disable AA, enable AF, cleanup OpenGL setupHEADmaster

1 files changed, 117 insertions, 55 deletions

diff --git a/sdl.c b/sdl.c
index 2b421b5..e875a6e 100644
--- a/sdl.c
+++ b/sdl.c
@@ -1,9 +1,11 @@
 /* sdl.c
  *
- * @2011 Kamil Kaminski
+ * Kamil Kaminski
+ * kkaminsk.com
  *
  * Skeleton for SDL
  *
+ *
  */
  
 #include <SDL/SDL.h>
@@ -16,6 +18,7 @@
 #include <math.h>
 
 /* function prototypes */
+static void gltErrorCheck(void);
 static void resize(int, int);
 static void setup_opengl(void);
 static void keys(SDL_keysym *, unsigned int *);
@@ -25,10 +28,27 @@ static void render(void);
 /* global */
 int program_running = 1;
 
-/* few arrays, they could make into the header at some point */
-GLfloat fNoLight[]     = { 0.0f, 0.0f, 0.0f, 0.0f };
-GLfloat fLowLight[]    = { 0.25f, 0.25f, 0.25f, 1.0f };
-GLfloat fBrightLight[] = { 1.0f, 1.0f, 1.0f, 1.0f };
+/* few light arrays */
+const GLfloat fNoLight[]     = { 0.0f, 0.0f, 0.0f, 1.0f    };
+const GLfloat fLowLight[]    = { 0.25f, 0.25f, 0.25f, 1.0f };
+const GLfloat fMedLight[]    = { 0.50f, 0.50f, 0.50f, 1.0f };
+const GLfloat fShinyLight[]  = { 0.70f, 0.70f, 0.70f, 1.0f };
+const GLfloat fBrightLight[] = { 1.0f, 1.0f, 1.0f, 1.0f    };
+
+/* light values and coordinates */
+const GLfloat lightPos[]     = { -10.f, 5.0f, 5.0f, 1.0f   };
+
+static void gltErrorCheck(void)
+{
+    GLenum err_code;
+    const GLubyte *err_str;
+
+    while ((err_code = glGetError()) != GL_NO_ERROR)
+    {
+        err_str = gluErrorString(err_code);
+        fprintf(stderr, "OpenGL error: %s\n", err_str);
+    }
+}
 
 static void resize(int w, int h)
 {
@@ -55,11 +75,6 @@ static void resize(int w, int h)
 
 static void setup_opengl(void)
 {
-    /* light values and coordinates */
-    GLfloat whiteLight[]  = { 0.05f, 0.05f, 0.05f, 1.0f };
-    GLfloat sourceLight[] = { 0.75f, 0.75f, 0.75f, 1.0f };
-    GLfloat lightPos[]    = { -10.f, 5.0f, 5.0f, 1.0f };
-
     /* setup fog */
     glEnable(GL_FOG);
     glFogfv(GL_FOG_COLOR, fLowLight); /* set fog color to match background */
@@ -67,38 +82,62 @@ static void setup_opengl(void)
     glFogf(GL_FOG_END, 20.0f);
     glFogi(GL_FOG_MODE, GL_LINEAR);   /* fog equation */
 
-    glEnable(GL_DEPTH_TEST);          /* hidden surface removal */
-    glFrontFace(GL_CCW);              /* counter clock-wise polygons face out */
-    glEnable(GL_CULL_FACE);           /* do not calculate inside of a pyramid */
+    glEnable(GL_DEPTH_TEST); /* hidden surface removal, aka Z-buffer */
+    glFrontFace(GL_CCW);     /* counter clock-wise polygons face out */
+    glEnable(GL_CULL_FACE);  /* do not calculate inside of a pyramid */
+
+    /* enable lighting, primitives now need to define color properties */
+    glEnable(GL_LIGHTING);
+
+    /* global illumination, ambient RGBA intensity of the entire scene */
+    glLightModelfv(GL_LIGHT_MODEL_AMBIENT, fLowLight);
 
     /* setup and enable light 0 */
-    /* ambient RGBA intensity of the entire scene */
-    glLightModelfv(GL_LIGHT_MODEL_AMBIENT, whiteLight);
-    glLightfv(GL_LIGHT0, GL_AMBIENT, sourceLight);
-    glLightfv(GL_LIGHT0, GL_DIFFUSE, fBrightLight);
+    glLightfv(GL_LIGHT0, GL_AMBIENT,  fMedLight);
+    glLightfv(GL_LIGHT0, GL_DIFFUSE,  fShinyLight);
     glLightfv(GL_LIGHT0, GL_SPECULAR, fBrightLight);
     glLightfv(GL_LIGHT0, GL_POSITION, lightPos);
-    
-    /* enable lighting */    
-    glEnable(GL_LIGHTING);
     glEnable(GL_LIGHT0);
-    
-    /* enable color tracking */
-    glEnable(GL_COLOR_MATERIAL);
-    
-    /* set Material properties to follow glColor values */
+
+    /* set material properties to follow all glColor values */
+    /* all primitives specified after the glMaterial call are affected by the
+     * last values set, until another call to glMaterial is made */
     glColorMaterial(GL_FRONT, GL_AMBIENT_AND_DIFFUSE);
+
+    /* enable color tracking, should be called after glColorMaterial */
+    glEnable(GL_COLOR_MATERIAL);
+
+    /* set globally, sets specular reflection to a white color,
+     * this call follows all subsequent primitives */
     glMaterialfv(GL_FRONT, GL_SPECULAR, fBrightLight);
-    glMateriali(GL_FRONT, GL_SHININESS, 128);
 
-    /* turn on anti aliasing for points, lines, and polygons */
+    /* default (0), by increasing this value you reduce the size and increase
+     * the focus of the specular highlight, causing a shiny spot to appear */
+    glMateriali(GL_FRONT, GL_SHININESS, 64);
+
+    /* multisampling for polygons, conflicts with *polygon* anti-aliasing */
+    /* enabled by default, that's what man page says, hmmm! */
+    glEnable(GL_MULTISAMPLE);
+
+    /* AA is disabled, but we will keep the blending function and hints though */
     glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
-    glEnable(GL_BLEND);
-    glEnable(GL_POINT_SMOOTH);
     glHint(GL_POINT_SMOOTH_HINT, GL_NICEST);
-    glEnable(GL_LINE_SMOOTH);
     glHint(GL_LINE_SMOOTH_HINT, GL_NICEST);
 
+    /* anisotropic filtering */
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_ANISOTROPY_EXT, 8);
+
+    /* how OpenGL combines the colors from texels with the color of the underlying
+     * geometry is controlled by the texture environment mode */
+    glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
+
+    /* once texture is loaded and enabled, it will applied to every primitive
+     * that specifies coordinates, ORLY? */
+    glEnable(GL_TEXTURE_2D);
+
+    /* specular highlights for textured items */
+    glLightModeli(GL_LIGHT_MODEL_COLOR_CONTROL, GL_SEPARATE_SPECULAR_COLOR);
+
     /* gray background */
     glClearColor(0.5f, 0.5f, 0.5f, 1.0f);
 }
@@ -107,8 +146,11 @@ static void keys(SDL_keysym *keysym, unsigned int *keys_held)
 {
     switch (keysym->sym)
     {
-    case SDLK_ESCAPE: program_running = 0; break;
-    default: break;
+    case SDLK_ESCAPE:
+        program_running = 0;
+        break;
+    default:
+        break;
     }
 }
 
@@ -125,21 +167,30 @@ static void process_events(void)
     
         switch (event.type)
         {
-        case SDL_KEYUP:
-        {
-            /* reset the key to 0 */
-            keys_held[sym] = 0;
-            break;
-        }
-        case SDL_KEYDOWN:
-        {
-            keys_held[sym] = 1;
-            keys(&event.key.keysym, keys_held);
-            break;
-        }
-        case SDL_VIDEORESIZE: { resize(event.resize.w, event.resize.h); break; }
-        case SDL_QUIT: { program_running = 0; break; }
-        default: break;
+            case SDL_KEYUP:
+            {
+                /* reset the key to 0 */
+                keys_held[sym] = 0;
+                break;
+            }
+            case SDL_KEYDOWN:
+            {
+                keys_held[sym] = 1;
+                keys(&event.key.keysym, keys_held);
+                break;
+            }
+            case SDL_VIDEORESIZE:
+            {
+                resize(event.resize.w, event.resize.h);
+                break;
+            }
+            case SDL_QUIT:
+            {
+                program_running = 0;
+                break;
+            }
+            default:
+                break;
         }
     }
 }
@@ -152,6 +203,10 @@ static void render(void)
     /* save the matrix state and do the rotations */
     glPushMatrix();
 
+    glDisable(GL_MULTISAMPLE);
+    glEnable(GL_BLEND);
+    glEnable(GL_LINE_SMOOTH);
+
     GLfloat fExtent = 20.0f;
     GLfloat fStep = 0.5f;
     GLfloat y = -0.4f;
@@ -168,6 +223,10 @@ static void render(void)
     }
     glEnd();
 
+    glDisable(GL_LINE_SMOOTH);
+    glDisable(GL_BLEND);
+    glEnable(GL_MULTISAMPLE);
+
     /* restore the matrix state */
     glPopMatrix();
 
@@ -181,7 +240,7 @@ int main(int argc, char **argv)
 
     if (SDL_Init(SDL_INIT_VIDEO) < 0 )
     {
-        fprintf(stderr, "unable to init SDL: %s\n", SDL_GetError());
+        fprintf(stderr, "SDL: unable to init, %s\n", SDL_GetError());
         exit(-1);
     }
     atexit(SDL_Quit);
@@ -191,12 +250,12 @@ int main(int argc, char **argv)
     SDL_GL_SetAttribute(SDL_GL_GREEN_SIZE, 8);
     SDL_GL_SetAttribute(SDL_GL_BLUE_SIZE, 8);
     SDL_GL_SetAttribute(SDL_GL_ALPHA_SIZE, 8);
-    SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 16);
     SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
+    SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 24);
 
     if ((screen = SDL_SetVideoMode(640, 480, 32, SDL_OPENGL | SDL_RESIZABLE)) == NULL)
     {
-        fprintf(stderr, "unable to set video mode: %s\n", SDL_GetError());
+        fprintf(stderr, "SDL: unable to set video mode: %s\n", SDL_GetError());
         exit(-1);
     }
     
@@ -213,20 +272,21 @@ int main(int argc, char **argv)
     GLenum glewerr = glewInit();
     if (GLEW_OK != glewerr)
     {
-        fprintf(stderr, "error: %s\n", glewGetErrorString(glewerr));
-        return -1;
+        fprintf(stderr, "GLEW error: %s\n", glewGetErrorString(glewerr));
+        exit(-1);
     }
     else
-        fprintf(stdout, "status: using GLEW %s\n", glewGetString(GLEW_VERSION));
-        
+        fprintf(stdout, "GLEW: using version %s\n", glewGetString(GLEW_VERSION));
+
     /* display OpenGL version */
     GLint major;
     GLint minor;
     glGetIntegerv(GL_MAJOR_VERSION, &major);
     glGetIntegerv(GL_MINOR_VERSION, &minor);
-    fprintf(stdout, "version: OpenGL %d.%d\n", major, minor);
+    fprintf(stdout, "GLEW: initialized OpenGL %d.%d\n", major, minor);
 
     setup_opengl();
+    gltErrorCheck();
 
     while (program_running)
     {
@@ -234,6 +294,8 @@ int main(int argc, char **argv)
         render();
     }
 
+    gltErrorCheck();
+    SDL_FreeSurface(screen);
     puts("bye!");
     
     return 0;