Added proof of concept code to render some text to the screen. Split up the two 'screens' that'll be using to keep the code clean.

build.sh

@@ -1 +1 @@
-gcc -o main src/main.c -lSDL2
+gcc src/main.c src/vscreen.c src/cpu_display.c -o main -lSDL2 -lSDL2_image -lSDL2_ttf

include/cpu_display.h

@@ -0,0 +1,22 @@
+#ifndef _CPU_DISPLAY_H
+#define _CPU_DISPLAY_H
+
+#include <stdio.h>
+#include <SDL2/SDL.h>
+#include <SDL2/SDL_rect.h>
+#include <SDL2/SDL_render.h>
+#include <SDL2/SDL_surface.h>
+#include <SDL2/SDL_ttf.h>
+#include <SDL2/SDL_pixels.h>
+
+#define CPU_STATS_DISPLAY_WIDTH         640
+#define CPU_STATS_DISPLAY_HEIGHT        480
+#define CPU_STATS_DISPLAY_COLUMN_COUNT  40
+#define CPU_STATS_DISPLAY_ROW_COUNT     30
+
+static const char *cpu_display_header_text = "CPU State";
+
+void renderStatsBox(SDL_Renderer *, TTF_Font *, char *);
+void renderBorderAndHeader(SDL_Renderer *, TTF_Font *);
+
+#endif

include/vscreen.h

@@ -1,13 +1,18 @@
 #ifndef _VSCREEN_H
 #define _VSCREEN_H
 
+#include <stdio.h>
 #include <SDL2/SDL.h>
+#include <SDL2/SDL_image.h>
+#include <SDL2/SDL_rect.h>
+#include <SDL2/SDL_render.h>
 
 #define VSCREEN_WIDTH           640
 #define VSCREEN_HEIGHT          480
-#define VSCREEN_COLUMN_COUNT    20
+#define VSCREEN_COLUMN_COUNT    40
 #define VSCREEN_ROW_COUNT       20
 
 void renderClientScreen(SDL_Renderer *);
 
+
 #endif

src/cpu_display.c

@@ -0,0 +1,38 @@
+#include "../include/cpu_display.h"
+
+void renderStatsBox(SDL_Renderer* renderer, TTF_Font* font, char* msg) {
+    SDL_Rect dest, text_rect;
+    SDL_Color fg = {.r = 0, .g = 255, .b = 0, .a = 255};
+    SDL_Surface* text = TTF_RenderText_Solid(font, msg, fg);
+    TTF_SizeText(font, msg, &text_rect.w, &text_rect.h);
+    SDL_Texture* tex = SDL_CreateTextureFromSurface(renderer, text);
+
+    SDL_RenderGetViewport(renderer, &dest);
+    text_rect.x = 0;
+    text_rect.y = 0;
+
+    dest.x = 0;
+    dest.y = 0;
+
+    SDL_SetRenderDrawColor(renderer, 255, 0, 0, 255);
+
+    SDL_RenderFillRect(renderer, &dest);
+
+    //SDL_SetRenderDrawColor(renderer, 0, 255, 0, 255);
+
+    SDL_RenderCopy(renderer, tex, NULL, &text_rect);
+
+    SDL_FreeSurface(text);
+    SDL_DestroyTexture(tex);
+}
+
+void renderBorderAndHeader(SDL_Renderer* renderer, TTF_Font* font) {
+    SDL_Rect viewPort;
+
+    SDL_RenderGetViewport(renderer, &viewPort);
+
+    SDL_Rect cell = {.x = 0, .y = 0};
+
+    cell.w = viewPort.w / CPU_STATS_DISPLAY_WIDTH;
+    cell.h = viewPort.h / CPU_STATS_DISPLAY_HEIGHT;
+}

src/main.c

@@ -1,14 +1,16 @@
 #include "SDL2/SDL.h"
 #include <SDL2/SDL_events.h>
 #include <SDL2/SDL_hints.h>
+#include <SDL2/SDL_keycode.h>
 #include <SDL2/SDL_rect.h>
 #include <SDL2/SDL_render.h>
 #include <SDL2/SDL_timer.h>
 #include <SDL2/SDL_video.h>
 #include <SDL2/SDL_image.h>
+#include <SDL2/SDL_ttf.h>
 #include <stdio.h>
-#include <string.h>
 #include "../include/vscreen.h"
+#include "../include/cpu_display.h"
 
 const int SCREEN_WIDTH = 1280;
 const int SCREEN_HEIGHT = 720;
@@ -16,14 +18,12 @@ const int SCREEN_HEIGHT = 720;
 typedef struct {
   SDL_Window *window;
   SDL_Renderer *renderer;
-  int up;
-  int down;
-  int left;
-  int right;
+  TTF_Font* font;
 } App;
 
 App app;
 
+
 void handleInput(void);
 void cleanup(void);
 void prepareScene(void);
@@ -33,8 +33,6 @@ int getIndex(int, int, int);
 int main(int argc, char* args[]) {
   memset(&app, 0, sizeof(app));
 
-  IMG_Init(IMG_INIT_JPG);
-
   atexit(cleanup);
 
   if (SDL_Init(SDL_INIT_VIDEO) < 0){
@@ -42,6 +40,18 @@ int main(int argc, char* args[]) {
     return -1;
   }
 
+  if (TTF_Init() < 0) {
+    printf("Failed to init TTF: %s\n", TTF_GetError());
+    return -1;
+  }
+
+  app.font = TTF_OpenFont("/usr/share/fonts/TTF/Hack-Regular.ttf", 14);
+
+  if (app.font == NULL) {
+    printf("Failed to load font\n");
+    return -1;
+  }
+
   app.window = SDL_CreateWindow("SDL Tutorial", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, SCREEN_WIDTH, SCREEN_HEIGHT, SDL_WINDOW_SHOWN);
 
   if (app.window == NULL){
@@ -66,12 +76,16 @@ int main(int argc, char* args[]) {
     presentScene();
 
     SDL_Delay(16);
+
+    //break;
   }
 }
 
 void cleanup(void) {
   SDL_DestroyWindow(app.window);
   SDL_DestroyRenderer(app.renderer);
+  TTF_CloseFont(app.font);
+  TTF_Quit();
   SDL_Quit();
 }
 
@@ -83,6 +97,8 @@ void handleInput(void) {
       case SDL_QUIT:
         exit(0);
         break;
+      case SDL_MOUSEBUTTONDOWN:
+        exit(0);
       case SDL_KEYDOWN:
       default:
         break;
@@ -95,11 +111,20 @@ void prepareScene(void)
 	SDL_SetRenderDrawColor(app.renderer, 96, 128, 255, 255);
 	SDL_RenderClear(app.renderer);
 
-  SDL_Rect rect = {0, 0, VSCREEN_WIDTH, VSCREEN_HEIGHT};
+  SDL_Rect rect = {.x=0, .y=0, .w=VSCREEN_WIDTH, .h=VSCREEN_HEIGHT};
 
   SDL_RenderSetViewport(app.renderer, &rect);
 
   renderClientScreen(app.renderer);
+
+  rect.x = VSCREEN_WIDTH;
+  rect.w = SCREEN_WIDTH - VSCREEN_WIDTH;
+  rect.y = 0;
+  rect.h = VSCREEN_HEIGHT;
+  
+  SDL_RenderSetViewport(app.renderer, &rect);
+
+  renderStatsBox(app.renderer, app.font, "Hello, World!");
 }
 
 void presentScene(void)

src/vscreen.c

@@ -1,8 +1,4 @@
 #include "../include/vscreen.h"
-#include <SDL2/SDL_image.h>
-#include <SDL2/SDL_render.h>
-#include <SDL2/SDL_surface.h>
-#include <stdio.h>
 
 void renderClientScreen(SDL_Renderer* renderer) {
     SDL_Rect dest;
@@ -14,22 +10,27 @@ void renderClientScreen(SDL_Renderer* renderer) {
     cell.h = dest.h / VSCREEN_ROW_COUNT;
     
     int row = 0;
-    unsigned char backgroundColor = 0x00;
+    unsigned int bg = 0x00000000;
 
     for (int i = 0; i < VSCREEN_ROW_COUNT; i++) {
 
-        for(int j = 0; j <VSCREEN_COLUMN_COUNT; j++) {
-            SDL_SetRenderDrawColor(renderer, backgroundColor, backgroundColor, backgroundColor, 255);
+        for(int j = 0; j < VSCREEN_COLUMN_COUNT; j++) {
+            char red, green, blue;
+            red = bg >> 16 & 0xFF;
+            green = bg >> 8 & 0xFF;
+            blue = bg & 0xFF;
+
+            SDL_SetRenderDrawColor(renderer, red, green, blue, 255);
 
             cell.x = j * cell.w;
             cell.y = i * cell.h;
 
             SDL_RenderFillRect(renderer, &cell);
 
-            backgroundColor ^= 0xFF;
+            bg ^= 0xFFFFFF;
         }
 
-        backgroundColor ^= 0xFF;
+        bg ^= 0xFFFFFF;
 
         row++;
     }