From 1a84d38bd04aa216434b190f769d356408909248 Mon Sep 17 00:00:00 2001
From: Lukas Krickl <lukas@krickl.dev>
Date: Mon, 23 Feb 2026 22:54:52 +0100
Subject: [PATCH] p_draw: Added basic single pixel draw command

---
 src/p_draw.h           | 13 ++++++++++++-
 src/p_r_sdl/p_draw.c   | 34 ++++++++++++++++++++++++++++++----
 src/p_r_sdl/p_init.c   |  9 ++++++++-
 src/p_r_sdl/p_window.c |  2 ++
 src/p_r_sdl/p_window.h |  3 +++
 src/r_color.c          |  8 --------
 src/r_color.h          |  9 +--------
 src/r_render.c         |  8 ++++++--
 src/r_render.h         |  4 ++++
 9 files changed, 66 insertions(+), 24 deletions(-)

diff --git a/src/p_draw.h b/src/p_draw.h
index 13eaeb3..c1f73e3 100644
--- a/src/p_draw.h
+++ b/src/p_draw.h
@@ -6,6 +6,17 @@
 
 
 /* draws a singel pixel directly to the screen */
-void p_draw_pixel(i32 x, i32 y, struct r_color color);
+void p_draw_pixel(i32 x, i32 y, r_color color);
+
+/* clears the current screen buffer */
+void p_draw_clear(void);
+
+/* inits the draw of a frame */
+void p_draw_begin(void);
+/* ends a frame draw */
+void p_draw_end(void);
+
+/* presents the current frame */
+void p_draw_present(void);
 
 #endif
diff --git a/src/p_r_sdl/p_draw.c b/src/p_r_sdl/p_draw.c
index b8dd58e..d4196c5 100644
--- a/src/p_r_sdl/p_draw.c
+++ b/src/p_r_sdl/p_draw.c
@@ -1,7 +1,33 @@
 #include "../p_draw.h"
+#include "p_window.h"
+#include "../u_assert.h"
 
-void p_draw_pixel(i32 x, i32 y, struct r_color color) {
-	LRTS_UNUSED(x);
-	LRTS_UNUSED(y);
-	LRTS_UNUSED(color);
+void p_draw_begin(void) {
+}
+
+void p_draw_end(void) {
+}
+
+void p_draw_clear(void) {
+	SDL_FillSurfaceRect(r_target, NULL, 0x000000FF);
+}
+
+void p_draw_pixel(i32 x, i32 y, r_color color) {
+	u32 *pixel = LRTS_NULL;
+	/* drop the draw if out of bounds */
+	if (x < 0 || x > r_target->w) {
+		return;
+	}
+	if (y < 0 || y > r_target->h) {
+		return;
+	}
+
+ pixel = (unsigned int*)(((char*)r_target->pixels) + r_target->pitch * y + x);
+ *pixel = color;
+}
+
+void p_draw_present(void) {
+	SDL_Surface* screen = SDL_GetWindowSurface(p_main_window);
+	SDL_BlitSurface(r_target, NULL, screen, NULL);
+	SDL_UpdateWindowSurface(p_main_window);
 }
diff --git a/src/p_r_sdl/p_init.c b/src/p_r_sdl/p_init.c
index fe05c0e..35b3285 100644
--- a/src/p_r_sdl/p_init.c
+++ b/src/p_r_sdl/p_init.c
@@ -13,18 +13,25 @@ int p_render_init(void) {
 		exit(-1);
 	}
 
-	p_main_window = SDL_CreateWindow(lrts_cfg()->name, 640, 640, 0);
+	p_main_window = SDL_CreateWindow(lrts_cfg()->name, R_WIDTH, R_HEIGHT, 0);
 	if (p_main_window == LRTS_NULL) {
 		u_log(U_LOG_ERR, "Failed to create window: %s\n", SDL_GetError());
 		exit(-1);
 	}
 
+	r_target = SDL_CreateSurface(R_WIDTH, R_HEIGHT, SDL_PIXELFORMAT_RGBX8888);
+	if (r_target == LRTS_NULL) {
+		u_log(U_LOG_ERR, "Failed to create surface: %s\n", SDL_GetError());
+		exit(-1);
+	}
+
 	u_log(U_LOG_DEBUG, "Init successful\n");
 
 	return 0;
 }
 
 int p_renderer_finish(void) {
+	SDL_DestroySurface(r_target);
 	SDL_DestroyWindow(p_main_window);
 	SDL_Quit();
 	u_log(U_LOG_DEBUG, "Exiting...\n");
diff --git a/src/p_r_sdl/p_window.c b/src/p_r_sdl/p_window.c
index 78bc01c..249e54a 100644
--- a/src/p_r_sdl/p_window.c
+++ b/src/p_r_sdl/p_window.c
@@ -2,6 +2,8 @@ SDL_Window *p_main_window;
 
 #include "../u_defs.h"
 
+SDL_Surface *r_target;
+
 int p_poll_events() {
 	SDL_Event e;
 	while (SDL_PollEvent(&e)) {
diff --git a/src/p_r_sdl/p_window.h b/src/p_r_sdl/p_window.h
index d281ac8..c71e23b 100644
--- a/src/p_r_sdl/p_window.h
+++ b/src/p_r_sdl/p_window.h
@@ -5,4 +5,7 @@
 
 extern SDL_Window *p_main_window;
 
+/* main surface to render to */
+extern SDL_Surface *r_target;
+
 #endif
diff --git a/src/r_color.c b/src/r_color.c
index f22a9b2..8b13789 100644
--- a/src/r_color.c
+++ b/src/r_color.c
@@ -1,9 +1 @@
 
-struct r_color r_color(u8 r, u8 g, u8 b, u8 a) {
-	struct r_color c;
-	c.r = r;
-	c.g = g;
-	c.b = b;
-	c.a = a;
-	return c;
-}
diff --git a/src/r_color.h b/src/r_color.h
index a968e9f..3a56e48 100644
--- a/src/r_color.h
+++ b/src/r_color.h
@@ -3,13 +3,6 @@
 
 #include "u_defs.h"
 
-struct r_color {
-	u8 r;
-	u8 g;
-	u8 b;
-	u8 a;
-};
-
-struct r_color r_color(u8 r, u8 g, u8 b, u8 a);
+typedef u32 r_color;
 
 #endif
diff --git a/src/r_render.c b/src/r_render.c
index 8c9e827..58c0972 100644
--- a/src/r_render.c
+++ b/src/r_render.c
@@ -3,7 +3,11 @@
 #include "p_draw.h"
 
 void r_render_frame() {
-	struct r_color c = r_color(0, 0, 0, 0xFF);
+	p_draw_begin();
+	p_draw_clear();
 
-	p_draw_pixel(0, 0, c);
+	p_draw_pixel(0, 0, 0xFF0000FF);
+
+	p_draw_end();
+	p_draw_present();
 }
diff --git a/src/r_render.h b/src/r_render.h
index 741be96..4cf94bb 100644
--- a/src/r_render.h
+++ b/src/r_render.h
@@ -1,6 +1,10 @@
 #ifndef R_RENDER_H__
 #define R_RENDER_H__
 
+/* internal rendering resolution */
+#define R_WIDTH 800
+#define R_HEIGHT 600
+
 void r_render_frame();
 
 #endif
-- 
2.30.2