intro.cpp

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <SDL.h>
#include <GL/glu.h>
#include <GL/glext.h>
#include <GL/glx.h>
#include <GL/glxext.h>
#include <math.h>
#include <time.h>
#include <unistd.h>
#include "shader.h"

PFNGLCREATEPROGRAMOBJECTARBPROC     glCreateProgramObjectARB = NULL;
PFNGLCREATESHADEROBJECTARBPROC      glCreateShaderObjectARB = NULL;
PFNGLSHADERSOURCEARBPROC            glShaderSourceARB = NULL;
PFNGLCOMPILESHADERARBPROC           glCompileShaderARB = NULL;
PFNGLGETOBJECTPARAMETERIVARBPROC    glGetObjectParameterivARB = NULL;
PFNGLATTACHOBJECTARBPROC            glAttachObjectARB = NULL;
PFNGLGETINFOLOGARBPROC              glGetInfoLogARB = NULL;
PFNGLLINKPROGRAMARBPROC             glLinkProgramARB = NULL;
PFNGLUSEPROGRAMOBJECTARBPROC        glUseProgramObjectARB = NULL;
PFNGLGETUNIFORMLOCATIONARBPROC      glGetUniformLocationARB = NULL;
PFNGLUNIFORM1FARBPROC               glUniform1f = NULL;
PFNGLUNIFORM2FARBPROC               glUniform2f = NULL;
PFNGLUNIFORM3FARBPROC               glUniform3f = NULL;
PFNGLUNIFORM1IARBPROC               glUniform1i = NULL;

#define glXGetProcAddress(x) (*glXGetProcAddressARB)((const GLubyte*)x)

static SDL_Surface* gDrawSurface = NULL;
static int width = 1024;
static int height = 720;
static float ratio = (float)width/height;
static int program, vert_shader, frag_shader;
static int lastFrame = 0;
static int frames = 0;
static uint t0 = 0;
static uint t;
static float view_angle = 45.0f;
static float quad_dist = 1.135f/tan(view_angle/4.0f/M_PI);
static float rot[] = {0.0f,0.0f,0.0f};

void DrawScene()
{
  float tf = (float)t/1000.0;
  uint dt = t-t0;
  t0 = t;
  float dtf = (float)dt/1000.0f;
  glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);

  //generate rotations
  rot[0] += dtf*10.0f;
  rot[1] += dtf*10.0f;
  rot[2] += dtf*10.0f;

  glLoadIdentity();
  glTranslatef(0.0,0.0,-quad_dist);
  glRotatef(rot[0],1,0,0);
  glRotatef(rot[1],0,1,0);
  glRotatef(rot[2],0,0,1);

  glUniform1f(glGetUniformLocationARB(program,"t"),tf);

  //draw full-screen quad
  glBegin(GL_QUADS);
  glTexCoord2f(-1.0f,-1.0f);
  glVertex2f(-1.0f,-1.0f);
  glTexCoord2f(1.0f,-1.0f);
  glVertex2f(1.0f,-1.0f);
  glTexCoord2f(1.0f,1.0f);
  glVertex2f(1.0f,1.0f);
  glTexCoord2f(-1.0f,1.0f);
  glVertex2f(-1.0f,1.0f);
  glEnd();
  glPopMatrix();

  SDL_GL_SwapBuffers();
  frames++;
}

void SetupGLSLProcs()
{
  glCreateProgramObjectARB = (PFNGLCREATEPROGRAMOBJECTARBPROC)glXGetProcAddress("glCreateProgramObjectARB");
  glCreateShaderObjectARB = (PFNGLCREATESHADEROBJECTARBPROC)glXGetProcAddress("glCreateShaderObjectARB");
  glShaderSourceARB = (PFNGLSHADERSOURCEARBPROC)glXGetProcAddress("glShaderSourceARB");
  glCompileShaderARB = (PFNGLCOMPILESHADERARBPROC)glXGetProcAddress("glCompileShaderARB");
  glGetObjectParameterivARB = (PFNGLGETOBJECTPARAMETERIVARBPROC)glXGetProcAddress("glGetObjectParameterivARB");
  glAttachObjectARB = (PFNGLATTACHOBJECTARBPROC)glXGetProcAddress("glAttachObjectARB");
  glGetInfoLogARB = (PFNGLGETINFOLOGARBPROC)glXGetProcAddress("glGetInfoLogARB");
  glLinkProgramARB = (PFNGLLINKPROGRAMARBPROC)glXGetProcAddress("glLinkProgramARB");
  glUseProgramObjectARB = (PFNGLUSEPROGRAMOBJECTARBPROC)glXGetProcAddress("glUseProgramObjectARB");
  glGetUniformLocationARB = (PFNGLGETUNIFORMLOCATIONARBPROC)glXGetProcAddress("glGetUniformLocationARB");
  glUniform1f = (PFNGLUNIFORM1FARBPROC)glXGetProcAddress("glUniform1fARB");
  glUniform2f = (PFNGLUNIFORM2FARBPROC)glXGetProcAddress("glUniform2fARB");
  glUniform3f = (PFNGLUNIFORM3FARBPROC)glXGetProcAddress("glUniform3fARB");
  glUniform1i = (PFNGLUNIFORM1IARBPROC)glXGetProcAddress("glUniform1iARB");
}

int resizeWindow(int width,int height)
{
  GLfloat ratio;
  if (height == 0) height = 1;
  ratio = (GLfloat)width/(GLfloat)height;
  glViewport(0,0,(GLsizei)width,(GLsizei)height);
  glMatrixMode( GL_PROJECTION );
  glLoadIdentity();
  gluPerspective(view_angle,ratio,0.1f,10000.0f);
  glMatrixMode(GL_MODELVIEW);
  glLoadIdentity();
  return(1);
}

void handleKeyPress(SDL_keysym *keysym)
{
  switch (keysym->sym)
  {
    case SDLK_ESCAPE:
      exit(0);
      break;
    case SDLK_F1:
      SDL_WM_ToggleFullScreen(gDrawSurface);
    break;
    default:
      printf("key: %d\n", keysym->sym);
      break;
  }
  return;
}

void handleKeyRelease(SDL_keysym *keysym)
{
  switch (keysym->sym)
  {
    //keys here
  }
  return;
}

void LoopSDL()
{
  SDL_Event event;
  while(1)
  {
    while(SDL_PollEvent(&event))
    {
      switch(event.type)
      {
        case SDL_QUIT:
          exit(0);
          break;
        case SDL_KEYDOWN:
          handleKeyPress(&event.key.keysym);
          break;
        case SDL_KEYUP:
          handleKeyRelease(&event.key.keysym);
          break;
      }
    }
#if DRAWONCE
    if(!done)
{
  done = 1;
#endif
      DrawScene();
      t = SDL_GetTicks();
      if(t > lastFrame + 1000)
      {

        printf("fps=%d\n", frames);
        lastFrame = t;
        //I++;
        frames = 0;
      }
#if DRAWONCE
}
#endif
  }
}

void SetupSDL(void)
{
  const SDL_VideoInfo* vidinfo;
  if(SDL_Init(SDL_INIT_VIDEO)<0);
  atexit(SDL_Quit);
  vidinfo = SDL_GetVideoInfo();
  SDL_GL_SetAttribute(SDL_GL_RED_SIZE,5);
  SDL_GL_SetAttribute(SDL_GL_GREEN_SIZE,5);
  SDL_GL_SetAttribute(SDL_GL_BLUE_SIZE,5);
  SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE,16);
  SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER,1);
  gDrawSurface = SDL_SetVideoMode(width,height,vidinfo->vfmt->BitsPerPixel,SDL_OPENGL);
  glViewport(0,0,width,height);
  glMatrixMode(GL_PROJECTION);
  glLoadIdentity();
  gluPerspective( 45.0f, (float)width/height, .00001f, 100.0f);
  glMatrixMode(GL_MODELVIEW);
  glClearColor(0.0f, 0.0f, 0.0f, 0.0);
  glClearDepth(1.0f);
  glEnable(GL_BLEND);
  glBlendFunc(GL_SRC_ALPHA,GL_ONE);

  //create shaders
  char str[1024];
  program = glCreateProgramObjectARB();

  //vertex shader
  vert_shader = glCreateShaderObjectARB(GL_VERTEX_SHADER);
  glShaderSourceARB(vert_shader,1,&vs,0);
  glCompileShaderARB(vert_shader);
  glAttachObjectARB(program,vert_shader);

  //fragment shader
  frag_shader = glCreateShaderObjectARB(GL_FRAGMENT_SHADER);
  glShaderSourceARB(frag_shader,1,&fs,0);
  glCompileShaderARB(frag_shader);
  glAttachObjectARB(program,frag_shader);

  glLinkProgramARB(program);
  glUseProgramObjectARB(program);
  glGetInfoLogARB(program,sizeof(str),0,str);
  printf("glsl program log:\n%s\n",str);
}

int main(int argc, char** argv)
{
  SetupGLSLProcs();
  SetupSDL();
  LoopSDL();
  return 0;
}