lib: Add igt_matrix

Add a helper library for basic matrix math.

v2: Make the identity matrix static const (Chris)
    Add the m(row,col) macro (Chris)

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 158 insertions, 0 deletions

diff --git a/lib/igt_matrix.c b/lib/igt_matrix.c
new file mode 100644
index 00000000..3fa6c96c
--- /dev/null
+++ b/lib/igt_matrix.c
@@ -0,0 +1,158 @@
+/*
+ * Copyright © 2018 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include "igt_core.h"
+#include "igt_matrix.h"
+
+#define m(row, col) ((col) * 4 + (row))
+
+/**
+ * SECTION:igt_matrix
+ * @short_description: Matrix math library
+ * @title: Matrix
+ * @include: igt.h
+ *
+ * This library contains helper functions for basic matrix math.
+ * The library operates on #igt_mat4 and #igt_vec4 structures.
+ */
+
+/**
+ * igt_matrix_print:
+ * @m: the matrix
+ *
+ * Print out the matrix elements.
+ */
+void igt_matrix_print(const struct igt_mat4 *m)
+{
+	for (int row = 0; row < 4; row++) {
+		igt_info("|");
+		for (int col = 0; col < 4; col++) {
+			igt_info("%4.4f,", m->d[m(row, col)]);
+		}
+		igt_info("|\n");
+	}
+}
+
+/**
+ * igt_matrix_identity:
+ *
+ * Returns:
+ * An identity matrix.
+ */
+struct igt_mat4 igt_matrix_identity(void)
+{
+	static const struct igt_mat4 ret = {
+		.d[m(0, 0)] = 1.0f,
+		.d[m(1, 1)] = 1.0f,
+		.d[m(2, 2)] = 1.0f,
+		.d[m(3, 3)] = 1.0f,
+	};
+
+	return ret;
+}
+
+/**
+ * igt_matrix_scale:
+ *
+ * Returns:
+ * An scaling matrix.
+ */
+struct igt_mat4 igt_matrix_scale(float x, float y, float z)
+{
+	struct igt_mat4 ret = {
+		.d[m(0, 0)] = x,
+		.d[m(1, 1)] = y,
+		.d[m(2, 2)] = z,
+		.d[m(3, 3)] = 1.0f,
+	};
+
+	return ret;
+}
+
+/**
+ * igt_matrix_translate:
+ *
+ * Returns:
+ * A translation matrix.
+ */
+struct igt_mat4 igt_matrix_translate(float x, float y, float z)
+{
+	struct igt_mat4 ret = {
+		.d[m(0, 0)] = 1.0f,
+		.d[m(1, 1)] = 1.0f,
+		.d[m(2, 2)] = 1.0f,
+		.d[m(0, 3)] = x,
+		.d[m(1, 3)] = y,
+		.d[m(2, 3)] = z,
+		.d[m(3, 3)] = 1.0f,
+	};
+
+	return ret;
+}
+
+/**
+ * igt_matrix_transform:
+ *
+ * Transform the vector @v by the matrix @m. @m is on the left,
+ * @v on the right.
+ *
+ * Returns:
+ * The transformed vector.
+ */
+struct igt_vec4 igt_matrix_transform(const struct igt_mat4 *m,
+				     const struct igt_vec4 *v)
+{
+	struct igt_vec4 ret = {};
+
+	for (int row = 0; row < 4; row++) {
+		for (int i = 0; i < 4; i++) {
+			ret.d[row] += m->d[m(row, i)] * v->d[i];
+		}
+	}
+
+	return ret;
+}
+
+/**
+ * igt_matrix_multiply:
+ *
+ * Multiply two matrices together. @a is on the left,
+ * @b on the right.
+ *
+ * Returns:
+ * The resulting matrix.
+ */
+struct igt_mat4 igt_matrix_multiply(const struct igt_mat4 *a,
+				    const struct igt_mat4 *b)
+{
+	struct igt_mat4 ret = {};
+
+	for (int col = 0; col < 4; col++) {
+		for (int row = 0; row < 4; row++) {
+			for (int i = 0; i < 4; i++)
+				ret.d[m(row, col)] += a->d[m(row, i)] * b->d[m(i, col)];
+		}
+	}
+
+	return ret;
+}