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Graphics.cpp
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Graphics.cpp
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#include <iostream>
#include <cassert>
#include "Graphics.hpp"
#define SHADER_ATTRIB_OUT "OutColor"
#define SHADER_ATTRIB_POSITION "Position"
#define SHADER_ATTRIB_NORMAL "Normal"
const char* vertexShader = R"str(
#version 330 core
uniform mat4 proj;
uniform mat4 view;
uniform mat4 model;
layout (location = 0) in vec3 Position;
layout (location = 1) in vec3 Normal;
out VS_OUT
{
float light;
} vs_out;
void main() {
// direction of the sun
vec3 sunDir = normalize(vec3(0.5, 1, 0.25));
mat4 rot = model;
rot[3][0] = 0;
rot[3][1] = 0;
rot[3][2] = 0;
vec3 N = normalize((rot*vec4(Normal, 1.0)).xyz);
vs_out.light = max(dot(N, sunDir), 0.0);
gl_Position = proj * view * model * vec4(Position, 1.0);
}
)str";
const char* fragShader = R"str(
#version 330 core
uniform vec3 color;
layout (location = 0) out vec4 OutColor;
in VS_OUT
{
float light;
} fs_in;
void main() {
OutColor = vec4(color * fs_in.light, 1.0);
}
)str";
bool loadShader( GLuint shaderId, const char* src, std::string& outputlog )
{
char buffer[512];
outputlog.clear();
glShaderSource(shaderId, 1, &src, NULL);
glCompileShader(shaderId);
glGetShaderInfoLog(shaderId, 512, NULL, buffer);
outputlog = std::string(buffer);
GLint status = GL_FALSE;
glGetShaderiv(shaderId, GL_COMPILE_STATUS, &status);
return (status == GL_TRUE);
}
bool Graphics::init( unsigned width, unsigned height )
{
// Use OpenGL 3.1 core
SDL_GL_SetAttribute( SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE );
SDL_GL_SetAttribute( SDL_GL_CONTEXT_MAJOR_VERSION, 3 );
SDL_GL_SetAttribute( SDL_GL_CONTEXT_MINOR_VERSION, 3 );
SDL_GL_SetAttribute( SDL_GL_DOUBLEBUFFER, 1 );
SDL_GL_SetAttribute( SDL_GL_ACCELERATED_VISUAL, 1 );
SDL_SetHint(SDL_HINT_RENDER_VSYNC, "1");
// Enable multisampling for a nice antialiased effect
SDL_GL_SetAttribute(SDL_GL_MULTISAMPLEBUFFERS, 1);
SDL_GL_SetAttribute(SDL_GL_MULTISAMPLESAMPLES, 4);
// Create window
_win.reset(
SDL_CreateWindow( "mctest", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED,
width, height, SDL_WINDOW_OPENGL | SDL_WINDOW_SHOWN ));
if (!_win)
{
std::cout << "Window could not be created! SDL Error: " << SDL_GetError();
return false;
}
// Create context
_context = SDL_GL_CreateContext(_win.get());
if (!_context)
{
std::cout << "OpenGL context could not be created! SDL Error: " << SDL_GetError();
return false;
}
// Enable VSync
if( SDL_GL_SetSwapInterval(1) < 0 )
std::cout << "unable to set VSync! SDL Error: " << SDL_GetError();
assert(glGetError() == GL_NO_ERROR);
std::cout << "Opengl Version: " << glGetString(GL_VERSION) << std::endl;
std::cout << "GLSL Version: " << glGetString(GL_SHADING_LANGUAGE_VERSION) << std::endl;
//Initialize GLEW
glewExperimental = GL_TRUE;
GLenum glewError = glewInit();
if( glewError != GLEW_OK )
std::cout << "impossible to initialize GLEW! " << glewGetErrorString( glewError );
// ignore gl's errors after glewExperimentat init:
//https://www.opengl.org/wiki/OpenGL_Loading_Library
glGetError();
//Load shaders
_fragId = glCreateShader(GL_FRAGMENT_SHADER);
_vertId = glCreateShader(GL_VERTEX_SHADER);
_programId = glCreateProgram();
std::string outputlog;
if (loadShader(_vertId, vertexShader, outputlog) == false
|| loadShader(_fragId, fragShader, outputlog) == false)
{
std::cout << "error while compiling shaders: \n" << outputlog << std::endl;
return false;
}
glAttachShader(_programId, _vertId);
glAttachShader(_programId, _fragId);
glBindFragDataLocation(_programId, 0, SHADER_ATTRIB_OUT);
glBindAttribLocation(_programId, 0, SHADER_ATTRIB_POSITION);
glBindAttribLocation(_programId, 1, SHADER_ATTRIB_NORMAL);
glLinkProgram(_programId);
assert(glGetError() == GL_NO_ERROR);
GLint programSuccess = GL_TRUE;
glGetProgramiv(_programId, GL_LINK_STATUS, &programSuccess);
if ( programSuccess != GL_TRUE)
{
std::cout << "failed to link shader program";
return false;
}
glUseProgram(_programId);
_unifProj = glGetUniformLocation(_programId, "proj");
_unifView = glGetUniformLocation(_programId, "view");
_unifModel = glGetUniformLocation(_programId, "model");
_unifColor = glGetUniformLocation(_programId, "color");
// Generate a Box
glGenVertexArrays(1, &_boxVAO);
glBindVertexArray(_boxVAO);
// Create a Vertex Buffer Object and copy the vertex data to it
glGenBuffers(1, &_boxVBO);
glBindBuffer(GL_ARRAY_BUFFER, _boxVBO);
GLfloat vertices[] = {
-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
};
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
// Specify the layout of the vertex data
glEnableVertexAttribArray(0/*SHADER_ATTRIB_POSITION*/);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(GLfloat), 0);
glEnableVertexAttribArray(1/*SHADER_ATTRIB_NORMAL*/);
glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(GLfloat), (void*)(3 * sizeof(GLfloat)));
// Application Settings
mat4 _proj = perspective( 3.14f/3.f, (float)width/(float)height, 0.1f, 1000.f);
mat4 _view = lookAt(vec3(5, 6, 5)*3.f, vec3(0.f, 0.f, -30.f), vec3(0.f, 1.f, 0.f));
glUniform(_unifProj, _proj);
glUniform(_unifView, _view);
glDepthMask( GL_TRUE );
glDepthFunc( GL_LESS );
glEnable(GL_DEPTH_TEST);
return true;
}
void Graphics::deinit( void )
{
if (_fragId) glDeleteShader(_fragId);
if (_vertId) glDeleteShader(_vertId);
if (_programId) glDeleteProgram(_programId);
glDeleteBuffers(1, &_boxVBO);
glDeleteVertexArrays(1, &_boxVAO);
_win.reset();
}
void Graphics::clear( void )
{
const GLfloat clearColor = 0.7f;
glClearColor(clearColor, clearColor, clearColor, 0.f);
glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
}
void Graphics::drawBox( const mat4& model, const Color& color )
{
glUniform(_unifModel, model);
glUniform(_unifColor, color);
glDrawArrays(GL_TRIANGLES, 0, 36);
}
void Graphics::refresh( void )
{
SDL_GL_SwapWindow(_win.get());
}