Fix surface transforms

include/wlr/render/matrix.h

@@ -10,6 +10,8 @@ void wlr_matrix_rotate(float (*output)[16], float radians);
 void wlr_matrix_mul(const float (*x)[16], const float (*y)[16], float (*product)[16]);
 
 enum wl_output_transform;
+void wlr_matrix_transform(float mat[static 16],
+		enum wl_output_transform transform);
 void wlr_matrix_texture(float mat[static 16], int32_t width, int32_t height,
 		enum wl_output_transform transform);
 

include/wlr/types/wlr_output.h

@@ -106,4 +106,6 @@ bool wlr_output_cursor_move(struct wlr_output_cursor *cursor,
 	double x, double y);
 void wlr_output_cursor_destroy(struct wlr_output_cursor *cursor);
 
+enum wl_output_transform wlr_output_transform_invert(enum wl_output_transform);
+
 #endif

render/matrix.c

@@ -118,6 +118,23 @@ static const float transforms[][4] = {
 	},
 };
 
+void wlr_matrix_transform(float mat[static 16],
+		enum wl_output_transform transform) {
+	memset(mat, 0, sizeof(*mat) * 16);
+
+	const float *t = transforms[transform];
+
+	// Rotation + relection
+	mat[0] = t[0];
+	mat[1] = t[1];
+	mat[4] = -t[2];
+	mat[5] = -t[3];
+
+	// Identity
+	mat[10] = 1.0f;
+	mat[15] = 1.0f;
+}
+
 // Equivilent to glOrtho(0, width, 0, height, 1, -1) with the transform applied
 void wlr_matrix_texture(float mat[static 16], int32_t width, int32_t height,
 		enum wl_output_transform transform) {

rootston/output.c

@@ -63,10 +63,25 @@ static void render_surface(struct wlr_surface *surface,
 			float scale[16];
 			wlr_matrix_scale(&scale, render_width, render_height, 1);
 
+			float translate_mdr[16];
+			wlr_matrix_translate(&translate_mdr, 0.5, 0.5, 0);
+
+			float surface_transform[16];
+			wlr_matrix_transform(surface_transform,
+				wlr_output_transform_invert(surface->current->transform)); // TODO
+
+			float translate_mdr2[16];
+			wlr_matrix_translate(&translate_mdr2, -0.5, -0.5, 0);
+
 			float transform[16];
 			wlr_matrix_mul(&translate_origin, &rotate, &transform);
 			wlr_matrix_mul(&transform, &translate_center, &transform);
 			wlr_matrix_mul(&transform, &scale, &transform);
+
+			wlr_matrix_mul(&transform, &translate_mdr, &transform);
+			wlr_matrix_mul(&transform, &surface_transform, &transform);
+			wlr_matrix_mul(&transform, &translate_mdr2, &transform);
+
 			wlr_matrix_mul(&wlr_output->transform_matrix, &transform, &matrix);
 
 			wlr_render_with_matrix(desktop->server->renderer, surface->texture,