sdl: make platform more generic by splitting some code into client struct

5 files changed, 100 insertions, 64 deletions

diff --git a/sdl/gltools.c b/sdl/gltools.c
index 2449cfc..7fc92f7 100644
--- a/sdl/gltools.c
+++ b/sdl/gltools.c
@@ -30,7 +30,10 @@ GLuint gltLoadTGATexture(const char *fname)
 
     pBytes = gltLoadTGA(fname, &iWidth, &iHeight, &iComponents, &eFormat);
     if (!pBytes)
+    {
         fprintf(stderr, "gltLoadTGA: failed to load texture!\n");
+        return -1;
+    }
 
     glTexImage2D(GL_TEXTURE_2D, 0, iComponents, iWidth, iHeight, 0, eFormat,
                  GL_UNSIGNED_BYTE, pBytes);
diff --git a/sdl/luatools.c b/sdl/luatools.c
index 5116df1..b403750 100644
--- a/sdl/luatools.c
+++ b/sdl/luatools.c
@@ -30,7 +30,7 @@ const char *luaGetFieldString(lua_State *L, const char *key)
         return ret;
     }
 
-    ret = lua_tostring(L, -1);
+    ret = lua_tostring(L, -1); /* should this be freed at some point? */
     lua_pop(L, 1);
 
     return ret;
diff --git a/sdl/platform.c b/sdl/platform.c
index a44bfd4..2d770a8 100644
--- a/sdl/platform.c
+++ b/sdl/platform.c
@@ -26,7 +26,7 @@ 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   };
+const GLfloat lightPos[]     = { -10.f, 5.0f, 5.0f, 1.0f   };
 
 /* variables that should be already defined and declared for us by main program */
 extern unsigned int xres_w;
@@ -40,8 +40,6 @@ extern unsigned int maxfps_w;
 
 void platform_init(struct platform *p)
 {
-    memset(p, 0, sizeof(struct platform));
-
     /* Lua */
     /* create new lua state */
     p->L = luaL_newstate();
@@ -49,54 +47,33 @@ void platform_init(struct platform *p)
     /* load lua libraries */
     luaL_openlibs(p->L);
 
-    /* ToDo: how would you make platform more generic? */
-    /* note, this should be already zero'ed out */
-    memset(&p->config_table, 0, sizeof(p->config_table));
-
     /* initialize SDL, GLEW, and OpenGL */
     load_config(p);
     p->screen = setup_sdl();
     setup_glew();
     setup_opengl();
 
-    /* set the camera to <0,0,0> */
-    glframe_reset(&p->camera);
-    p->textures[0] = gltLoadTGATexture("stone.tga");
-    p->textures[1] = gltLoadTGATexture("grass.tga");
-
-    /* display list, precompile commands */
-    p->ground_list   = glGenLists(2);
-    p->triangle_list = p->ground_list + 1;
-
-    /* a triangle with a texture */
-    glNewList(p->triangle_list, GL_COMPILE);
-       glBindTexture(GL_TEXTURE_2D, p->textures[0]);
-       /* glBindTexture(GL_TEXTURE_2D, p->textures[1]); */
-       glColor3f(1.0f, 1.0f, 1.0f);
-       glDrawTriangle();
-    glEndList();
-
-    /* a ground drawn using magneta lines */
-    glNewList(p->ground_list, GL_COMPILE);
-       glColor3ub(255, 0, 255);
-       glDrawGround();
-    glEndList();
-
     /* add a simple timer / callback function */
     p->timer_id = SDL_AddTimer(5000, sdlTimerCallback, &(p->camera));
 
     /* apply a custom cursor */
     p->my_cursor = sdlInitCursor(arrow);
     SDL_SetCursor(p->my_cursor);
+
+    /* set the camera to <0,0,0> */
+    glframe_reset(&p->camera);
+
+    /* init client */
+    p->client_init(p->c);
 }
 
+/* it's a good idea to destroy things in reverse order */
 void platform_destroy(struct platform *p)
 {
-    glDeleteTextures(2, p->textures);
-    glDeleteLists(p->ground_list, 2);
+    /* destroy client */
+    p->client_destroy(p->c);
 
     SDL_FreeSurface(p->screen);
-
     lua_close(p->L);
 }
 
diff --git a/sdl/platform.h b/sdl/platform.h
index dc34788..d546749 100644
--- a/sdl/platform.h
+++ b/sdl/platform.h
@@ -7,21 +7,13 @@
 #include "glframe.h"
 #include "luatools.h"
 
+struct client;
+
 /* platform struct */
 struct platform
 {
     GLFrame camera;
 
-    /* display lists identifiers */
-    GLuint ground_list;
-    GLuint triangle_list;
-
-    /* pyramid texture handle */
-    GLuint textures[2];
-
-    GLfloat xrot;
-    GLfloat yrot;
-
     /* SDL surface, our screen */
     SDL_Surface *screen;
 
@@ -31,6 +23,11 @@ struct platform
     /* Lua */
     lua_State *L;
     struct luat_table_platform config_table;
+
+    /* client */
+    struct client *c;
+    int (*client_init)(struct client *);
+    int (*client_destroy)(struct client *);
 };
 
 extern const GLfloat fNoLight[];
diff --git a/sdl/pyramid.c b/sdl/pyramid.c
index 1260dff..94c3946 100644
--- a/sdl/pyramid.c
+++ b/sdl/pyramid.c
@@ -31,15 +31,10 @@
 #include "sdltools.h"
 #include "window.h"
 
-/* function prototypes */
-static void keys(SDL_keysym *, const unsigned int *, const int);
-static void process_events(void);
-static void render(void);
-
 /* globals */
 struct platform p;
 
-/* sane defaults, these can be overwritten by config.lua */
+/* sane defaults, these are overwritable by config.lua */
 int program_running = 1;
 unsigned int xres_w = 640;
 unsigned int yres_w = 480;
@@ -50,6 +45,61 @@ const char *window_icon_path = "tux.png";
 const unsigned int sdl_video_flags = SDL_OPENGL | SDL_RESIZABLE;
 unsigned int maxfps_w  = 60;
 
+/* client extends functionality of the host platform */
+struct client
+{
+    /* display lists identifiers */
+    GLuint ground_list;
+    GLuint triangle_list;
+
+    /* pyramid texture handle */
+    GLuint textures[2];
+
+    GLfloat xrot;
+    GLfloat yrot;
+};
+
+/* function prototypes */
+static int client_init(struct client *);
+static int client_destroy(struct client *);
+static void keys(SDL_keysym *, const unsigned int *, const int);
+static void process_events(void);
+static void render(void);
+
+static int client_init(struct client *p)
+{
+    p->textures[0] = gltLoadTGATexture("stone.tga");
+    p->textures[1] = gltLoadTGATexture("grass.tga");
+
+    /* display list, precompile commands */
+    p->ground_list   = glGenLists(2);
+    p->triangle_list = p->ground_list + 1;
+
+    /* a triangle with a texture */
+    glNewList(p->triangle_list, GL_COMPILE);
+       glBindTexture(GL_TEXTURE_2D, p->textures[0]);
+       /* glBindTexture(GL_TEXTURE_2D, p->textures[1]); */
+       glColor3f(1.0f, 1.0f, 1.0f);
+       glDrawTriangle();
+    glEndList();
+
+    /* a ground drawn using magneta lines */
+    glNewList(p->ground_list, GL_COMPILE);
+       glColor3ub(255, 0, 255);
+       glDrawGround();
+    glEndList();
+
+    return 0;
+}
+
+static int client_destroy(struct client *p)
+{
+    glDeleteTextures(2, p->textures);
+    glDeleteLists(p->ground_list, 2);
+
+    return 0;
+}
+
 static void keys(SDL_keysym *keysym, const unsigned int *keys_held, const int flag)
 {
     if (!flag)
@@ -57,10 +107,10 @@ static void keys(SDL_keysym *keysym, const unsigned int *keys_held, const int fl
         switch (keysym->sym)
         {
         case SDLK_ESCAPE: program_running = 0; break;
-        case SDLK_w: p.xrot -= 5.0f; break;
-        case SDLK_s: p.xrot += 5.0f; break;
-        case SDLK_a: p.yrot -= 5.0f; break;
-        case SDLK_d: p.yrot += 5.0f; break;
+        case SDLK_w: p.c->xrot -= 5.0f; break;
+        case SDLK_s: p.c->xrot += 5.0f; break;
+        case SDLK_a: p.c->yrot -= 5.0f; break;
+        case SDLK_d: p.c->yrot += 5.0f; break;
         case SDLK_UP: glframe_move_forward(&p.camera, 0.5f); break;
         case SDLK_DOWN: glframe_move_forward(&p.camera, -0.5f); break;
         case SDLK_LEFT: glframe_rotate_local_y(&p.camera, 0.1f); break;
@@ -73,13 +123,13 @@ static void keys(SDL_keysym *keysym, const unsigned int *keys_held, const int fl
     else
     {
         if (keys_held[SDLK_w])
-            p.xrot -= 5.0f;
+            p.c->xrot -= 5.0f;
         if (keys_held[SDLK_s])
-            p.xrot += 5.0f;
+            p.c->xrot += 5.0f;
         if (keys_held[SDLK_a])
-            p.yrot -= 5.0f;
+            p.c->yrot -= 5.0f;
         if (keys_held[SDLK_d])
-            p.yrot += 5.0f;
+            p.c->yrot += 5.0f;
 
         if (keys_held[SDLK_UP])
             glframe_move_forward(&p.camera, 0.05f);
@@ -96,8 +146,8 @@ static void keys(SDL_keysym *keysym, const unsigned int *keys_held, const int fl
             glframe_rotate_local_x(&p.camera, -0.02f);
     }
 
-    p.xrot = (GLfloat) ((const int) p.xrot % 360);
-    p.yrot = (GLfloat) ((const int) p.yrot % 360);
+    p.c->xrot = (GLfloat) ((const int) p.c->xrot % 360);
+    p.c->yrot = (GLfloat) ((const int) p.c->yrot % 360);
 }
 
 static void process_events(void)
@@ -154,16 +204,16 @@ static void render(void)
     glPushMatrix();
         /* apply camera transform, and draw the ground */
         glframe_apply_camera_transform(&p.camera, 1);
-        glCallList(p.ground_list);
+        glCallList(p.c->ground_list);
 
         glPushMatrix();
         /* move object back and do in place rotation */
         glTranslatef(0.0f, 0.2f, -3.5f);
-        glRotatef(p.xrot, 1.0f, 0.0f, 0.0f);
-        glRotatef(p.yrot, 0.0f, 1.0f, 0.0f);
+        glRotatef(p.c->xrot, 1.0f, 0.0f, 0.0f);
+        glRotatef(p.c->yrot, 0.0f, 1.0f, 0.0f);
 
         /* draw the pyramid */
-        glCallList(p.triangle_list);
+        glCallList(p.c->triangle_list);
         glPopMatrix();
 
         /* draw a snowman */
@@ -182,6 +232,15 @@ static void render(void)
 
 int main(int argc, char **argv)
 {
+    memset(&p, 0, sizeof(p));
+
+    /* setup client platform */
+    struct client c;
+    p.c = &c;
+    p.client_init = &client_init;
+    p.client_destroy = &client_destroy;
+
+    /* initialize host platform */
     platform_init(&p);
 
     gltErrorCheck();