Merge pull request #4 from McrRaspJam/surface

Simplified code by making Canvas an SDL_Surface

Author: Jack Kelly

examples/4_splash.c

@@ -11,8 +11,8 @@
 
 int main(int argc, char *argv[])
 {
-	int width = 64;
-	int height = 64;
+	int width = 256;
+	int height = 256;
 
 	canvas_create(width, height);
 
@@ -25,9 +25,9 @@ int main(int argc, char *argv[])
 	for (y = 0; y < height; y++)
 		for (x = 0; x < width; x++)
 		{
-			Uint8 r = 255 - ((255 / height) * y);
-			Uint8 g = (255 / width) * x;
-			Uint8 b = (255 / height) * y;
+			Uint8 r = 255 - ((255.0 / height) * y);
+			Uint8 g = (255.0 / width) * x;
+			Uint8 b = (255.0 / height) * y;
 
 			draw_pixel(x, y, r, g, b);
 		}

program.c renamed to main.c

@@ -11,8 +11,8 @@
 
 int main(int argc, char *argv[])
 {
-	int width = 32;
-	int height = 32;
+	int width = 64;
+	int height = 64;
 
 	canvas_create(width, height);
 
@@ -35,8 +35,8 @@ int main(int argc, char *argv[])
 		for (y = 0; y < height; y++)
 			for (x = 0; x < width; x++)
 			{
-				Uint8 r = 255 - ((255 / height) * y);
-				Uint8 g = (255 / width) * x;
+				Uint8 r = 255 - ((255.0 / height) * y);
+				Uint8 g = (255.0 / width) * x;
 				Uint8 b = frame % 255;
 
 				draw_pixel(x, y, r, g, b);

pixels/canvas.c

@@ -1,82 +1,48 @@
+/* canvas.c -- The Canvas
+ *
+ * The Canvas is an SDL surface which is used as the "virtual image" for user
+ * progams. It is scaled up to fit the window.
+ *
+ * Draw functions create pixels on the Canvas, and Screen updates blit the
+ * surface to the window
+ */
+
 #include <stdio.h> 
 #include <stdlib.h>
 #include <stdbool.h>
 #include "SDL.h"
 
 #include "canvas.h"
 
-Canvas canvas;
-
-Canvas * canvas_get()
-{
-	return &canvas;
-}
+SDL_Surface * canvas;
 
 
-/* Return false if coordinate lies outside canvas */
-bool coordinate_validate(Coordinate *coordinate)
+/* Initialise and allocate the Canvas */
+void canvas_create(int width, int height)
 {
-	bool valid = true;
-
-	if (coordinate->x < 0)
-		valid = false;
-	else if (coordinate->x >= canvas.size_x)
-		valid = false;
-	else if (coordinate->y < 0)
-		valid = false;
-	else if (coordinate->y >= canvas.size_y)
-		valid = false;
-
-	return valid;
+	if (canvas != NULL)
+		canvas_cleanup();
+
+	canvas = SDL_CreateRGBSurface(0,
+			width,
+			height,
+			32,
+			0xff000000,
+			0x00ff0000,
+			0x0000ff00,
+			0x000000ff);
 }
 
 
-/* Clip coordinate to canvas size */
-void coordinate_bound(Coordinate *coordinate)
+/* Variable accessor */
+SDL_Surface * canvas_get()
 {
-	if (coordinate->x < 0)
-		coordinate->x = 0;
-	else if (coordinate->x >= canvas.size_x)
-		coordinate->x = canvas.size_x - 1;
-
-	if (coordinate->y < 0)
-		coordinate->y = 0;
-	else if (coordinate->y >= canvas.size_y)
-		coordinate->y = canvas.size_y - 1;
+	return canvas;
 }
 
 
-/* Return pointer to a canvas pixel */
-struct canvas_pixel * canvas_getpixel(Coordinate coordinate)
+/* Free the Canvas */
+void canvas_cleanup()
 {
-	coordinate_bound(&coordinate);
-	return canvas.pixels + ((coordinate.y * canvas.size_y) + coordinate.x);
-}
-
-/*
- * Allocate the canvas array to a given pixel value
- */
-void canvas_create(int width, int height)
-{
-	if (canvas.allocated == true) {
-		free(canvas.pixels);
-		canvas.allocated = false;
-	}
-
-	struct canvas_pixel defaultpixel;
-	defaultpixel.r = 0x00;
-	defaultpixel.g = 0x00;
-	defaultpixel.b = 0x00;
-
-	canvas.size_x = width;
-	canvas.size_y = height;
-	
-	canvas.pixels = (struct canvas_pixel *) malloc((width * height) * sizeof(struct canvas_pixel));
-	canvas.allocated = true;
-
-	int i;
-	int j;
-	for (j = 0; j < height; j++)
-		for (i = 0; i < width; i++)
-			*(canvas.pixels + ((j * width) + i)) = defaultpixel;
+	SDL_FreeSurface(canvas);
 }

pixels/canvas.h

@@ -2,31 +2,8 @@
 
 #define CANVAS_H_INCLUDED
 
-struct canvas_struct {
-	int	size_x;
-	int	size_y;
-	struct canvas_pixel *pixels;
-	bool	allocated;	
-};
-
-struct canvas_coordinate {
-	int x;
-	int y;
-};
-
-struct canvas_pixel {
-	Uint8	r;
-	Uint8	g;
-	Uint8	b;
-};
-
-typedef struct canvas_struct Canvas;
-typedef struct canvas_coordinate Coordinate;
-
-Canvas * canvas_get();
-bool coordinate_validate(Coordinate *coordinate);
-void coordinate_bound(Coordinate *coordinate);
-struct canvas_pixel * canvas_getpixel(Coordinate coordinate);
 void canvas_create(int width, int height);
+SDL_Surface * canvas_get();
+void canvas_cleanup();
 
 #endif

pixels/draw.c

@@ -6,69 +6,54 @@
 
 #include <stdbool.h>
 #include "SDL.h"
+
 #include "canvas.h"
+#include "screen.h"
 
 
 /* Draw a single pixel on the canvas */
 void draw_pixel(int x, int y, Uint8 r, Uint8 g, Uint8 b)
 {
-	struct canvas_coordinate coord;
-	coord.x = x;
-	coord.y = y;
-
-	if (coordinate_validate(&coord) == false)
-		return;
-
-	struct canvas_pixel *pixel = canvas_getpixel(coord);
+	SDL_Renderer * renderer = screen_getrenderer();
 
-	pixel->r = r;
-	pixel->g = g;
-	pixel->b = b;
+	SDL_SetRenderDrawColor(renderer, r, g, b, 0xFF);
+	SDL_RenderDrawPoint(renderer, x, y);
 }
 
 
 /* Draw a rectangle of pixels on the canvas */
 void draw_rectangle(int x1, int y1, int x2, int y2,  Uint8 r, Uint8 g, Uint8 b)
 {
-	int x, y;
-	struct canvas_coordinate coord;
-	struct canvas_pixel * pixel;
-
-	for (y = y1; y < y2; y++)
-		for (x = x1; x < x2; x++) {
-			coord.x = x;
-			coord.y = y;
-			
-			if (coordinate_validate(&coord) == false)
-				continue;
-			
-			pixel = canvas_getpixel(coord);
-		
-			pixel->r = r;
-			pixel->g = g;
-			pixel->b = b;
-		}
+	SDL_Rect rect;
+
+	if (x2 > x1) {
+		rect.x = x1;
+		rect.w = x2 - x1;
+	} else {
+		rect.x = x2;
+		rect.w = x1 - x2;
+	}
+
+	if (y2 > y1) {
+		rect.y = y1;
+		rect.h = y2 - y1;
+	} else {
+		rect.y = y2;
+		rect.h = y1 - y2;
+	}
+
+	SDL_Renderer * renderer = screen_getrenderer();
+	
+	SDL_SetRenderDrawColor(renderer, r, g, b, 0xFF);
+	SDL_RenderDrawRect(renderer, &rect);
 }
 
 
 /* Draw over the whole canvas */
 void clear(Uint8 r, Uint8 g, Uint8 b)
 {
-	Canvas *canvas = canvas_get();
-
-	int x, y;
-	struct canvas_coordinate coord;
-	struct canvas_pixel * pixel;
-
-	for (y = 0; y < canvas->size_y; y++)
-		for (x = 0; x < canvas->size_x; x++) {
-			coord.x = x;
-			coord.y = y;
-			
-			pixel = canvas_getpixel(coord);
-		
-			pixel->r = r;
-			pixel->g = g;
-			pixel->b = b;
-		}
+	SDL_Renderer * renderer = screen_getrenderer();
+	
+	SDL_SetRenderDrawColor(renderer, r, g, b, 0xFF);
+	SDL_RenderClear(renderer);
 }