Make alpha checker texture from code (8d7a925)

main.c

@@ -39,23 +39,32 @@ void cfail(const int cond, const char* msg, const int showsdl) {
     }
 }
 
-/* load and return alpha checkers, relative to iv binary */
-SDL_Texture* checker(SDL_Renderer* ren, char* progname, int* w, int* h) {
-    char* tpath = malloc(strlen(progname) + 32);
-    cfail(!tpath, "allocate memory", 0);
-    sprintf(tpath, "%s/alpha_checker.bmp", dirname(progname));
-    SDL_Surface* acs = SDL_LoadBMP(tpath);
-    if (w) {
-        *w = acs->w;
+/* make alpha checker pattern */
+SDL_Texture* checker(SDL_Renderer* ren, int w, int h) {
+    SDL_Texture* tex = SDL_CreateTexture(
+        ren,
+        SDL_PIXELFORMAT_RGBA8888,
+        SDL_TEXTUREACCESS_STREAMING,
+        w, h
+    );
+    cfail(!tex, "make background texture", 1);
+
+    void* pixels;
+    int pitch;
+    cfail(
+        SDL_LockTexture(tex, NULL, &pixels, &pitch),
+        "lock background texture", 1
+    );
+
+    for (int y = 0; y < h; ++y) {
+        Uint32* row = (Uint32*)((Uint8*)pixels + y * pitch);
+        for (int x = 0; x < w; ++x) {
+            row[x] = 0xB0B0B0FF + 0x40404000 * (x + y & 1);
         }
-    if (h) {
-        *h = acs->h;
     }
-    cfail(!acs, "load alpha checker texture", 1);
-    SDL_Texture* act = SDL_CreateTextureFromSurface(ren, acs);
-    cfail(!act, "create surface", 1);
-    SDL_FreeSurface(acs);
-    return act;
+
+    SDL_UnlockTexture(tex);
+    return tex;
 }
 
 /* process command-line options, setting pointed strings */
@@ -206,8 +215,8 @@ int main(int argc, char** argv) {
     cfail(!ren, "create renderer", 1);
 
     /* make images into textures */
-    int cw, ch;
-    SDL_Texture* act = checker(ren, argv[0], &cw, &ch);
+    int cw = 64, ch = 64;
+    SDL_Texture* act = checker(ren, cw, ch);
     struct ViewState* sl = calloc(fc, sizeof(struct ViewState));
     for (int i = 0; i < fc; i++) {
         sl[i].tex = SDL_CreateTextureFromSurface(ren, isurf[i]);


...	...	@@ -4,7 +4,7 @@ To compile:
4	4	make iv
5	5
6	6	To install, with $INSTALL_DIR somewhere in your $PATH:
7		-cp iv alpha_checker.bmp $INSTALL_DIR
	7	+cp iv $INSTALL_DIR
8	8
9	9	To make iv the default, if on Linux:
10	10	ULSA=/usr/local/share/applications

...	...	@@ -39,23 +39,32 @@ void cfail(const int cond, const char* msg, const int showsdl) {
39	39	}
40	40	}
41	41
42		-/* load and return alpha checkers, relative to iv binary */
43		-SDL_Texture* checker(SDL_Renderer* ren, char* progname, int* w, int* h) {
44		- char* tpath = malloc(strlen(progname) + 32);
45		- cfail(!tpath, "allocate memory", 0);
46		- sprintf(tpath, "%s/alpha_checker.bmp", dirname(progname));
47		- SDL_Surface* acs = SDL_LoadBMP(tpath);
48		- if (w) {
49		- *w = acs->w;
	42	+/* make alpha checker pattern */
	43	+SDL_Texture* checker(SDL_Renderer* ren, int w, int h) {
	44	+ SDL_Texture* tex = SDL_CreateTexture(
	45	+ ren,
	46	+ SDL_PIXELFORMAT_RGBA8888,
	47	+ SDL_TEXTUREACCESS_STREAMING,
	48	+ w, h
	49	+ );
	50	+ cfail(!tex, "make background texture", 1);
	51	+
	52	+ void* pixels;
	53	+ int pitch;
	54	+ cfail(
	55	+ SDL_LockTexture(tex, NULL, &pixels, &pitch),
	56	+ "lock background texture", 1
	57	+ );
	58	+
	59	+ for (int y = 0; y < h; ++y) {
	60	+ Uint32* row = (Uint32)((Uint8)pixels + y * pitch);
	61	+ for (int x = 0; x < w; ++x) {
	62	+ row[x] = 0xB0B0B0FF + 0x40404000 * (x + y & 1);
50	63	}
51		- if (h) {
52		- *h = acs->h;
53	64	}
54		- cfail(!acs, "load alpha checker texture", 1);
55		- SDL_Texture* act = SDL_CreateTextureFromSurface(ren, acs);
56		- cfail(!act, "create surface", 1);
57		- SDL_FreeSurface(acs);
58		- return act;
	65	+
	66	+ SDL_UnlockTexture(tex);
	67	+ return tex;
59	68	}
60	69
61	70	/* process command-line options, setting pointed strings */
...	...	@@ -206,8 +215,8 @@ int main(int argc, char** argv) {
206	215	cfail(!ren, "create renderer", 1);
207	216
208	217	/* make images into textures */
209		- int cw, ch;
210		- SDL_Texture* act = checker(ren, argv[0], &cw, &ch);
	218	+ int cw = 64, ch = 64;
	219	+ SDL_Texture* act = checker(ren, cw, ch);
211	220	struct ViewState* sl = calloc(fc, sizeof(struct ViewState));
212	221	for (int i = 0; i < fc; i++) {
213	222	sl[i].tex = SDL_CreateTextureFromSurface(ren, isurf[i]);
214	223