Driver for SDL-based display emulator, updated lcd.h documentation

openrtx/include/interfaces/lcd.h

@@ -15,16 +15,14 @@
  *   along with this program; if not, see <http://www.gnu.org/licenses/>   *
  ***************************************************************************/
 
-#ifndef LCH_H
+#ifndef LCD_H
-#define LCH_H
+#define LCD_H
 
 #include <stdint.h>
 #include <stdbool.h>
 
 /**
- * Low level driver for Tytera MD380 display, which is has an HX8302-A controller.
+ * Standard interface for all low-level display drivers.
- * Actually, no datasheet for the display controller exists on the internet,
- * however a fairly compatible chip, for which datasheet exists, is the HX8353-E.
  *
  *********************** HOW TO MANAGE FRAMEBUFFER *****************************
  *
@@ -46,9 +44,9 @@
  */
 
 /**
- * This function initialises the display, configures TIM8 for backlight control
+ * This function initialises the display, configures backlight control and
- * and allocates framebuffer on the heap. After initialisation, backlight is
+ * allocates framebuffer on the heap. After initialisation, backlight is set
- * set to zero.
+ * to zero.
  * NOTE: framebuffer allocation is the first operation performed, if fails an
  * error message is printed on the virtual COM port and this function returns
  * prematurely, without configuring the display and the backlight timer. Thus, a
@@ -57,8 +55,8 @@
 void lcd_init();
 
 /**
- * When called, this function turns off backlight, shuts down TIM8 and
+ * When called, this function turns off backlight, shuts down backlight control
- * deallocates the framebuffer.
+ * and deallocates the framebuffer.
  */
 void lcd_terminate();
 
@@ -118,4 +116,4 @@ bool lcd_renderingInProgress();
  */
 uint16_t *lcd_getFrameBuffer();
 
-#endif /* LCH_H */
+#endif /* LCD_H */

platform/drivers/display/display_libSDL.c

@@ -0,0 +1,142 @@
+/***************************************************************************
+ *   Copyright (C) 2020 by Federico Izzo IU2NUO, Niccolò Izzo IU2KIN and   *
+ *                         Silvano Seva IU2KWO                             *
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 3 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ *   This program is distributed in the hope that it will be useful,       *
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
+ *   GNU General Public License for more details.                          *
+ *                                                                         *
+ *   You should have received a copy of the GNU General Public License     *
+ *   along with this program; if not, see <http://www.gnu.org/licenses/>   *
+ ***************************************************************************/
+
+/**
+ * This driver provides an lcd screen emulator to allow UI development and
+ * testing on a x86/x64 computer.
+ * Graphics control is provided through SDL2 library, you need to have the SDL2
+ * development library installed on your machine to compile and run code using
+ * this driver.
+ */
+
+#include "lcd.h"
+#include <stdio.h>
+#include <string.h>
+#include <SDL2/SDL.h>
+#undef main            /* necessary to avoid conflicts with SDL_main */
+
+/* 
+ * Screen dimensions, adjust basing on the size of the screen you need to
+ * emulate
+ */
+#define SCREEN_WIDTH 160
+#define SCREEN_HEIGHT 128
+
+SDL_Window  *window;
+SDL_Surface *renderSurface;
+uint16_t *frameBuffer;
+bool inProgress;
+
+void lcd_init()
+{
+    if(SDL_Init(SDL_INIT_VIDEO) < 0)
+    {
+        printf("SDL video init error!!\n");
+
+    }
+    else
+    {
+
+        window = SDL_CreateWindow("",
+                                  SDL_WINDOWPOS_UNDEFINED,
+                                  SDL_WINDOWPOS_UNDEFINED,
+                                  SCREEN_WIDTH,SCREEN_HEIGHT,
+                                  SDL_WINDOW_SHOWN);
+
+        renderSurface = SDL_GetWindowSurface(window);
+        SDL_FillRect(renderSurface,NULL,0xFFFFFF);
+
+        unsigned int scrSize = SCREEN_HEIGHT * SCREEN_WIDTH * sizeof(uint16_t);
+        frameBuffer = (uint16_t *)(malloc(scrSize));
+        memset(frameBuffer, 0xFFFF, scrSize);
+        inProgress = false;
+    }
+}
+
+void lcd_terminate()
+{
+    SDL_DestroyWindow(window);
+}
+
+uint16_t lcd_screenWidth()
+{
+    return SCREEN_WIDTH;
+}
+
+uint16_t lcd_screenHeight()
+{
+    return SCREEN_HEIGHT;
+}
+
+void lcd_setBacklightLevel(uint8_t level)
+{
+    printf("Backlight level set to %d\n", level);
+}
+
+void lcd_renderRows(uint8_t startRow, uint8_t endRow)
+{
+    Uint32 *pixels = (Uint32*)renderSurface->pixels;
+    inProgress = true;
+
+    for(int x = 0; x < SCREEN_WIDTH; x++)
+    {
+        for(int y = startRow; y < endRow; y++)
+        {
+            /*
+             * SDL pixel format is ARGB8888, while ours is RGB565, thus we need
+             * to do some conversions when writing framebuffer content to the
+             * window. We also set alpha value to its maximum.
+             */
+            uint32_t r = (frameBuffer[x + y*SCREEN_WIDTH] & 0xF800) >> 11;
+            uint32_t g = (frameBuffer[x + y*SCREEN_WIDTH] & 0x07E0) >> 5;
+            uint32_t b = (frameBuffer[x + y*SCREEN_WIDTH] & 0x001F) & 0x1F;
+
+            /*
+             * Here we do conversions by multiplying by some scaling factors,
+             * we use ints just because the precision of floats is not really
+             * needed.
+             * Conversion factors:
+             * - five bit to eight bit: 8.226
+             * - six bit to eight bit: 4.0476
+             */
+            r = (r * 8) + (r * 226)/1000;
+            g = (g * 4) + (g * 476)/10000;
+            b = (b * 8) + (b * 226)/1000;
+
+            pixels[x + y*SCREEN_WIDTH] = 0xFF000000 | (r << 16) | (g << 8) | b;
+        }
+    }
+
+    inProgress = false;
+    SDL_UpdateWindowSurface(window);
+}
+
+void lcd_render()
+{
+    lcd_renderRows(0, SCREEN_HEIGHT);
+}
+
+bool lcd_renderingInProgress()
+{
+    return inProgress;
+}
+
+uint16_t *lcd_getFrameBuffer()
+{
+    return frameBuffer;
+}

tests/platform/.keep

@@ -1 +0,0 @@
- 

tests/platform/display_test_SDL.c

@@ -0,0 +1,80 @@
+/***************************************************************************
+ *   Copyright (C) 2020 by Federico Izzo IU2NUO, Niccolò Izzo IU2KIN and   *
+ *                         Silvano Seva IU2KWO                             *
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 3 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ *   This program is distributed in the hope that it will be useful,       *
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
+ *   GNU General Public License for more details.                          *
+ *                                                                         *
+ *   You should have received a copy of the GNU General Public License     *
+ *   along with this program; if not, see <http://www.gnu.org/licenses/>   *
+ ***************************************************************************/
+
+/**
+ * Testing module for SDL-based display driver, serves both to check that
+ * everything is fine and as a simple example on how to use both the driver and
+ * the SDL platform.
+ *
+ * To adjust screen dimensions you have to adjust the corresponding constants in
+ * the driver source file.
+ */
+
+#include "lcd.h"
+#include <unistd.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <SDL2/SDL.h>
+#undef main     //necessary to avoid conflicts with SDL_main
+
+
+void drawRect(int x, int y, int width, int height, uint16_t color)
+{
+    int x_max = x + width;
+    int y_max = y + height;
+    uint16_t *buf = lcd_getFrameBuffer();
+
+    for(int i=y; i < y_max; i++)
+    {
+        for(int j=x; j < x_max; j++)
+        {
+            buf[j + i*lcd_screenWidth()] = color;
+        }
+    }
+}
+
+int main()
+{
+    lcd_init();
+    lcd_setBacklightLevel(254);
+
+    /* Horizontal red line */
+    drawRect(0, 10, lcd_screenWidth(), 20, 0xF800);
+
+    /* Vertical blue line */
+    drawRect(10, 0, 20, lcd_screenHeight(), 0x001F);
+
+    /* Vertical green line */
+    drawRect(80, 0, 20, lcd_screenHeight(), 0x07e0);
+
+    /*
+     * Use SDL event listener to check if window close button has been pressed,
+     * in this case quit.
+     */
+    SDL_Event eventListener;
+
+    while(1)
+    {
+        lcd_render();
+        SDL_PollEvent(&eventListener);
+        if(eventListener.type == SDL_QUIT) break;
+    }
+    
+    lcd_terminate();
+    return 0;
+}