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Pandinosaurus/CubeTut.cpp

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Created December 13, 2022 10:47
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OpenGL draw cube and triangle
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CubeTut.cpp
#define GLEW_STATIC
#include<stdio.h>
#include<stdlib.h>
#include<GL\glew.h>
#include<GL\GL.h>
#include<GLFW\glfw3.h>
#include<glm.hpp>
#include<gtx\transform.hpp>
#include<string>
#include<vector>
#include<fstream>
#include<time.h>
using namespace glm;
GLuint LoadShaders(const char* vertex_file_path, const char* fragment_file_path);
int main(int argc, char** argv)
{
glfwInit(); // one of two windows that were set up as if(!glfwInit()) cout << error; Deprecated?
glfwWindowHint(GLFW_SAMPLES, 4); //4x AA
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3); // sets the first part of the version [3].3
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3); // sets the second part of the version 3.[3]
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
GLFWwindow* window = glfwCreateWindow(1024,768,"OpenGL", nullptr, nullptr);
glfwMakeContextCurrent(window);
// Initialize GLEW
glewExperimental = GL_TRUE; // needed in core profile
glewInit(); // two of two windows that were set up as if(!glewInit()) cout << error; Deprecated?
// glfwSetWindowTitle( window, "Tutorial 04" );
// Ensure we can capture the escape key being pressed below
//glfwEnable( GLFW_STICKY_KEYS );
// Dark blue background
glClearColor(0.0f, 0.0f, 0.4f, 0.0f);
// Enable depth test
glEnable(GL_DEPTH_TEST);
// Accept fragment if it closer to the camera than the former one
glDepthFunc(GL_LESS);
GLuint VertexArrayID;
glGenVertexArrays(1, &VertexArrayID);
glBindVertexArray(VertexArrayID);
// Create and compile our GLSL program from the shaders
GLuint programID = LoadShaders( "first.vs", "first.fs" );
// Get a handle for our "MVP" uniform
GLuint MatrixID = glGetUniformLocation(programID, "MVP");
// Projection matrix : 45° Field of View, 4:3 ratio, display range : 0.1 unit <-> 100 units
mat4 Projection = perspective(45.0f, 4.0f / 3.0f, 0.1f, 100.0f);
// Camera matrix
mat4 View = lookAt(
vec3(4,3,-3), // Camera is at (4,3,-3), in World Space
vec3(0,0,0), // and looks at the origin
vec3(0,1,0) // Head is up (set to 0,-1,0 to look upside-down)
);
// Model matrix : an identity matrix (model will be at the origin)
mat4 Model = mat4(1.0f);
// Our ModelViewProjection : multiplication of our 3 matrices
mat4 MVP = Projection * View * Model; // Remember, matrix multiplication is the other way around
// Our vertices. Tree consecutive floats give a 3D vertex; Three consecutive vertices give a triangle.
// A cube has 6 faces with 2 triangles each, so this makes 6*2=12 triangles, and 12*3 vertices
static const GLfloat g_vertex_buffer_data[] = {
-1.0f,-1.0f,-1.0f,
-1.0f,-1.0f, 1.0f,
-1.0f, 1.0f, 1.0f,
1.0f, 1.0f,-1.0f,
-1.0f,-1.0f,-1.0f,
-1.0f, 1.0f,-1.0f,
1.0f,-1.0f, 1.0f,
-1.0f,-1.0f,-1.0f,
1.0f,-1.0f,-1.0f,
1.0f, 1.0f,-1.0f,
1.0f,-1.0f,-1.0f,
-1.0f,-1.0f,-1.0f,
-1.0f,-1.0f,-1.0f,
-1.0f, 1.0f, 1.0f,
-1.0f, 1.0f,-1.0f,
1.0f,-1.0f, 1.0f,
-1.0f,-1.0f, 1.0f,
-1.0f,-1.0f,-1.0f,
-1.0f, 1.0f, 1.0f,
-1.0f,-1.0f, 1.0f,
1.0f,-1.0f, 1.0f,
1.0f, 1.0f, 1.0f,
1.0f,-1.0f,-1.0f,
1.0f, 1.0f,-1.0f,
1.0f,-1.0f,-1.0f,
1.0f, 1.0f, 1.0f,
1.0f,-1.0f, 1.0f,
1.0f, 1.0f, 1.0f,
1.0f, 1.0f,-1.0f,
-1.0f, 1.0f,-1.0f,
1.0f, 1.0f, 1.0f,
-1.0f, 1.0f,-1.0f,
-1.0f, 1.0f, 1.0f,
1.0f, 1.0f, 1.0f,
-1.0f, 1.0f, 1.0f,
1.0f,-1.0f, 1.0f
};
static const GLfloat triangle_buffer_data[] = { 2.0f, 0.5f, 0.0f,
1.5, 0.5, 0.0f,
2.0f, 1.0f, 0.0f};
srand(time(NULL));
static GLfloat g_color_buffer_data[12*3*3];
for(int v = 0; v < 12*3; v++)
{
g_color_buffer_data[3*v+0] = 1.0f; //1/(rand() % 10 +1);//red;
g_color_buffer_data[3*v+1] = 1.0f; //1/(rand() % 10 +1);//green;
g_color_buffer_data[3*v+2] = 1.0f; //1/(rand() % 10 +1);//blue;
}
static GLfloat triangle_color_buffer_data[3*3];
for (int i = 0; i < 3*3; i++)
{
triangle_color_buffer_data[3*i+0] = 1/(rand() % 5 + 1);
triangle_color_buffer_data[3*i+1] = 1/(rand() % 5 + 1);
triangle_color_buffer_data[3*i+2] = 1/(rand() % 5 + 1);
}
GLuint vertexbuffer;
glGenBuffers(1, &vertexbuffer);
glBindBuffer(GL_ARRAY_BUFFER, vertexbuffer);
glBufferData(GL_ARRAY_BUFFER, sizeof(g_vertex_buffer_data), g_vertex_buffer_data, GL_STATIC_DRAW);
GLuint colorbuffer;
glGenBuffers(1, &colorbuffer);
glBindBuffer(GL_ARRAY_BUFFER, colorbuffer);
glBufferData(GL_ARRAY_BUFFER, sizeof(g_color_buffer_data), g_color_buffer_data, GL_STATIC_DRAW);
GLuint trianglebuff;
glGenBuffers(1, &trianglebuff);
glBindBuffer(GL_ARRAY_BUFFER, trianglebuff);
glBufferData(GL_ARRAY_BUFFER, sizeof(triangle_buffer_data), triangle_buffer_data, GL_STATIC_DRAW);
GLuint trianglecolorbuff;
glGenBuffers(1, &trianglecolorbuff);
glBindBuffer(GL_ARRAY_BUFFER, trianglecolorbuff);
glBufferData(GL_ARRAY_BUFFER, sizeof(triangle_color_buffer_data), triangle_color_buffer_data, GL_STATIC_DRAW);
while (!glfwWindowShouldClose(window))
{
glfwPollEvents();
if(glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
glfwSetWindowShouldClose(window, GL_TRUE);
glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
for(int v = 0; v < 12*3; v++)
{
g_color_buffer_data[3*v+0] = 0.1f + 1/(rand() % 10 +1);//red;
g_color_buffer_data[3*v+1] = 0.1f + 1/(rand() % 10 +1);//green;
g_color_buffer_data[3*v+2] = 0.1f + 1/(rand() % 10 +1);//blue;
}
for(int v = 0; v < 3*3; v++)
{
triangle_color_buffer_data[3*v+0] = 0.1f + 1/(rand() % 10 +1);//red;
triangle_color_buffer_data[3*v+1] = 0.1f + 1/(rand() % 10 +1);//green;
triangle_color_buffer_data[3*v+2] = 0.1f + 1/(rand() % 10 +1);//blue;
}
glBindBuffer(GL_ARRAY_BUFFER, colorbuffer);
glBufferData(GL_ARRAY_BUFFER, sizeof(g_color_buffer_data), g_color_buffer_data, GL_STATIC_DRAW);
glUseProgram(programID);
// Send our transformation to the currently bound shader,
// in the "MVP" uniform
glUniformMatrix4fv(MatrixID, 1, GL_FALSE, &MVP[0][0]);
// 1rst attribute buffer : vertices
glEnableVertexAttribArray(0);
glBindBuffer(GL_ARRAY_BUFFER, vertexbuffer);
glVertexAttribPointer(0,3,GL_FLOAT,GL_FALSE,0,(void*)0);
// 2nd attribute buffer : colors
glEnableVertexAttribArray(1);
glBindBuffer(GL_ARRAY_BUFFER, colorbuffer);
glVertexAttribPointer(1,3,GL_FLOAT,GL_FALSE,0,(void*)0);
// Draw the triangles !
glDrawArrays(GL_TRIANGLES, 0, 36); // 12*3 indices starting at 0 -> 12 triangles
//glUniformMatrix4fv(MatrixID, 1, GL_FALSE, &MVP[0][0]);
glBindBuffer(GL_ARRAY_BUFFER,trianglebuff); //bind the new buffers
glVertexAttribPointer(0,3,GL_FLOAT,GL_FALSE,0,(void*)0); // Send in the new data
glBindBuffer(GL_ARRAY_BUFFER, trianglecolorbuff);
glBufferData(GL_ARRAY_BUFFER,sizeof(triangle_color_buffer_data), triangle_color_buffer_data, GL_STATIC_DRAW);
glVertexAttribPointer(1,3,GL_FLOAT,GL_FALSE,0,(void*)0);
glDrawArrays(GL_TRIANGLES,0,9);
glDisableVertexAttribArray(0);
glDisableVertexAttribArray(1);
glfwSwapBuffers(window);
}
glDeleteBuffers(1, &vertexbuffer);
glDeleteBuffers(1, &colorbuffer);
glDeleteProgram(programID);
glDeleteVertexArrays(1, &VertexArrayID);
glfwTerminate();
//system("pause");
}
GLuint LoadShaders(const char* vertex_file_path, const char* fragment_file_path)
{
GLuint VertexShaderID = glCreateShader(GL_VERTEX_SHADER);
GLuint FragmentShaderID = glCreateShader(GL_FRAGMENT_SHADER);
// Read the vertex Shader code from the file
std::string VertexShaderCode;
std::ifstream VertexShaderStream(vertex_file_path, std::ios::in);
if(VertexShaderStream.is_open())
{
std::string Line = "";
while(getline(VertexShaderStream, Line))
VertexShaderCode +="\n" + Line;
VertexShaderStream.close();
}
// Read the Fragment Shader code from the file
std::string FragmentShaderCode;
std::ifstream FragmentShaderStream(fragment_file_path, std::ios::in);
if(FragmentShaderStream.is_open())
{
std::string Line = "";
while(getline(FragmentShaderStream, Line))
FragmentShaderCode +="\n" + Line;
FragmentShaderStream.close();
}
GLint Result = GL_FALSE;
int InfoLogLength;
// Compile Vertex Shader
printf("Compiling shader : %s\n", vertex_file_path);
char const * VertexSourcePointer = VertexShaderCode.c_str();
glShaderSource(VertexShaderID,1,&VertexSourcePointer, NULL);
glCompileShader(VertexShaderID);
// Check Vertex Shader
glGetShaderiv(VertexShaderID, GL_COMPILE_STATUS, &Result);
glGetShaderiv(VertexShaderID, GL_INFO_LOG_LENGTH, &InfoLogLength);
if(InfoLogLength > 0)
{
std::vector<char> VertexShaderErrorMessage(InfoLogLength);
glGetShaderInfoLog(VertexShaderID, InfoLogLength, NULL, &VertexShaderErrorMessage[0]);
printf("%s\n", &VertexShaderErrorMessage[0]);
}
// Compile Fragment Shader
printf("Compiling shader : %s\n", fragment_file_path);
char const * FragmentSourcePointer = FragmentShaderCode.c_str();
glShaderSource(FragmentShaderID,1,&FragmentSourcePointer, NULL);
glCompileShader(FragmentShaderID);
// Check Fragment Shader
glGetShaderiv(FragmentShaderID, GL_COMPILE_STATUS, &Result);
glGetShaderiv(FragmentShaderID, GL_INFO_LOG_LENGTH, &InfoLogLength);
if(InfoLogLength > 0)
{
std::vector<char> FragmentShaderErrorMessage(InfoLogLength+1);
glGetShaderInfoLog(FragmentShaderID, InfoLogLength, NULL, &FragmentShaderErrorMessage[0]);
printf("%s\n", &FragmentShaderErrorMessage[0]);
}
// Link the program
printf("Linking program\n");
GLuint ProgramID = glCreateProgram();
glAttachShader(ProgramID, VertexShaderID);
glAttachShader(ProgramID, FragmentShaderID);
glLinkProgram(ProgramID);
// Check the Program
glGetProgramiv(ProgramID, GL_COMPILE_STATUS, &Result);
glGetProgramiv(ProgramID, GL_INFO_LOG_LENGTH, &InfoLogLength);
std::vector<char> ProgramErrorMessage(max(InfoLogLength, int(1)));
printf("%s\n", &ProgramErrorMessage[0]);
glDeleteShader(VertexShaderID);
glDeleteShader(FragmentShaderID);
return ProgramID;
}
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