old-Testgame/main.cpp
2016-08-27 21:59:52 +02:00

116 lines
3 KiB
C++

#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) {
TestGame game;
game.start();
return 0;
}