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Learning how to take input from the keyboard.

This commit is contained in:
Barra Ó Catháin 2023-03-15 23:18:08 +00:00
parent 0c86f60f85
commit 9344fc9cd8
2 changed files with 56 additions and 38 deletions
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0
01-TGT.png → 02-TGT.png
View File

Side by Side Swipe Overlay

Before

Width:  |  Height:  |  Size: 613 B

After

Width:  |  Height:  |  Size: 613 B

88
SDL2-Experiment-01.c → SDL2-Experiment-02.c
View File

@ -1,4 +1,4 @@
// SDL Experiment 01, Barra Ó Catháin.
// SDL Experiment 02, Barra Ó Catháin.
// ===================================
#include <SDL2/SDL.h>
#include <SDL2/SDL_image.h>
@ -55,7 +55,7 @@ int main(int argc, char ** argv)
{
SDL_Event event;
bool quit = false;
int width = 0, height = 0, mouseX = 0, mouseY = 0;
int width = 0, height = 0, positionX = 0, positionY = 0, velocityX = 0, velocityY = 0;
uint32_t rendererFlags = SDL_RENDERER_ACCELERATED;
// Initialize the SDL library, video, sound, and input:
@ -71,7 +71,7 @@ int main(int argc, char ** argv)
SDL_Renderer * renderer = SDL_CreateRenderer(window, -1, rendererFlags);
SDL_Texture * targetTexture;
targetTexture = IMG_LoadTexture(renderer, "./01-TGT.png");
targetTexture = IMG_LoadTexture(renderer, "./02-TGT.png");
SDL_Rect targetText;
targetText.w = 16;
targetText.h = 8;
@ -87,10 +87,51 @@ int main(int argc, char ** argv)
switch (event.type)
{
case SDL_QUIT:
{
quit = true;
break;
}
case SDL_KEYDOWN:
{
switch (event.key.keysym.sym)
{
case SDLK_LEFT:
{
velocityX += -1;
break;
}
case SDLK_RIGHT:
{
velocityX += 1;
break;
}
case SDLK_UP:
{
velocityY += -1;
break;
}
case SDLK_DOWN:
{
velocityY += 1;
break;
}
default:
{
break;
}
}
break;
}
default:
{
break;
}
}
}
// Move the position:
positionX += velocityX;
positionY += velocityY;
// Store the window's current width and height:
SDL_GetWindowSize(window, &width, &height);
@ -101,44 +142,21 @@ int main(int argc, char ** argv)
// Clear the screen, filling it with black:
SDL_RenderClear(renderer);
// Set the colour to neon green:
SDL_SetRenderDrawColor(renderer, 0, 255, 0, 255);
// Draw the "radar circle" as large as possible, centered in the window:
DrawCircle(renderer, width/2, height/2, getRadius(width, height));
// Draw 16 vertical grid lines, spaced evenly from each other and the window borders:
for(int verticalPosition = (height - ((height/16) * 16)) / 2;
verticalPosition <= height; verticalPosition += (height / 16))
{
SDL_RenderDrawLine(renderer, 0, verticalPosition, width, verticalPosition);
}
// Draw 16 horizontal grid lines, spaced evenly from each other and the window borders:
for(int horizontalPosition = (width - ((width/16) * 16)) / 2;
horizontalPosition <= width; horizontalPosition += (width / 16))
{
SDL_RenderDrawLine(renderer, horizontalPosition, 0, horizontalPosition, height);
}
// Set the colour to yellow:
SDL_SetRenderDrawColor(renderer, 255, 255, 0, 255);
// Store the mouse pointer's current position in the window:
SDL_GetMouseState(&mouseX, &mouseY);
// Draw a line from the center of the window to the position pointer:
SDL_RenderDrawLine(renderer, width/2, height/2, positionX, positionY);
// Draw a line from the center of the window to the mouse pointer:
SDL_RenderDrawLine(renderer, width/2, height/2, mouseX, mouseY);
// Draw a circle around the mouse pointer:
DrawCircle(renderer, mouseX, mouseY, 15);
// Draw a circle around the position pointer:
DrawCircle(renderer, positionX, positionY, 15);
// Set the rect at the correct position to put the TGT down:
targetText.x = mouseX + 20;
targetText.y = mouseY - 4;
if(mouseX < width/2)
targetText.x = positionX + 20;
targetText.y = positionY - 4;
if(positionX < width/2)
{
targetText.x = mouseX - 36;
targetText.x = positionX - 36;
}
SDL_RenderCopy(renderer, targetTexture, NULL, &targetText);
// Present the rendered graphics:
@ -151,5 +169,5 @@ int main(int argc, char ** argv)
}
// ===========================================================================================
// Local Variables:
// compile-command: "gcc `sdl2-config --libs --cflags` SDL2-Experiment-01.c -lSDL2_image -lm"
// compile-command: "gcc `sdl2-config --libs --cflags` SDL2-Experiment-02.c -lSDL2_image -lm"
// End: