Adding shader support

5 files changed, 238 insertions, 7 deletions

diff --git a/src/arider.cpp b/src/arider.cpp
new file mode 100644
index 0000000..0bb2f96
--- /dev/null
+++ b/src/arider.cpp
@@ -0,0 +1,29 @@
+#include "arider_config.hpp"
+#include "game.hpp"
+
+#include <exception>
+#include <iostream>
+#include <SDL2/SDL.h>
+
+int main()
+{
+    std::cout<<"Arider\nVersion: "<<ARIDER_MAJOR_VERSION<<"."<<ARIDER_MINOR_VERSION
+	     <<"."<<ARIDER_PATCH_VERSION<<std::endl;
+
+    Game game;
+
+    try
+    {
+	game.run();
+    }
+    catch(std::exception &e)
+    {
+	std::cerr<<"Error : "<<e.what()<<std::endl;
+    }
+    catch(...)
+    {
+	std::cerr<<"Error : Exception occured"<<std::endl;
+    }
+
+    return 0;
+}
diff --git a/src/game.cpp b/src/game.cpp
new file mode 100644
index 0000000..196b735
--- /dev/null
+++ b/src/game.cpp
@@ -0,0 +1,77 @@
+#include "game.hpp"
+#include "sprite.hpp"
+
+#include <stdexcept>
+
+Game::Game() 
+{}
+
+Game::~Game()
+{
+    SDL_DestroyWindow(window_);
+    SDL_Quit();
+}
+
+void Game::initSystems()
+{
+    if(SDL_Init(SDL_INIT_VIDEO))
+	throw std::runtime_error("SDL_Init failed");
+
+    window_ = SDL_CreateWindow("Arider", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED,
+			       width_, height_, SDL_WINDOW_OPENGL);
+    if(window_ == nullptr)
+	throw std::runtime_error("SDL_CreateWindow failed");
+
+    SDL_GLContext glContext = SDL_GL_CreateContext(window_);
+    if(glContext == nullptr)
+	throw std::runtime_error("SDL_GL_CreateContext failed");
+
+    GLenum error = glewInit();
+    if(error != GLEW_OK)
+	throw std::runtime_error("glewInit failed");
+
+    SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
+    glClearColor(0.f, 0.f, 1.f, 1.f);
+}
+
+void Game::processInput()
+{
+    SDL_Event event;
+
+    while(SDL_PollEvent(&event))
+    {
+	switch(event.type)
+	{
+	case SDL_QUIT:
+	    game_state_ = GameState::EXIT;
+	}
+    }
+}
+
+void Game::gameLoop()
+{
+    Sprite sprite;
+    sprite.init(-1.f, -1.f, 1.f, 1.f);
+    while(game_state_ != GameState::EXIT)
+    {
+	processInput();
+	sprite.draw();
+	drawGame();
+    }
+}
+
+void Game::drawGame()
+{
+    glClearDepth(1.0);
+    // clears buffer with clear color
+    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+
+    // swap buffer and draw everything to the screen
+    SDL_GL_SwapWindow(window_);
+}
+
+void Game::run()
+{
+    initSystems();
+    gameLoop();
+}
diff --git a/src/glsl_program.cpp b/src/glsl_program.cpp
new file mode 100644
index 0000000..2af956e
--- /dev/null
+++ b/src/glsl_program.cpp
@@ -0,0 +1,73 @@
+#include "glsl_program.hpp"
+
+#include <fstream>
+#include <stdexcept>
+#include <vector>
+
+GlslProgram::GlslProgram()
+{}
+
+GlslProgram::~GlslProgram()
+{
+    if(fragment_shader_id_ != 0)
+	glDeleteShader(fragment_shader_id_);
+    
+    if(vertex_shader_id_ != 0)
+	glDeleteShader(vertex_shader_id_);
+    
+    if(program_id_ != 0)
+	glDeleteProgram(program_id_);
+}
+
+void GlslProgram::compileShader(const GLuint &shader, const std::string &file_path)
+{
+    std::ifstream file(file_path);
+    if(!file.is_open())
+	throw std::runtime_error("Failed to open '"+file_path+"'");
+
+    std::string content = "";
+    std::string line;
+
+    while(std::getline(file, line))
+	content+=line+"\n";
+    file.close();
+
+    const char *vertex_char = content.c_str();
+    glShaderSource(shader, 1, &vertex_char, nullptr);
+    glCompileShader(shader);
+
+    GLint is_compiled = 0;
+    glGetShaderiv(shader, GL_COMPILE_STATUS, &is_compiled);
+
+    if(is_compiled == GL_FALSE)
+    {
+	GLint max_length = 0;
+	glGetShaderiv(shader, GL_INFO_LOG_LENGTH, &max_length);
+ 
+	std::vector<char> error_log(max_length);
+	glGetShaderInfoLog(shader, max_length, &max_length, &error_log[0]);
+	std::string error_log_str(&error_log[0]);
+	
+	throw std::runtime_error("Couldn't compile "+file_path+" : "+error_log_str);
+    }
+}
+
+void GlslProgram::compileShaders(const std::string &vertex_shader_path, const std::string &fragment_shader_path)
+{
+    // create the program that will be run on GPU
+    program_id_ = glCreateProgram();
+    
+    vertex_shader_id_ = glCreateShader(GL_VERTEX_SHADER);
+    if(vertex_shader_id_ == 0)
+	throw std::runtime_error("Vertex shader failed to be created");
+    
+    fragment_shader_id_ = glCreateShader(GL_VERTEX_SHADER);
+    if(fragment_shader_id_ == 0)
+	throw std::runtime_error("Fragment shader failed to be created");
+
+    std::string vertex_shader_content;
+    std::string fragment_shader_content;
+
+    compileShader(vertex_shader_id_, vertex_shader_path);
+    compileShader(fragment_shader_id_, fragment_shader_path);    
+}
diff --git a/src/main.cpp b/src/main.cpp
deleted file mode 100644
index 5260233..0000000
--- a/src/main.cpp
+++ /dev/null
@@ -1,7 +0,0 @@
-#include <cstdio>
-
-int main(int, char**)
-{
-    printf("Hello World\n");
-    return 0;
-}
diff --git a/src/sprite.cpp b/src/sprite.cpp
new file mode 100644
index 0000000..34d7864
--- /dev/null
+++ b/src/sprite.cpp
@@ -0,0 +1,59 @@
+#include "sprite.hpp"
+
+Sprite::Sprite()
+{}
+
+Sprite::~Sprite()
+{
+    if(vbo_id_ != 0)
+	glDeleteBuffers(1, &vbo_id_);
+}
+
+void Sprite::init(float x, float y, float width, float height)
+{
+    x_ = x;
+    y_ = y;
+    width_ = width;
+    height_ = height;
+
+    if(vbo_id_ == 0)
+    {
+	glGenBuffers(1, &vbo_id_);
+    }
+
+    float vertex_data[12];
+
+    vertex_data[0] = x+width;
+    vertex_data[1] = y+height;
+
+    vertex_data[2] = x;
+    vertex_data[3] = y+height;
+
+    vertex_data[4] = x;
+    vertex_data[5] = y;
+
+    vertex_data[6] = x+width;
+    vertex_data[7] = y;
+
+    vertex_data[8] = x;
+    vertex_data[9] = y;
+
+    vertex_data[10] = x+width;
+    vertex_data[11] = y+height;
+
+    glBindBuffer(GL_ARRAY_BUFFER, vbo_id_);
+    glBufferData(GL_ARRAY_BUFFER, sizeof(vertex_data), vertex_data, GL_STATIC_DRAW);
+    glBindBuffer(GL_ARRAY_BUFFER, 0);
+}
+
+void Sprite::draw()
+{
+    glBindBuffer(GL_ARRAY_BUFFER, vbo_id_);
+    glEnableVertexAttribArray(0);
+
+    glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 0, 0);
+    glDrawArrays(GL_TRIANGLES, 0, 6);
+    
+    glDisableVertexAttribArray(0);
+    glBindBuffer(GL_ARRAY_BUFFER, 0);    
+}