Continue SDL frontend

frontend_sdl.c

@@ -1 +1,100 @@
+#include <stdio.h>
+#include <SDL2/SDL.h>
+
 #include "game.h"
+#include "debug.h"
+
+SDL_Window *window;
+SDL_Renderer *renderer;
+SDL_Texture *texture;
+SDL_Surface *screenSurface;
+uint16_t screen[LCR_SETTING_RESOLUTION_X * LCR_SETTING_RESOLUTION_Y];
+
+const uint8_t *keyboardState;
+
+uint8_t LCR_keyPressed(uint8_t key)
+{
+  switch (key)
+  {
+    case LCR_KEY_UP: return
+      keyboardState[SDL_SCANCODE_W] | keyboardState[SDL_SCANCODE_UP]; break;
+
+    case LCR_KEY_RIGHT: return
+      keyboardState[SDL_SCANCODE_D] | keyboardState[SDL_SCANCODE_RIGHT]; break;
+
+    case LCR_KEY_DOWN: return
+      keyboardState[SDL_SCANCODE_S] | keyboardState[SDL_SCANCODE_DOWN]; break;
+
+    case LCR_KEY_LEFT: return
+      keyboardState[SDL_SCANCODE_A] | keyboardState[SDL_SCANCODE_LEFT]; break;
+
+    case LCR_KEY_A: return
+      keyboardState[SDL_SCANCODE_K] | keyboardState[SDL_SCANCODE_RETURN]; break;
+
+    case LCR_KEY_B: return
+      keyboardState[SDL_SCANCODE_L] | keyboardState[SDL_SCANCODE_ESCAPE]; break;
+
+    default: break;
+  }
+
+  return 0;
+}
+
+void LCR_sleep(uint16_t timeMs)
+{
+}
+
+void LCR_drawPixel(unsigned int x, unsigned int y, uint_fast16_t color)
+{
+  screen[y * LCR_SETTING_RESOLUTION_X + x] = color;
+}
+
+int main(int argc, char *argv[])
+{
+  uint8_t running = 1;
+  LCR_gameInit();
+
+  SDL_Init(0);
+
+  window =
+    SDL_CreateWindow("Licar", SDL_WINDOWPOS_UNDEFINED,
+    SDL_WINDOWPOS_UNDEFINED, LCR_SETTING_RESOLUTION_X, LCR_SETTING_RESOLUTION_Y,
+    SDL_WINDOW_SHOWN); 
+
+  renderer = SDL_CreateRenderer(window,-1,0);
+
+  texture =
+    SDL_CreateTexture(renderer,SDL_PIXELFORMAT_RGB565,SDL_TEXTUREACCESS_STATIC,
+    LCR_SETTING_RESOLUTION_X,LCR_SETTING_RESOLUTION_Y);
+
+  screenSurface = SDL_GetWindowSurface(window);
+
+  SDL_ShowCursor(0);
+
+  SDL_PumpEvents();
+  keyboardState = SDL_GetKeyboardState(NULL);
+
+  while (running)
+  {
+    SDL_PumpEvents();
+    keyboardState = SDL_GetKeyboardState(NULL);
+    running = !keyboardState[SDL_SCANCODE_Q];
+
+    running &= LCR_gameStep(SDL_GetTicks());
+
+    SDL_UpdateTexture(texture,NULL,screen,
+      LCR_SETTING_RESOLUTION_X * sizeof(uint16_t));
+
+    SDL_RenderClear(renderer);
+    SDL_RenderCopy(renderer,texture,NULL,NULL);
+    SDL_RenderPresent(renderer);
+  }
+
+  SDL_DestroyTexture(texture);
+  SDL_DestroyRenderer(renderer); 
+  SDL_DestroyWindow(window); 
+
+  LCR_gameEnd();
+
+  return 0;
+}

game.h

@@ -1,3 +1,9 @@
+/**
+  Licar game: this file implements the backend of a complete, actually playable
+  licar game, and is meant to be included and used by specific frontends (which
+  will handle each platform's hardware details and I/O).
+*/
+
 #ifndef _LCR_GAME_H
 #define _LCR_GAME_H
 
@@ -10,33 +16,76 @@
 #define LCR_KEY_A     0x04 ///< confirm, restart race
 #define LCR_KEY_B     0x05 ///< cancel, open menu
 
+#define LCR_KEYS_TOTAL 6
+
+/*
+  FOR FRONTENDS:
+  - Implement the below described functions according to their description.
+  - Implement the main program and game loop.
+  - Call the below described functions as described.
+*/
+
+/**
+  Implement this in your frontend. Returns 1 if given key is pressed or 0
+  otherwise.
+*/
 uint8_t LCR_keyPressed(uint8_t key);
 
+/**
+  Implement this in your frontend. This function pauses program execution for
+  given amount of milliseconds and relieves the CPU usage. On platforms that
+  don't support this the function may simply do nothing.
+*/
 void LCR_sleep(uint16_t timeMs);
 
+/**
+  Implement this in your frontend. This function draws a pixel of given color
+  to the screen back buffer (i.e. NOT directly to screen, back buffer shall
+  only be copied to front buffer once the LCR_gameStep function finishes all
+  rendering). This function should NOT check for out-of-screen coordinates, this
+  is handled by the game internals and out-of-screen pixels will never be drawn.
+  The color value depends on game settings but is normally an RGB565 value.
+*/
 void LCR_drawPixel(unsigned int x, unsigned int y, uint_fast16_t color);
 
 /**
-  Call at the start of the program.
+  Call this function in your frontend at the start of the program.
 */
 void LCR_gameInit(void);
 
 /**
-  Call right before program end.
+  Call this function in your frontend right before program end.
 */
 void LCR_gameEnd(void);
 
 /**
-  Call this repeatedly in your main loop, pass the current time as the number
+  Call this function in your frontend repeatedly inside the main loop, pass the
-  of milliseconds since program start. Returns 0 if program should end,
+  current time as the number of milliseconds since program start. This function
-  otherwise 1.
+  will perform the game step AND other things such as checking the input states,
+  rendering or sleeping (all using the above functions you should implement).
+  Returns 0 if program should end, otherwise 1.
 */
 uint8_t LCR_gameStep(uint32_t timeMs);
 
 //------------------------------------------------------------------------------
 
+uint8_t _LCR_keyStates[LCR_KEYS_TOTAL]; /**< Assures unchanging key states
+                                             during a single frame. */
+
+/**
+  Internal pixel drawing function that checks for out-of-screen coordinates.
+*/
+static inline void _LCR_drawPixel(unsigned int x, unsigned int y,
+  uint_fast16_t color)
+{
+  if (x < LCR_SETTING_RESOLUTION_X && y < LCR_SETTING_RESOLUTION_Y)
+    LCR_drawPixel(x,y,color);
+}
+
 void LCR_gameInit(void)
 {
+  for (int i = 0; i < LCR_KEYS_TOTAL; ++i)
+    _LCR_keyStates[i] = 0;
 }
 
 void LCR_gameEnd(void)
@@ -45,6 +94,14 @@ void LCR_gameEnd(void)
 
 uint8_t LCR_gameStep(uint32_t time)
 {
+  for (int i = 0; i < LCR_KEYS_TOTAL; ++i)
+    _LCR_keyStates[i] = LCR_keyPressed(i);
+
+  for (int i = 0; i < 100; ++i)
+    for (int j = 0; j < 50; ++j)
+      _LCR_drawPixel(i,j,0x00ff);
+
+  return 1;
 }
 
 #endif // guard

main_sdl.c

@@ -1,57 +0,0 @@
-#include <stdio.h>
-#include <SDL2/SDL.h>
-
-#include "game.h"
-#include "debug.h"
-
-SDL_Window *window;
-SDL_Renderer *renderer;
-SDL_Texture *texture;
-SDL_Surface *screenSurface;
-
-const uint8_t *sdlKeyboardState;
-
-int main(int argc, char *argv[])
-{
-  uint8_t running = 1;
-  LCR_gameInit();
-
-  SDL_Init(SDL_INIT_AUDIO | SDL_INIT_JOYSTICK);
-
-  window =
-    SDL_CreateWindow("Licar", SDL_WINDOWPOS_UNDEFINED,
-    SDL_WINDOWPOS_UNDEFINED, LCR_SETTING_RESOLUTION_X, LCR_SETTING_RESOLUTION_Y,
-    SDL_WINDOW_SHOWN); 
-
-  renderer = SDL_CreateRenderer(window,-1,0);
-
-  texture =
-    SDL_CreateTexture(renderer,SDL_PIXELFORMAT_RGB565,SDL_TEXTUREACCESS_STATIC,
-    LCR_SETTING_RESOLUTION_X,LCR_SETTING_RESOLUTION_Y);
-
-  screenSurface = SDL_GetWindowSurface(window);
-
-  SDL_ShowCursor(0);
-
-  SDL_PumpEvents();
-  sdlKeyboardState = SDL_GetKeyboardState(NULL);
-
-  while (running)
-  {
-    SDL_PumpEvents();
-    sdlKeyboardState = SDL_GetKeyboardState(NULL);
-    running = !sdlKeyboardState[SDL_SCANCODE_Q];
-
-    SDL_RenderClear(renderer);
-    SDL_RenderCopy(renderer,texture,NULL,NULL);
-    SDL_RenderPresent(renderer);
-  }
-
-  SDL_DestroyTexture(texture);
-  SDL_DestroyRenderer(renderer); 
-  SDL_DestroyWindow(window); 
-
-  LCR_gameEnd();
-
-  return 0;
-}

settings.h

@@ -2,11 +2,11 @@
 #define _LCR_SETTINGS_H
 
 #ifndef LCR_SETTING_RESOLUTION_X
-  #define LCR_SETTING_RESOLUTION_X 800
+  #define LCR_SETTING_RESOLUTION_X 1024
 #endif
 
 #ifndef LCR_SETTING_RESOLUTION_Y
-  #define LCR_SETTING_RESOLUTION_Y 600
+  #define LCR_SETTING_RESOLUTION_Y 768
 #endif
 
 #ifndef LCR_SETTING_MAP_MAX_SIZE