From 5cb6ff3c7186cbf48247e13c498a78f92b166d27 Mon Sep 17 00:00:00 2001
From: Krow Savcik <krow@savcik.xyz>
Date: Sun, 21 Jan 2024 01:24:28 +0200
Subject: improved: faster rendering

---
 src/canvas.c | 45 ++++++++++++++++++++++++++++++++++-----------
 src/canvas.h |  2 +-
 src/cdraw.c  |  2 +-
 3 files changed, 36 insertions(+), 13 deletions(-)

(limited to 'src')

diff --git a/src/canvas.c b/src/canvas.c
index 8d48d0f..ea50d53 100644
--- a/src/canvas.c
+++ b/src/canvas.c
@@ -72,12 +72,24 @@ canvas_init(uint w, uint h, void *ren)
             SDL_TEXTUREACCESS_TARGET,
             w, h);
 
+	c->half_pres = SDL_CreateTexture(
+		ren, SDL_PIXELFORMAT_RGBA8888,
+		SDL_TEXTUREACCESS_TARGET,
+		w, h);
+
     if (c->back == NULL) {
         printf("SDL_CreateTexture failed: %s\n", SDL_GetError());
         free(c);
         return NULL;
     }
 
+	if (c->half_pres == NULL) {
+		printf("SDL_CreateTexture failed: %s\n", SDL_GetError());
+		free(c);
+		return NULL;
+	}
+	SDL_SetTextureBlendMode(c->half_pres, SDL_BLENDMODE_BLEND);
+
     c->pres = SDL_CreateTexture(
             ren, SDL_PIXELFORMAT_RGBA8888,
             SDL_TEXTUREACCESS_TARGET,
@@ -101,6 +113,9 @@ canvas_init(uint w, uint h, void *ren)
             SDL_RenderFillRect(ren, &dest);
         }
     }
+	SDL_SetRenderTarget(ren, c->half_pres);
+	SDL_SetRenderDrawColor(ren, 0, 0, 0, 0);
+	SDL_RenderClear(ren);
     SDL_SetRenderTarget(ren, NULL);
 
     return c;
@@ -166,6 +181,7 @@ canvas_destroy(Canvas *c)
 	if (c == NULL) return;
 	SDL_DestroyTexture(c->pres);
 	SDL_DestroyTexture(c->back);
+	SDL_DestroyTexture(c->half_pres);
 	for (i = 0; i < c->layer_arr_cnt; ++i)
 		layer_destroy(c->layers[i]);
 	free(c->layers);
@@ -182,14 +198,7 @@ canvas_redraw(Canvas *c, void *ren, int mx, int my)
 	long int x, y;
 	SDL_SetRenderTarget(ren, c->pres);
 	SDL_RenderCopy(ren,c->back,NULL,NULL);
-	/* TODO: Draw the pointer between selected layers instead of on top of all layers */
-	/* TODO: Draw by copying data, not calling SDL function */
-	for (x = 0; x < c->w; ++x) {
-		for (y = 0; y < c->h; ++y) {
-			SDL_SetRenderDrawColor(ren, INTTOCOLA(c->pres_pix[COORD(x, y)]));
-			SDL_RenderDrawPoint(ren, x, y);
-		}
-	}
+	SDL_RenderCopy(ren,c->half_pres,NULL,NULL);
 	if (mx > 0 && my > 0 && canvas_coord_get(c, mx, my, &x, &y) == 0) {
 		SDL_SetRenderDrawColor(ren,
 			    ((Palette *)def_palette)->clist[c->cur_col].r,
@@ -249,10 +258,12 @@ canvas_point_draw(Canvas *c, long int x, long int y)
 	if (newcol == oldcol)
 		return;
 
-	SDL_SetRenderTarget(ren, c->pres);
+	SDL_SetRenderTarget(ren, c->half_pres);
 	if (tool_array[tool_cur] == TOOL_TYPE_ERASER) {
 		c->layers[c->cur_layer]->pix[COORD(x,y)] = 0;
 		canvas_point_redraw(c, x, y);
+		SDL_SetRenderDrawColor(ren, INTTOCOLA(c->pres_pix[COORD(x,y)]));
+		SDL_RenderDrawPoint(ren, x, y);
 	} else if (tool_array[tool_cur] == TOOL_TYPE_PENCIL) {
 		c->layers[c->cur_layer]->pix[COORD(x,y)] = COLTOINTA(
 		        ((Palette *)def_palette)->clist[c->cur_col].r,
@@ -260,10 +271,15 @@ canvas_point_draw(Canvas *c, long int x, long int y)
 		        ((Palette *)def_palette)->clist[c->cur_col].b,
 		        255);
 		canvas_point_redraw(c, x, y);
+		SDL_SetRenderDrawColor(ren, INTTOCOLA(c->pres_pix[COORD(x,y)]));
+		SDL_RenderDrawPoint(ren, x, y);
 	} else if (tool_array[tool_cur] == TOOL_TYPE_FILL) {
 		oldcol = canvas_fill_bfs(c, x, y, oldcol, newcol);
-		for (i = 0; i < oldcol; ++i)
+		for (i = 0; i < oldcol; ++i) {
 			canvas_point_redraw(c, ((SDL_Point *)c->temp_pix)[i].x, ((SDL_Point *)c->temp_pix)[i].y);
+			SDL_SetRenderDrawColor(ren, INTTOCOLA(c->pres_pix[COORD(((SDL_Point *)c->temp_pix)[i].x,((SDL_Point *)c->temp_pix)[i].y)]));
+			SDL_RenderDrawPoint(ren, ((SDL_Point *)c->temp_pix)[i].x, ((SDL_Point *)c->temp_pix)[i].y);
+		}
 	}
 	SDL_SetRenderTarget(ren, NULL);
 }
@@ -411,10 +427,16 @@ canvas_add_layer(Canvas *c, unsigned char pos)
 void
 canvas_refresh(Canvas *c)
 {
+	/* Fully redraws the canvas */
 	int i, j;
+	SDL_SetRenderTarget(ren, c->half_pres);
 	for (i = 0; i < c->w; ++i)
-		for (j = 0; j < c->h; ++j)
+		for (j = 0; j < c->h; ++j) {
 			canvas_point_redraw(c, i, j);
+			SDL_SetRenderDrawColor(ren, INTTOCOLA(c->pres_pix[COORD(i,j)]));
+			SDL_RenderDrawPoint(ren, i, j);
+		}
+	SDL_SetRenderTarget(ren, NULL);
 }
 
 static void
@@ -526,6 +548,7 @@ canvas_blend_color(uint a, uint b)
 static void
 canvas_point_redraw(Canvas *c, long int x, long int y)
 {
+	/* expects for the render target to be c->half_pres */
 	int i;
 	c->pres_pix[COORD(x, y)] = 0;
 
diff --git a/src/canvas.h b/src/canvas.h
index 2bdb775..104f130 100644
--- a/src/canvas.h
+++ b/src/canvas.h
@@ -9,7 +9,7 @@ struct Canvas {
 	char *proj_path;
 	struct Layer **layers;
 	int x, y;
-	void *back, *pres;
+	void *back, *pres, *half_pres;
 	void *temp_pix;
 	uint *pres_pix;
 };
diff --git a/src/cdraw.c b/src/cdraw.c
index 5b67c5e..c0c06c5 100644
--- a/src/cdraw.c
+++ b/src/cdraw.c
@@ -83,7 +83,7 @@ main_window_init(const char *s)
     }
 
     SDL_SetRenderDrawColor(ren, 18, 18, 18, 255);
-    SDL_SetRenderDrawBlendMode(ren, SDL_BLENDMODE_BLEND);
+	SDL_SetRenderDrawBlendMode(ren, SDL_BLENDMODE_NONE);
     SDL_RenderPresent(ren);
 
     def_palette = palette_open_gpl(def_palette_path);
-- 
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