From 6797eeaf9e92830f11924afffaed6683f706f0f5 Mon Sep 17 00:00:00 2001
From: Stefan Arentz <stefan@arentz.ca>
Date: Sun, 1 Oct 2017 16:38:33 -0400
Subject: [PATCH] Experiment with streamable texture

---
 src/tty.c      | 17 +++++++++++++++++
 src/tty.h      |  1 +
 src/tty_test.c |  8 +-------
 3 files changed, 19 insertions(+), 7 deletions(-)

diff --git a/src/tty.c b/src/tty.c
index 22298aa..4eb3232 100644
--- a/src/tty.c
+++ b/src/tty.c
@@ -35,6 +35,8 @@ struct ewm_tty_t *ewm_tty_create(SDL_Renderer *renderer) {
       EWM_ONE_TTY_ROWS * ewm_chr_height(tty->chr), 32, 4 * EWM_ONE_TTY_COLUMNS * ewm_chr_width(tty->chr),
          ewm_sdl_pixel_format(renderer));
 
+   tty->texture = SDL_CreateTexture(renderer, ewm_sdl_pixel_format(renderer), SDL_TEXTUREACCESS_STREAMING, 280, 192);
+
    ewm_tty_reset(tty);
    return tty;
 }
@@ -115,6 +117,21 @@ void ewm_tty_reset(struct ewm_tty_t *tty) {
 }
 
 void ewm_tty_refresh(struct ewm_tty_t *tty, uint32_t phase, uint32_t fps) {
+
+   uint32_t *pixels;
+   int pitch;
+   if (SDL_LockTexture(tty->texture, NULL, (void**) &pixels, &pitch) != 0) {
+      printf("Cannot lock texture: %s\n", SDL_GetError());
+      exit(1);
+   }
+
+   uint32_t green = tty->chr->green;
+   for (int i = 0; i < 192 * 280; i++) {
+      *pixels++ = green;
+   }
+
+   SDL_UnlockTexture(tty->texture);
+
    for (int row = 0; row < 24; row++) {
       for (int column = 0; column < 40; column++) {
          ewm_tty_render_character(tty, row, column, tty->screen_buffer[(row * EWM_ONE_TTY_COLUMNS) + column]);
diff --git a/src/tty.h b/src/tty.h
index 41e70ff..519cace 100644
--- a/src/tty.h
+++ b/src/tty.h
@@ -46,6 +46,7 @@ struct ewm_tty_t {
 
    uint32_t *pixels;
    SDL_Surface *surface;
+   SDL_Texture *texture;
 };
 
 struct ewm_tty_t *ewm_tty_create(SDL_Renderer *renderer);
diff --git a/src/tty_test.c b/src/tty_test.c
index 65fcd18..e958d33 100644
--- a/src/tty_test.c
+++ b/src/tty_test.c
@@ -18,13 +18,7 @@ void test(struct ewm_tty_t *tty) {
       SDL_RenderClear(tty->renderer);
 
       ewm_tty_refresh(tty, 1, EWM_ONE_FPS);
-
-      SDL_Texture *texture = SDL_CreateTextureFromSurface(tty->renderer, tty->surface);
-      if (texture != NULL) {
-         SDL_RenderCopy(tty->renderer, texture, NULL, NULL);
-         SDL_DestroyTexture(texture);
-      }
-
+      SDL_RenderCopy(tty->renderer, tty->texture, NULL, NULL);
       SDL_RenderPresent(tty->renderer);
    }
    Uint64 now = SDL_GetPerformanceCounter();