From a40d0cdbb0dff7cf2b65a18be7b7085f0eca3408 Mon Sep 17 00:00:00 2001
From: Kyle K <kylek389@gmail.com>
Date: Mon, 18 Jul 2011 09:00:19 -0500
Subject: sdl: handle anisotropic filtering

---
 sdl/platform.c | 44 ++++++++++++++++++++++++++++++++++++++------
 sdl/pyramid.c  |  8 ++++----
 2 files changed, 42 insertions(+), 10 deletions(-)

diff --git a/sdl/platform.c b/sdl/platform.c
index 677b5b8..aba5789 100644
--- a/sdl/platform.c
+++ b/sdl/platform.c
@@ -9,6 +9,7 @@
 #include <SDL/SDL.h>
 #include <SDL/SDL_image.h>
 #include <GL/glew.h>
+#include "gltools.h"
 #include "platform.h"
 
 /* few light arrays */
@@ -25,6 +26,7 @@ const GLfloat lightPos[]    = { -10.f, 5.0f, 5.0f, 1.0f   };
 extern const unsigned int xres_w;
 extern const unsigned int yres_w;
 extern const unsigned int bpp_w;
+extern const unsigned int af_w;
 extern const unsigned int sdl_video_flags;
 extern const char *window_caption;
 extern const char *window_icon_path;
@@ -94,18 +96,43 @@ void setup_opengl(void)
     glHint(GL_LINE_SMOOTH_HINT, GL_NICEST);
 #endif
 
+#if 0
+    /* screws up snowman, this has been replaced by superior multisampling */
+    glEnable(GL_POLYGON_SMOOTH);
+    glHint(GL_POLYGON_SMOOTH_HINT, GL_NICEST);
+#endif
+
     /* we will keep the blending function and hints though */
     glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
     glHint(GL_POINT_SMOOTH_HINT, GL_NICEST);
     glHint(GL_LINE_SMOOTH_HINT, GL_NICEST);
 
-    /* XXX: anisotropic filtering */
+    /* anisotropic filtering */
+    if (gltQueryExtension("GL_EXT_texture_filter_anisotropic") == GL_TRUE)
+    {
+        GLint af_amount;
+        glGetIntegerv(GL_MAX_TEXTURE_MAX_ANISOTROPY_EXT, &af_amount);
+        printf("platform: anisotropic filtering is supported, with max amount "
+               "of: %d\n", af_amount);
+
+        if (af_amount < af_w)
+            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_ANISOTROPY_EXT, af_amount);
+        else
+            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_ANISOTROPY_EXT, af_w);
+
+        /* see what value was set */
+        glGetTexParameteriv(GL_TEXTURE_2D, GL_TEXTURE_MAX_ANISOTROPY_EXT, &af_amount);
+        printf("platform: set anisotropic filtering to %d\n", af_amount);
+    }
+    else
+        printf("platform: anisotropic filtering is not supported\n");
 
-#if 0
-    /* screws up snowman, this has been replaced by superior multisampling */
-    glEnable(GL_POLYGON_SMOOTH);
-    glHint(GL_POLYGON_SMOOTH_HINT, GL_NICEST);
-#endif
+    /* texture compression */
+    if (gltQueryExtension("GL_ARB_texture_compression") == GL_TRUE)
+    {
+        printf("platform: host gfx device supports texture compression\n");
+        /* ToDo */
+    }
 
     /* how OpenGL combines the colors from texels with the color of the underlying
      * geometry is controlled by the texture environment mode */
@@ -121,6 +148,11 @@ void setup_opengl(void)
     /* only if lighting is disabled */
     /* glEnable(GL_COLOR_SUM); */
 
+    /* draw fragments that pass this test, fragments with lower than 0.2f
+     * alpha are discarded, this is just for the kicks */
+    glAlphaFunc(GL_GREATER, 0.2f);
+    glEnable(GL_ALPHA_TEST);
+
     /* gray background */
     glClearColor(0.5f, 0.5f, 0.5f, 1.0f);
 }
diff --git a/sdl/pyramid.c b/sdl/pyramid.c
index 42c7a22..bc0fd7a 100644
--- a/sdl/pyramid.c
+++ b/sdl/pyramid.c
@@ -38,14 +38,14 @@ static void render(void);
 
 /* global */
 int program_running = 1;
-const int xres_w = 640;
-const int yres_w = 480;
-const int bpp_w  = 32;
+const unsigned int xres_w = 640;
+const unsigned int yres_w = 480;
+const unsigned int bpp_w  = 32;
+const unsigned int af_w   = 8;
 const char *window_caption   = "Textured Pyramid";
 const char *window_icon_path = "tux.png";
 const unsigned int sdl_video_flags = SDL_OPENGL | SDL_RESIZABLE;
 
-
 /* platform struct */
 static struct
 {
-- 
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