/*
 * Copyright (c) 2026 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Radoslaw Kujawa.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

/* Canonical rlvec CPU vertex kernels for the verite driver. */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "rlvec.h"

static void
xform_points3_c(float *to, const float m[16], const float *from,
    int from_stride, int count)
{
	int i;

	for (i = 0; i < count; i++) {
		const float *o = (const float *)((const char *)from +
		    (size_t)i * from_stride);
		float x = o[0], y = o[1], z = o[2];
		float *d = to + i * 4;

		d[0] = m[0] * x + m[4] * y + m[8] * z + m[12];
		d[1] = m[1] * x + m[5] * y + m[9] * z + m[13];
		d[2] = m[2] * x + m[6] * y + m[10] * z + m[14];
		d[3] = m[3] * x + m[7] * y + m[11] * z + m[15];
	}
}

static uint32_t
outcode5_c(uint8_t *oc, uint32_t *and_out, const float *clip, int count)
{
	uint32_t or_acc = 0, and_acc = 0x1f;
	int i;

	for (i = 0; i < count; i++) {
		const float *c = clip + i * 4;
		float x = c[0], y = c[1], z = c[2], w = c[3];
		uint32_t o = 0;

		if (z + w < 0.0f)
			o |= 0x01;
		if (w + x < 0.0f)
			o |= 0x02;
		if (w - x < 0.0f)
			o |= 0x04;
		if (w + y < 0.0f)
			o |= 0x08;
		if (w - y < 0.0f)
			o |= 0x10;
		oc[i] = (uint8_t)o;
		or_acc |= o;
		and_acc &= o;
	}
	*and_out = and_acc;
	return or_acc;
}

static void
project_c(float *out9, const float *clip, const float *attr,
    const float k[8], int count)
{
	int i;

	for (i = 0; i < count; i++) {
		const float *c = clip + i * 4;
		const float *a = attr + i * 6;
		float *s = out9 + i * 9;
		float q = 1.0f / c[3];
		float zz;

		s[0] = a[0]; s[1] = a[1]; s[2] = a[2];
		s[3] = k[0] + k[1] * (c[0] * q);
		s[4] = k[2] - k[3] * (c[1] * q);
		zz = k[4] + k[5] * (c[2] * q);
		if (zz < 0.0f)
			zz = 0.0f;
		if (zz > 65000.0f)
			zz = 65000.0f;
		s[5] = zz;
		s[6] = a[4] * k[6];
		s[7] = a[5] * k[7];
		s[8] = q;
	}
}

static uint32_t *
emit_tris_c(uint32_t *dst, const float *verts9, const uint8_t *idx,
    int ntris, uint32_t hdr)
{
	int t, k;

	for (t = 0; t < ntris; t++) {
		*dst++ = hdr;
		for (k = 0; k < 3; k++) {
			memcpy(dst, verts9 +
			    (uint32_t)idx[t * 3 + k] * 9,
			    9 * sizeof(float));
			dst += 9;
		}
	}
	return dst;
}

const struct rlvec_ops rlvec_c = {
	xform_points3_c,
	outcode5_c,
	project_c,
	emit_tris_c,
};

#ifdef RLVEC_PPC
rlvec_xform_points3_fn rlvec_xform_points3_ppc;
rlvec_outcode5_fn rlvec_outcode5_ppc;
rlvec_emit_tris_fn rlvec_emit_tris_ppc;

const struct rlvec_ops rlvec_ppc = {
	rlvec_xform_points3_ppc,
	outcode5_c,
	project_c,
	rlvec_emit_tris_ppc,
};
#endif

struct rlvec_ops rlvec;

void
rlvec_init(void)
{
	static int done;
	const char *noasm;

	if (done)
		return;
	done = 1;
	rlvec = rlvec_c;
#ifdef RLVEC_PPC
	rlvec = rlvec_ppc;
	noasm = getenv("RLGL_NOASM");
	if (noasm != NULL) {
		if (strcmp(noasm, "1") == 0) {
			rlvec = rlvec_c;
			fprintf(stderr, "rlvec: all-C forced\n");
		} else {
			if (strstr(noasm, "xform") != NULL)
				rlvec.xform_points3 = rlvec_c.xform_points3;
			if (strstr(noasm, "outcode") != NULL)
				rlvec.outcode5 = rlvec_c.outcode5;
			if (strstr(noasm, "project") != NULL)
				rlvec.project = rlvec_c.project;
			if (strstr(noasm, "emit") != NULL)
				rlvec.emit_tris = rlvec_c.emit_tris;
			fprintf(stderr, "rlvec: C forced for: %s\n", noasm);
		}
	}
#else
	(void)noasm;
#endif
}