From 51c07a662a883352c888243ecada6a0c70b84919 Mon Sep 17 00:00:00 2001
From: Alexander Orzechowski <alex@ozal.ski>
Date: Mon, 27 Jan 2025 13:48:07 -0500
Subject: [PATCH] util/matrix: Simplify matrix_projection

The transform argument is always passed WL_OUTPUT_TRANSFORM_FLIPPED_180
---
 include/util/matrix.h |  6 ++----
 render/gles2/pass.c   |  3 +--
 render/vulkan/pass.c  |  4 +---
 util/matrix.c         | 14 +++-----------
 4 files changed, 7 insertions(+), 20 deletions(-)

diff --git a/include/util/matrix.h b/include/util/matrix.h
index e6197cecc..5c9db1634 100644
--- a/include/util/matrix.h
+++ b/include/util/matrix.h
@@ -31,12 +31,10 @@ void wlr_matrix_transform(float mat[static 9],
 void wlr_matrix_project_box(float mat[static 9], const struct wlr_box *box);
 
 /**
- * Writes a 2D orthographic projection matrix to mat of (width, height) with a
- * specified wl_output_transform.
+ * Writes a 2D orthographic projection matrix to mat of (width, height).
  *
  * Equivalent to glOrtho(0, width, 0, height, 1, -1) with the transform applied.
  */
-void matrix_projection(float mat[static 9], int width, int height,
-	enum wl_output_transform transform);
+void matrix_projection(float mat[static 9], int width, int height);
 
 #endif
diff --git a/render/gles2/pass.c b/render/gles2/pass.c
index f27a6a755..a1a593fd9 100644
--- a/render/gles2/pass.c
+++ b/render/gles2/pass.c
@@ -327,8 +327,7 @@ struct wlr_gles2_render_pass *begin_gles2_buffer_pass(struct wlr_gles2_buffer *b
 		pass->signal_point = signal_point;
 	}
 
-	matrix_projection(pass->projection_matrix, wlr_buffer->width, wlr_buffer->height,
-		WL_OUTPUT_TRANSFORM_FLIPPED_180);
+	matrix_projection(pass->projection_matrix, wlr_buffer->width, wlr_buffer->height);
 
 	push_gles2_debug(renderer);
 	glBindFramebuffer(GL_FRAMEBUFFER, fbo);
diff --git a/render/vulkan/pass.c b/render/vulkan/pass.c
index 92c771f06..104fbda3c 100644
--- a/render/vulkan/pass.c
+++ b/render/vulkan/pass.c
@@ -1131,9 +1131,7 @@ struct wlr_vk_render_pass *vulkan_begin_render_pass(struct wlr_vk_renderer *rend
 		.maxDepth = 1,
 	});
 
-	// matrix_projection() assumes a GL coordinate system so we need
-	// to pass WL_OUTPUT_TRANSFORM_FLIPPED_180 to adjust it for vulkan.
-	matrix_projection(pass->projection, width, height, WL_OUTPUT_TRANSFORM_FLIPPED_180);
+	matrix_projection(pass->projection, width, height);
 
 	wlr_buffer_lock(buffer->wlr_buffer);
 	pass->render_buffer = buffer;
diff --git a/util/matrix.c b/util/matrix.c
index d049b6ce3..d111926df 100644
--- a/util/matrix.c
+++ b/util/matrix.c
@@ -97,19 +97,11 @@ void wlr_matrix_transform(float mat[static 9],
 	wlr_matrix_multiply(mat, mat, transforms[transform]);
 }
 
-void matrix_projection(float mat[static 9], int width, int height,
-		enum wl_output_transform transform) {
+void matrix_projection(float mat[static 9], int width, int height) {
 	memset(mat, 0, sizeof(*mat) * 9);
 
-	const float *t = transforms[transform];
-	float x = 2.0f / width;
-	float y = 2.0f / height;
-
-	// Rotation + reflection
-	mat[0] = x * t[0];
-	mat[1] = x * t[1];
-	mat[3] = y * -t[3];
-	mat[4] = y * -t[4];
+	mat[0] = 2.0f / width;
+	mat[4] = 2.0f / height;
 
 	// Translation
 	mat[2] = -copysign(1.0f, mat[0] + mat[1]);