Can draw a triangle

.kdev4/testgame.kdev4

@@ -0,0 +1,46 @@
+[CMake]
+Build Directory Count=1
+Current Build Directory Index=0
+ProjectRootRelative=./
+
+[CMake][CMake Build Directory 0]
+Build Directory Path=file:///usr/home/morten/projects/testgame/build
+Build Type=Debug
+CMake Binary=file:///usr/local/bin/cmake
+Environment Profile=
+Extra Arguments=
+Install Directory=
+
+[CustomDefinesAndIncludes][ProjectPath0]
+Defines=\x00\x00\x00\x00
+Includes=\x00\x00\x00\x01\x00\x00\x00H\x00/\x00u\x00s\x00r\x00/\x00h\x00o\x00m\x00e\x00/\x00m\x00o\x00r\x00t\x00e\x00n\x00/\x00p\x00r\x00o\x00j\x00e\x00c\x00t\x00s\x00/\x00t\x00e\x00s\x00t\x00g\x00a\x00m\x00e\x00/\x00.
+Path=.
+
+[Defines And Includes][Compiler]
+Name=GCC
+Path=gcc
+Type=GCC
+
+[Launch]
+Launch Configurations=Launch Configuration 0
+
+[Launch][Launch Configuration 0]
+Configured Launch Modes=execute
+Configured Launchers=nativeAppLauncher
+Name=testgame
+Type=Native Application
+
+[Launch][Launch Configuration 0][Data]
+Arguments=
+Dependencies=@Variant(\x00\x00\x00\t\x00\x00\x00\x00\x01\x00\x00\x00\x0b\x00\x00\x00\x00\x02\x00\x00\x00\x10\x00t\x00e\x00s\x00t\x00g\x00a\x00m\x00e\x00\x00\x00\x10\x00t\x00e\x00s\x00t\x00g\x00a\x00m\x00e)
+Dependency Action=Build
+EnvironmentGroup=
+Executable=file:///usr/home/morten/projects/testgame/
+External Terminal=konsole --noclose --workdir %workdir -e %exe
+Project Target=testgame,testgame
+Use External Terminal=false
+Working Directory=
+isExecutable=false
+
+[Project]
+VersionControlSupport=kdevgit

CMakeLists.txt

@@ -1,6 +1,13 @@
 cmake_minimum_required(VERSION 2.6)
 project(testgame)
-
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11 -I..")
-add_executable(testgame main.cpp)
+set(CMAKE_LD_FLAGS "${CMAKE_LD_FLAGS} -L/usr/local/bin")
-
+add_executable(testgame main.cpp renderer/main.cpp)
+INCLUDE(FindPkgConfig)
+PKG_SEARCH_MODULE(SDL2 REQUIRED sdl2)
+INCLUDE_DIRECTORIES(${SDL2_INCLUDE_DIRS})
+find_library(SDL SDL2)
+find_library(GLEW GLEW)
+find_library(GL GL)
+TARGET_LINK_LIBRARIES(testgame ${SDL} ${GLEW} ${GL})
 install(TARGETS testgame RUNTIME DESTINATION bin)

main.cpp

@@ -1,6 +1,116 @@
 #include <iostream>
+#include <cstdlib>
+#include <main.h>
+#include <SDL.h>
+#include <GL/glew.h>
+using namespace std;
+bool TestGame::init()
+{
+  GLint compile_ok = GL_FALSE, link_ok = GL_FALSE;
+  //Compile Vertex shader
+  GLuint vs = glCreateShader(GL_VERTEX_SHADER);
+  const char *vs_source =
+    //"#version 100\n"  // OpenGL ES 2.0
+    "#version 120\n"  // OpenGL 2.1
+    "attribute vec2 coord2d;                  "
+    "void main(void) {                        "
+    "  gl_Position = vec4(coord2d, 0.0, 1.0); "
+    "}";
+  glShaderSource(vs, 1, &vs_source, NULL);
+  glCompileShader(vs);
+  glGetShaderiv(vs, GL_COMPILE_STATUS, &compile_ok);
+  if (!compile_ok) {
+    cerr << "Error in vertex shader" << endl;
+    return false;
+  }
+  //Compile Fragment shader
+  GLuint fs = glCreateShader(GL_FRAGMENT_SHADER);
+  const char *fs_source =
+    //"#version 100\n"  // OpenGL ES 2.0
+    "#version 120\n"  // OpenGL 2.1
+    "void main(void) {        "
+    "  gl_FragColor[0] = 0.0; "
+    "  gl_FragColor[1] = 0.0; "
+    "  gl_FragColor[2] = 1.0; "
+    "}";
+  glShaderSource(fs, 1, &fs_source, NULL);
+  glCompileShader(fs);
+  glGetShaderiv(fs, GL_COMPILE_STATUS, &compile_ok);
+  if (!compile_ok) {
+    cerr << "Error in fragment shader" << endl;
+    return false;
+  }
+  //Linking
+  program = glCreateProgram();
+  glAttachShader(program, vs);
+  glAttachShader(program, fs);
+  glLinkProgram(program);
+  glGetProgramiv(program, GL_LINK_STATUS, &link_ok);
+  if (!link_ok) {
+    cerr << "Error in glLinkProgram" << endl;
+    return false;
+  }
+  const char* attribute_name = "coord2d";
+  attribute_coord2d = glGetAttribLocation(program, attribute_name);
+  if (attribute_coord2d == -1) {
+    cerr << "Could not bind attribute " << attribute_name << endl;
+    return false;
+  }
+  
+  return true;
+}
+void TestGame::stop()
+{
+  //To be written
+}
+bool TestGame::tick()
+{
+  SDL_Event ev;
+  while (SDL_PollEvent(&ev)) {
+    if (ev.type == SDL_QUIT)
+      return false;
+    }
+  render();
+  return true;
+}
+void TestGame::render()
+{
+  //Clear Background
+  glClearColor(1.0, 1.0, 1.0, 1.0);
+  glClear(GL_COLOR_BUFFER_BIT);
+  
+  glUseProgram(program);
+  glEnableVertexAttribArray(attribute_coord2d);
+  GLfloat triangle_vertices[] = {
+    0.0,  0.8,
+    -0.8, -0.8,
+    0.8, -0.8,
+  };
+    // Describe our vertices array to OpenGL (it can't guess its format automatically)
+    glVertexAttribPointer(
+    attribute_coord2d, // attribute
+    2,                 // number of elements per vertex, here (x,y)
+    GL_FLOAT,          // the type of each element
+    GL_FALSE,          // take our values as-is
+    0,                 // no extra data between each position
+    triangle_vertices  // pointer to the C array
+  );
+
+  // Push each element in buffer_vertices to the vertex shader
+  glDrawArrays(GL_TRIANGLES, 0, 3);
+
+  glDisableVertexAttribArray(attribute_coord2d);
+
+  // Display the result
+  SDL_GL_SwapWindow(window);
+}
+TestGame::~TestGame()
+{
+  glDeleteProgram(program);
+}
 
 int main(int argc, char **argv) {
-    std::cout << "Hello, world!" << std::endl;
+    TestGame game;
+    game.start();
     return 0;
 }

main.h

@@ -0,0 +1,15 @@
+#include <renderer/main.h>
+#include <GL/glew.h>
+class TestGame: public MainClass {
+private:
+  GLuint program;
+  GLint attribute_coord2d;
+  auto render() -> void;
+protected:
+  virtual auto tick() -> bool;
+  virtual auto init() -> bool;
+public:
+  TestGame(): MainClass(640,480) {};
+  virtual ~TestGame();
+  virtual auto stop() -> void;
+};

renderer/main.cpp

@@ -0,0 +1,30 @@
+#include <renderer/main.h>
+#include <iostream>
+#include <GL/glew.h>
+using namespace std;
+MainClass::MainClass(int width, int height)
+{
+  SDL_Init(SDL_INIT_VIDEO);
+  window = SDL_CreateWindow("Testgame", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, width, height, SDL_WINDOW_RESIZABLE | SDL_WINDOW_OPENGL);
+  SDL_GL_CreateContext(window);
+}
+void MainClass::start()
+{
+  /* Extension wrangler initialising */
+  GLenum glew_status = glewInit();
+  if (glew_status != GLEW_OK) {
+    cerr << "Error: glewInit: " << glewGetErrorString(glew_status) << endl;
+    throw nullptr;
+  }
+  if(!init()) {
+    cerr << "Error: could not init game!" << endl;
+    throw nullptr;
+  }
+  while(tick());
+  stop();
+}
+MainClass::~MainClass()
+{
+  SDL_DestroyWindow(window);
+  SDL_Quit();
+}

renderer/main.h

@@ -0,0 +1,17 @@
+#ifndef __RENDERER_MAIN_H
+#define __RENDERER_MAIN_H
+#include <SDL.h>
+class MainClass {
+private:
+  MainClass() {};
+protected:
+  SDL_Window* window;
+  virtual auto tick() -> bool = 0;
+  virtual auto init() -> bool = 0;
+public:
+  MainClass(int width, int height);
+  virtual ~MainClass();
+  virtual auto start() -> void;
+  virtual auto stop() -> void =0;
+};
+#endif