VAO);
// Data for first shader and first VBO
glBindBuffer(GL_ARRAY_BUFFER, VBO[0]);
glBufferData(GL_ARRAY_BUFFER, sizeof(verticesCube), verticesCube, GL_STATIC_DRAW);
GLint posAttribLoc = glGetAttribLocation(ourShader.Program, "position");
glVertexAttribPointer(posAttribLoc, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (GLvoid*)0); // specify (to the active VAO) how to retrieve the values for the attribute "position" from the data stored ("vertices" here) on the active VBO (GPU)
glEnableVertexAttribArray(posAttribLoc); // enable attribute for rendering
GLint colAttribLoc = glGetAttribLocation(ourShader.Program, "color");
glVertexAttribPointer(colAttribLoc, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (GLvoid*)(3 * sizeof(GLfloat)));
glEnableVertexAttribArray(colAttribLoc);
GLint texAttribLoc = glGetAttribLocation(ourShader.Program, "texCoord");
glVertexAttribPointer(texAttribLoc, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (GLvoid*)(6 * sizeof(GLfloat)));
glEnableVertexAttribArray(texAttribLoc);
// ##### PART GIVING A WEIRD RESULT #####
// Data for second shader and second VBO
glBindBuffer(GL_ARRAY_BUFFER, VBO[1]);
glBufferData(GL_ARRAY_BUFFER, sizeof(verticesRectangle), verticesRectangle, GL_STATIC_DRAW);
GLint posAttribLoc2 = glGetAttribLocation(screenShader.Program, "position");
glVertexAttribPointer(posAttribLoc2, 2, GL_FLOAT, GL_FALSE, 4 * sizeof(GLfloat), (GLvoid*)0); // specify (to the active VAO) how to retrieve the values for the attribute "position" from the data stored ("vertices" here) on the active VBO (GPU)
glEnableVertexAttribArray(posAttribLoc2); // enable attribute for rendering
GLint texAttribLoc2 = glGetAttribLocation(screenShader.Program, "texCoord");
glVertexAttribPointer(texAttribLoc2, 2, GL_FLOAT, GL_FALSE, 4 * sizeof(GLfloat), (GLvoid*)(2 * sizeof(GLfloat)));
glEnableVertexAttribArray(texAttribLoc2);
// ##### END #####
// Setting up texture that will be used for the first shader
GLuint texture;
int width, height;
glGenTextures(1, &texture);
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, texture); // makes "texture" the current texture and attaches it to texture unit 0
// Set the wrapping
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
// Set the filtering
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
unsigned char* image = SOIL_load_image("res/images/image1.jpg", &width, &height, 0, SOIL_LOAD_RGBA);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, image);
glGenerateMipmap(GL_TEXTURE_2D);
SOIL_free_image_data(image);
// Unbind VBO, texture before main loop
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindTexture(GL_TEXTURE_2D, 0);
glfwSwapInterval(1);
glfwSetKeyCallback(window, Input::keyCallback); // Input is a singleton class handling inputs. It works well.
glfwSetCursorPosCallback(window, Input::mouseCallback);
glfwSetScrollCallback(window, Input::scrollCallback);
while (glfwWindowShouldClose(window) == GLFW_FALSE) {
// MAIN LOOP
// ...
}
glDeleteVertexArrays(1, &VAO);
glDeleteBuffers(2, &VBO[0]);
The mainloop is not important I think. What I want to say is that if I remove the few lines dealing with the the second VBO, then the scene renders well. Otherwise, I get a weird-colored triangle.
And my two shaders use those source files for their respective vertex shader and fragment shader. By the way, I get no compilation errors from my shaders.
core.vs :
#version 330 core
in vec3 position;
in vec2 texCoord;
in vec3 color;
out vec2 TexCoord;
out vec3 Color;
uniform mat4 model;
uniform mat4 view;
uniform mat4 projection;
void main()
{
gl_Position = projection*view*model*vec4(position, 1.0);
TexCoord = vec2(texCoord.x, 1.0 - texCoord.y);
Color = color;
}
core.frag :
#version 330 core
in vec2 TexCoord;
in vec3 Color;
out vec4 outColor;
uniform sampler2D ourTexture0;
void main()
{
outColor = vec4(Color, 1)*texture(ourTexture0, TexCoord);
}
core2.vs :
#version 330 core
in vec2 position;
in vec2 texCoord;
out vec2 TexCoord;
void main()
{
gl_Position = vec4(position, 0.0, 1.0);
TexCoord = texCoord;
}
core2.frag :
#version 330 core
in vec2 TexCoord;
out vec4 outColor;
uniform sampler2D texFramebuffer;
void main()
{
outColor = texture(texFramebuffer, TexCoord);
}
The vertices look like this (but only the way to read them is important) :
GLfloat verticesRectangle[] = {
// position // texture coordinates
-0.5f, -0.5f, 0.0f, 0.0f,
0.5f, -0.5f, 1.0f, 0.0f,
-0.5f, 0.5f, 0.0f, 1.0f,
0.5f, 0.5f, 1.0f, 1.0f
};
GLfloat verticesCube[] = {
// position // color // texture coordinates
-0.5f, -0.5f, -0.5f, 1.0f, 1.0f, 1.0f, 0.0f, 0.0f,
0.5f, -0.5f, -0.5f, 1.0f, 1.0f, 1.0f, 1.0f, 0.0f,
0.5f, 0.5f, -0.5f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f,
0.5f, 0.5f, -0.5f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f,
-0.5f, 0.5f, -0.5f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f,
-0.5f, -0.5f, -0.5f, 1.0f, 1.0f, 1.0f, 0.0f, 0.0f,
-0.5f, -0.5f, 0.5f, 1.0f, 1.0f, 1.0f, 0.0f, 0.0f,
0.5f, -0.5f, 0.5f, 1.0f, 1.0f, 1.0f, 1.0f, 0.0f,
0.5f, 0.5f, 0.5f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f,
0.5f, 0.5f, 0.5f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f,
-0.5f, 0.5f, 0.5f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f,
-0.5f, -0.5f, 0.5f, 1.0f, 1.0f, 1.0f, 0.0f, 0.0f,
-0.5f, 0.5f, 0.5f, 1.0f, 1.0f, 1.0f, 1.0f, 0.0f,
-0.5f, 0.5f, -0.5f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f,
-0.5f, -0.5f, -0.5f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f,
-0.5f, -0.5f, -0.5f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f,
-0.5f, -0.5f, 0.5f, 1.0f, 1.0f, 1.0f, 0.0f, 0.0f,
-0.5f, 0.5f, 0.5f, 1.0f, 1.0f, 1.0f, 1.0f, 0.0f,
0.5f, 0.5f, 0.5f, 1.0f, 1.0f, 1.0f, 1.0f, 0.0f,
0.5f, 0.5f, -0.5f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f,
0.5f, -0.5f, -0.5f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f,
0.5f, -0.5f, -0.5f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f,
0.5f, -0.5f, 0.5f, 1.0f, 1.0f, 1.0f, 0.0f, 0.0f,
0.5f, 0.5f, 0.5f, 1.0f, 1.0f, 1.0f, 1.0f, 0.0f,
-0.5f, -0.5f, -0.5f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f,
0.5f, -0.5f, -0.5f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f,
0.5f, -0.5f, 0.5f, 1.0f, 1.0f, 1.0f, 1.0f, 0.0f,
0.5f, -0.5f, 0.5f, 1.0f, 1.0f, 1.0f, 1.0f, 0.0f,
-0.5f, -0.5f, 0.5f, 1.0f, 1.0f, 1.0f, 0.0f, 0.0f,
-0.5f, -0.5f, -0.5f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f,
-0.5f, 0.5f, -0.5f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f,
0.5f, 0.5f, -0.5f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f,
0.5f, 0.5f, 0.5f, 1.0f, 1.0f, 1.0f, 1.0f, 0.0f,
0.5f, 0.5f, 0.5f, 1.0f, 1.0f, 1.0f, 1.0f, 0.0f,
-0.5f, 0.5f, 0.5f, 1.0f, 1.0f, 1.0f, 0.0f, 0.0f,
-0.5f, 0.5f, -0.5f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f,
-1.0f, -0.5f, 1.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, // reflection surface // not a part of the cube itself
-1.0f, -0.5f, -1.0f, 0.0f, 0.0f, 0.0f, 1.0f, 1.0f,
1.0f, -0.5f, 1.0f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f,
1.0f, -0.5f, -1.0f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f,
-1.0f, -0.5f, -1.0f, 0.0f, 0.0f, 0.0f, 1.0f, 1.0f,
1.0f, -0.5f, 1.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f
};
I've already looked at Binding a second vertex buffer seems to spoil my first vertex buffer, OpenGL OES ios 5.1 but the person had this problem because he didn't use his VAO correctly.
Most probably two of your attribute locations have the same value. Since you use just one VAO, you override some of the bindings. The correct way of using multiple independent geometries is to use on VAO per geometry.
The correct code has to look somehow like this:
glBindVertexArray(vao1);
glBindBuffer(VBO[0])
glVertexAttribPointer...
glEnableVertexAttribArray...
//Setup all attributes for first VBO
glBindVertexArray(vao2);
glBindBuffer(VBO[1])
glVertexAttribPointer...
glEnableVertexAttribArray...
//Setup all attributes for second VBO
When rendering do the following:
glBindVertexArray(vao1);
glDraw*... //Draw VAO1
glBindVertexArray(vao2);
glDraw*.... //Draw VAO2
I wrought basic OpenGL 2.1\ES example for supposed target platform, using Qt 4.7.1 library on Windows. Target is some kind of Linux, with Qt 4.8 max available, no glm or similar libraries. Embedded GPU supports ES 1.0 or OpenGL 2.1 only. Example is "classic" texture cube, which you might met in various OpenGL examples.. but those examples use direct calls to OpenGL functions, what isn't available to me for lack of proper headers and glew - both on development and on target platforms. Development platform is Windows 7.
Geometry
static const int vertexDataCount = 6 * 4 * 4;
static const float vertexData[vertexDataCount] = {
// Left face
-0.5f, -0.5f, -0.5f, 1.0f,//0
-0.5f, -0.5f, 0.5f, 1.0f,//1
-0.5f, 0.5f, 0.5f, 1.0f,//2
-0.5f, 0.5f, -0.5f, 1.0f,//3
// Top face
-0.5f, 0.5f, -0.5f, 1.0f, //4
-0.5f, 0.5f, 0.5f, 1.0f, //5
0.5f, 0.5f, 0.5f, 1.0f, //6
0.5f, 0.5f, -0.5f, 1.0f, //7
// Right face
0.5f, 0.5f, -0.5f, 1.0f,//8
0.5f, 0.5f, 0.5f, 1.0f,//9
0.5f, -0.5f, 0.5f, 1.0f,//10
0.5f, -0.5f, -0.5f, 1.0f,//11
// Bottom face
0.5f, -0.5f, -0.5f, 1.0f,//12
0.5f, -0.5f, 0.5f, 1.0f,//13
-0.5f, -0.5f, 0.5f, 1.0f,//14
-0.5f, -0.5f, -0.5f, 1.0f,//15
// Front face
0.5f, -0.5f, 0.5f, 1.0f,//16/
0.5f, 0.5f, 0.5f, 1.0f,//17
-0.5f, 0.5f, 0.5f, 1.0f,//18
-0.5f, -0.5f, 0.5f, 1.0f,//19
// Back face
0.5f, 0.5f, -0.5f, 1.0f,//20
0.5f, -0.5f, -0.5f, 1.0f,//21
-0.5f, -0.5f, -0.5f, 1.0f,//22
-0.5f, 0.5f, -0.5f, 1.0f //23
};
// Normal vectors
static const int normalDataCount = 6 * 4 * 3;
static const float normalData[normalDataCount] = {
// Left face
-1.0f, 0.0f, 0.0f,
-1.0f, 0.0f, 0.0f,
-1.0f, 0.0f, 0.0f,
-1.0f, 0.0f, 0.0f,
// Top face
0.0f, 1.0f, 0.0f,
0.0f, 1.0f, 0.0f,
0.0f, 1.0f, 0.0f,
0.0f, 1.0f, 0.0f,
// Right face
1.0f, 0.0f, 0.0f,
1.0f, 0.0f, 0.0f,
1.0f, 0.0f, 0.0f,
1.0f, 0.0f, 0.0f,
// Bottom face
0.0f, -1.0f, 0.0f,
0.0f, -1.0f, 0.0f,
0.0f, -1.0f, 0.0f,
0.0f, -1.0f, 0.0f,
// Front face
0.0f, 0.0f, 1.0f,
0.0f, 0.0f, 1.0f,
0.0f, 0.0f, 1.0f,
0.0f, 0.0f, 1.0f,
// Back face
0.0f, 0.0f, -1.0f,
0.0f, 0.0f, -1.0f,
0.0f, 0.0f, -1.0f,
0.0f, 0.0f, -1.0f
};
// Texure coords
static const int textureCoordDataCount = 6 * 4 * 2;
static const float textureCoordData[textureCoordDataCount] = {
1.0f, 0.0f,
1.0f, 1.0f,
0.0f, 1.0f,
0.0f, 0.0f,
1.0f, 0.0f,
1.0f, 1.0f,
0.0f, 1.0f,
0.0f, 0.0f,
1.0f, 0.0f,
1.0f, 1.0f,
0.0f, 1.0f,
0.0f, 0.0f,
1.0f, 0.0f,
1.0f, 1.0f,
0.0f, 1.0f,
0.0f, 0.0f,
1.0f, 0.0f,
1.0f, 1.0f,
0.0f, 1.0f,
0.0f, 0.0f,
1.0f, 0.0f,
1.0f, 1.0f,
0.0f, 1.0f,
0.0f, 0.0f
};
// Indices
//
// 3 indices per triangle
// 2 triangles per face
// 6 faces
static const int indexDataCount = 6 * 3 * 2;
static const unsigned int indexData[indexDataCount] = {
0, 1, 2, 0, 2, 3, // Left face
4, 5, 6, 4, 6, 7, // Top face
8, 9, 10, 8, 10, 11, // Right face
12, 14, 15, 12, 13, 14, // Bottom face
16, 17, 18, 16, 18, 19, // Front face
20, 22, 23, 20, 21, 22 // Back face
};
This is how I load texture
glEnable(GL_TEXTURE_2D);
m_texture = bindTexture(QImage("cube.png"));
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
if(m_shaderProgram)
m_shaderProgram->setUniformValue("texture", 0); // texture unit 0, assuming that we used
Vertex shader
#version 120
uniform mat4 projectionMatrix;
uniform mat4 modelViewMatrix;
attribute vec4 vertex;
attribute vec3 normal;
attribute vec2 texturecoord;
varying vec3 fragmentNormal;
varying vec2 outtexture;
void main( void )
{
// Transform the normal vector
fragmentNormal = ( modelViewMatrix * vec4( normal, 0.0 ) ).xyz;
// Calculate the clip-space coordinates
gl_Position = projectionMatrix * modelViewMatrix * vertex;
outtexture = texturecoord;
}
Fragment shader
#version 120
// in
uniform sampler2D texture;
varying vec2 outtexture;
varying vec3 fragmentNormal;
// out
// gl_FragColor
void main( void )
{
// Calculate intensity as max of 0 and dot product of the
// fragmentNormal and the eye position (0,0,1).
float intensity;
intensity = max( dot( fragmentNormal, vec3( 0.0, 0.0, 1.0 ) ), 0.15 );
gl_FragColor = intensity * texture2D(texture,outtexture); // vec4( 1.0, 0.0, 0.0, 1.0 );
}
I bind buffers this way (prepareBufferObject is little snippet function I took from Qt sample):
// Prepare the vertex, normal and index buffers
m_vertexBuffer = new QGLBuffer(QGLBuffer::VertexBuffer );
if ( !prepareBufferObject( m_vertexBuffer, QGLBuffer::StaticDraw, vertexData, sizeof(vertexData) ) )
return;
m_normalBuffer = new QGLBuffer(QGLBuffer::VertexBuffer );
if ( !prepareBufferObject( m_normalBuffer, QGLBuffer::StaticDraw, normalData, sizeof(normalData) ) )
return;
m_texBuffer = new QGLBuffer(QGLBuffer::IndexBuffer );
if ( !prepareBufferObject( m_texBuffer, QGLBuffer::StaticDraw, textureCoordData, sizeof(textureCoordData) ) )
return;
m_indexBuffer = new QGLBuffer(QGLBuffer::IndexBuffer );
if ( !prepareBufferObject( m_indexBuffer, QGLBuffer::StaticDraw, indexData, sizeof(indexData) ) )
return;
loadShaders("vertexshader120.glsl", "fragshader120.glsl");
// Enable the "vertex" attribute to bind it to our vertex buffer
m_vertexBuffer->bind();
m_shaderProgram->setAttributeBuffer( "vertex", GL_FLOAT, 0, 4 ); //xyzw
m_shaderProgram->enableAttributeArray( "vertex" );
// Enable the "normal" attribute to bind it to our texture coords buffer
m_normalBuffer->bind();
m_shaderProgram->setAttributeBuffer( "normal", GL_FLOAT, 0, 3 ); //xyz
m_shaderProgram->enableAttributeArray( "normal" );
m_texBuffer->bind();
m_shaderProgram->setAttributeBuffer( "texturecoord", GL_FLOAT, 0, 2 ); //uv
m_shaderProgram->enableAttributeArray( "texturecoord" );
// Bind the index buffer ready for drawing
m_indexBuffer->bind();
Finally , paintGL method
void GWidget::paintGL()
{
QMatrix4x4 model;
model.setToIdentity();
model.rotate(m_rotation);
QMatrix4x4 mv = m_view * model;
// MVP = projection * view * model
// uploading MVP into shader (may add code to check if MVP was update since last redraw)
m_shaderProgram->setUniformValue("modelViewMatrix",mv);
m_shaderProgram->setUniformValue("projectionMatrix",m_projection);
// set up to render the scene
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
// Draw stuff
glDrawElements( GL_TRIANGLES, // Type of primitive to draw
indexDataCount, // The number of indices in our index buffer we wish to draw
GL_UNSIGNED_INT, // The element type of the index buffer
0 ); // Offset from the start of our index buffer of where to begin
}
Everything works except texture looks misaligned and skewed -both on development and on target platforms. I checked UVs and that they correspond to proper vertices - yet it looks like order of texture coordinates is wrong. Where is error here?
For reference: source code
This is my first attempt at usage of flexible pipeline, so I could do something dumb there.
You're setting up your texture coordinate buffer as an index buffer:
m_texBuffer = new QGLBuffer(QGLBuffer::IndexBuffer );
Since it contains vertex attribute data, it should be created as:
m_texBuffer = new QGLBuffer(QGLBuffer::VertexBuffer);