1 files changed, 70 insertions, 0 deletions
diff --git a/render/fx_renderer/matrix.c b/render/fx_renderer/matrix.c
new file mode 100644
index 0000000..8f0fe15
--- /dev/null
+++ b/render/fx_renderer/matrix.c
@@ -0,0 +1,70 @@
+#include <math.h>
+#include <string.h>
+#include <wlr/types/wlr_output.h>
+
+#include "render/fx_renderer/matrix.h"
+
+static const float transforms[][9] = {
+	[WL_OUTPUT_TRANSFORM_NORMAL] = {
+		1.0f, 0.0f, 0.0f,
+		0.0f, 1.0f, 0.0f,
+		0.0f, 0.0f, 1.0f,
+	},
+	[WL_OUTPUT_TRANSFORM_90] = {
+		0.0f, 1.0f, 0.0f,
+		-1.0f, 0.0f, 0.0f,
+		0.0f, 0.0f, 1.0f,
+	},
+	[WL_OUTPUT_TRANSFORM_180] = {
+		-1.0f, 0.0f, 0.0f,
+		0.0f, -1.0f, 0.0f,
+		0.0f, 0.0f, 1.0f,
+	},
+	[WL_OUTPUT_TRANSFORM_270] = {
+		0.0f, -1.0f, 0.0f,
+		1.0f, 0.0f, 0.0f,
+		0.0f, 0.0f, 1.0f,
+	},
+	[WL_OUTPUT_TRANSFORM_FLIPPED] = {
+		-1.0f, 0.0f, 0.0f,
+		0.0f, 1.0f, 0.0f,
+		0.0f, 0.0f, 1.0f,
+	},
+	[WL_OUTPUT_TRANSFORM_FLIPPED_90] = {
+		0.0f, 1.0f, 0.0f,
+		1.0f, 0.0f, 0.0f,
+		0.0f, 0.0f, 1.0f,
+	},
+	[WL_OUTPUT_TRANSFORM_FLIPPED_180] = {
+		1.0f, 0.0f, 0.0f,
+		0.0f, -1.0f, 0.0f,
+		0.0f, 0.0f, 1.0f,
+	},
+	[WL_OUTPUT_TRANSFORM_FLIPPED_270] = {
+		0.0f, -1.0f, 0.0f,
+		-1.0f, 0.0f, 0.0f,
+		0.0f, 0.0f, 1.0f,
+	},
+};
+
+void matrix_projection(float mat[static 9], int width, int height,
+		enum wl_output_transform transform) {
+	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];
+
+	// Translation
+	mat[2] = -copysign(1.0f, mat[0] + mat[1]);
+	mat[5] = -copysign(1.0f, mat[3] + mat[4]);
+
+	// Identity
+	mat[8] = 1.0f;
+}